DOCUMENT RESUME ED 132 306 CE 008 627 Construction

DOCUMENT RESUME

ED 132 306 CE 008 627

TITLE Construction Electrician 3& 2.Rate Traininy Manual and Nonresident Career Course. INSTITUTION Naval Education and Training Command, rensacola, Fla- REPORT NO NAVEDTRA-10636-11 PUB DATE 76 NOTE 6261:- AVAILABLE FROMSuperintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 (Stock Number 0502-LP-053-1810)

EDES PRICE MF-$1.16 HC-$34.15 Plus Postage. DESCRIPTORS Autoinstructional Aids; *Construction (Process); Correspondence Courses; Electrical Systems; *Electricians; Instructional Materials; *Job Training; Manuals; Military Training; Textbooks TEENTIFIERS Navy

ABSTRACT One of a series of training manuals prepared for enlisted personnel in the Navy and Naval Reserve, this self-study package provides subject matter that relates directly to the tasks required of the Construction Electrician, which include abilities to install, operate, service, and overhaul electric generating and distribution systems and wire communications systems; and control the activities of individuals and crews who string, install, end repair interior, overhead, and underground wires and cables, and attach and service units, such as transformers, switchboards, motors, and controllers. Contents include a 15-chapter text followed by a subject index and the associated nonresident career course (12 reading assignments and technical questions based upon each occupational standard in the respective assignment.) Chapter headings are (1) Meet the Ccnstruction Electrician,(2) Safety,(3) Blueprints, Diagrams, and Schematics,(4) Special Tools,(5) Test Equipment,(6) Control and Protective Equipment,(7) Shopwork,(8) Interior Wiring, (9) Central Power Stations,(10) Overhead Power Distribution, (12) Communications Systems, (13) Telephone Cable Splicing, (14) Administration, and (15) Basic Electronic Components and Circuits. The appendix includes the U.S. customary and metric *ystem units of measurement. (HD)

*********************************************************************** Documents acquired by ERIC include many informal unpub2 slled * materials not available from other sources. ERIC makes eve effort * * to obtain the best copy available. Nevertheless, items of ma_ginal * * reproducibility are often encountered and this affects the quality * * of the microfiche and hardcopy reproductions ERIC makes available * * via the ERIC Document Reproduction Service (EDRS). EDRS is 'Ice * responsible for the quality of the original document. Reproductions * * supplied by EDRS are the best that can be made from the original. ***********************************************************************

PREFACE

Theultiln at )U1 poeof training naval personnel isto produce (Join'-)atintNavywhieli can unsure victoryat sea. A consequence ofthequalityuf training given them is their superior state of read- Its result is a victorious Navy. This Rate Training Manual and Nonresident Career Course (RTM/ NRt.:C) form a sell-study package that will enable ambitious Construc- tionElectricians tohelp themselves fulfillthe rating. Among these requirumonts arethu,abilities to install, operate, service , and overhaul electric generatIng and distribution system and wire communications system: and control the activities of individuals and crews who string,install,and repair interior, overhead, and underground wires and cables, and attauh and service units, such as transformers, switchboards, motors, and controllers. Designed for individual study and not formal classroom instruction, the RTM provides subect matter that relates directly to the tasks eqiiiredoftheConstructionElectrician.The NRCC provides the ustialwayofsatisfying the requirements for completing the RTM. The set of assignments in the NRCC includes learning objectives andsupporting items designedtoleadstudents through the RTM. This RTM/NRCC was prepared by the Naval Education and Train- ing Program Development Center, Pensacola, Florida for theChief of Naval Education and Training. Technical assistance was provided by the Civil Engineer Support Office, NCBC Port Hueneme, California, theNaval Construction Training Center, Port Hueneme, California; andtheNaval Construction Training Center, Gulfport, Mississippi.

Stock Ordering No. Revised 1976 0502-LP-053-1810 Published by NAVAL EDUCTION AND TRAINING SUPPORT COMMAND

UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON, D.C.: 1976

3 THE UNITED STATES NAVY

GUARDIAN OF OUR COUNTRY The United States Navy is r .sponsible for maintaining control of the sea and is a ready force on.,ich at home and overseas, capabie of strong action to preserve the peace or of instant offensi ie action to wvir, in war. It is upon the maintenance of this control that our country s glorious future depends; the United States Navy exists to make it so.

WE SERVE WITH HONOR Tradition, valor, and victory are the Navy's heritage from the past. To these may be added dedication, discipline, and vigilance as the watchwords of the present and the future.

At home or on distant stations .ye serve with pride, confident in the respect of our country, our shipmates, and our families. Our responsibilities sober us; our adversities strengthen us. Service to God and Country is our special privilege. We serve with honor.

THE FUTURE OF THE NAVY The Navy will always employ new weapons, new techniques, and greater power to protect and defend the United States on the sea, under the sea, and in the air. Now and in the future, control of the sea gives the United States her greatest advantage for the maintenance of peace and for victory in war. Mobility, t:urprise, dispersal, and offensive power are the keynotes of the new Navy. The roots of the Navy lie in a strong belief in the future, in continued dedication to our tasks, and in reflection on our heritage from the past. Never have our opportunities and our responsibilities been greater.

4 CONTENTS

Page

"AIect thc Contruction Electrician 1

2.Sakit: 12 hlu-,Trints, Diagrams, and Seh.2imit1cs 45

4.special iocls 61 Test equipment o.Control and protective equipment 123

7.Shopwork 175 s.Interior wiring 235

9.central stations 270 Ov head ,'uwei distribution 311

11.1.ncicrground power distribution 357

12.Commun1:1!ions systems...... 385 13. Telopncno cable splicing 437

14.Administration 465

15.Ilasic electronic components and circuits 475

.\PPENDIX

I.Tne Metric System 507

INDEX 511 Nonresident Career Course follows Index CREDITS

Source ligures A ssoeiated Research, Inc. 5-14 thru 5-20 5-30 thru 5-33 Daystrom Weston, Inc. Instruments Division 5-26 thru 5-28 Multi-Amp Corp. 5-29 Bacharach Instrument Co. 5-23 thru 5-25 TelaCable, Inc. 5-60 thru 5-63 Automatic Electric 6-31 thru 6-34 United Electric Controls 6-40 National .1cme 6-43, 6-44, 6-46 Martindale Electric Co. 7-6

:\rnerican Telephone 8.: Telephone Co. 13-21

iv CHAPTER 1 MEET THE CONSTRUCTION ELECTRICIAN

1onstruction Electricians plan, supervise, and established..1Public Works Center performs arm tasks required to install, operate, surv-the public works duties for a number of Navy and overhaul electric generating and dis- activities in that vicinity. itionsystemsandwire communications ems;control activities of individuals and The Public Works Department is headed by is who install and repair interior, over- a Public Works Officer, who is an officer of the 1, and underground wires and cables; attach CivilEngineer Corps. The organizationand service units, such as transformers, switch- staffing of the Department varies considerably, ds, motors , and controllers; and schedule depending on the size, location, and mission of evaluate installation andoperational routines. the activity. The larger Public Works Departments are generally divided into Administrative and 1s a CE you will probably be performing Technical Divisions (Administrative, Engineer- assigned tasks while serving in a Naval ing, Maintenance Control, and sometime s Housing) dle Construction Battalion that is engagedand Operating Divisions (Maintenance, Utilities, verseas construction. There you can expect andTransportation). The Operating Divisions .)ein "B" company, which operates as aare usually headed by a CEC officer who has ;ial construction company for battalion pro- the titleShops Engineer.Smaller stations s or as a rifle company in acombat situation. might have only three divisions: Administrative, re is also a chance you could beassigned Engineering,and Shops. The ShopsDivision in Amphibious ConstructionBattalion, either usually has a Transportation Branch, one at Little Creek, Virginia or Coronado, ifornia. Some CE's are assigned to Con- Soma Public Works Departments, particularly ietionBattalion MaintenanceUnits. Their at small, isolated stations, may be staffed en- Ls concern maintenance of advanced bases. tirely by military personnel, but most Public ar billets to which CE's are assignedinclude Works Departments, both in the United States CE schoolatPort Hueneme, Californiaand overseas, are staffed largely by civilians. instructor duty), Naval Education and Train- The Administrative and Technical Divisions (ex- Program Development Center at Pensacola, cept for Maintenance Control) are mainly staffed rida (for development of training publications with civil servants classed as GS, or per annum, advancement examinations), and Public Works or white collar employees. The Operating Di- lartments at naval shore activities. visions are mainly staffed with civil servants classed as wage board, or per diem, or blue collar employees. Supervisory blue collar em- TH.E PUBLIC WORKS DEPARTMENT ployees have titles such as (in ascending order ofresponsibility)snapper,head, leadingman, When you are assigned to duty at a shore quarterman, and chief quarterman. Very large ivity, either within the United States or over- stations may also have master mechanics and s, you will most likely be assigned tothe foreman mechanics. At bases overseas, foreign )lic Works Department of the station. Mostnationals may be hired to work in the Public tions which have more than about 100 men Works Department. They may be employed di- 15 or 20 buildings have a Public Worksrectly as a special category of civil servant, )artment (which administers and maintains orthey may beutilizedas contractlabor dic works and utilities), except that in scri)e through the negotiation of a labor contract with alitiesPublic Works Centers haveoeer thehost government of the country involved.

1 CONSTRUCTION ELECTRICIAN 3 & 2

DUTY WITHIN THE An example of the General Rating is the Construction Electrician (CE)rating, which is Asstatedbefore,if you are assigned to a straight progression from Construction Re- shoreactivitywithin the U.S. you will most cruit (CR) to Master Chief Utilitiesman (UTCM). likely be assigned to Public Works; but this is not always the case. In areas where there is Construction Electrician alargestable supply of manpower, most of the utilities work isclone by blue collar em- CR-(7A-CN-CE3-CE2-CE1-CEC-CECS-UTCM ployees, Therefore, you may be assigned to themasterat arms force, special services, SERVICE RATINGS identify subdivisions or the salvage yard, the commissary, or to any specialtieswithinageneral rating. Although of a great variety of jobs, service ratings can exist at any petty officer level, they are most common at the PO 3 and Your chances of working at your trade are P02 levels. Both Regular Navy and Naval Re- much better in areas where there isa relative serve personnel may hold service ratings. shortage of manpower. In these areas, you may expect to be assigned to the Utilities Division or the Maintenance and Utilities Branch of the OCCUPATIONAL STANDARI/S Shops Division of a Public Works Department. Some Public Works Officers prefer to organize A most important step in develop: g your two separate lines of authority: one for civilians career isto acquire the skills that have been and oneforthemilitary personnel. Othersprescribed specificallyfor each paygrade of prefer to integrate the civilians and militarythe CE rating. These skills, expressed in terms completely; in the latter case you may work of task statements called occupational standards, beside a civilian and report to a C El, who re- are contained in the Manual of Navy Enlisted portstoa quarterman, who answers to theManpower and Personnel Classificationsand Shops Engineer, who is an officer. There are Occupational Standards,NAVPERS 18068-D. some activities which are staffed completely Other requirements, called naval standards, are by military personnel because the mission isnot specifically rating oriented. These tooare highlY classified; if you are assigned toa sta- contained in NAVPERS 18068-D. Studying this tion of this type you may expect to work withinrate training manual should help you meet the your rating. occupational standards for CE3 or CE2. Naval standards can be met by studying other trainit g manuals which are named later in this DUTY AT OVERSEAS BASES chapter. In general, you may expect to work in your tradeif assigned to a shore activity outside NAVY ENLISTED CLASSIFICATIONS theU.S.At smaller, relatively isolated sta- tionstheentirepublic Works staff may be Associated with the Construction Electrician military personnel. At the larger activities you rating are Navy Enlisted Classifications(NEC's) may expect to work with civil servants from which identifyskills requiring more specific the U.S., both white collar and blue collar, and identificationthanis provided byrates and with foreign nationals. ratings, and which are not rating-wide requirements. NEC's are designed to facilitatemanage- ment of manpower byidentifyingaccurately THE ENLISTED RATING STRUCTURE billets and personnel. They help in distribution and detailing of personnel. The following NEC's The two main types of ratings in the presentmay be earned by Construction Electricians: enlisted rating structure are general ratings and service ratings. I. SHORE-BASED POWERPLANT TECHNI- CIAN, CE-5632He operates, services, and per- GENERAL RATINGS identify broad occupa-forrns organizational and/or intermediate level tionalfieldsofrelated duties and functions. maintenance on electrical systems of shore-based Some general ratings include service ratings; powerplants. This NEC is assigned only toper- others do not. Both Regular Navy and Naval sonnelinpay grades E-5 through E-7 upon Reserve personnel may hold general ratings. satisfactory completion of the applicable course. 8 2 Chapter 1 MEET TI1E CONSTRUCTION ELECTRICIAN

2. CENTRAL OFFICE EXCHANGE TECHNI- welding;seafloorsurveying; founi'ations and CIAN, CE-5642-11e installs, inspects, main- anchor emplacement; rigging; cable laying and tains,and performs organizational and/or splicing; and system testing. This NEC is avail- intermediatelevelmaintenance onautomatic able to SEABEE personnel who are graduates PBX or PAX telephone exchange equipment, of the Basic Underwater Construction Techni- incluthng switchboards, dial selection mecha- cian course. nisms, and telephones; performs troubleshooting operations; performs necessary adjustments and 7. SAFETY INSPECTOR, SW-6021-11e or- replacements; cleans and adjusts contacts and ganizes and supervisestheoperation of the adjusts contact clearances; tests circuits using safety department. In doing this, he investigates spring tension gages, voltmeters, and ohmmeters; accidents, analyzes accidents and problem areas, performs daily or periodic ground or insulation and recommenci methods to decrease frequency tests on switchboards. This NEC is assignedand/or eliminateaccidents;collectsdatato onlyto personnel E-5 through E-7 upon satis- ascertain accident trends; inspects project sites, factorycompletionoftheapplicable course. grounds,buildings and machinery toisolate hazardstolife,health, and equipment; con- 3. CABLE SPLICING TECHNICIAN,CE- ducts safety education campaigns by preparing 5644He splices multiple conductor cables used and/or distributing literature, posters, chart3, in telephone and telegraph communications and and displays; organizes and directs the safety electric--)ower transmission systems. This NEC committee; directs placement of traffic control is assigned only to personnel E-5 through E-7 signsand devices. This NEC is assigned to upon satisfactory completion of the applicable SEABEE personnel in paygrades E-6 and E-7 course. who satisfactorily complete two courses: Basics ofOccupationalSafetyand Health (OSH-300) 4. CONSTRUCTION PLANNER AND ESTIMA- TOR SPECIALIST, EA-5515-11e plans and es- and Occupational Safety and Health Standards of timatesmaterial,manpower, and equipment the Construction Industry (0511-220). requirements forvariousconstructionjobs; performsscheduling, procurement, production 8.. NUCLEAR POWERPLANT OPERATOR, control, and management reporting of construc- 3391He operates,maintains,and performs tion projects. This NEC is assigned not oniy organizational level maintenance on nonpropul- toCE's,but also toEA's, BU's, UT's, and ;ive nuclear powerplants and radioisotope power SW's in pay grades E-5 through E-7, who are devices, as an Electrical, Mechanical,Instrument graduates ofthecourse, EngineeringAids/ or Health Physics/Plant Chemistry Specialist. Planning and Estimating. This NEC is normally assigned to CE's in pay 5. ADVANCED UNDERWATER CONSTRUC- grades E-4 through E-7 who are graduates of TION TECHNICIAN, BU-5931 He performs the course, Nuclear Powerplant Operators, which underwater construction operations usingall is offered at the Naval Nuclear Power Unit at typesofunderwater equipment and tools. In Fort Belvoir, Virginia. NEC 3391 is also avail- doingthis,heplans and supervisessimple able to personnel in the UT, EO, CM, SW, and underwater construction operations; estimates HM ratings. manpower and equipment requirements for various underwater construction projects; inspects material condition, monitors general readiness, THE NAVY ENLIST ED ADVANC EM ENT diagnoses improper operating procedures and SYST EM equipment failures. This NEC is available to SEABEE personnel in paygrades E-5 through Many of the rewards of Navy life are earned E-9. throughtheadvancement system. The basic ideas behind the system have remained stable 6. BASIC UNDERWATER CONSTRUCTION for many years but specific portions may change TECHNICIAN, 3U-5932He performs under-rather rapidly. It is importa,,t that you know waterconstructionoperations using common the system and follow changes carefully. BU PE RS underwater tools, equipment, and materials. In Notice 1418 will normally keep you up to date. doing this, he performs duties related to underwater construction blasting; component emplace- The norm al system of advancement m ay be ment and assembly; underwater cutting and easier to unciPrstand if it isbroken into two parts:

3 9 CONSTRUCTION ELECTIUCIAN & 2

1 Those requirementsthatmustbe met the factors that determine whichpersons, out before you may be considered for advancement, ofallof those QULIFIED, will actually be advanced inrate are; the score made on the 2. Thosefactors thatactuallydetermine advancement examination,thelength of time whether or not you will be advanced. in service, the performance marks earned,and the number of vacancies being filled ina given QUALIFYING FOR ADVANCEMENT r ate.

In general, to QUALIFY (be considered) for Ifthe number of vacancies in a given rate advancement, you must first: exceeds the number of qualified personnel, then ALL of those qualified will be advanced. More 1. Have a certain amount of time in pay grade often, the number of qualified people exceeds the vacancies. When this happens, the Navy has 2. Demonstrate knowledge of material inyour devised a procedure for advancing those who mandatory Rate Training Manuals by achievinga are BEST qualified. This procedure is based suitable score on your CommancPs test, bysuc- on combining three personnel evaluation sys- cessfully completing the appropriate Nonresident tems; Career Courses (NRCC's) or, in some cases, by successfully completing anappropriate Navy Merit rating system (Annual evaluation and School. CO recommendation). 3. Demonstrate the ability to perform allthe Personnel testing system (Advancementex- skill requirements listed on the Record ofPrac- amination score ,7-with some credit for passing tical Factors, NA VEDTRA 1414/1. previous advancement exams). 4. Be recommended by yourcommanding Longevity (seniority) system (Time in Rate officer. and Time in Service). 5. For petty officer third and second candi- Simply, credit is given an individual in three dates ONLY, demonstrate knowledge of military areas: performance, knowledge, and seniority. subjects by passingalocally administered A composite known as the final multiplescore MILITARY/LEADERSHIP examination based on is generated from these three factors. Allof the naval standards (from NAVPERS 18068-D). the qualified candidates froma given advancement examination populationare then placed on 6. Demonstrate knowledge of the skillre- one list, based on this composite figure, the quirements for your rate by Eiljr_laa Navywide highest achiever first, andso on down to the advancement examination basedon the occupa- last qualified person in the population.For candi- tional standards (from NAVPERS 18068-D). dates for E-4,E-5,and E-6,advancement authorizations are thenissued, beginning at Figure 1-1 gives a detailed view of there- the top of the list, for the number ofpersons quirements foradvancement ofactive duty needed to fill the existing vacancies.Candidates personnel; figure 1-2 gives this view for ad-for E-7 whose final multiplescores are high vancement of inactive duty personnel. Remember enough will be designated PASS SELBDELIG that the naval and occupational standardscan (PassSelection BoardEligible). This means change. Check with yourdivision officer or thattheir names willbe placed before the training officer to be sure that you have the Chief 1Htty Officer Selection Board,a BUPERS most recent standards. chErged with considering all so-designated cIL blecandidates foradvancement to CPO. If you meet allof the above requirements Advance: ent authorizations for those beingad- satisfactorily,you becomea member ofIli: vanced CPO are issued by this board. group from which advancements will be mac: WhT, then, are the individuals whoare ad- WHO WILL BE ADVANCED? ? Basically,theyare the oneswho leved the most in preparing for advancement. Advancement is not automatic. Meeting all of they were not content to just qualify; theywent the requirements makes you eligible but doesthe extra mile in their training,and through not guaranteeyouradvancement.Some of thattraining and their work experience they 4

1 0 Chapter 1MEET THE CONSTRUCTION ELECTRICIAN

tE7 # E3 # E4 E5 tE6 tE8 to E9 REQUIREMENTS* El to E2 E2 to E3 to E4 to E5 to E6 to E7 to E8

4 mos. 6 mos. 12 mos. 24 mos. 36 mos. service- as E-3. as E-4. as E-5. as E-6. 36 mos. or 8 mos. 2 years 3 years 6 years 9 years 36 mos. as E-7. as E-8. SERVICE comple- as E-2. time in time in time in time in tion of service.service.service.service.8 of 12 10 of 15 Recruit years years time in Training. time in service service Recruit Class A .Navy must be must be Training. :for PR3, .: School enlisted.enlisted. : for ACC, (C.O. :::: , DT3, .: MUC, may ad- : IS3, :MNC.tt SCHOOL vance up : AME3,

to 10% .::::::. .. HM3,

of gradu-M* : PN3,

ating .ii::::iiii:- :: FTB3, class.) U* MT3.

Locally be PRACTICAL prepared Record of Practical Factors, NAVEDTRA 1414/1, must FACTORS check- completed for E-3 and all PO advancements. offs.

PERFORMANCE :Specifiedratings must complete TEST .:applicableperformance tests be- .foretaking examinations.

ENLISTED As used by CO in ad- PERFORMANCE when approving Counts toward performance factor credit vancement multiple. EVALUATION advancement.

EXAMINATIONS**Locally See Navywide examinations prepared below, required for all PO Navywide selection board. tests. advancements. Nonresident career RATE TRAINING *Required for E-3 and all PO advaniaments courses and MANUAL (INCLUD- unless waived because of school comple- recommendoi ING MILITARY , tion, but need not be repeated if identi- reading. See REQUIREMENTS) cal course has already been completed. See NAVEDTRA 10052 (current edition). NAVEDTRA 10052 (current edition).

AUTHORIZATION Commanding NAVEDTRAPRODEVCEN Officer

* All advancements require commandingofficer's recommendation. t 3 years obligated service required for E-7,E-8, and E-9. # Military leadership exam required forE-4 and E-5. ** For E-2 to E-3, NAVEDTRAPRODEVCEN exams orlocally prepared tests may be used. tt Waived for qualified EOD personnel.

Figure 1-1.Active duty advancement requirements.

5 CONSTRIXTR)N ELECTRICIAN 3 k 2

1 I _ ; ii E(,)1,11I I.: AI EN TS to . to En to E11

:U; mos:II; mos2-1 !nos. ( \ 1,TII\IL with with with I )s IN GRADE oS I mos2 1 mos.total total total yrs 1 2 yrs 1 5 yrs 6ervireserviceservice ToTA I. TRAINING 1.1(11,\!HII (1:1vsj1.1(111,5 1.1 DUTY IN GIA t (la\ (javs 12 days12 days2S days

PER F( )R MA NC E Siwcificd ratings must complete applicable TESTS performance tests before taking examination.

DRILL Satisfactory participation as wrIc II ':\ Tv it member of a drill unit in accirdanec with IWPERSINST 5-10.-1 2 series.

PRACTICAL [-,A("p mt.; (INC LUDING MI LITA HY Record of Practical [actors, NavEdTra1.11.11. must REQUIREMErs) be completed for all advancements.

RATE TRAtNING NIANUAL (INCLUDING Completion of applicablecourse or courses must he entered MILITA RY II I:QUM E- in service record. MENfS)

Standard Exam required for all Po EXAMINATION Standard Exam advancements. Standard Exam. Also Vass Selection Board. Military Leadership Exam for E-4 and E-5.

AUTHORIZATION Commanding Officer NA V EDTRA PROD EVC EN

*Recommendation by commanding officer requiredfor all advancements, Active duty periods may be substituted fortraining duty.

Figure 1-2. --Inactive duty advancementrequirements. 1 2

6 RICIAN Chapter 1 E ET Til E CONST ilt CTION EL EC T developedgreaterskills,learned more, and Record of Practical Factors accepted inure responsibility, Before you can take the Navywideexaminatia While it cannot guarantee that any one person for advancement, there must be an e: vin your will he advanced, the advancement systemdoes service record to show that you fit let the guarantee thatall persons within a particular naval and occupational standards fo. for the vacancies andrating. The RECORD OF 1. I. ratewillconipeteequally this that exist. VACT(dtS, NA VEDTRA 1414/1, is us isirpose.Available for each rating, L. orn, listsall performance factors, or task state- HOW TO PR EPA RE FOR A DVA NC EM ENT ments for the rating. As you demonstrate your What must you do to prepare for advance- ability to perform each factor, appropriate entries ment? You must study the naval and occupa- are made in the DATE and INITIALScolumns. tionalstandards, demonstratethatyou can Spaceisprovided onthe form for entering perform required skills, study the required rate additionalperfornnince factors oriecording training manuals, and study other material that demonstrated proficiencyinskills which are is required for advancement. To preparefor within the general scope of the rating but which advancement, you will need to be familiar with arenotidentifiedas occupational standards. (1)the Manual of Navy Enlisted Manpower and PersonnelClassifications andOccupational Until e bid, the NA V EDT RA 1414/1 ts Standards, (2) the Record of Practical Factors, usuallyhelsoyyourdivisionofficer;after (3) the Bibliography for Advancement Study,and consilution,itis forwarded to the personnel inyour service record. (4)the applicable rate training manuals. The officeforinsertion following sections describe each of these and If you are transferred before qualifying in all give you some practical suggestions onhow performance factors, the incomplete for111 shoUld inpreparingforadvancement. be forwarded with your service record to your tousethem next duty station. You can save yourself itlot Manual of Navy Enlisted Manpower of trouble by making sure that this form actually and Personnel Classifications and is inserted in your service record before you arctransferred.IIthe form isnotin your Occupational Standards service record, you may be required to start The M:inual of Navy, Enlisted Manpowerand all over again and requalify in th,- perforniance Personnel Classifications and Occupational Stand- factors which have already IHJen checked off. ards, NA VPERS 18068-D,definesratesand ratings hy describing the Navy's requirements Bibliogialehy for \dvar.uic.t Study for enlisted skills. The manual consists of two sections. The first section contains the occupa- P..hliography .ulvancenientStudy, tional standards and naval standards thatform Nay; \10052 (revised) is inraortant to all the basis for what eclisted personnel arctrained enlisteu 1.,:rsonnel preparing for advancement. in and advanced upon. The second suction con- 11 liststherate training manuals and other tains the Navy Enlisted Classifications (NEC's) publications prescribed forIlseby naval per- which were definedearliw.inthis chapter, sonnel concerned with training and advancement examinations. The naval standards contained in NA VPERS 18068-D express the niinimuni skillsrequired NA VEDTRA 10052isrevised andissued of unlit-stud personnel which are not specifically yearlybytheNavalEducation and Training is ratingoriented.For the most part they are s;upport Command, Each revised edition stated as knowledge requirementsbecause they identifiedbya letterfollowingthu number. represent basic things which should lxi known, When using this publication be sure thud you and not necessarily done 11ft matter of routine. have the most, recent, edition. The occupationalstandardsappearas tithk statements only since Hwy define what enlisted iiextensive changes in standards OdetIV In their rate or rating. In botw,:im110: annualrevisionsof personnel insist do in finy of study otherWordit,theyII re Pe 11011111111de 111(1,01'11. NA VEDIRA 10052, a supplenLintary list ft1St PERS Thu knowledge required to perform fltaski material may be issued in the form of inherent to the proper performance of thetask. NO ice. When you (WO preparing foradvancement,

1 3 CONSTRI CFR iN EI,E(."11UCIAN 3 b 2

check to see .,,,hether changes havebeen made The revision of a rate training manualis iden- in the standards for your rating,IIso, look tifiedby ile tterfollowingthe NA VEDTRA for a BU PERS Notice that supplementsN ,VED- number. you can tell whetherany particular TIL\ 10052 for your rating. copy of a training manual is the latest edition by checking the NAV EDTRA The required and reconimended number and the letter references following this number in the mostrecent edition are listed by pay grade in NAVEDTRA 10052, of List of Training 'Manualsand Correspondence lfyou are workinz fur advancement to third Courses, NA VEDTRA 10061. (NAVEDTRA class,study 10061 thematerialthatislisted for is actually a catalog that lists allcurrent training third class If you arc working foradvancement manuals and correspondence to second class, study the material that is listed courses; you will find th:s catalog useful in planningyourtudy for second chis;-;;but remendier that you are program.) alsoresponsible for the references, listedat the third class level. Each time a rate training manual isrevised, it is brought into conformance with In the official using NA VEDTRA 1005:2you will notice publications and directiveson which it is 1.ased; that some ratetraining nutnu ds are marked but during the life ofany edition, discrepancies with an asterisk (1, Any manualmarked in this between the manual and the way is NI \ NDATORYthat is, it must be com- official sources are pleted at the indicakA rate level alr»ost certain to arise becauseof changes to before you can the latter which are issuedin the interim. In be eligible to take the serviecwideexamination the performance of for advancement. Each mandatory your duties, you should al- manual may be ways reter to the appropriate officialpublication completed by (1) passing theappropriate non- ordirect: ve.If resident Ulu 11:d1. the official tource is listed colt isetf:!1 tisInised on the in NA VEDA 1(A10052, the !.ival Education and mandatory training manual; (2)passing locally Training Pr ograrn DevelopmentCenter uses it prepared tests based on theinlornuttion given its a source of questions in preparing inthe training manual; the fleet- or (3) in some cases, wide examinations for advancement.In case of successlullycompletirrhanappropriate Navy discrepancy between school. any publications listed in NAVEDTRA 10052for a given rate, theex- Do nut overlonk the heetion (A NAV El aRA andnationwriter'swillusethemost recent 10052 which li;;ls the required andrecommended mate Hid. roferenee:-; relating to th, wival standards.Per- sonnolof rating; imt completethe Bate training manuals are designedto 1-1p mandatory military requirement:, trainingman- you prepare for advancement. The followingsug- ual for the appropriate level beforethey ean gestions may help you to makethe best use be eligible to wlvance. of this manual tind otherNavy training publications when you are preparingfor advancement. Ther eferencesiii NV EDINA 10052 which are recommended butnotmandatory should I. Look up the occupational al:,0IA; studied carefully. ALI references standards for listed your rating before you study thetraining manual, iiiNAVEDTRA 10052 may beic.,ed nenree and refer to thorn frequently material for the written examlnation::, as you study. Re- atthe member, you are studying themanual primarily appropriak: rate levels. in order to meet the standards. Rate Training 2. Sot up a regular study plan.It will probably be easier for you to stickto a schedule if There are two general types ol rate training you win plan to study at thestallti time each day. 11110111ftih. TEN(; Oat; one) postitid.Q,fichodolo your studying for areprepared tuim ruuu.ut a time Unlit/UPIratingl-;. A ofdaywhen you will not have toomany in- rating manual glveh inlormation that in directly terruptions or distractions. related to the ocelipational qualifications;III ()NE NI 'ITERrujitrutrula orli,\ ;-IC lieforeyou begin to study any part of ItItillt11111,givelakirnuttltin that appile:, to more the than one rating. retillUalintensively, become familiar with the waive hmk. Rend thepreface and the table !tate training nitwit:1ln are revised from Uwe of to time to keop them up to date contonts. Check through the index.1,00jc itt tw.hrileally. apnendixen. Thumb ti rough the bookwithout

it chaptor 1 E ET THE CONSTRUCTION ELECTRICIAN

really any particular plan, lookingat the illustrationswords, the chances are that you have not and reading bits here and there as you seethings mastered the information. that interest you. 9. Usc nonresident career courseswhenever completion of a 4. Look at the training manual in morede- you can. As mentioned before, tail, to see how it is organized. Lookat the table mandatory rate training manual can be accom- chapter, read plished by passing an NRCC based onthe rate of contents again. Then, chapter by find it help- the introduction, the headings, and thesubhead- training manual. You will probably ings. This will give you a pretty clearpicture ful to take other NRCC's as well asthose based of the scope and content of thebook. As you on mandatory manuals.Taking an NRCC helps ask yourself youtomaster theinformationgiven in the look through the book in this way, how such questions as: training manual, and also helps you see much you have learned. What do I need to learn about this'.' 10. Think of your future as youstudy rate training manuals. You are workingfor advance- What do I already know about this? ment to third class or second classright now, in- but some day you will be working towardhigher Howisthisinformationrelated to learn now formation given in other chapters? rates. Anything extra that you can will help you both now and later. flowisthisinformationrelated to the occupational standards'? SOURCES OF INFORMATION 5. When you have a general idea of whatis organized, One of the most useful things you canlearn in the training manual and how it is about fillin the details by intensive study. Ineach about a subject is how to find out more study period, try to cover a completeunititit. No single publication can give you allthe chapter, or information you need to perform the duties of may be a chapter, a section of a look for a subsection. The amount ofmaterial that you your rating. You should learn where to can cover at one timewill vary. ff you know accurate, authoritative, up-to-date information the subject well, or ifthe material is easy,on all subjects related to thenaval standards you can cover quite a lot at onetime. Difficult and occupational standards of your rating. require more study Some publications aro subject to change or or unfamiliar material will revision from time to time some at regular time, intervals,others as the need arises. When 5. In Studying any one unitchapter,section, using any publication that is subject tochange or subsection write down thequestions that or revision, be sure that youhave the latest occur to you. Many peoplefind it helpful to make edition. When using any publication that is kept a written outline of theunit as they study, or current by means of changes, be sure youhave important ideas. a copy in which all officialchanges have been at least to write down the most made. Studying canceled or obsoleteinformation 7. As you study, relate the informationin will not help you to do your work or to advance; the training manual to theknowledge you al- it is likely to be a waste of time, and may even ready have. When you readabout a process, be seriously misleading. askill, or a situation, try to ace how thisIn- formation ties in with your own past experience. GOVERNMENT PUBLICATIONS studying a unit, There are various Government publications 8. When you have finished which you may find useful as sources of ref- take time out to EiW.;what you have learned. Look back over your notes and questions.May- erence. A number of publicationsissued by the be s011143 of your questions have beenanswered, Naval Facilities Engineering Command (NAV- but perhaps you still have WNW., that are not FAC) which will be of interest to SEABEES are answered. Without looking at the trainingmanual, listedinthe NAVFAC Documentation Index, have gotten NAVFAC P-349 (updated semiannually). A pub- write down the main ideas that you lications program is one of the principal com- fromstudying this unit. Don't just quotethe book. If you can't give these ideas in your own munications media used by NAVFAC to provide

15 CONSTRUCTION ELECTRICIAN 3 & 2

a ready referenceof current technicaland Handbook H30. At the time of w iting of this administrative data for use by its subordinate course, the latest amending handbook was Hand- units. NAVFAC publications are listedn alpha- book 81, issued 1 November 1961, and containing betical and numerical order in NAVFAC P-349; a complete reissue of section1(definitions), copies of NAVFAC P-349 may be obtained through section 9 (rules covering methods of protective proper channels from the U.S. :':aval Publications grounding), and Part 2 (rules for the installation and Forms Center, 5801 Tabor Avenue, Phila-and maintenance of electric supply andcom- delphia, Pennsylvania 19120. munication lines). Some of the training publications that you will need to study or refer to as youprepare for Safety precautions applying to just aboutevery advancement havealready been mentioned intype of construction are codified and issued by this chapter. Some additional publicationsthat the Headquarters, Naval Material Commandin you may find useful are listed below. Dapartment of the Navy Safety Precautions for Shore Activities NAVMAT P-5100. Electrical Engineering, DM-4 Chapter 15of NAVMAT P-5100 contains Electric Power Distribution Systems Main-precautions which have particular application tenance, MO-200 toelectricit,General electrical precautions Advanced Base Electrical and Communica- arecontainedn articles 1501 through 1503. tion Systems, TP-PL-15 Precautionsclating to electrical equipmentare given in articles1510 through 1520. Article The Army publishes a number 9f technical 1525 contains precautions to be observed when manuals (TMs) relating to the field of the Con- working on energized circuits. Precautionsre- struction Electrician.Among these are the lating to line construction and distributionere following: in articles l5`oG through 1535. Electrical Power Transmission and Distri- Many of the nonelectrical chapters of Saiet-v bution, TM 5-765 Precautions to. Sbore Activities contain information of inter )st ara Poncern to the Construction ElectricalFacilities,Substations,Repairs Electrician,such as chapter3, "Materials and Utilities, TM 5-680F Handling and Storage;" chapter 8,"Construc- Electric Motor and Generator Repair, TM tion;" chapter 14, "Portable Tools;" and chapter 5-764 20, "Hazardous Materials." Fundamentals of Telephony, TM 11-678 You will also find safety precautions applicable to yourratinginNaval Construction v.orce The National Bureau of Standards of the U.S. Safety Manual, COMCBPACBLANT In- Department of Commerce publishes the National struction 5100.1 series. Electrical Safety Code as National Bureau of Standards Handbook H30. Section 1 of this work MANUFACTURERS' MANUALS contains electrical definitions; section 9 contains rules covering methods of protective grounding. When new equipment is procured by the Navy, The remainder of the book consists of 5 parts, it usually is accompanied bya manual of oper- as follows; ating, maintenance, and installation instructions. These manuals should be kept readily available Part 1. Rules for the installation and main-for reference. They describe in detail thepro- tenance of electrical supply stations. cedures for installing, maintaining and operating Part 2. Rules for the installation and main- a specific piece of equipment. tenance of electric supply and communication lines. Study the manuals. Take care of them. Do not Part 3. Rules for the installation and main-lose or damage them. When youare required to tenance of elPotric utilization equipment. repair a piece of equipment, follow the manual's Part 4. ,dles for the operation of electric instructions carefully. equipment and lines. Part 5. Rules for radio installations. COMMERCIAL PUBLICATIONS The Bureau of Standards issues from time A wealth of information on electricalcell- tothne a handbook which amends parts ofstruction exists in various reports, pamphlets,

10 16 Chapter 1 MEET THECONSTRUCTION ELECTRICIAN

published in July prepared by manu- Catalog, NAVAIR 10-1-777, handbooks, and textbooks 1971. Copies may be orderedin accordance with facturers, trade associations,technical and pro- Forms and Publications, fessional societies and other sources.Much of the Navy Stock List of station libraries, NAVSUP 2002. Supplementsto the Film Catalog this literature is available in are issued periodically. Public Works Departments,and battalion offices When selecting a film, noteits date of issue and libraries. listedinthe Film Catalog. As youknow, procedures sometimes changerapidly. Thus some TRAINING FILMS films become obsoleterapidly. A film that is sometimes be shown Trv:Ining films - available tonaval personnelobsolete only in part may effectivelyif,'r;foreor during itsshowing, are a valuable sourcecf supplementary infor- procedures that Lave changed arepointed out mation on many technicalsubiocts. Training films are listed in the UnitedStaLes Navy Film to the viewer.

1 7

11 CHAPTER 2

SAFETY

All electrical systems are potentialKILLERS. EL ECTRICAL SHOCK: Personnel should be awareofthepotential CAUSES AND CONSEQUENCES danger. CE's especially should have complete knowledge of the inherent and manmadeelec- Most fatalelectric trical hazards because they WORK shocks do not happen on electrical to the uninitiatedthey happen to peoplewho equipment or systems. But safety appliesnot should know better. As a CE, carelessness in onlyto electrical equipment or systems, butyour work can sentence you to death by elec- to the entire construction field and its hazards trocution. Familiarity with the equipment tends which are always present. to make you forget the little precautions taught in trade school. In this chapter, we will examine some of these hazards and provide provenways of pro- Unfortunately,itis impossible to bring the tecting yourself and others against them.By dead back tolife or change the results of the adheringtosafe working practices, you willaccident; that is why it is necessary,even at minimize danger to life and equipment. Fur-the risk of monotony, to constantly stressor thermore,bylearningfirstaidand how toeven preach SAFETY. It may make you think applyit correctly, you may be able tosave twice before taking that last chance. omeone's life. Most of us are apt to remember only the most important safety precautions, but howmany ofusstop to think of the small details that ACCIDENT PREVENTION really ENSURE safety? Also, howmany of us realizeitis the current, not the voltage, that is lethal

Accident prevention depends on your knowing Although the sign CAUTION HIGH VOLTAGE the appropriate safety factors fora given haz- serves as a reminder to keep hands off, don't ardous condition, on your ability to recognizeforget that an electric shock from 10,000 volts a condition as hazardous. Conditions change from is no more deadly than a shock from ordbary job to job and from day to day on thesame job, 115-volt house current.Industrial equipment so you must be constantly alert to the possibility using as little as 42 volts of direct current of new hazards. Whenever you observea safety has bfen fatal (30 volts a-c is consideredhaz- hazard, even though you may not be involved ardous). CURRENT, NOT VOLTAGE, ISTHE in thewr.,rk being done, call it to the attention LETHAL AGENT, of a responsible person. Makea prompt report of any unusual condition, whether ina gener- The seriousness of an electric shock depends ating station, a substation, an undergroundor upon the magnitude of the current flow in the overhead cable system, or any electrical eq,ip- victini. Current flow, in turn, dependsupon the ment.Unusual conditionsarefrequentlythe electrical resistance of the circuit path through forerunners of a break in continuity of service, the victim's body. Thiscan vary consideri; biy and they usually increase the hazard When depending upon the degree of contact and the they occur the best procedure is to take im- skin resistance at the time of contact. mediate protective steps, rather than wait until We are all aware of the presence of moist it is obvious that a hazard has developed. skin causcd by perspiration ona hot day, but 18 12 Chapter 2 SAF ETY few of us think about the sudden moistening of SAFE WORKING PRACTICES the skin when we are frightened or startled. The unexpected discharge of a capacitor or the When working with or around electrical equip- inadvertentshortingofa voltage point when ment,don't wear looseclothing with metal troubleshootiag often will startle the technician,buttons or metallic ornamentsthey may come make him jump, and at the same time bringinto contact with a live circuit and cause the on a momentary cold sweat. Such reactions are wearer to flinch3.ndcome into bodily contact not uncommon, and obviously they set up awith exposed live parts. Remove rings, wrist- shocking situation. watches, and metal identification bracelets and store them in a safe place (not in your pocket). Although this may be considered an extreme Don't examine live equipment when mentally case,itdoesillustratehow anindividual's or physically fatigued. Use rubber gloves, fuse resistance can vary considerably from minute and other safety tools and stand on a to minute, depending upon his emotional state tongs, at the instant of contact. Skin resistances of safety mat. Wear safety footwear. a few hundred ohms when wet, to well over Familiarity with the equipment is no excuse 500,000 ohms when dry, have been measured, for taking chances. If you must work cri hot sobe carefultake everysafety precaution equipment, don't work alone. It takes only an possibleit inay save your life. instant for a person to get injured and it may take minutes before the victim is discovered. Figure 2-1 illustrates what a person mayThose minutes can mean the difference between expect when he is subjected to increasing (cur- life and death. rent) electric shock. His first reaction occurs Ifyoudiscoveran accident victim, don't when the current is only 2- or 3- milliamps. wastevaluable time looking forthe power At 1.0milliamps,theshockis no longer a switch. Use a rope, a dry length of wood, your mild tinglingsensationbut becomes painful.belt, or other insulating material to pull the As the current flow increases beyond 20 milli- victimloose,T.ae resistance of the victim's arnp.3, muscular paralysis begins and the victim body decreases with time, and a delay in getting cannot release the contact. In the range from him loose can prove fataL 50to 100 milliamps, breathing becomes dif- ficultin fact it often stops. Between 100 and 200milliamps,ventricular fibrillation (unco- ordinated twitching)of the hrart occurs. This is usually fatal. Above 200 .nilliamps severe BURNING ODOR burns will be produced, a sjc.1,e 'big odor occurs, (HEART CLAMPS I and the muscular rcilc a 'he heart is so USUALLY FATAL severe that it "clamp clamping prevents (HEART TWITCHES) damaging ventricular .1 and the victim's chancesof survival are -.2if help is im- SEVERE mediately available. (BREATHING O oirricuLT)

u. Unfortunately it is impossible to tell whether VERY PAINFUL an unconscious victimhasrecei,,,41afatal w (CAN'T LET G01 i- shock, so artificial resuscitation must be applied x immediately ifbreathing has stopped. Do not PAINFUL stop efforts at resuscitation until medical authority pronounces the victim beyond help. Vic- tims have been known to revive after 8 hours MILD af artificial resuscitation. ( TINGLING) I l''"I r FF If this description of the effects of shock 2 3 4 5 10 20 50 100 200 sounds gruesome, remember that being aware CURRENT IN MILLIAMPERES of the possibility of very serious consequences will remind you to take every safety precaution 27.314 available to avoid such eventualities. 19 Figure 2-1. Electrical shock scale. 13 CONSTRUCTION ELECTRICIAN 3 & 2

Ifatall possible, work on open or dead circuits. Lock and tag the power switch inthe OPEN position, particularly if the switch is not inthe area in which you are working. Rope KEEP off and place danger signs in hazardousareas. THIS LINE Considerall circuits alive until theyare proved otherwise. NEVER use your fingers to NEARLY check the line; use a meter. Whenmeasuring VERTICAL over 300 volts, don't hold the test prods. Pull the power, clip the meter leads in place,and turn onthe power. It takes :longer, but it's worth it. Don't forget to discharge large capacitors after the equipment has been turned off. Dis- charge them not once but twice for at least5 second;3. A charged capacitor can packa real wallop. Useasuitable insulated shorting or grounding bar.

Ensure that equipment is adequately grounded. 90.22 Don't bridge a fuse or interlock. Figure 2-2.Lifting heavy material. Finally, do not relax caution just because Closed containers should be provided for protective measures have been taken. No safe- greasy rags. guard is 100 percent effective. Temporary wiring should not be strung over LIFTING SAFELY m ake shift supports. All circuits should be fused properly. You Look over the object to decide the bestway must abideby the rules for each hazardous to hold it. Place your feet close together and location. close to the object to be lifted. Get a good grip on the load. Bond your knees and keep your Know the proper fire extinguishers to use, back straight(fig.2-2). Keeping your bodyparticularly on electrical fires. A ClassC upright,liftwiththeleg and arm mustAes,extinguisher is preferred sinceitis noncon- not with the back and stomach. G3ta good ductive and can be directed against energized footing and crouch when starting to lift. T 3..ke circuits witheut danger of shock. a deep breath and hold it while lifting or lower- MEMORIZE YOUR BASE FIRE TELEPHONE' ing a load. NUMBER. In case of fire, immediately deenergize the circuit affected. Call the Fire De- Test the load first, lifting gradually. Avoidputment. Control the fire insofaras possible jarky motions and keep the load close toyour until firefighting personnel arrive. body. Avoid twisting motions and don't shift positionsofthefeet while making the lift. WALKING SAFELY B.) sure you can see past the load and get help for large or heavy objects. It is safer to walk around trenches or other excavations than to jump over themor walk FIRE SAFETY over an unsafe plank. Where hoisting or overhead work is being done, keepaway from un- Gasoline should be kept in safety containers.protected areas so you will not be struck by Flammable cleaning fluids should not be usedfalling or swinging materials. on electrical apparatus. Look where you are going so you won't trip over materials or step on nails. In wet B: sure that. fires are out when pots andweather, be extra sure of your footing where torches are not in use. walkways or platforms may be slippery. 14 2 0 Chapter 2SAFETY

HANDT(OL SA ETI Before emergizing a line, doublecheck to makesuretnat everything and everyoneis Do not use n)akeshift tools. Most electricalclear. toolsarespecialized. For example, hot-line toolsarenecessarytoensure uninterrupted Wh:qeve): possiblein your work on live service. Use them correctly and do not use electrical equipment use only one hand and have substitutes. a rubber glove on each hand, Keep all cutting tools sharp. They are safer G)gglesshouldbe worn when pouring sharp. See that jaws of wrenches are in good acid and when performing grinding, drilling or condition. soldering operations. Toolbeltsshould be kept in good repair Knowartificialrcspiration (discussed foryour own protectionas well as for the later). protectionof men working under you. Make sure that handles of all tools are not cracked WEAR HARD HAT:-) or otherwise damaged, Regular protective heln)ets (hard hats) must LADDER SA 1,'ETY provide the necessary insulation resistance so thatpersonnelotherthan electrical workers Before climbing a ladder, make sure it is willbeprotected from accidental head con- ingood condition, with no cracked, split, ortactswithelectricalcircuitsand equipment patched side rails, rungs, or cleats. Check the at comparatively low voltages (less than 2200 ladder to see thatitisplaced with the base volts),Electrical workers requiring head pro- setoutone-fourth the ladder length and set tection incidental to their duties or to the work- firmly soitwon't tip or slip. See that the top ing environment, particularly those engaged in of the ladder extends at least 3 feet above thetransmission ordistriluutionlineinstallation platform for a handhold to get on and off safely, and repair, must wear electrical worker's in- andisresting firmlyor thid to a support. sulatingsafetyhelmets orall-pu7pose protective helmets for which the proof-test voltage Use both hands for climbing. If you must carry is not less than 20,000 volts. The hat shown in tools, put then) in a br,g slung over your shoulder. figure 2-3 saved one man's life.\Vill use of Do notusemetalladderswhile working a similar one save yours? around hot lines or equipn)ent. Avoid contact with metal parts of wooden !adders. Despite the fact that most head injurie:, are Move theladder when necessary. Do not serious,thereare some workers whoseezii try to overreach. reluctant to wear hard hats. Everyone should take advantage of such valuable protection as INSTALLTION SA FET't thehard hat. Men give various reasons for refusingto wear these hats. Here are somc Be sure of overcur rent protection since proper of the common objections and reasons they (10 size wire and fuses may save a life or building.not hold true. YOu must also be sure that temporary wiring isinstalledassafelyas permanent wiring, Objection: TOO HEAVY Portable tools and machines must be grounded J'istification: I-Fird hats are a few ounces heavier for the protection of everybody. Be sure that than conventional headgear, but the extra pro- flexible cords are protected as much as pos- tectionis worth the extra weight. .ctually, a sible and are in good condition. hard hat is less than one-third the weight of an Army helmet and liner. P ERSONAL SA ETY Objection:T)0 HOT Horseplay can result in death. Justification:On a hot summer day with the temperature above 1000, it may not be as com- Be sure to ground &energized lines before fortable as you'd like, butitisstill30 performing work. cooler than inside an ordinary hat.

15 2 I CONSTRUCTION ELECTRICIAN 3 & 2

on the wearer's ears. Noises are not intensified by tile hat.

ELECTRICAL SAFETY REFERENCES

you must recognize that it is impossible to supply a complete list of electrical safety precautions in this manual. A number of invaluable references relating to safety are as follows: SAFETY PRECAUTIONS FOR SHORE AC- TIVITIES, NAVMAT P-5100. This reference book by Hcadquarters, Naval Material Command of the DEPARTMENT OF THE NAVY is an ex- cellentguidewhich disseminates safety precautions known to be instrumental in preventing accidentsandinmaintaining a safe working environment. Chapter 15 is devoted to electrical and.E:lectronicssafety. Ask your Chief Con- struction Electrician to let you look it over at bAtalion headquarters. He is sure to have it there. Knowledge of the contents of this chapter is a prerequisite for promotion to the s.mior levels. 26.203 NATIONAL ELECTRICAL CODE. Tiis book, Figure 2-3.Hard hat saves man's life. bytheNational Fire Protection AssJciation, Will use of a similar one save yours? ismodified and published every 3 years. It contains basic minimum provisions considered Objection: TOO COLD necessaryfor safety from electrical hazards of p-rsonnel and buildings. Requirements for Justification: Couldbe, butthe problemis electricconductors andelectricequipment solvedby wearinga winter liner. It'll keep utilized in a variety of areas are covered. Many head, neck, and oars warm without lessening Navy specifications are based on these minimum the protective value. requirements. Objection: CAUSES n EADA CH ES NAT:ONAL ELECTRICAL SAFETY ;ODE. This code is published by the U.S. Department Justification:There's no medical reason whyof Commerce's National Bureau of Standards PROPERLY DJUSTED hard hats would bring and should not be confused with the one de- thE;se complaints. More than likely there's an- scribed inthe preceding paragraph. Handbook otherreason s,ich as hunger, thirst or eye- H-30 is another title for this book. It discusses strain. methods of protective grounding of circuits, equipment, and lightning arresters for stations, Objc:r.:tion: W;)N'T STAY ON lines,andutilization equipment. Additionally, rules for installation, operation, and mainte- J!istification:Inahighwind,you'll:lead anance of electrical supply stations and equip- chinstrap on your hard hat. Normally, however, ment, and electrical and communication lines that hat will stay on despite a lot of stoopingare spelled out. Portions of this text have been and bending iou may do in your work. superseded byNational B ireauof Standards Hundbook H-43. Objection:MPLIFIES NOISE :NSTALLAT:ON AND MAINTENANCE OF Justification: N.A at all., In fact, tests show that ELECTRIC SUPPLY AND COMMUNICATIONS ploperly worn hard hats have a shielding i;ffect LINES SAFETY -,(ULES AND DISCUSSION. This

22 Chapter 2SAFETY publication, Handbook H-43, of the National Bu-exposed electrical equipment, do not wear any reau of Standards has superseded portions ofclothing with exposed zippers, buttons, or other the National Electrical Safety Coue related metal fasteners, or loose or flapping clothing. the installation and maintenance of electric sup- Take no chances; dress appropriately.Obviously, ply and communication lines. Much engineering flammable a licles, such as celluloid cap visors, dataincludedinthistext is useful to Con- should not be worn. P.ersonnel should remove struction Electricians. rings, wristwatches, bracelets, and other similar metal items before performing work on or SAFETY RULES FOR THE INSTALLATION within 4 feet)f electrical equipment with ex- AND MAINTENANCE OF ELECTRIC SUPPLY posed current-carrying parts. AND COMMUNICATION LINES. National Bu- reau of Standards HEndbook 81 supersedes parts en performing line construction and mainte- of the above listed nandbooks. It is imperative nance work should wear high-cut shoes with that you use the latest rules ano regulations insewed soles for work on live electrical circuits your work to minimize safety h :ds. above 50 volts. Thin-soled shoes and shoes with metal plates or hobnails are prohibited. Safety ELECTRIC SHOCK, ITS CAUSES AND PRE- shoes with nonconductive soles should be worn, VENTION. This 37page text, NAVSHIPS 250- if available. 660-42,containsvitalinformation extremely valuable to all personnel who use electric ap- Keepall insulating and protective devices pliances or who work al'ound electrical equip- storedflat, and free of oils, chemicals, and ment.Itdescribes avarietyof cause3 andother materials. preventions for shock. It is normally avullati::: in the battalion office or the library of thP base Air-test rubber gloves daily before starting to which you are attached. Be sure to read thiswork on live conductors or equipment. Testing manual sincecomplete understanding the is done by grasping the cuff of the rubber glove information presented may save your life. at opposite points and twirling (fig. 2-4). While the end is closed with one hand so the air cannot CLEANING escape, squeeze the glove to force air into thumb, fingers, and palm. Hold the glove to your ear to Electricalaneelectronic equipment mustlisten for escaping air, making a thorough visual be kept clean at ail times to ensure proper per- inspection for holes and thin spots, or hold the formance. Brushes, dusters, brooms, or other glove under water and check for air bubbles. If such articles which may be used within 4 feetit is defective, tag it and turn it in for replace- of or on electrical equipment having exposedment. or current-carrying parts should not themselves contain any exposed metal parts. Lf a vacuunl When cutting holes in masonry material, or cleaneris necessary, use only with anon- performing grinding or drilling operations, wear metallic hose and an adequate dust receiver. safety goggles. Use only rubber or insulating hose in air lines for blowing out equipment. Use no more Wear a hard hatespecially when working than 10 pounds of pressure to avoid damage tounder other workers or in close quarters. the insulation and injury to personnel. Be sure the airis free from water. Never turn com- Body belts and safety straps should be in- pressed airon yourself or others, sinceit spected before each use. can cause serious injury. Use sandpaper and files only upon competent BG sure that gaffs on climbers are properly advice. Emery paper should never be used onsharpened. When gaffs are shorter than 1-1/4 electrical equipment because of the conductive inch, replace them. residue remaining after use. Do not put rubber gloves or other rubber SAFETY EQUIPMENT protective equipment in containers with tools. Do not work on electrical apparatus with No work should ever be done on live con- wet hands or while wearing any wet clothing.ductors of any voltage except in case of emer- When performing work on or within 4 feet ofgency. If the work requires that one hand be

2 3 CONSTRUCTION ELECTRICIAN 3 & 2 freeofcovering,arubberglove should be Rubbev Gloves 30 days worn on the other. Personnel intending to work Rubber Blankets 90 days onlivecircuits,or on eruipment containing Rubber line hoses .3xposed current-carrying parts where the volt- and :r.00ds 180 days ageisgreaterthan 30volts, should put on rubbergloves before.:.,orning within reach of Inaddition,before each use, they should the live parts, and should not remove the gloves be checked by the user for punctures, tears, until entirely clear of such equipment. Rubber or abrasions. Gloves should be air-tested. If gloves should not be used for any purpose except there is evidence of any leakage or thin spots, live-line electrical work. the gloves should not be used. Electrical tests, testing equipment, and method of marking should Leather protectors should a'ways dorn be in accordance with current American Society over rubber gloves and should not be used for forTesting and Materials (AST VI)standards. any purpose other than with rubber gloves. Each,,love or other piece of rubber protective equiiHent should be marked with the last date Rubbersleevesorrubber glovesshould tested. Items failing to pass the test should never be rolled down or worn inside out. Under bereplaced. Tests should be made by naval no circumstances should two pairs of rubber activities having the necessary equipment, by gloves be used. reputable eleztrical testing laboratories, or by local power companies which may have testing Pe:r sonnel should wear rubber gloves when equipment and are willing to perform thr) tests. cuttingasuppos.idlydead cable,ortesting supposedly dead cable, or testing supposedly All rubber protective equipment should be burned-out transfor mers. given a thorough visual inspection and electrical test whenever the last test was made more than 6 months prior to issue or ch-.1livery for actual TEST:NG RUBBER PROTECTIVE useof personnel. Equipment maintained in a EQUIPMENT standbystatus for emergency use only may be considered to be in the same category. If -tubberglovc,-, and other rubber protectiveit has been used more than 6 weeks, but less equipmentbl,caId be laboratory tested at in- than6 months, after the last test,it should tervalsno'tr,.-;xceedthe following when in again be tested before being returned to standby regular use except as described later: status or placed in regular use.

Figure 2-1. Testing rubber gloves. 73.274

18 2 4 Chapter 2 SAE' ET t"

INSULATING FLOOR COVERING One source of dtmger that often is neglected or ignored is the use of handtools which are no longerconsidered serviceable. Toolshaving On all circuits where the voltage is in excess plasticor wooden handles that are cracked, of 30 volts, the men should be insulated from chipped,splintered, or broken rray result in accidentalgrounding by use of approved in- injuriestopersonnel fromcuts, bruises o.. sulating material on the floor at operating and particlesstrikingthe eye. Such tools should working locations. The niaterial must hay:: the be condemned, replaced, or if at all following qualities: repaired, before they cause accidents. It should be dry, without holes, and must not Another source of danger tha'Aten is neg- contain conducting materials. The voltage ratinglected or ignored is the unsafe work practice for wh;ch it is made should be clearly markedof covering the metal handle of a tool with a on the material, and the proper material must layer of friction tape, or with a cambric sleeving, be used so that optimum protection from the to form an improvised insulated tooL This prac- voltage can be supplied. ticedoes notaffordan adequateinsulating barriertoprotect personnel from dangerous On voltage below 600 volts, dry wood may be voltages;therefore, steps should be taken to used, or, as an alternative, at least two layersensure that this unsafe practice is not permitted. of dry canvas, sheets of phenolic material, or rubber mats. Where other than approved rubber In an emergency, when itis neces- ary to mats are used, the marking provision of the improviseaninsulating barrier between the paragraph above does not apply; however, care toolandtheindividual'shand,anapproved must be taken to ensure that .,ubstitute n.erial method isfirst to apply several layers of ap- is capable cf providing the required insulation proved rubber insulating tape (half lapped), or value. insulating tubing removed from scraps of electrical cable, to the metal surface areas to be On circuits above 600 volts, norconductingcovered. Then apply a layer or two of friction rubber matting of an approved type'Iould be tapeovertheinsulating materiaL Inthis used. manner, an adequate insulating barrier is provided and the possibility of accidental contact Exercise care to ensure that moisture, dust, with a lethal voltage is min:.mized. metal chips, and so on, which may collect on insulating materials are removed at once. Small As a general precaution, be sure that all deposits of such materials can hecome hazardous. tools conformto Navy standardsofquality and type. Use each tool only for the purpose for whichitis intended. All tools in active PLAT]. ORMS use should be maintained in good repair and all damagod or nonworking tools should be returned to the toolkeeper. Do not leave tools on flpors, Whenever it is necessary to work on elec-platforms, ladders, or on shelves above moving tricalcircuits or equipment in wet or damp machinery. Keep tools and hands free of grease, locations, dry wooden (or similar nonconducting and clean tools with an approved solvent. Tools material) platforms should be provided so that and other materials should not be thrown or there will be no possibility of contact between dropped down to personnel working on another the wet floor and the workmen's shoes. leveL They are to be raised or lowered by means ofhandlines or canvastoolbagsor buckets. Men should stand clear when tools and TOOLS other materials are being raised or lowered. Care must be taken when selecting pliers, Shop machinery and handtools are frequeatly sidecutters,ordiagonalcutters. Pliers or overlooked sources of danger to personnel. Be- cutters should never be used on nuts or pipe- cause of their familiarity and use in everyday fittings. Teach your men to always holdthc applications, we lose sight of their potentialpliers or cutters so that the fingers are not danger. Let's examine them. wrapped around the handle in such a way that

19 2 5 CONST UCTION EL ECTItICL1N 3 & 2 they can be pinched or jammed if the tool slips. Never carry a loaded tool away from the When cutting short pieces, t3ke care that parts immediate jobsite. B..; sure Ihe tool is unloaded of the work do not fly and cause injury. NEVER when not in use, Unload the tool if your work is PUT EXTEN::IONS ONFOOL HANDLES To interrupted after -loading. INCREASE LEVERAGE. Be sure the tool is held perpendicular to the Whin selecting a screwciriver for electrical work surface, work, be sure that it has a nonconducting handle. Usetheright guard for the job. Special T'ie screwdriver selected shouldb.? of the proper size to fit the screw and shoull" be guards are used where recommended, used as a substitute for a punch or a uh The Neverattempttodrive a stud through a blades of screwdrivers can be kel,t,ill proper prodrilled or prepunched hole in fixtures or shape with a file or a grinding wheel, material withcut a special guard designed for Use wrencheonly if they are right for the this type of operation. job and onlyifthey Ire in good condition. An adjustable wrench should bef:-.ned so that the In case of misfire or failure to fire, do not movable jaw is located forwaru n tile direction remove the tool from the working surface for at in which the handle is to be turned. least15seconds, Open thetool and remove the powder charge BETORE removing the guard Remembertouse goggleswheneverthe from the ..iork surface. danger of flying debris exists or in any grinding operation. Never attempt to drive studs into very hard Grease must be handled carefully and usedor brittle materials, including but not limited only for the purpose intended, Serious injury to cast iron, glazed tile, surface hardened steel, has resulted when grease has been shot out ofglass block, thin slate, live rock, face brick, or a grease gun in horseplay; NEVER point the gun hollow tile. toward another person. When anchoring fixtures or any structural material. toaconcrete, steel or other sub- Powder-actuated Tools surfaco suitable for stud driving, be sure there Powder-actuated tools should be operated,is no void or air space between the fixtures or repaired, serviced, and handled only by personnel structural material and subsurface. When work- who have been trained and certified by the manu- ing on precast concrete block, be sure to drive facturer, his authorized representative, or Navy studs so they penetrate a wall between the cells. Department certified instructors. In applinations Lower holding power will result if studs are to concrete, approval for use of the tool ,uld driven at hollow cell locations. be given only after it, has been ascertained that itwill give satisfactory results and cause no Never attempt to drive a stud closer to the spalling or shelling out. edge of structural materials than the distance recommended by the manufacturer. As the opzirator of a powder-actualed tool, Never use the tool in material or surfaces observe the following safety precautions; which may be completely penetrated by the stud. Do not operate in an explosive or inflam- mable atmesph...:re, or in an area where non- The tool operator, together with other per- spar':ing tools are required. s:Innel in the vicinity, should wear safety goggles or other approved safety-type face and eye pro- Whether loaded or unloaded, never point the tective devices and a hard hat. tool at yourself or other persons; 'Keep it pointed in a safe direction. CAUTION; The powder-actuated tool uses powder-loaded cartridges in its operation. Check Before starting a day's work, check the bore first when handling to determine 't is loaded. of the barrel to be sure it is free of any obstruction. Failure to clean the bore may damage the Soldering barrel beyond repair. Never clear the bore by firing a powder charge. Use a piece of wire or One sizzling burn experience isusually enough rod. to breed a healthy rospect for not objects. Many

26 Chapter 2 ofthe;eeNpc:1'1211ctit, OCC,11' during welding op- 511(11, \CIIINERY eration:;:Hid the used such itty!Is soldering irons,lead pots, torches, nithe tixtures In your work as a Construction 1.:lectrician, ut- brace, clamp, or hold thew,l'o avoid ouIn aylierequiredto use shop machinery the ; skotscalding or charring your flesh, such as apow,,:r grinder ora drill press. ln don't liave t ltcn material or heated objects addition tothe general precautions on the use unatb:nded. D splay HUT 11ZA RD signs if you oftools, there are several other pcecautions mustleave; and return as soon as possible. which should Icobserved when y..)ti work with I. se tongs, hooks, or other protective devices to machineryOr assign men to operateit. The handle hot pots and piecJs ot stock. If there is nio:e I wportant Ones arL: any chance k.11spatter Iron) ho: fly ing particles, be sure to ',it Never upirate mechanical or powered equipment unless you are thoroughly far'iliar with itscontrols. When in doubt,con;..it the ap- Soldering Irons propriate instructions or ask someone who knows. Always make sure that everyone is clear When using aHoldering iron, bear in mind b,:fore starting or operating mechanical equip- the folowing; ment, Electricsolderingirons must not remain Never tly to clear jammed machinery with- connected longer than necessary and must be out first cuttins; off the source of power. 'kept away from flammable material. Wlen hoisting heavy machinery (or equipment) To avoid burns, always assume that a soldering by a chain fall,always keep everyone clear, iron that is plugged in is hot. and guide the hoist with linos attached to the equipnient, Never rest a heated iron anywhere but on a metal surface or rack provided for this purpose. Never dlug in portable electric machinery Carelessness on your part could result in fire, without that the source is the kind of extensive equipn:ent damage, and serious electricity (a-c or d-c) called for or th_ name- injuries. plate of the machine. Never swing an iron to r,move solder be- Drillsmust bestraight,u.tdarna,f3d,art causethebitsof s-Ader that come off may pr.-iperly sharpened. Tighten the secureiy cause serious skin or eye burns or ignite com- inthechu7k uy.ingthekey provided; never bustible materials in the Aork area. secureit with pliers or with a wrench. It is importantthatthedrillbe set straight and When clearnng an iron, use a cleaning cloth, true inthe chuck. The work should be firmly but DO NOT hold the cloth in your hand. Always clamped and, if of metal, a center punch should place the cloth on a suitable surface and wipebe used to score the material before drilling theironacrossittopreventburning your is started. hand. Be sure that power cords do not come in Hold small soldering jobs with your plierscontact with sharp objects. T le cords should or a suitable (gawping device. Never hold the not be allowed to kink, nor should they be allowed werk in your hand. to come in contact with oil, gr.Dase, hot surfaces, or chemicals. When cords are damaged, they Itis not so obvious, but the power supply should be replaced instead of being 1:it-Ached with strpuld always be disconnected from The equip- tape. ment needing to be worked on, to prevent serious burns front contact with high voltages. USE OF WARNING SIGNS, After completing the ta:-..k requiring the use PLATES, AN.D TAGS of a soldering iron, disconnect the power cord fromthereceptacleand, when theiron has Miming signs and suitable guarkis should be cooled off, stow itin its assigned storage area. provided to prevent personnel from coming into

21 27 CuN.STRUCT1ON ELECTRICIAN 3 & 2

ee Ital contactall dangerous voltages, to w,Arnp,:rsonnel thepossibkpresence of explosivevapors,to warn personnel working aloft of poisonous eifects of stack gases, and to warn of other dangers which way cause injuries tod,:rsonnel. Equipment installation should not beconsideredcoiirñet I ntilassurancehas been made that appropriate warning signs have IN:en posted in full view of operating personnel. PERSONNEL ARE CAUTIONED TO GUARD AGAINST POISONOUS EFFECTS OF SMOKE PIPE Certain types of staadard electronics warn- GASES WHILE SERVICING EOUIPMENT ALOFT. ingsignsareavailableforprocurement. WHEN SERVICING EOUIPMENT INTHE WAY list of signs that are available has been dis- OF SMOKE PIPE GASES USE OXYGEN BREATHING tributedtoallships, commands, and shore APPARATUS AND A TELEPHONE CHEST OR activities. Any warning signs not listed should THROAT MICROPHONE SET FOR COMMUNICATION be ordered on a separate requesting document. WITH OTHERS IN WORKING PARTY. OBTAIN NECESSARY EOUIPMENT BEFORE Drawings of the standard warning signs most 0 GOING ALOFT. frequently used have been prepared by the Naval Ship System3C onnuand.

High Voltage Warning S4a, N VSHIPSDraw- 40.67 ing N. RE B GOSH (fig. 2-5) is to be displayed Figure 2-6. Smoke pipe gases warning sign. atalllocations wh:re danger topersonnel exists, either through direct contact with high Warning signs should be temporarily dis- voltage or through high voltage arc over. Ap-played where explosive vapors are present in propriateguardsshouldalso be installed atany compartment or space. No electrical or these locations. electronic equipment or auxiliary control units should be energized with areas where these Warning Sign for Personnel Working Aloftsigns are posted. Explosive Vapors (RE 10 A in Way of Smoke Pipe Gases, NAVSHIPS U .v- 589A) is such a sign. ing No. RE 10 AA 529A is tO be displayed al the bottom and top of access ladders to elec- Warning tags requiring open-circuit condition tronic and electrical equipment in the way of should be placed on all necessary power supply smoke pipe gases (fig. 2-6). switchestoprevent accidental application of power to units of an electrical or electronic system that are under repair or overhaul. Warning tags, NAV%iIPS 3950(3-63),for marking open position of switches and cutout circuits (fig. 2-7), are used to indicate switches which must be left in the OFF or OPEN (safe) position during repairs. These tags are available for ship ti.nd shore personnel through normal supply channels. Appropriate warning signs shouldbe displayed in electrical, aviation, electronic, and special weapons shops. Danger or warning signs should be permanently posted in conspicuous places and suitable guards should be installed inappropriate areas to personnel from making ac- cidentalco....b.ct with antennas, antenna leads, power supply leads or terminals, fuses, or any uncovered contacts that have sufficient voltage 40.67 and current characteristics to constitute a haz- Figure 2-3.High voltage warning sign. ard to personnel. (See figs. 2-5 and 2-6.)

22 28' Chapter 2SAFETY

A July1,1968 amendment to the s7ec- ificationsfor electricalarid electronic wcrk- benches makes it mandatory to have a 1-foot ground leadforevery4 feet of workbench. The grounding conductor should have a ( rOss COLOR: BLACK OVER RED sectional area at least equal to, and preferably OVERPRINT greater than, the cross sectional area of the line conductors which carry power to the equipment. The grounding conductor should make positive metal-to-metal, low resistance contact with the equipment at one end and at the other end with the metal object used as a ground, the hull of the ship in shipboard installations, and the ground rods, water pipes or installed grounding object in shore installations. The resistance between k)410° the earth and the metal object used ab ground should not exceed 3 ohms. SkkOM Grounding shcald be checked at regular intervals after repair work has bee.a performed, CHANGE and be in accordance with the National Electric DO Code. Never open ground connections at ground ?os1110tA pipe or at grot:nd bus bars unless they first $1110 have been disconnected at the point of contact with the equipment they are intended to ground. This prevents an accident if the ground wire 0*-13IOf or bus bar should become energized. Whenever DIRECI\01 a ground wire on a pole is to be connected, im.ke the ground pipe connection first. ooktE

5950 0-651 N1,45OPS DANGE:!. FROM METAL OBJECTS G "a

Personnel should exercise care when it is necessary to walk above open electrical equip- 40.67 ment or exposed wires to ensure against drop- Figure 2-7. Warning tag. ping orlossof metallic objects attached to clothing. GROUNDING Tools of magnetic material can be pulled into Metal cases, bases, frames, and other metal contact with dangerous circuits when these tools parts of electrical equipment,appliances, ma- are used in the vicinity of electrical circuitry. chines, and fixtures powered from supply circuits Care must be taken to avoid this hazard. in excess of30volts a-c or d-c should he grounded. Where inherent grounding is not provided by the mounting arrangements, groan:: INTERLOCKS AND SAFETY DEVIC ES connections should be provided to ground the frame, enclosure,or support of permanently installed electrical equipment. Semiportable Safety devices such as interlocks, overloas: equipment which is normally used at fixed lo-relays, and fusesshould not bealtered or cation shouldalsobe grounded.Portable disconnected except for replacement, nor should electrical equipment inconductive housings safeguard circuits be modified without specific should have adequate grounding. authority.

23 29 CONSTRUCTION ELECTRICIAN 3 & 2

PAINTING ELECTRICAL EQUIPMENT NEW INSTALLATTONS New installations should comply with appli- Specialprecautionsarc necessarywhen cablerules andregulationsintheNational removing paint or repainting electrical equip- E.ectric Code. For example, electric light pull ment.In general, the removal of paint from chainsand keyedmetalsockets must be of olectrical equipment shouldbeavoided. The use of scraping or chipping tools on such equip- the insulated type. n-ient is liable to injure the insulation or damage delicate parts. Furthermore, paint dust is composed of abrasive and semiconducting materials ELECTRICAL SAFETY PRECAUTIONS which impair the insulation. All electrical equip- The safe working practices discussed so ment, such as generators, switchboards, motors,far in this chapter are applicable not only to controllers, and so on, should be covered tothe electrician, but to anyone working in the prevent entrance of the pLint dust when paintconstruction field. In addition to these general isbeing scraped in the vicinity. After com-safety precautions, there are safety rules that pletion:)fthepaint removal,theelectrical aprily specifically to electrical equipment. Here equipment should be thoroughly cleaned, pre- are some safety suggestions to follow when you ferablywitha vacuum cleaner, ifavailable. are working on electrical tools and appliances and energized circuits. Repaintingofelectrical equipment should be done only when necessary to prevent ineipient corrosion. The painting shoAd then be confined PORTABLE EQUIPMENT tothearea affected.General repainting of Portable electrical cables should be care- electrical equipment or enclosures for electrical fully selected and maintained. Spliced portable equipment for the sole purpose of improving cablesare extremely dangerous andshould their appearance is not desirable. Paint should never be used unless an emergency warrants never be applied to any insulating surfaces in the great risk involved. Portable cables should electrical equipment. Common sense tells you beofsufficientlength that they will not be not to paint over identification plates. subjectedto longitudinal stresses or need to be pulled taut to make connections. Current- carryng capacity should be ample for all expected power demand. Portable cables should PROTECTION OF NONELECTRICAL be cheked frequentlywhileinserviceto WORKERS ascertain degree of heating. Any cable which feels more than comfortably warm to th e. bare hand placed outsidethe insulation should be An insulating barriershould be provided checked immediately for overloadlng.Inter- between the work area and any live electrical connections between lengths of portable cable parts;orthe circuits should be deenergizedshould be made only on approved connection Wiere work is being performed within 4 feetblocks orby approved fittings which should from the exposed pa.'ts of electrical or elec- be suitably insulated and enclosed to eliminate tronic equipment by painters, carpenters, or allpossible hazards fromfireor shock to other trades, regardless of the voltage. In allpersonnel. such cases, the supervisors of the nonelectrical workers should report the loeation of the work to the Construction Electrician in eharge. The ConstcuctionElectrician should instructthe PORTABLE POWER TOOLS supervisors of nonelectrical workers regarding proper precautions against electrical hazards, The hazards associated with the useof and provide properinsulating barriers, or portable power tools are similar to stationary proviuefordeeriergizingandlockingout of machines and include electrical shock, bruises, circuits where possible. The supervisor of the cuts,particlesinthe eye, falls, explosions, nonelectrical workers is responsible fo.' carry-fires, and so on. Safe practice in the use of ing out precautionary instructions given by the thesetools will reduceoreliminatesuch Construction Electrician in charge. accidents. 3°24 Chapter 2SAFETY

All portable power tools should be inspected equipment. If the insulation resistance is several beforeuse, tosee that they are clean, well megohms orless,the equipment should be oiled, and in the proper state of repair. The provided with a grounded plug and suitable cord, switches should operate normally, and the cords thegrounding conductorofthecordbeing should be clean and free of defects. Tie metal connectedtothechassis and exposed metal case of any electrically driven power tool shouldparts of the equipment at one end and to the be well grounded. Sparking electric tools should ground contact of the plug at..ne,other end. never be used in places where flammable gases This arrangement will ground th' chassis and or liquids or exposed explosives are present. exposed metal parts of the equipment, but will The power should always be disconnected before not ground the power supply. accessories ona portable tool are changed. b) If the equipment does not have a power Inspect the cord and plug for proper con- transformer which isolatesthe primary and nection. Do not use any tool that has a frayed secondary sides as described above, an isolation cord or broken or damaged plug. Always connect transformer must be installed to perform this the cord of a portable power tool into the exten- function. A grounded plug and suitable cord sion cord before the extension cord is inserted should be used with the grounding conductor into a live receptacle. Always unplug the exten- of the cord connected to the chassis and the sion cord from the receptacle before the cordpower conductors of the cord connected to the of the portable power tool is unplugged from the primary of the isolation transformer. extension cord. Seethat allcablesare positionedsothattheywillnotconstitute T ie molded housing on an electric shaver tripping hazards. Wear eye protection when isa nonconducting plastic material, and the working where particles may strike the eyes. cutting blades are isolated from any contact withtheelectricalcomponentswithinthe After completing the task requiring the use shaver. For this reason, 3-prong groundingplugs of a portable power tool, disconnect the power are not required on electric shavers. For safe cord as described above, and stow the tool inuse, your electric shaver should have a com- its assigned location. pletelyinsulated housing and isolated cutting blades, and the housing and cord must be free of cracks. If there is any doubt as to whether PORTABLE PERSONAL EQUIPMENT an electricshaver complies with the above, have it checked by the electric shop. If an elec- Personal radios, televisionsets,record tric shaver falls into a washbowl of water, LET players,and wire ortape recorders having IT GO. Unplug the cord before you remove it metal cases or metal back or bottom are .afrom the water and be sure to take it to the safety hazard in many cases. In much of this electricshop forinspection before using it typeof equipment, the chassis forms a part again. ofthecircuitand theexposed metal parts are energized, thereby creating the danger of Personally owned or non-Navy standard elec- shock to personnel touching them. tric lights, fans, and tools could be a shock hazard because of inferior insulation, leakage The above equipment must have the safetycurrents,and flimsystructure. Periodic in- officer's approval and must satisfy one of the spections should be made to eliminate defective following conditions to be permitted on the base: appliances from the station. a) The equipment has abuilt-inpower Personnel are allowed to own hobby equip- transformer which completely isolates the pri- ment if the following stipulations are met: mary or line side of the transformer from the secondary or equipment side. The isolation of a) Portable, electrically operated hobby de- the primary and secondary sides of the trans- vicesshould be inspected and tested by the former must never be inferred merely from theelectrical crew. Equipment which passes this presence of the power transformer, but must be ins7ectionshould be taggedassafe,giving checked by measuring the insulation resistance the date of inspection. This equipment should from each lineterminal of the transformerbe frequently reinspected, at least once each to the chassis and exposed metal parts of the 6 months.

25 31 CONSTRUCT-,ON ELECTRICIAN 3 Sz2

b)If the hobby tool is damaged or is ob-to placing the machine in motion when machines viously defective, thatis,if molded housings, are equipped with a grol.Inded wire. cords, or plugs contain cracks or breaks, or if the cord insulation breaks when sharply bent, REPL.-,c EMENT OF FUSES the tool must not be used until repaired and reinspected by the electrical crew. Wnene ,-erpractical, a circuitshouldbe checked out before replacing a burned-out fuse. No personal electrical equipment, such as Tile trouble is usually indicative of a circuit radios, television sets, record players, wire or fault.Sincefuses aresafetydevices,they taperecorders, or other personal appliances should be used as such. A olown fuse should be aslistedabove,shouldbe used without the replaced by a fuse of the same rated voltage and safety officer's tag of approval. Periodic in- ampere capacity. Where removo....e fuse links spe,-tion should be made to enforce this vital are used, only one link of the correct rating is sdety regulation. to be used for each fuse. Insertion of rietal discsorcoinsin the back of plug fuses or One station has been eminently successful the shorting out of cartridge fuses IS ST-RICTLY in enforcing the above regulations by requiring PROHIBITM. the approval signature of someone in authority at the electrical shop attached to each piece of Wi-len it is necessary to remove a fuse, the portable equipment. Tnis signature is on a piece operating switch should be opened to remove the of colored Scotch tape. The color is then changed load, and the fuse extracted with an insulated at required intervals. The results are obvious.fuse puller except where, as is usually the case Can you use this idea at your base? or. switchboards, the fuses are mounted in plug type fuse holders. These fuses are removed by unscrewing the plugs. OFFIC E MACHINES Only fuses of 10-ampere rated capacity or Sufficientattention is not always given to less should be removed from or replaced in the dangers of low voltage electricity in offices. energizedcircuitsand onlyif an emergency In general, all electrical installation in offices exists. should be made in compliance with the rules and regulations contained in the National Electric Fuses larger than 10-ampere rated capacity Code. Among the more common electrical haz- should be removed or replaced only when the ards found in offices are: (1) office machines, circuitiscompletelydeenergized. After the lighting fixtures, and appliances not properly replacement, thecircuit should be energized grounded; (2)defective electric cords, lighting only when the cover over the fuses is closed. fixtures, appliances, and switches; (3) inauthor-Neglect of this precaution has led to injuries ized and improperly supervised electrical con- caused by explosion of a fuse when the circuit nections and repairs; and (4) loose outlet plateswas energized. which may result in short circuits and cause shocks through contact with them. WI,en removing transformerfuses,wear rubbergloves with leather overgloves. This Bofore using office machines, be sure they applies also to fuses which are being replaced are properly located and not in danger of falling by means of switch sticks equipped with fuse while in use. Never clean, oil, or adjust elec- tongs or by means of regular fuse tongs, where trical appliances when they are in operation. the circuit voltage exceeds 150 volts but is less When cleaning appliances which are controlled than 5,000 volts. by a switch on the machine, be sure the switch isturned off and the plug pulled. Protection LOCK CIRGUIT BREAKER HANDLES should be provided against moving parts on AND TAG CIRCUITS addressograph, mimeograph, bookkeeping tab- ulating machines,and other types of power- Work should not be done on any energized driven machines. circuit, switchboard, controller, or other piece of electrical equipment unless the urgency of Bo surethatallelectrical equipment isthe work, together with the vital importance of grounded. Ground wires must be connected priorthe equipment concerned, dictates its necessity.

32 Chapter 2SAFETY

FSN 9N5925-360-3984 FSN H5930669-7524 FSN H5930-669-7572 A/

DA,Ni1GER AQB-A250, AQB-LF250 AQB-A100, AQB-A101 AQB-A400,AQB-AT400aAQB- LF 400 WARNING TAG NAVSHIPS aAQB-LF100 3950 (3-63) TO BE APPLIED BY REPAIR PARTY TO LOCK CIRCUIT BREAKERS IN "OFF AQB -ASO POSITION DURING REPAIRS ON CIR- CUITS SUPPLIED BY CIRCUIT BREAKER

20.204 Figure2-8. Handle locking devices for circuit breakers. Circuits to be overhauled or repaired shouldthe fuses,provided the contactor is deener- be deenergized by opening all switches through gized first. whichthe power could be supplied, and the Metal locking devices are available that can circuitshould be tested with a voltmeter or beattached to the switch handles to prevent voltage tester. Tlese switches should be tagged: accidental operation. Tiese locking devices can "DANGER SHOCK 111,ZARD.Do notchange be obtained through the Ships Parts Segment of position of switch except by direction of the Navy Supply System. (See fig. 2-8.) All breaker handles are now provided with NAME. . .RATE/RANK." a 3/32-inch hole permitting fastening the locking device with a standard cotter pin. On earlier Warning Tg NAVSHIPS 3950 (3-63), may be breakers, it may be necessary to drill a 3/32- used for this purpose. In case more than one inch hole in the handle, using the locking device repair party is engaged in repair work on an as a drilling guide. The warning tags can be electrical circuit, a tag for each party should attached in the eye of the cotter pin. be placed on the supply switches. After the work has been completed, each party should remove When checking to see whether circuits are its own tag but no other. Loads supplied from deenergized, MAKE SURE YOU CHECK METER- the controller in group control centers should ING AND CONTROL CIRCUITS AS WELL AS not be worked on until the associated circuit POWER CIRCUITS. In many cases metering and breaker is open. If the group controller has controlcircuits are connected to the supply fuses in place of a circuit breaker, the loadside of a circuit breaker. A check of power isolation may be accomplished by removingcircuits on the load side of a circuit breaker

27 CONSTRUCTION ELECTRICIAN 3 & 2 may show that they are dead after the circuit incontact with a live part, thereby causing a breaker is opened, but such a check gives noshort circuit, an arc, or injury to personnel. assuratwe whatsoever that associated metering and control circuits are dead. They may or may Great careshould be exercised to avoid not be, and MUST be checked to make sure. contact with any live parts of the switchboards. Many deaths havr3 been caused by personnel in SWITCH t toAlWS the rear of the switchboards being thrown against live bus bars or terminals. Rear-service switch- Energized switchboards are a big source ofboards are raquired to have an expanded metal danger, Nc work should be undertaken on switch- enclosure with a door, enclosing all means of boards (energized or deenergized) without first access to the rear of the switchboard. Battens obtaining the approval of the safety officer. Tae must be kept in place. The door should be kept commanding officer'sapproval must also be locked.Inthecase of front-service switch- obtained prior to the commencement of work boards,hinged panelsshould not be opened on an energized switchboard. except in an emergency and not until the entire Grab rods and guardrails around switch- switchboard is completely deenergized. boards and other equipment should always be All structural parts, bases, frames, and all inposition whenthe equipment is energized unless emergency repairs are necessary whileother metal parts of a switchboard which are equipment is in service. Grab rods and guard- not intended to operate above ground potential rails should be carefully maintained to ensure should be grounded. Care must be taken to that they are secure and will not accidentally removeallpaintanddirt from around the be dislodged, The insulating mattings provided mounting boltsto ensure a positive electric grounding connection. WY:ere suchinherent for covering the deck in the front and rear ofgrounding is not provided, as in the case of switchboards should always be in place. some switchboards in which shock mounts are When maintenance work is performed on a used, ground connections must be provided. circuit, care must be exercised to ensure that Ifstructural and other metal parts arenot the circuit remains dead and is not energized grounded, a breakdown of insulation may raise by the closing of a remote circuit breaker. Allthem to fullline voltage and create a hazard. circuit breakers or switches which could energize the circuit, if closed, should be locked open BATTERY CHARGING byattachingastandard locking clip tothe breaker handle with a cotter pin. Tae locked circuit breaker should then be marked with a When engaged in electrolyte handling, mixing, warning tag. The lock and tag pre not tobe or filling operations, personnel should wear face removed until the work is complete. Even though shields and chemically resistant gloves,footwear all circuit breakers to and from a switchboardand aprons. To protect the eyes from burning are open,itis still possible for voltage to be caused by splashing, goggles should be worn. presentintheswitchboard throughcontrol Deluge showers and eyewash fountains should circuits,Switchboard system drawings shouldbe providedin the immediate vicinityofall he examined to determine if voltage could be batterymaintenanceand electrolyte handling present under such circumstances. A note of operations. If an emergency occurs, quick use the requirement for additional protective steps ofthese facilities may save a man's vision. should be added to the standard procedures for maintaining or troubleshooting in such switch- Water should NEVER I,%e poured directly h:ards. intobatteryacid. Theacid must always be poured SLOWLY into the water to prevent ex- \,,.:,ere removable covers (plates or grilles) cessive heating, and CAUTiOUSLY t'o prevent are provided on switchgear units, great caresplashing. The strong acid will cause painful should be used in removal when equipment is burns. The solution should be stirredcontinuously energized. For example, unless care is ex-to prevent the heavier acid from flowing to the ercised, a large grille cover on the rear of a bottem of the tank without mixing. switchboard section may tipinat thcta7- bottom alter reincwal of some of the tz,ure to open the switch prior to removing or while it is being lifted off. This may . unections from the batteries while they are

3 4 Chapter 2SAFETY being charged, since an inadvertent spark maydone permits, rubber gloves should be worn on cause an explosion of any escaping hydrogen. both hands. For the same reason, never smoke in this area, Have men stationed by circuit breakers or and besureto provide adequate ventilation. switches, and telephone manned if necessary, so that the circuit or switchboard can be de- IfIGULED CIRCUITS OR EQUIPMENT energized immediately in case of emergency. -tepairs are notto be made on energized A man qualifiedinmouth-to-mouthre- circuits except in an emergency. T le command- suscitationand cardiac massage for electric ingofficerorhisauthorized representative shock should be immediately available while determines whetheran emergency exists. the work is being done. When military considerations require that electrical repair or maintenance work be performed, Make sure that the connections of removable but prohibit deenergizing the circuits involved, test leads on portable meters are tight. The free extreme measures of precaution must be used. endofan energized testlead which comes The work shouldheaccomplished only by adrift from its meter during a check of live adequately supervised personnel fully cognizantcircuits is a shock and fire hazard. of the dangers involved. Every care should be taken to insulate the person performing the work Checking the Circuit from ground andto use all practical safety When acircuit below 600 volts isto be measures, isle following precautions should bechecked, the voltmeter or voltage tester should taken when applicable: first be tested on a circuit known to be operating in order to determine if the testing device is in Provide ample illumination. good condition. When voltages of 600 volts or The person doing the work should not wear more are to be measured, the following pre- wristwatch, rings, watch chain, metal articles, cautions are to be observed: or loose clothing which might make accidental contact withliveparts, or which might ac- (1) D...energize the equipment to be tested. cidentally catch and throw some part of his body (2) High voltage caparAtors and the terminals into contact with live parts. Clothing and shoes to which the test equipment is to be connected should be as dry as possible. should bedischargedatleast twice, with a minimum 15-second interval, by the use of a Insulate the worker from ground by means suitableinsulatedshorting or grounding bar. ofinsulating material covering any adjacent grounded metal with which he might come in (3) Attach a temporary, but secure, ground contact. Suitable insulating materials are dry to the circuit. wood, rubber mats, dry canvas, dry phenolic material, or even heavy dry paper in several (4) Ascertain that the test equipment controls thicknesses. Bo sure that any such insulating are set correctly for testing of the high voltages. materialisdry,hasno holes init,and no conducting materials embeddedinit.Cover (5) Connect to the desired test points the test sufficientareassothatadequate latitude is leads capable of safely carryingthe high voltages. permitted for rno%enient by the worker in doing the work. (6) Remove the temporary ground from the circuit. Insofar aspractical,provideinsulating barriers between the work and any live metal (7) Withdraw from the equipment under test, parts immediately adjacent to the work to be making sure that you are free from the leads done. and in a proper position for taking meter readings correctly. Use only one hand in accomplishing the work, if practical. Taking the Measurements A tubber glove should be used on the hand (1) Dc not use flexible leads or probes that not used for handling tools. If the work being are attached temporarily.

Cts 1.° i) CONSMUCTION ELECTRICL-1N 3 & 2

(2) Assign the responsibility of energizing the established byavisual check, anapproved equipment to an assistant standing by the switch. voltage detector should be used. Before being used, the detector must be checked on a con- (3) Do not touch the test instruments while ductor that is known to be alive and a positive the power is on. indication noted. This check on a known live conductor mst be repeated after the test on a (4) After taking the reading, deenergize the dead conductor has been made. When it is not equipment. possible to recheck the voltage detector on a live conductor, two voltage detectors should be (5) Before removing the test leads, di scharge used, one as a check against the other. highvoltagecapacitors and the terminals to which the test equipment is connected at least (2) Insulating Equipment. When work is to twice, with a minimum 15-second interval, by be done on or within reach of conductors or theuseofasuitaNeinsulatedshorting or equipment operating between 600 and 5,000 volts, grounding bar. energized and grounded conductors or equipment within reach must be isolated with suitable (6) Attach temporary ground to the terminalsbarriers or covered with rubber hose line, to which the test instrument is connected. insulator hoods,lineprotectors(pigs),or blank;ts. If it becomes necessary for the work- (7) Remove the test leads. man to change his working position, he must cover or barricade any energized or grounded (8) Remove the temporary ground. conductors or equipment thatwill be within reach in the new position. (9) Repeat the above precautions for each measurement at applicable. High Voltage Wouk, 5,000 Volts and Over Low Voltage Work, 0 to 600 Volts Lines and equipment operating at 5,000 volts Live conductors and equipment operating ator over must be deenergized and grounded 600 volts or less may be worked upon if thebefore work is started, except in emergency following requirements are met: repairs on overhead lines, which may be worked on alive with approved hot-line tools. (1) Adjacent live or grounded conductors and equipment should lx; covered with insulating material or approved rubber protective equipment. Body Clearance for High Voltage Wtmk (2) Two men should work together, partic- A minimum body clearance from energized ularly when work is done on energized partslines and equipment should be maintained by carrying more than 150 volts, in wet weather,men working on or around electrical equipment or at night. When working on energized lines, of high voltage, as shown below: a man should not change his position on a pole without first informing others working nearby. Operating Voltage Minimum Distance (3) BRre or exposed places on one conductor (Kllovolts) (Feet) must be taped or covered before another conductor is exposed. 5 to 7.5 1 7.5 to 12 2 Intermediate Voltag3 Work, 12 to 33 3 600 to 5,000 Volts Remember: Never hold a line clear of a lineman (1) Testing Voltage Meters. All conductorson the pole. Secure it by live-line tools and lock and equipment must be considered as carryingit in a clamp. currentand as being alive until it has been determined beyond doubt that they are dead. Additional information relative to safety may When positive proof as to whether a conductorbe obtained from the Department of the Navy or a piece of equipment is energized cannot be Safety Precautions for Shore Activities, NAVMAT

30 36 Chapter 2SAFETY

P-5100. Become familiar with its contents. This WORLD'S BE:ST PROT EC TWE DE ViC E knowledge may save your life or the livesof some of y-mir men. In setting forth these rules and regulations for safe practices,itis fully recognized that all possible hazardous conditions cannot be fore- Live-Line Brehand Work seen and covered byadequate precautionary measures. Mental alertness and effective procedures in handling equipment and performing The live-line barehand technique utilizingwork are required at all times by all men so the insulated aerial servicing platform is pro-that hazards may bedetected and overcome hibited unless specific approval is granted bybefore they lead to personnel injury, or damage the Naval Facilities Engineering Connnand. to equipment. Remember Use and Care of Hot-Line Tools THE WORLD'S BEST PROTECTIVE DEVICE The following precautions must be taken IS A CAREFUL INDIVIDUAL when hot-line tools are used: (1) Work with hot-line tools should not be performed when rain or snow is imminent or FIGHTING FIRES falling, or when heavy fog, dew, or any form of excessive moisture is present. It is extremely important that all personnel know and understand all there is to know about (2) When wor'&ing on lineb energizod at more lireprevention and firefighting.Part of the than5,000 volts, use approved hot-line tools knowledge isto know the type and location of WITHOUT -ubber gloves. (R-bber gloves pre- all firefighting equipment and apparatus in the vent detectionofbrush discharges.) Handle immediate working andliving spaces, and series street lighting circuits supported on armsthroughout the area. Itis too late to get this with other lines energized at more than 5,000 knowledge after a fire has started; the time is volts, the same as the power supply conductors. now. RememberIf there is a special phone number on your base to call in case of fire, (3) No more than one conductor may be require all the men to memorize it. The time worked on at a time with hot-line tools. lost looking for this emergency number may put the fire beyond control. (4) Hot-linetools must be kept dryand free from dirt. Tools which have been subjected to damp weather must be thoroughly dried and RULES TO FOLLOW tested before being used again. They must never be placed on the ground. Incaseofan electrical fire proceed as follows; (5) Ha-line tools being transported on lino trucksshould bestoredso as toprevent Deenergize the circuit or equipment af- damage to them. Waterproof canvas bags may f:cted andshift the load to standby circuits be used forthis purpose. A compartment or equipment. n case no standby circuitor equipped with padded hooks or binds may be equipment is available, deenergize the circuit built into the truck for this purpose. or equipment affected by the fire, except in extreme emergency when the need for uninter- Periodic treatmentofhot-line tools in arupted power outweighs the risk incurred by drying cabinet for 48 hours to 1 week per month leaving it energized. at 90 to 100 degrees Fahrenheit is recommended under average conditions. Hot-line sticks must 2. Report the fire. be tested with 75,000 volts per foot Coy 5 minutes. If they break down, they must be returned to 3. Secureventilationby closing air vents the drying room. or windows.

31 37 CONSTRUCTION FLECTRICIAN 3 & 2

4. Attackthefirewith portable CO? ox- armor are burning, the only positive method of tinguishers(ora CO2 hose reel system, if preventing the fire from running the length of available) as follows; the cable is to cut the cable. Use an ax with a wooden handle, taking care to protect your eyes a. Remove the locking pin from the re- from any flash when the wires are severed, and lease valve. separate the two ends. b. Grasp the horn handle by the insulated (thermal)grip;thegripis insulated against Don't forget to request the r.z.,placement or possible hand frostbite. recharge of fire extinguishers immediately after they have been discharged. Never turn on cur- c. Squeezetherelease lever(or turn rent in a building in which a fire has occurred, the wheel)to open the valve and thus release if electric wiring has been affected. A careful the carbon dioxide;at the same time, direct inspection should be made, because parts dam- the discharge flow of the carbon dioxide towardaged by heat, water, or foam may become short the base of the fire. circuited and restart the fire. d. Ain)and move the horn of the ex- PREVENTING FIRES tinguisher slowly from side to side. General cleanliness of the work area and e. Do not stop the discharge from the ofelectricalapparatus isessential forthe extinguisher too soon. WI:en the fire has been preventionoffires.Oil, grease, and carbon extinguished,coatthecritical surface areasdust can be ignited by electrical arcing. There- involved with carbon dioxide "snow" in orderfore, electrical equipment should be kept ab- to cool the substances (fuels) invoived and pre- solutelyclean and free ofall such deposits. vent a rekindling of the fire. Wiping rags and other flammablewaste Care must be taken to avoid high concentra- material must always be placed in tightly closed tions of carbon dioxide in confined spaces,as metal containers, which must be emptied at the thereisdangerofsuffocationto personnel end of the day's work. unless special apparatus is available. In electrical fires, remember that quick action is most Containers holding paints, varnishes, clean- needed for deenergizing the circuit. When this ers,orany volatile solvents should be kept has been done,stop, look, and think, and then tightly closed when not in actual use. They must act fast to extinguish the fire before it spreads.be stored in a separate building or in a fire- resisting room whichiswell-ventilated and Carbon dioxideisthe preferred fire ex- where they will not be exposed to excessive tinguisher for use on electrical fires. It is aheat or to the direct rays of the sun. noncorrosive gas which does not damage cables cr equipment.Itisnonconducting,andthe Alcohol should never be used for cleaning stream of carbon dioxide from an extinguisher electrical equipment sinceit not only consti- can be directed against energized circuits with-tutes a fire hazard, but it also results in damage out danger of shock. to many kinds ofinsulation. When cleaning electrical equipment or parts, always use an Extreme care must be used if freshwater or approved cleaning agent such as FSN W t850- saltwater or foam is directed at an energized 274-5421. It is a dry cleaning solvent, Type II, circuit,sinceall or these can conduct currentcovered bythelatestissueof Specification and shock firefighters. In addition, equipment D-680. damaged bysaltwater or foam is more difficult to recondition than if carbon dioxide had been used. Consequently, while water or foam SAFETY EDUCATION may have to be used to prevent a disastrous fire, it is decidedly advantageous and preferable Many supervisors feel that it is only nec- to use carbon dioxide alone. essary to provide safeguards, after which safety will take care of itself. Provision of safeguards In cases of cable fires, in which the inner is a move in the right direction, but it alone layersof insulation or insulation covered by will not get good results. T ) maintaina good

32 38 Chapter 2SAFETY IIIMIIMI=11111111. safety record, you, as the supervisor, need to ACCIDENT aEPORT1NG employ a combinationofsafety devices and safetytraining.Ifeach man has had sound Wren an accident occurs in your shop, office, safety training, he will be able to guard against or within your crew, you must fill out an OPNAV hazards for which safety devices are imprac-Form 5100/1, Accidental Injury/Death Report ticable. You must, however, train every man(figs. 2-9 through 2-12). This form provides a in the use of safeguards, explaining why, as well method of recording the essential facts con- as how, they should be used. How many timescerning an accident, from which data for use have you seen a man shut off the power to ain accident prevention can be compiled. Item motor-driven machine and then walk away from 27 'Corrective action taken/recommended" it before it has stopped turning? This man knew is the most important part of this report. Your how, but not why. By providing the necessaryresponse to this item provides a clue to your training, the alert supervisor makes sure his attitude toward safety. Too many supervisors men are no. careless with safeguards. respond with,"The man was warned to be more careful."Such a responseis useless Standup safety meetings should be held in the sinceitdoes not tiein with the rest of the shop once every week. ne meetings should bereport. If an unsafe working condition is the causeofthe accident, you cannot correctit. heldator near the work area. Instead of aby warning the man to be more careful. Study routine safety lecture, itis better to hold a thereport;analyzeit;thentake corrective group discussion on specific accidents that are action. When properly used, this report is one to be guarded against or that have happened in of your best accident prevention tools. In many theunit. The men should be encouraged to cases, the difference between a minor accident express their ideas. Your group should reach and a major one is a matter of luck. Do not a conclusion as to how specific accidents can ignore accidents that result in small cuts and be prevented. bruises; investigate the reason3 for them and Another typeof safety meeting is one incorrect thecauses. If you do this, you will which the supervisor presents a safety problem have a safe and efficient shop or office. that has developed because of new work of new equipment. Aga'n,the men should be invited ACCIDENT ?NVESTIGATION to express their ideas. To fill out OPNAV Form 5100/i properly, RS shown in figures 2-9 and 2-10, you must Iiiathird type of safety meeting, actual demonstrations and practice by the group are conduct an accident investigation to get answers carried out. You demonstrate how to lift, forto questions such as those in the six categories example, and then have the men practice lifting. below. 1. UNSAFE CONDITIONS. Was the equipment Ifthe subject of your safety meeting is the improperly guarded? Was the equipment or ma- safe use of a portable grinder, bring a portable terialrough,slippery, sharp-edged, decayed, grinder to the meeting and show how to use itworn, or cracked? Was thereahazardous do not just talk about how to use it. Again, letarrangement, such as congested work space, the men practice after thc.,have been shown lackof proper lifting equipment, or unsafe how. planning? Was there properillumination or ventilation? Was the man dressed properly for Make these meetings interesting; it takes a thejob? Was the man provided with proper lot of ingenuity to keep them from becomingrespirator, goggles, gloves, etc? dull. Consider having the men themselves rotate as leaders of the safety meetingsan excellent 2. TYPE OF ACCIDENT. Was the man struck device to maintain interest. Hundreds of goodby an object? Did the man fall at the same motion pictures and other visual aids are avail-level or to a different level? Was he caught able on safety subjects. Use them: But selectin or between objects? Did he slip (not fall) subject mater that is timely and fitting. Never or overexert himself ? complain orscoldatthese meetings. Also, make sure to set a time limit for each meeting, 3. UNSAFE ACT. Was the man operating a and avoid exceeding it. machine without proper authorization? Wve he

33 39 CONSTRUCTION ELE,.:TRICIAN 3 & 2

ACCIDENTAL INJURY/DEATH REPORT JON OFFICIAL UNE ONLY OPKAV FM 510011 (5-133) 518-0107-7715-0010 SPECIAL HANDLING REQUIRED IN ACCORDANCE WITH OPNAVINST 5100.11 REPONY NMBOL ONAY 5IW-3 ' TO: COMMANDER, NAVAL SAFETY CENTER. NAVAL AIR STATION, NORFOLK, VA. 23511 NAIYALREPONM6871'n --2A. COMAAND AUTHORITY EXERCISED BY: 3. REPORT NUMBER BATTALION CEINTI2 CONSTRUCTION CENTER PORT }MENDE, C,LIFURNIA 93041 28, GCM AUTHORITY EXERCISED BY: 5 4. NAME OF PERSON INJURED/KILLED tAiAss. MIDOLE.LAST) 5A. SERVICE/BADGE NO. 6. RANK & DES1GNATC; RATE AND NEC/CIVILIAN ANDERSON, John P. B48234% OCCUPATION 58' 2r24.31:j.WY NO. CM2, USN 7. SEX8. AGE9A. TIME IN SERVICE (MIL ONLv/ 10A. MIL:0 usm 6 § III US. III OTHCH M 24 98. YEARS EXloxPLNIENCEtctv ONLY) 108. CIV: EmpLOTEE DEPENDENT 07.11 11A. PUY STATUS IIB. DUTY STATUS ElEA Acs ou El AGOUTI. CHILL 0 TRAVEL CIE: RIO. MIL ElTVAI. TRAVEL LV/ltS [El UA OTHER UMAUTH WORN 0 OTTER PSON103114411300bilOWEAMOUOINS 13, PLA E OF OCCU,R NCE 14. HOUR OAT( MONTH YE. OAT OF RICA DAYS LOST/CHARGED . 0.0 SHIP 5.0 AT Hoot (0 ) 0950 19 Apr. 19.- Tin-sday DESCRISE LOCATIOR AuCornotive Shop 5 .cATHER/NA RAL 615A lEit Id. LIGHT CONDITIONS AT SI1E NA 17. DESCNIPTION Cr EVENTS. Conri IDESCAIBE THE CONTRIBUTING EEEEEE LEADING UP TO TNE INJuAY/OtATH SO THAT THE REVIEW!.OFFICIAL RILL HAVE A CLEAN PICTURE OF wHAT CAUSE(' THE INJURY/0E0'TH, SELECT THE APPROPRIATE ENTRY FROM EACH MAJOR FACTOR CATEGORT LISTE0 ON SAGA OF INSTRUCTION SHEET AND ENTER IT RITH AmPLIFTINO OtTAIL IN sOOES IS THROUGH 23 ELOW./ p Petty Officer ANDERSON was standing on the front bumper of a 5-ton truck leaning over the radiator grill to inspect the radiator hoses and fan belts when his feet slipped off the wet bumper, causing him to fall on the upper section of the radiator grill.

WITNESSES: NNAE. RANK/RATE. ADORESS None

18. KIND OF INJURY: 19, BODY PART INJURED: Abrasion Chest 20. SOURCE CF INJURY !OBJECT. SUBSTANCE. ETC. *RICH com.21. KIND OF ACCIDENT tAALL, cNumsto, vow,: Iv, tsc.1: V;111t4f"IapCiregVIIII-1 Striking Against

22. HADAROOUS CONDITION totAs coNotsIom cAusco. PER- 23. AGENCY (AND AGENCY PART) OF ACCIDENT tosAccs, suIsTANcc.Esc. so MITTEO, CONTRIOUTO :0 ACCIDENT 'ANION RESULTE0 IN WHICH THE MAZAROOUS GONOITION APPLIE01, NoT APPLICAPLC ¶jet unper U.S. Navy a NOT APPLICASLE 24. UNSArE ACT two PERSONAL AGTION GLUM OR ALLONE0 I 25. UNSAFE PERSONAL FACTOR (MENTAL Eta PMVSKAL COW:MID% wm1CM RESULTED ACCIOENT TO OMNI' IN OR CONTRIBUTE(' TO T. UNSAFE ACT), fl BP INJURED St.I MAN ANOTHER NOT APPLICASLE Failure to use step stands 25. REASON FOR BEING ON GOVERMENT PROPERTY IscouLAN OUTT ASSIGNMENT.Clv EmP, PATIENT, vistsom, eusINEss. Esc,1) Regular dutyassignment

29.52.1 Flpre 2-9. Accidental Injury/Death Report, OPNAV Form 5100/1 (front).

34 4 0 Chapter 2SAFETY

199LL11-111 ilAV1 IF"2"IALe.00Ricr yt ACTION TAITENITIECOMIWINDEC A TN"NIRO fffffff 1607,111. ACC IOW 0, 7.1 Instructed Petty Officer ANDERSON in the use of the step stands with non-skid treads which are provided by the shop for this type work.

AoAD GRAL,E 24 'A 1 OEN 29 I 30. LATE

Jim Nel on CMCS USN 1 Ann 1 9- voVitoAND I COAANNI, 61sAT T OH IU W.COMMAND iNG OFF ICER

3. TI ILE AND GRATA 34. DATE

- ADDI TIONAL INFORMATION WHIN REW I RID BY JAG ' (.W10 . 0. ,,I I hi, to i WA, ATf !ME OF THIS OCCURRENCE A.vs ImIPark Aft, ,. Li it , 4.EMAPCO /ICSID OAPS/. 00 /mt le 0 00, A..t. 1 CAR( /UNATIS 1S.ICIFT)

[ i.....,0 ,i, U1,1.1.41 OA I. Orly,(AL ,0.01/IOM I gAmimirm

15 HA% P To ANTN1 ow U01 1 (//4 ai

91,1' 91, Ai sof , Iwo AO00A TOO/ /0 WI (m tot c istm SINT

01.Io /11III/Allitr IS ho (.;4.61 ffereh9 AriMvrTO HATurfraND lATINT or INJuav:

14 ITAS SUIT fHOS', I,C 1110 AS A RI SOL IOfNI S39IF NI SURJECTWERE ALREAOY ON THESICKLISTFOROTHERREASONsATTImE (jr Iortoi Tv I or INJURY WIXILD TSI 5 INJURY' IN IT5ELFHAvEREQUIREDHOSPI TAL I ZAT ION? F.] IIVII Li - [-]SOT APPL ICA ill I

4) I / .1% I /HA / !HI IDIHAING D :TAR L TY AI. DATE OF( AP 11/A E ION W I NC STMENT/TERM OF OWL !GATT() %IA, RI Sui I. SIRVIFF Li ri

.41 I f I AST , OAS Au forty °Now TOW .. III, ArnAf. COPY OP AU /OP 11010(0k ArrivraurTy TAATA00 GA IAAGTI" "Ty f"""luPOLy Tml 4 I ADDI f I , PdAt I NIOPIMAYI(.F0A MI Tf 0 V 1 T7---TUrTS 171T:TrIn TTA42. MT 71"' .1..J%J 1.1L1 _InkyIllt?I.QmQt1 VP 94ILL mel I(iiII Ills,

II U, AL TH (IN iGNA 000 145. GRADE

y HITTri AT INN To 'TIE UMW OSITAI 0 NAT THIINJURY/DEATH IN QUESTION WAS INCURRED IN THE LINr. or DUTY AND NOT A%fillNt $OIfQ THE S110111 1MAN'S COM MI SCONDUC f . VII 0 .0

HAIMANDINIT 01 f IFT ION ONI AufHOR FED TO SIGN I1Y HIS DIRECTION IF LATTER SO INDICATE, 40 1(.101100 49, TYPED NAME AND GRAD, O. DATE

S I AT illod ToTor IT 1 ITI AIPft I 'WO.(TINT RAI, (.(M)TUAkTIAL JUNI SDK f !WI DATE] I WM,

TO. OHO./ AOVOCA ff DENHIAl OfTIN NAVY

/MO MANI OF OFFICIO AUTOOIIIII 10A 0.I AVINOIIII0 PO 110M OIOICII0011

29.52.2 figure 2-10. Accidental Injury/Doath Report, OPNAV Yorrn 5100/1 (back).

4 1 CONSTRUCTION ELECTRICIAN 3 & 2

ACC !DENTAL INJURY /DEA TH REPORT OPNA4 FORM 5(00/I (5-69) Pr, t tr-pen or t.pe,1,011 spp.... obi ui k Prf /At.. to th in.., death 1',1 be ,iirlsed N.A

. .

1,1 C...).1 r th s hel s c, /se Iv re Ito JAC

11 bose r tne ,t74111 1,, . luring thef 1st ..sr 24.9 is in. Ft, et 'Sem. Pers., r. .ck It. tie `.1 . up, toot or. 41,-;;ft iji, FI, n Pone :'.g,st tip 114, 1 1-eq.1 on etrv 414. Ige ir A. 1111, e "I.,

fia r-011 '111r. Exper..... c Indi, oaxtbr uf ***** in. etr.pre..., 'pi. ion,in, ludins ,sr. of experience ga,neri emu 'p.m., 1.1 silos 01 cry or death to c lions t hetthen employes.

.th,et:ht the lire "(thr" is ...acted (ur et cher to 1tor. or Ion,ape,iy s control-, ereplo)..e.

(Ii,..., !..,. Ilt./!II., aaaaa n ppli, ho.e. 1.st esr.) hive the noh-ani res. th tit 11 ..ing funr digit 1 s ten diet" sch fur the dats., P.a... lo ricirg tr. I..at hter point eat her deli, fligh: Jerk, math., shop, gl I ey, et, so spprop It, t locit (.1,tge.) ft al o :or 4,1.44 4,1110,11, ntr 1,4)00 tor ell othr .4 JiliaTi74-77 tme harge nt ors a emtr th nuolu, of pslendsf dot's us! og the sr he.1.11 .1i-srgsTehl I Appendi 1. When.....r the schedule x cum/ ,,rnb.r ofslrobir di... ta ty not en,r.I charge. le osed the Bin, a 11 itether hat..1.1 lit aaaaa r I! fa, thr, de, r.b ,O4,111.10/1 or nturst di taster eh, h tont ributed to the injury. ,g, -7 internali;44.)%r. 4 440 14,,4 s,ss spplicsble, ciatir.g stthe imeedist t end title

. 4 F tents 4.4 tr nar '11,1,1 ,I Cr .1011ItatO et ,111 sent hifh directly oi indirectly led to the in,ory,

2%4 rr, it es.pl it @He ship sr II ihent rport seri.: in this In.:lode in this block, so appropriste, ton...ht. on the following r.f. floe inJr..) peril,' h.ftpen ko. mdits) f re, rep veto ,s411,,:x.rndi:Irrr.:::11,e 44.41 to soothe r ahip (military persoonel /or I o sae. ot fwmehere, si 4%%%44%4. h dsr r typ sub° an, e,content ',Lion end t ype.o I exposure.. n1 ;18 n c..47.:20, r 01..11,1,2r Sn .0;2. t;,.1,101-. !It?, t 1,,, t., !he at, 1.1ent I 110111. IlleJ1 Cele. y .o.1,1./roe. Itt1,11re...riles, de ..f sheet/ which beet deer rib.. nature of injury. 11n 1, Parf , .redVoter fro,. bloo h 19 ******* vide !hioh., .1..0, hest dell. 111,1 laid, port of Inc tell by nous,. ofII1J1Ift e.e,I rpm blIf 20 (o re...rile made of thin sheet Ischii ), best deer. Le4 snort. of injury 471{S.. "11 "ha,urrof Inr " and "hind c.I1 n,u ry " most he mtabli a hod

ots'il,s1 j rl'e,1 .1!e rs 'I".111'1r8:tVP::1 S(orr. rr r "1 ehsp en!h "Soar'of ;nit" Ild .111111) Of Ao.dent" cons, U. ecir ahed, Ilsrstp,,,41,t112,1,j. Enter the otolit thn foie 111,1,'22Ion rec.. se rode of Ow. thtstitch lost Oa, rt hes th. hatetitous .801 tion air/. pe re,4e.4 "en, e pie siousl y sh, p ted "hand of Atidentn (MYR A direct logics! rel @Lion- "I...1 of Air idnt", t I Oh"0/1,1 "Anew.- ol Arcidrot", Iiich is to follae, must be establialmr1L 114,41 .21

II, , I Ithe senry laa tshl vs.fr/l/Uelitri.the bled suer./ lis ben ren.o.11, 'IN.:1Ig..1h1:r1,)10.1l;/1,thefI:7"For s,cce sear les au. as a length of ictp, tope, lumber, ic., oo 111,4 the surds roma 07.lt .. Ode." In .1 .111, I ,,,,, part It cello Is,/ in by named.The role for @genet, pert se- 41,141 for the parr,involved sdiferent too the me... port (WM. mir "on eny other pert of th sgnr y, name the A di riot el., sha et, p he, n,no ao,s "Agency of An, I dent" must he 81,4)I( re is no hatt.hois cohdlt the,. cat, egen, des, ril,d me "Noi .1 eat,. y prt n1 incidentend ell three trate ohm! Ibe 1111,x :4. /" "/ fr.., Illuch 24 Ion ,,,,,,, side of oh" itheetl ehirh b..) Oetribee kileeff 1 or 4.141,1 tor rti, e p11,14.41.. IIOTSII Iwo/ ol at, idtnt NC whsth per "44in.1 of A. riderit must be eteld shed! (4/11. A dia..) 1..7, ...Ire/ st innship betefin "1)..1. Act" end Uloyg glegtifjp,j,pi 4,11.ri. the ',re sonI roteIII ocli rrrrrrr stgre of To / *harts heat decrihee thdonee1e, pereonI stmaklf ix; .1.;.141.4 er. y ir t 1,1111 he lel tont ill/III,/I I he o. 411. soh for lloime Goyihmeot Ptoperiz !,elfmplametory. fp.,qt.,Letz,na.sligt,1 tper remedial sr i lona 4,11. top,. Tf ett ty h hot, ehorild be teh, pro...et re,Urrelic unk000ti" oi "too," appropt at. ,an rep! aliallOn 01011 r 11.4 be rron.ntoled Npeoi 1/0gi V11 elII/ why tor rrti se at tino y whether or, sons 11"f 1,1011tehrer or soe only re, onesended I ftheI .00,, ghat action is expertd' Mollie:II 10 rhirojh is rat ...2.&rt lah ReportIII I, be wind end doted by the Inds .1111.1 lin prepared the report to thispoint, Block 11 Pa.,. .. .4 frogaents of.gsfLr or fonen.,2112/L2/112.1. A.1.11 t tonal terrommendot on. may U. med. 1 opproprs mt.. HloLka12 thrtaAll It_ tio,ond tiirsiote Sel explenvory lemeinder of she ilocri. form Its!) only be filled nut int /loot Inst.,. where the ru 44 y/de, h to the so t ery !member se reportblth JAG. e Moth. 1.14 Prepared II,.4,411,164%C. 11.41 61,1111. tittruri tone.

4411, '21,":r0i'd".'4.4through 4b ehel r U. completed end aigned by the erlicel of (sot, on the boa,. of hie IIIthe intured or der eemed member andnformL.att than alai table to lit, rrrrr t ton or cl 111of 41, 41 OW/ 47 through SO .h.I I of I ir rr .n010,1.4.1 awl be completed end signed by the riterroinding Of fireron the heti. Of his in rrrrr Foot,,n kr by en rr tea lay the commending 10141,01. to investigate the to, dent end ign thereport by ds rye Lion/.

4 2 29.52.3 Figure 2-ll .-Instructions for Accidental Injury/Death Report (front).

36 Chapter 2SAFETY

ENVIRONMENTAL HAZARD. NEC DLOCK IB KIND QF INJL,RY ELECTRIC & LLECTRONIC APPARATUS. NEC MAZAAO OF OUTSIOE NONA AMPUTATION OR ENUCLEATION FLAME. FIRE. SMOKE ENVINONMIENT - OTHE ASPHYXIA. STRANGULATION 'FOREIGN BODIES OR UNIDENT.FIED ARTICLES IN00001ILY GUAR000 rixT,AEs, FURNISEI:NGS euRN OR SCALD ITNERmALI PLACEMENT HAZARD 'GLASS & CERAMIC ITEMS, NEC B URN (CHEMICAL/ PUBLIC HAZARD CAISSON DISEASE. BENDS "HAND TOOLS (NOT PORERED: WHEN IN USE, CARRIED BY A PERSON) UNDETERMINED CONCuSSION, BRAIN 'HAND TOOLS (MECH. If ELEC. MOTOR POWERED; NO NAZARDOUS CONDITION IN USE, CARRIT.D AND HELD BY A PERSON) CONTUSION, CRuSHING. BRUISE HAZARDOUS CONDITION, NEC CUT. LACERATION, PUNCTURE. OPEN BOJNC 'HEATING EQUIPMENT. NEC (NOT ELEC.) wHEN IN USE (FOR ELEC. FURNACES SEE ELECTRONIC DISLOCATION APPARATUS) DRORNING . HOISTING APPARATUS KOCK.24. URWE kcir ELECTRIC SHOCK. ELECTROCUTION * ELEVATORS 'WORKING ON MOVING OR OANGEROUS FOREIGN BODY LOOSE (DUST. RUST. SOOT) 'HUMAN BEING EQUIPMENT FOREIGN BODy. RETAINEO OR EMBEDDED 'INSTRUMENTALITIES OF wAR DRIVINC BY VEHICLE OPER.- FRACTURE 'MACHINES (PORTABLE & FIRED. ExCEPT WHEELED VEHICLES) FAILURE *ERSONAL FREEZING. FROSTBITE PROTECT., EQUIPMENT "METAL ITEMS. NEC HEARING LOSS. OR IMPA RmENT FAILURE TO NEAR SAFE PERSONAL MINERAL ITEMS. NEC ATTIRE HEAT STROKE. SUNSTROKE, HEAT ExHAuSTION NATURAL POISONS ANO TOXIC AGENTS. NEC FAILURE TO SECURE OR WARN H ERNIA NOISE HORSEPLAY AND SKYLARKING INJuRIES. INTERNAL PERSONNEL SUPPORTING SURFACES )DECK, QUARRELING DR FIGHTING LANDER, STAGE. BROW PLATFORM) 'POISONING. SYSTEMIC IMPROPER uSE OF EQUI04ENT PLASTIC ITEMS. NEC RADIATION, IONIZING IMPROPER USE OF HANDS OR 0000 RAD,TION, NONIONIZING PUMPS, ENGINES, TURBINES (NOT ELEC.) PARTS RAC ATrCIN, ACTINIC RADIATING SUBSTANCES AND EQUIPMENT (USE INATTENTION TO FOOTING OR ONLY FOR RADIATION INJURIES) SURROUNDINGS S.- -.ES, ABRASIONS SCRAP. DEBRIS, WASTE MATERIAL. ETC.. NEC FAILURE TO USE SAFETY DEVICES SAR, STRAINS (EXCEPT RADIOACTIVE) OPERATING OR WORKING AT UNSAFE SUBmERSION. NONFATAL SHIP STRUCTURE - PARTS SPEED MULTIPLE INJURIES SPORTS TAKING UNSAFE POSITION OR POSTURE TEMPERATJRE (ATMOSPHERIC, CNVIROHmENTAL) UNDETERMINED UNSAFE PLACING, miYING. OCCuPOIONAL DISEASE, NEC TEXTILE ITEMS, NEC COMBINING, ETC. OTHE:: INJURY. NEC VEHICLES. (AIR, LAND. SEA) INCLUDING USING UNSAFE EQUIPMENT MILITARY AND INDUSTRIAL OTHER UNSAFE ACTS, NEC RATER AND STEAM BLOCK I9 BODY PART INJURIX UNDETERMINED .0000 ITEMS, NEC NO UNSAFE ACT MISCELLANEDUS. NEC .110.0 (INCLUDING FACE) NEC - NOT ELSEWHERE CLASSIFIED .NECK UNDETERMINED UPPER ExTREMITIES 0THER, NEC B K ,_r;8:4,SAFE E:731EHERS A 'TRUNK BLOCK 21. KIND OF ACC1OENT LOWER EATREMITIES UNDER INFLUENCE DRUG/ALCOHOL 'MULTIPLE PARTS 'STRUCK AGAINST FATIGUE * BOOT SYSTEM 'STRUCK BY ILLNESS .1000 PARTS. NEC 'FALL OR JUMP FROM ELEVATION ImPROPER ATTITUDE 'FALL DR JUMP ON SAME LEVEL LACK OF KNOWLEDGE OR SKILL OLLICIEE 20 & 22 SOURCE OF INJURY AND Eir===.171T CAL,: ITIN, UNDER. OR BETWEEN BODILY DEFECTS BITE DR STING, VENOMOUS AND NON-VENOMOUS UNDETERMINED 'AIR PRESSURE 'RUBBED, ABRADED, PUNCTURED OR CUT NO UNSAFE PERSONAL FACTOR ANIMALS BODILY REACTION OR MOTION OTHER UNSAFE PERSONAL FACTOR, 'BODILY MOTION NEC 'OVEREKERTION 'BOILERS, PRESSURE VESSELS - PARTS 'CONTACT wiTH . BOKES, BARRELS, CONTAINERS, PACKAGES (Empre OR FULL, EXCEPT GLASS) UNDETERMINED BUILDINGS fiSTRUCTURES PARTS 'OTHER, NEC SPECIFY/DETAIL CHEMICALS & CHEMICAL COMPOUNDS CLEITHING, APPAREL, SHOES BLOCK 22. HAZARDOUS CONDITION

COAL AND PETROLEUM PRODUCTS 'DEFECT OF THE AGENCY OF ACCIDENT CONSTRUCTION MATERIALS (NOT PART OF A STRUCTURE) 'DRESS OR APPAREL HAZARD CoNvEYDRS. GRAVITy OR POWERED ..IMPROPER ILLUMINATION INDUSTRIAL VEHICLES) (ExCEPT PLANT If ImPROPER VENTILATION ORVGS AND MEDICINES

4 3 29.52.4 Figure 2-12.Instructions for Accidental Injury/Death Report (back).

37 CONSTRUCT:ON ELECTRICIAN 3 & 2

working at an unsafe speed, that is, too fasttherefore, for you and other CE's to be well or too slow? Was a safety device made inop-trained in first aid procedures. erative, that is, blocked outor removed? Was a load made unsafe, or were tools or equipment put in an unsafe place where they would fall? GENERAL Did someone fail to wipe oil, water,grease, paint, or some other substance from working Place the victimin a prone position (lying surfaces? Did the injured man takean unsafe flat), with his head level with the bodyuntil positionor posture? Did he lift with a benttreatment requires movement. Check for hem- back or whileinan awkward position? Didorrhage, stoppage of breathing,wounds, frac- he lift jerkily? Was he using impropermeans tures, dislocations, and other injuries. If clothing of ascending or descending? Was theinjury must be removed, cut it awaydo notmove caused by failure to wear the provided safethe injured person. Do not permit the victim attire or personal protective devices, suchas to see his injury and keep onlookersaway from goggles, gloves,masks,aprons,orsafety the scene. shoes? Provide IMMEDIATE treatment for serious 4. UNSAFE PERSONAL FACTOR.Was the bleeding, stoppage of breathing, and poisoning man absentminded or inattentive ? Did he failin that order. Keep the victimwarm and treat to understand instructions, regulations,or safetyfor shock. Call a medical officer and give the rules? Did he willfully disregard instructions following information:(1) the location of the or safety rules? Was he unaware of safe prac- victim;(2)thenature, cause, and probable tices, unpracticed, or unskilled? Was he ,:nable extentoftheinjury;(3)availablesupplies; to recognize or appreciate the hazards?Did and (4) the type of first aid being given. he have a bodily defect, suchas poor eyesight, defective hearing, or hernia? Unless it is absolutely necessary, to avoid complicating theinjury do not hurrywhile 5. TYPE OF INJURY. Did he sustaina cut, moving the injured personand KEEP CALM. bruise, sprain, strain, hernia, or fracture ? Bleeding 6. PART OF BODY AFFECTED. Did the injury involve an arm, leg, ribs, feet, fingers, A break in the skin may be subject to two head, or other part of the body? primary dangers: serious bleeding andjor in- f;ction. When the bleeding issevere, stopit These categories suggest some of the things as rapidly as possible by applying a thick layer (notall)a supervisor must investigateand of gauze or clean folded handkerchiefs against eport when accidents occur, Rememberthere the bleeding point and applying firmpressure are some questionsin these categories thatwith your hand.Elevatetheinjured part if request medical information whichcan only be possible. ohtained from a doctor. Each accident is different, and each should beinvestigated and If the bleeding is not controlled in thismanner, judged individually. Do not jump to conclusions. apply hand pressure at a pressure point. Start each investigation withan open mind. The most important reason for any accident A PRESSURE POINT is a point between the investigationispreventionofa similar ac-heart and the wound where pressuremay be cident. appliedtotheartery to close off the blood supply to the wounded part. The mainpressure points are shown in figure 2-13. FIRST AID First aid is the immediate and temporary Ifa prow:luredressing or hand pressure caregiventhevictim of an accident before does not control the hemorrhage,a tourniquet treatment can be administered by trained med- (fig. 2-14) may be used. Thetourniquet should ical personnel. Your work may frequently bebe placed above the wound andas near it as performed in areas where medical personnelpossible. (Tourniquetsa:elused only on ex- arenot readilyavailable.It isimportant,tremities.) To be effective, the tourniquetmust 38 4 4 Chapter 2SAFETY

WHERE TO APPLY PRESSURE TO STOP BLEEDING casualty tag or on a tag attached to the tourniquet. A properly applied tourniquet can be re- FOR SCALP AND UPPER PORTION tained safely for 2 or 3 hours without being OF HEAD loosened.Incold weatherit can be left on FOR NECK OR HEAD even longer. It is best, especially among those FOR SHOULDER with limited experience and knowledge in the OR ARM treatment of shook and hemorrhage, to leave FOR LOWER ARM the tourniquet on until the hemorrhage can be controlled by other means. A TOURNIQUET SHOULD NOT BE USED UNLESS THE HEM- FOR BACK SURFACE ORRHAGE CANNOT BE CONTROLLED BY ANY OF LOWER LEG OTHER MEANS. After the bleeding is controlled, FOR THIGH OR LEG treat the victim for shock.

Shock Symptoms and Treatment FOR LOWER LEG AND FOOT Every injured person is potentially in shock, YOU SHOULD FEEL THE since shock usually occurs whenever there is PULSE IN EVERY CASE, severeinjury of any part of the body. Start OTHERWISE YOU ARE NOT PRESSING THE ARTERY treatment for shock immediately; do not wait PRESSURE SHOULD BE for symptoms-to develop. Some symptoms are SUFFICIENT TO STOP sliown in Lgure 2-15. THIS PULSATION 136.3(73G) Figure 2-13.Seven pressure points to stop In treating a victim for shock, try to retain arterial bleeding. the victim's body heat. Place blankets or clothing underneath as well as on top of the victim (fig. 2-16). Remove cold or wet clothing avoid- RA,k, OVIWNC ing unnecessary exposure, and keep the victim's head lower than his feet unless he has a head OW/ OtNI or chestinjury.If he is conscious, provide him with small doses of hot coffee ctea if available, and he is not nauseated or RE:member shockiseasierto prevent than to cure.

totmououct EMERTe NCY PROC EDU RES elf Resuscitation is a general term which covers 1. IMMEDIATE CONTROL all of the measures taken to restore life or 2. PRESSURE, TOURNIQUET. LIGATION consciousnesstoone apparently dead. These 3. PROTECT WOUND measures include ARTIFICIAL RESPIRATION torestore normal respiratory functions and 136.2;4 CLOSED CHEZT CARDIAC MASSAGE to restore Figure 2-14.-- Measures for control of ar- normal heart beat. terial hemorrhage. Artificial Respiration be tightened until the arterial flow stops, but no tighter. Excessive pressure will cause dam- Begin artificial respiration IMMEDIAT73LY. age te the tissue beneath it. However, if the Seconds, rather than minutes, count. Tao person tourniquet isnot appliedtightly enough and nearest the victim should start the resuscita- onlystopsthevenous Flow,it may actually tion without delay and call or send others for increase the loss of artei!al blood. assistance and medical aid. Tie only logical permissible delay is that required to free the The tourniquet should never be covered, and man from his contact with electricity in the the time it was applied must be noted on the quickest safest way. TiIs step, while it must

39 4 5 CONSTRUCTION ELECT4ICIAN 3 & 2

/EYES (--;;" P Vacant Lackluster 1 Pupils Dilated )ri---- '-' --BREATHING \t-1 ('-' Shallow / Irregular I.G..-4:9------S KIaN -wow' 136.6 Colid Figure 2-16. Patient in position for treatment of shock, -NAUSEA

PULSE / Weak or Absent

ARTIFICIAL RESPIRATION MOUTH-TO-MOUTH OR MOUTH-TO-NOSE RESCUE BREATHING

PLACE CASUALTy ON BACKIMMEDIATELY DON'T WAsTE TIME MOVINGTO A BETTER PLACE, LOOSENING CLOTHING, OR LUNGS. DRAINING WATER FROM

QUICKLY CLEAR MOUTH ANDTHROAT REMOVE MUCUS, FOOD, DENTURES,CHEWING GUM, 136.5 AND OTHER OBSTRUCTIONS. Figure 2-15. Look for these symptomsin TILT HEAD BACK AS FAR AS POSSIBLE THE HEAO SHOULD HE IN A "CHIN-UP"OR "SNIFF" shock. POSITION AND THE NECK STRETCHED. LIFT LOWER JAW FORWARD be taken quickly, must be done with 0GRASP JAW BY PLACING THUMB INTOCORNER OF great care; MOUTH. DO NOT HOLD OR DEPRESS otherwise, there might be two victimsinstead TONGUE. PINCH NOSE SHUT OR SEAL MOUTH of one. PREVENT AIR LEAKAGE.

OPEN YOUR MOUTH WIDE AND BLOW TAKE A DEEP BREATH AND BLOWFORCEFULLY (EXCEPT FOR BABIES) INTO MOUTH ORNOSE UNTIL WARNING YOU SEE CHEST RISE. LISTEN FOR EXHALATION 0QUICKLY REMOVE YOUR MOUTH WHEN CHEST RISES. LIFT JAW HIGHER IF VICTIM MAKES SNORINGOR DO NOT attempt to administer first GURGLING SOUNDS. aid or come into physical contact with ce;REPEAT STEPS SIX AND SEVEN 12 TO 20 TIMESPER anelectricshock victimbeforethe MiNUTE CONTINUE UNTIL VICTIM BEGINS TO BREATHE voltage is cut off, or if the voltage can- NORMALLY. not be turned off immediately, before the FOR INFANTS SEAL BOTH MOUTH AND NOSEWITH victim has been removed from the live YOUR MOUTH BLOW WITH SMALL PUFFS OF AIR FROM YOUR conductor. CHEEKS.

To aida victimofelectricshock after removing him fromcontactwith electricity, immediately apply mouth-to-mouth or mouth- 4.224 to-noseartificialrespiration(figs. 2-17 and Figure 2-17.Procedure for artificial 2-18), or both if it is a childor a porson with respiration. 40 46 Chapter 2SAFETY

E:,ternal Cardiac Massage If the victim has suffered an electric shock and has no heart beat, he has had a cardiac arrest. This is demonarated by complete absence of any pulse at the wrist or the neck, dilated CLEAR THE MOUTH pupils, and weak or stopped respiration. The AND THROAT victim may appear to be dead. The object of closed chest...2diac massage is to squeeze the heart through the chest wall, thereby emptying it to create a peripheral pulse. This must be done about 60 times each minute. TILT HEAD BACK AND LIFT JAW DIRECTION5. Place the victim on hs back on the floor or other iirm surface. Expose his chest. Kneel beside victim; feel for lower end of his breastbone; place one hand across the breastbone so the heel of your hand covers the PINCH NOSE lower part; place your other hand on top of the (OR SEAL LIPS) firstsothatthefingers pointtowardthe victim's neck (fig. 2-19). With arms nearly straight, rock forward so that a controlled amount of your body weight is transmitted througli your arms and hands to the breastbone. Ttle amount of pressure to apply will vary with the victim. It should be applied BLOW as smoothly as possible. With an adult,the chest wall should be depressed 2 to 3 inches for the first pressure application and 1 to 1-1/2 inches for each additior -1 pressure application. Repeat application of pressure about 60 to 80 times per minute. An assistant should b, ventilatingthevi, tim's lungs preferably %vial pure oxygen under interrnittentpositive pressure; otherwisewith mouth-to-mouth resuscitation. 4.224 However, closed'IL st massage will cause some Figure 2-18.-- Mouth-to-mouth respiration. ventilation of the lungs. Therefore, if you are alone, you must concentrate on the massage a smallface. If there is no pulse, immediately until help arrives. apply heart massage also (fig. 2-19). Don't waste precious seconds carrying the D'rect other,.suistants, when available, to victim frOm cramped, wet, or isolated locations keep checl,ing victim's pulse. Use the least or to loosen his clothing. Revival chancesde- preasu )11secure an effective pulse crease rapidlyifnot started within 3 minutesbeat.Ti.,epupt19will become smaller when after shock, effective cardiac massage is being performed. Pause occauionally to determine if a spontaneous To eliminate physical contact from mouth-heart beat has returned. to-mouth artificial respiration, an oropharyngeal airway may be used if available; if note a cloth PRECAUTTONS.Make every effort to keep or handkerchief may be placed over the victim'sthe hands positioned as described in order to face. Lf assistanceisavailable, taketurns prevent injuriesto the liver, ribs, or other breathingintothevictim and rnassagthg his vitalorgans.Since the heart cannot recover heart. unless hupplied with oxygenated blood,itis 41 4 7 CONSTRUCTION ELECTRICIAN 3 & 2

4.224 Figure 2-19.Cardiac massage. nece:ssary to accompany cardiac massage with (lig. 2-20). First-degree burnsare character- mouth-to-mouth or mouth-to-noseartificialized only by reddeningoftheskin. Second- respiration. W,en there is only one operator,degree burns are characterized by blistering of the cardiac massage must be interrupted every the skin, either early or late. They are the most half minute or so to institute rapid mouth-to- painfultype of burn. The complete thickness mouth breathing for three or four respirations. of the skin is not destroyed. Third-degree burns are characterized by complete destruction of the skin with charring and cooking of the deeper BURNS tissues. This is the most serious type of burn, for it produces a deeper state of shock andmore permanent damage and disfigurement. It is not The principal dangers from burns are shock aspainfulasa second-degree burn because and infection. All casualty care measures mustthe sensory nerve erangs have been destroyed. be directed toward combating shock, relieving thecasualty'spain, and preventing infection. Emergency T reatment Classification of Burns The degree of the burn, as well as the skin Burns are classJledietwo wve;their area involved, determines the procedures used causes and the doi)th of sk,.e in treatment of burns. Involvement of large skin areas requires a different approach than small 'r iermal burnt:: are tho difeet i osult of heat, areas. To estimate the amount of skin area such as firo, scu.tdllig,u n o Aosion blast. affected, use fig. 2-21. Chemical burns are hy chemical actionEitlehas battery uu:.d un tissues. Elec- Ar a guideline, consider that a burn of more trical. burns may be caused by electrical current than 20 percent of the body surface endangers passing through tissues or a superficial woundlife. The old or the very young victim does not caused by electrical flash. tolerate burn injuries well. Without adequate Burns may be classified as first, second, ortreatment, a burn of more than 30 percent of third degree, based on the dopth of skin damage thebody surfaceisusually fatal to adults. 42 48 Chapter 2SAFET'l:

3RD DEGREE EPIDERMIS la°

ORWM

FATTY TISSUE

f ;4, 471 MUSCLE

2ND DEGREE I ST DEGREE

NOR MA )NORMAL

136.32 Figure 2-20. Types and degreesof burns.

If timc andfacilitiespermitcaring for shock first. Make him as comfortable 1:s possible, superficial burns, the area should be cleaned and protect him from cold, excessive heat, end with soap and water. A 'Ample sterile dressing rough handling. of fine-mesh, dry gauze is then applied over the The loss of body fluids is the main factor in area to protect it from infection and mechanice burn shock. Start oral therapy gradually at first tr aum a. by giving him small amounts of hot coffee or tea frequently. These drinks, or fruit juice or sugar Based on field level casualty treatment con-water, must be givcn only if the victim is conditions, superficial burns include first-degree scious,able to swallow, and has no internal burns and leseer second-degree burns1 which injuries. need little attention beyond self-care. Treatment Pain is closely allied to the degree of shock, of the more serious second-degree burns andand should be relleved as soon as possible. third-degreeburnsisthe subject ofthe To enable personnel trained in the manage- following discussion. ment of burns to determine the type of treatment, When emergency treatmentofdeep burn no medication should be applied to burns during casualtiesisrequired,treatthevictim for emergency treement.

4 9 eraahraarumaraw.7.'- a. CONSTRUCTION ELECTRICIAN 3 & 2

the victimis being treated andtransported. Clothing thatsticks to the burn may be cut around the burn and the adhering cloth allowed 9 %. to remain until it can be removed at the medical facility. Tle area of the burn is usually sterile; therefore, care should be taken not to contaminate I t, Rememberin electric shock, the burn may have to be temporarily ipored while resuscita- tive measures are carried out. Treatment for chemical burns varies uepending upon the agent that caused theburns. Flooding the affected area caused by the burn with large amounts of preferably clean, fresh, cool water will minimize damage provided that not too much force is used uponapplication. Icewater treatmentis aa effective pain reducer, if available. Bccome familiar with the STANDARD FIRST AID TRAINING COURSE, NAVPERS 10081-B. Your prompt and correct response to an emergency may save a life. Above all, remember your A B C's,. Always B.: Careful. (See fig. 2-22.)

R RIM WALLOP

136.31 Figure Compt.ting body surfaoe. After the victim has been treated for pain and shock, a compress and bandage may be applied toprotect the burned area. IfaUniversal protective dressing is not available, fine-mesh gauze may be substituted. Censtrictint articles of clothing and ornaments should be cutaway or removed, and the burned area should be elevatzd and immobilized. sictims with extensive deep burns must be evacuated to a medical facility for treatment as rapidly as possible. Pain should. be allevi- ated and shock must be controlled before and during evacuation. Debris and loose clothing must be removed 40.67 from burned areas to prevent irritation while 5 0 Figure 2-22.--Safety. 44 CHAPTER 3 BLUEPRINTS, DIAGRAMS AND SCHEMATICS

Diagrams and schematics are maps which training manual Blueprint Reading and Sketch- indicatethe location of circuits and circuit ing, NAVEDTR.A 10077-C. If necessary, review connections of electrical installations and equip- chapters 1 through 5 of NAVEDTRA 10077-C; ment.When properly utilized,they arean these chapters provide information that will invaluable aid in troubleshooting or in deter- aid the CE in duties involving blueprint reading. mining faults in an electrical circuit. Locating and repairing faults are some of the most important work assignments you will have. You CARE OF BLUEPRINT, will also be required to install new circuits or repair old construction. Blueprints are valuable permanent records which can be used again and again if you take Blueprints arc reproductions of the working care of them. Here are a few pointers on the drawingsof schematics. The proper use of care of prints: blueprints pays dividends in many ways. For example, blueprints will save many man-hours 1. K2ep then)out of sunlight to prevent of "sight-traveling" cables as you seek mal- fading. functions oran unknown termination point. 2. DO NOT make pencil or crayon notations The ships, planes, buildings, and guns of onaprint without proper authority. If you the Navy were built from plans on blueprints should be instructed to mark a blueprint, use and they are operated, checked, and maintained a crayon or pencil with appropriately colored according to information found on those blue- lead. A yellow crayon provides good contrast prints. N,Vien mechanisms fail in service or are to a blue background while ordinary black lead damaged in battle, blueprints are used to aid pencil marks are hard t.o see. the repairman. When new parts are to be made or the system is expanded, blueprints provide 3. Avoid getting the prints wet or grease- thenecessaryinformation. Remember, too, smudged. that much planning and manpower and material estimating are based on the information con- 4. Keep prints stored properly so they can tained in these blueprints. This chapter dis- be located quickly the next time you need them. cussestheiunction and care of blueprints, A standardized, accurate system of filing blue- a:ic,the importance of being able to read and prints is necessary. This system ensures that work iron) then). the identifying marks appear in the same place, preferably at the top, when the prints are in vertical filing order. BLU EPRINT READING l'he term "blueprint reading" refers to the FOLDING 13U EPIUNTS ability to express the meanings conveyed in drawings, whether the drawings are actually Most of the prints you see will already be blueprints or not. J3c aware that all blueprints folded properly. Your only concern will be to aro not blue in color, butt drawing of an; see that they are refolded correctly after being color which delineates a master or key plan. used.Ifyou use prints that have not been An importantreferenceisthebasic Navy folded at all, or that have been folded improperly,

45 51 CONSTitUCTJON ELECTRICIAN 3 & 2

fold them in such a manner that thedrawing Drawing Number number in the right-hand corner ofthe title block appears on theoutside. (Some older The drawing number is especially important, drawings may have the draw:ng numbers placed both for purposes of filing the blueprint,and for in other portions oi the title block.) locating the correct drawing when it is specified on another blueprint. For example, wherea The method of folding prints dependsupon number of separate buildings shownon a series the type and size of the filing cabinet,and the of blueprints are to have identicalwiring sys- location of the identifying markson the prints. It is preferable to place identifying marks at tems, cross-referencing the other drawingsto the top of prints when filing them vertically one plan which shows all the detailssaves the labor of repeating the wiring systemon every (upright), and at the bottom right-handcorner, drawing. when filing them flat. In somecases construction prints are stored in rolls. Bill of Material PARTti OF A PRINT The bill of material is a list of all the items The chief part of a drawing is, of required to install a particular piece ofequip- course, ment or to erect a particular building.The the graphic representation of the object,what- list includes stock number, description,and ever it may be, together with dimension lines, quantity of each item. As you can dimensions, symbols, and other graphic devices see by referring to figure 3-2, the list is completedown to which explain the representation. Additionalin- the last screw. formation is insc,'ibed in the title block, the bill of materials, the scale, and thelegends and notes. When equipment assemblies are receivedat an advanced base, it is possible foryou, by Title Block checking the bill of material, to quicklydeter- mine if the items shipped are whatyou need for the job in hand, and whether or notthey allowfor The title block (fig. 3-1) gives the title of changes made necessary by local conditions. the drawing, and the number that hasbeen assigned to that drawing. It also indicateswho Scale prepared the drawing, who checkedit,the authority under which it was issued, andthe The scaleof date approved. a drawing is particularly important to the Builders, but it hasa practical

RESPONSIBLE DESIG .ITY GOVERNMENT ACTIVITY AS APPLICABLE DRAWING ENGINLER CHECKED TITLE PREPARED APPROVED DATE SIZECODE IDENT.NO. DRAWING NUMBER SIGNATURE (DESIGN ACTIVITY ) (LETTER(OF DESIGN SIZE OF ACTIVITY) APPROVED DATE OWG) SIGNATURE (OTHER THAN DEGIGN AcaeLdSCALE : (OF DRAWING)! !SHEET OF

45.159 Figure 3-1. Title block.

46 52 Chapter 3BLUEPRINTS, DIAGRAMS AND SCHEMATICS

0 (2)MACHINE SCREWS 6-32 X3/4 L3 0 PROTECTIVE SHIELD DRILL 8 TAP°, HOLE IN HANDLE DRILL (2 )HOLES (0 144 DIA.) USE A 41N DIA X 1/4IN THK FOR THREADED END OF ROD -USE NO 27 DRILL (SHIELD ONLY) DRILL 8 TAP DRILL 1/4 IN HOLE IN A NO 6 DRILL (0 204) (2 )HOL ES 6-32 X3/4 DEEP (HANDLE ONLY) CENTER OF SHIELD (SEE NOTE 3) USE A NO. 34 DRILL (0 111) ()BAKELITE 00 DRILL 8 TAP(2)HOLES tN HANDLE LINE FOR(2) 4-40 NC XI/4 IN (SEE NOTE I) SCREWS-USE A NO 41 DRILL (0 096) SCREW 8 SOLDER CONN IN PLACE

4 (;\ LENGTH, FLEXIBL E COPPER WIRE NO 6 MECHANICAL OR LARGER SOLDER CONNECTION NOTES: 1 HANDLE MAY HAVE SQUARE CROSS SECTION WITH 0 MESH TEETH CHAMFERED EDGES INSTEAD 07 ROUND CROSS TEST CLIP SECTION. 2. IN FASTENING FLEXIBLE COPPER WIRE TO ROD, WIRE SHOULD BE FASTENED WITH TWO SCREWS AND SOLDERED OR,WRAP SIMILAR TO WESTERN UNION SPLICE UNTIL MECHANICALLY STRONG AND SOLDER. 3. THREAD por (ITEM 3) WITH A 1/4-20NC DIE AND 0 FLEXIBL E SCREW ROD INTO HANDLE ( ITEM 1) . INSULATOR (RUBBER) I FLEXIBLE INSULATOR MUELLER NO.26 9 2 MACHINE SCREW 9253,5-812-6647 6-32 X 3/4 IN. LG. NYLON 8 7 1 PROTECTIVE SHIELD 909330-290-3462MIL-P-15035 BAKELITE,TYPE FBE 3B IN X 413 IN. X 1/4 IN. 2 MACHINE SCREW K25305-637-5E184 4-40NC X1/4 IN BRASS 6 I SOLDER CONNECTION SEE NOTE 3 5

1 MESH TEETH TEST CLIP MUELLER NO.24A OR EQUIV. 4 I ROD 929530-233-1299 1/4 IN.COPPER, BEND 3 Et FIT PER DRAWING

I GROUND WIRE, 30 IN. NO.6 FLEXIBLE WIRE,COPPER 2

1 HANDLE, BAKELITE, 909330-29B-713B MIL-P- 79 BAKELITE 36IN,LENGTH 1 1-3/4 IN. DIA. X !SIN. OTY NOMENCLATURE PART NO. OR SPEC. MATERIAL OR NOTE ITEM OR DECRIPTION IDENTIFICATION NO NO.

1.1(26D) Figure 3-2.--A bill of material on a drawing. value to the Construction Electrician as well. to a scale different than that of the rest of the The dimensions indicated on a drawing deter- drawing. Playit safe and READ dimensions; mine the amount of wire and conduit needed in they always remain the same. a group of buildings. The number of poles to be erected can be figured by noting the distances Notes and Legends between buildings. Avoid measuring distance on a blueprint. An example of the notes and legends which Why? One reason is that the drawing may have appear on a drawing is illustrated in figure 3-3. been reduced in size from the original. Another These notes contain equipment specifications, is that the print may have shrunk or stretched. procedures for installing, and operating in- Whenever possible, you should READ the di- structions. They may also contain explanations mensions indicated on the drawings in pre- of parts of the drawing, and other pertinent ference to measuring the distance with a scale. information not included in the views them- LI this is unavoidable, the graphic scale must selves. be checked for possible expRnsion or shrink- The legend lists the meaning of various age. Note especially if any details are drawn symbols,abbreviations, and item numbers.

47 53 CONSTRUCT:ON ELEC'2RICIAN 3 & 2

ELECTAICAL SYMBOLS

NOTES The number of symbols and abbreviations t-ours As SHOWN INDICATE STUB GuyS ONALL DEAD-END,TERMIN4L,RIGHT that may be used on drawings runs into the TURN ,LEFT TURN AND THREE WAY JUNCTION POLES;AND MATERIAL AS LISTED IN BILL OF MATERIAL SUPPLIES THE NECESSARY QUANTITIES OF thousands. All draftsmen do not employ the EACH ITEM FOR SUCH GUYING HOWEVER AS INDICATEDON GUYING DE - TAILS. STUB GUYS ARE TO E2E USED ON THE ABOVEMENTIONED POLES same symbol to represent a particular item. ONLY WHERE 74E LINE WIRE SIZE IS 2/0 A w, O AND LARGERWHEN SMALLER WIRE SIZES ARE USED POLE GUYS WILL SUPPLANTAL L STUB These two facts can make blueprint reading a GUYS AND SURPLUS MATERIAL MAY BE USED FOR OTHERGUYING WHERE NEEDED major task for any rating.

2. ALL WOODEN INSULATOR PINS ARE TOREHELD IN PLACE BY MEANS OF A PENNY NAIL DRIVEN THRU THE SIDE OF THE ARM ANDINTO THE PIN. Fortunately, however, the Department of 3-DEFINITE POSITIONS ARE TOSE ASSIGNED TO THETHREE PHASE WIRES AND Defense prescribes MILITARY STANDARDS NEUTRAL WIRE THE SEOUENCE TOSE USED IS A a, N,cLEFT TONIGHT WHEN FAC'NG TOWARD THE LOAD END OF THE LINE inthis and other areas, which make fora 4 -GAINS TOSE CUT AND BOLT HOLES BORED FORTHE NUMBER OF ARMS TOSE high degree of uniformiy in symbols employed INSTALLED GAINS TORE SQUARE wall THE AXIS OFTHE POLE APPROYIMATEIY 1/2 INCH DEFP AND OF PROPER HEIGHT TO F I T ARM in draviings used by the armed services. Graphic 5-GUYS ARE TO BE INSTALLED WHERE NECESSARY TO HOLD POLES AND APMS IN symbols for electrical diagrams are prescribed PROPER POSITION IN THE LINE EXPOSED SECTIONSOF LINE mAY, WHERE ADVISABLE BE GUYED TO FURNISH ADDITIONALSTABIL1T Y IN CASE OF in the .1;:ierican National Standard Institute's TRANSVERSE LOADS DUE TO STORMS THE POLESSELECTEC FOR STORM GUTS To BE SUPPORTED, IF POSSIBLE, PARALLEL TO AND Standard 4'Y32.9, dated 1972. Refer to table TO THE LINE AT RIGHT ANGLES 3-1 which illustrates a number of electrical -POL E HARDWARE TO BE HOT DIPPED GALVANIZED symbols used on drawings. Use every opportunity you have to study theblueprints of the job to which you are LEGEND assigned. Try topicture in your mind the ROWER HOUSE item represented by each symbol. Trace the electricalcircuits estimating thelength of 4111-41-0- POLE LINE (SECONDARY wire required for each circuit, and the lo-

POLE LINE (PRIMARY/ cationsof conductors and parts. When the lines, symbols, abbreviations, and notes make 3-10- TRANSFORMERS -POLE MOUNTED an understandable mental picture, you have learned toread an electrical drawing. Re- STUB GUY (SEE DETAIL NO 13 member. .if you do not understand what POLE GUI (SEE DE TAIL NO 12) portions of the diagram mean, ask your super- v3sing petty officer. 3-14 - TRANSFORMERS-MOUNTED ON STRUCTURE

NUMBERS REFER TO DETAIL OF POLE DIAGRAMS AND SCHEMATiCS WIRE SIZES-ALL 4160/2400 VOLT PRIMARY TORE:I 6, SECONDARY WIRES TO BE 116 OR II 2 AS REQUIRED TO GIVE PROpER VOLTAGE DROP ConstructionElectricians, who know the trade,"talk with diagrams." When a technical question is brought up, a single diagram is often worth more than hours of discussion. 73.2 There are a number of types of electrical Figure 3-3.--- Representative notes and drawings. These may vary from wiring di- legends. agrams (scale drawings of electrical apparatus which show the exact location ofall wiring and connections) to schematic diagrams and architectural plans. This is a great help to themen of various ratings who may be engaged in t'le work, In figure 3-4, a pictorial drawing, an ele- since not all of them would know the symbols mentary wiring diagram, and a schematic are well enough immediately to grasp the overall compared. They show exactly the same thing, plan for the construction job. You willfind but they look quite different. legends a help when the drawings relate to Let's see how diagrams prove their worth ajob where you must planthe laying of conduit and running of wire around plumbing in voltage distribution, interior wiring, com- fixtures, valves, duct work, or pipelines. munications,and planning. Your work may 5 4involve youin any orall of these areas. Chapter 3BLUEPRINTS, DIAGRAMS Al-SCHI:nATICS Table 3-1. Electrical Symbols

GRAPHIC SYMBOLS

RESISTORS TRANSFORMERS RECTIFIERS -AA.Ar lsutO :,ENERAL GENERAL TAPPEt itin) SEMICCNOuCTOR øf MAGNETIC CORE (NORVAL CURRENT FLOW IS AGAINST TRANSFORMER ADJUSTABLE TAP GENERAL THE ARRow

C,.)NTNuJuSLY vARABLE FuLL WAVE BRIDGE T,PE PEUR :2i9<7\1 AUTOTRANS CAPACITORS SWITCHES ROTATING MACHINES

2ir GEN r GENERAL E *Er,.AR ABLE TRImmER (SINGLE THRG-A MOTOR GENERATOR

GENERAL 0 TYPES OF WINDINGS t DOUBLE THROW)

GAN TvvO ROLE 0 010 DOUBLE THROW 0020 5E1:HER 0 0 SWITCH KNIFESvvITCH___/0____ SPLIT-STATOR FEED THROUGH 5 E.,A9ATELY .SHBUTTON G TEO am ARE) 00 INDUCTIVE COMPONENTS PUSHBUTTON al_sa GENERAL BREAKI SHUNT FuSHBUTTON QL mAO.NETC CORE Twc C,ROuIT 0 0 CIRCUIT PROTECTORS TAPPED Th FuSE DYNAMOTOR

ADJUSTABLE

FUSE OR OVERLOAD BATTERIES CIRCUIT BREAKERS ADJUSTABLE OR CONTINUOUSLY ONE CELL ADJUSTABLE ___/.3195..t_ --11-- SWITCH (-1\ mULTICELL PUSH PULL SATURABLE OR PUSH CORE REACTOR TAPPED muLTICELL GANGED (LONG LINE IS ALWAYS POSITIVE)

ARCHITECTURAL SYMBOLS SINGLE RECPT OUTLET e FLOOR DUPLEX RECPT.OUTLET PUSH Bot "ON HE._ OR SIGNAL DUPLEX RECPT. 161 a SINGLE POLE SWITCH S CEILING INCAN. LIGHT BUZZER 0 THREE voter SWITCH Sa SINGLE FLUOR. FIXTURE IG I SWITCH FOR LOW VOLTAGE SYSTEM SL CHIME CONTINUOUS ROw FLUOR FIXTURE THERMOSTAT

PUSH BUTTON STATION BELL TRANSFORMER EXIT LIGHTICEILINGI 0 MOTOR CONTROLLER ) ExIT LIGHT (WALL) --0 WIRE CONCEALED IN FLOOR WIRE CONCEALED IN WALL OR CEILING JUNCTION BOX 0 NNE WIRE CONCEALED IN FLOOR RECESSED PANEL CLOTHES DRYER OUTLET -*CD BRANCH CIRCUIT EXPOSED

13.5 .

49 5 5 CONSTRUCTION ELECTRICIAN 3 & 2

generatingstation,3-phase /4-wirefeeders carry the power overhead to the distribution points, from which primary mains branch off. One of these carries power to a lighting system and single-phase motor in a motor pool,

ooth designed to , ,rate on 120 volts, and to a three-phase mutor designed to operate on 208 olts. The 208-volt three-phase motor is connected directly to the 208-volt three-phase SCHEMAT(C main. For the lighting system and 120-volt mo`ar, only single-phase power is necessary. Similarly, power is run to operational headquarters, living quarters, and mess hall. A PLAN drawing is another type of drawing useful in exterior layout. The objects in views and C of figure 3-7 are depicted as seen from directlyabove. In this way, the proportion and relations of the parts of the drawing to one another can be shown. The PLOT WIRING PLC'; (fig. 3-7, view A) shows an area and gives the exact layout of various buildings, roads, equipment, and so on. Figure 3-7, view A, is a plot plan showing five buildings which are to be supplied with electricity for power and lighting. An electrical layout has been superimposed. General notes (fig,3-7, vlew B), one detail (fig. 3-7, view C) and section AA (fig. 3-7, view D) of that detail are shown. The dotted lineat thebottomof the drawing indicates underground ducts containing previously laid cable. The design engineer has decided to tap the cable at manhole (M.H.) 22, and run lines from there overhead to dead end at the rear of building 126. Figure 3-7, view C, shows that lines are to be run underground from M.H. 22 to the first pole, up the pole to conductorson the pole crossarms. At building 126, linesare to be carried down the pole, regathered through a pothead into conduit again, and run underground to a concrete slab, and out through PICTORIAL another ;:othead to a transformer bank. Where do you get this information? Refer to figure 3-8. Figure 3-8 sho - the detail B indicated in 73.269 figure 34, view A, This represents the in- Figure 3-4. Variety of diagrams. stallation behind building 126, where the overhead lineterminates. The last pole in the EXTERNAL DIST -LIBUTION SYSTEMS f;ystemisshown in the lower left corner. From the pole to the transformer bank, the Figures 3-5 and 3-6 :11ustrate a pictorial underground conduit is indicated by dottedlines. and schematic view of a 3-phase/4-wire dis- The conduit runs underground to the concrete tribution system. Assume that the system has slab on which the transformers rest. Section an alternator generating 208 volts. From the A-A gives construction details of this slab.

50 56 Chapter 3BLUEPRINTS, DIAGRAMS AND SCHEMATICS

GENERATOR PLANT 208/120 V 60 Hz 3 PH 4 WIRE

DISTRIBUTION POINTS 208/120 V 10

MOTOR POOL LIGHTS AND 120 VOLT SINGLE-PHASE MOTER

208/120 V 10

208 V 3 0

LIVING QUATERS OPERATIONS 208 V 120 V 10 3-PHASE MOTOR

208 V 3 0 120 V1 0 TO MESS HALL

82.71 Figure 3-5. 3-phase/4-wire distribution system, pictorial view.

5 7

51 CONSTRUCTION ELECTalCIAN & 2

INTF,RIOR WIRING Figure 3-9 shows an electrical layout super- GEN 208/120V imposed on an outline taken from an architec- 3 PH tural floor plan. The service line bringingpower 60 Hz into the house is a three-wire line in 1 1/4-in. conduit. However, the fact that the line voltage is 120/240 indicates that these three wires 208V 3 0 must be two hot wires and a neutral wire from a four-wire system. The third hot wire is not brought into the house.

NETURAL-() The service line feeds power by way of a service switch to a lighting panel, from which three BRANCH CIRCUIT:3 run to the lighting fixtures and convenience outlets in the rooms. The symbols for these fixtures and outlets, and of the service switch and the lightincr panel, are shown at the bottom of figure 3-9. Figure 3-10 is a wiring diagram showing the connections for the layout shown in figure 3-9. After entering the building, the two .iot wires (black) in the service lead are connected 20.J12 0 V1 0 MOTOR POOL LIGHTS to and fused at the service switch, while the AND 120 VOLT neutral wire bypasses the switch and runs to SINGLE-PHASE MOTOR the NE1JT1tAL BAR in the panelboard, with a branch off to a waterpipe ground. Bayond the service switch, the two hot wires run to vertical. LINE 13&RS in the panelboard. The panelboard is equipped to handle six circuits, with only three shown in the diagram. Consider branch circuit4.It contains two wires, a hot wire running out from a circuit breaker in the panelboard, and a neutral (white) 208/120V 208V 3 0 208/120 V0 wire running back to the neutral bar in the 1 0 120 V 1 0 OPERATIONS LIVING MESS panelboard. This circuit contains only a single OUATERS HALL switch, which turns all the lights in the circuit on oroffsimultaneously,but has no 82.72 effect on the flow of power in circuits 2 and 6. Figure 3-6. 3-phase/4-wire distribution system schematic. Circuit 2 similarly contains a hot wire out from the panelboard and a neutral wire back. The angle-iron symbols in figure 3-8, with Each of the lights in this circuit has its own the dimensions 3" x 3", indicate that the BUS switch, which controls the flow of power to (connecting conductor) running along the trans- that light only. Like circuit 6, circuit 2 has f')rmer primaries will be supported on posts a hot wire out from the panelboard live bar, and made of 3" x 3" angles. From the transformer a neutral wire back to the panelboard neutral secondaries, underground conduits (indicated by bar. dotted lines) will run to the junction box on building 126. Pay attention to the various notes and details WIRE COMMUNICATIONS indicated in drawings. Your life, and the lives of your coworkers, may depend on the care you Schematics and wiring diagrams are used ex- take when reading and interpreting drawings. tensively in telephone communications. Figure

52 58 C hapter 3BLU EPRIN TS, DIAGRAMS AND SCH E.MA TIC S

ExISTING DUCTS To EMH 21 POWER COMPARTMENT SEE DETAIL '13'

APPROX DISTANCE STUB POLE 2010' BETWEEN POLES ,TISTING DUCTS TO EMN 23

-3

2"ExISTING STEEL CONDUIT , - 9 TO BLDG 132 ABOVE DUCT

1! SEE NOTES j ; 4 5 5 4-STL CONDUIT INTO EMH 22 8 UP POLE TO POTHEAD HEAD GUY-3/8' STEEL CABLE - I-3/C 6110 VCL STRAIN INSULATORS-B" SCREW ANCHOR OR SIMILAR METHOD (TyPICALWITH ADDITIONAL ISM GUYS AS NEEDED)

0 011 3- iic .2 wEATHERpRooF WIRE DR EQUAL

EXISTING ROAD APPROX DISTANCE DURUM POLES 25.0"

SEE NOTE BLOC ,30

PORCELAIN INSULATOR sEE DETAIL A. BLDG 132 APPROx DrSTANCE BETWEEN POLES BO.0 mn22 SEE NOTES4 5 5 L'GHTYNG ARRESTER

5KV POTHEAD. WITH 4" CONDUIT COUPLING

GENERAL NOTES ROLE. 35.0" CLASS 3 I- TREES OBSTRUCTING POLE LINE TO BE TRIMMED OR REAKIVED AS DIRECTED (TYPICAL) BY CONSTRUCTION OFFICER 2- PROVIDE LIGHTNING ARRESTERS. AT EACH END OF POLE LINE, ON ALL THREE OVERHEAD WIRES GROUND LIGHTNING ARRESTERS WITH SUITABLE BARE WIRE CONNECTED TO DRIVEN GROUND ROC( 3- INSULATORS TO BE PORCELAIN, pIN TYPE, INSULATOR PINS TO BE LOCUST WOOD OR EQUAL 4- TERMINAL POLES, AND POLES AT POINT OF CHANGE IN LINE DIRECTION, TO HAVE DOUBLE CROSSARMS, ALL OTHER POLES, SINGLE CROSSARM. CROSS-ARMS TO GROUND LEVEL 1111 BE STANDARD 4 PIN, 5.- T". 3 VV. 4 I/2", PIN SPACING 3!Co. ON CENTERS AND 14weON SIDES 5- TERMINAL POLES TO HAVE ONE GUY, POLES AT POINT OF CHANGE IN LINE 4" STL CONDUIT DIRECTION TO BE GUYED ACCORDING TO STANDARD PRACTICE EACH GUY LINE To HAVE TWO PORCELAIN STRAIN INSULATORS, THE LOCATION AND SPACING OF STRAIN INSULATORS AND GUY ANCHORS TO BE IN ACCORDANCE WITH STANDARD PRACTICE - MATERIAL ANO WORKMANSHIP SHALL CONFORM TO ALL STANDARD CODES. REGULATIONS AND SPECIFICATIONS LISTED IN NAVFAC SPECIFICATIONS 1SECTION A-A

65.67 Figure 3-7. Plot plan with electrical layout, general notes, detail and sectiondrawings.

53 5 9 s'-o

BOLDING WIRE MESH ex461.65/..

SECTION 'AA' TRANSFORMER PLATFORM

55:0"

FUTURE SERVICE

25 KVA 25 KVA 25 KVA

DISCONNECT SWITCHES

,11 (CONDUIT 01111MMIMMIIIMM1111 .NNCONCRETESLAB IN116E11111.

X A X

DETAIL 'El' PART PLOT a FLOOR PLAN BLDG *126 Figure 3-8.Detail B indicatedin figure 3-7. 6 0 BUILDING

WIRE MESH et( kb .850/:

SECTQN'A-141 TRANSFORMER PLATFORM

55=0"

FUTURE SERVICE

rCONDUIT \CONCRETE SLAB

- 0- X z -4Y X

sfaLL'A; PART PLOT a FLOOR PL AN -BLDG 1126

Figure 3-8.Detail B indicatedin figure 3-7. 65.69 Chapter 3 BUJ EPR1NT,, DIAG.i-AMSAND SCHEMATICS

INCOMING 120/240 V SINGLE PHASE SERVICE 3-NO 4 STORE ROOM 11 OFFICE NO i OFFICE NO2 TYPE PH IN 1-I/4 BRANCH C1RGU/r CONDUIT

OUTER OFFICE

BRANCH CIRCUIT 4

L.) OFFICE NO 3

SCALE 1/8". 1.-0"

SYMBOLS 0CEILING LIGHTING FIXTURE mD DUPLEX CONVEMENCE OUTLET 0-, 100 AMP 2 POLE,SOLID NEUTRAL,110/220 VOLT SINGLE THROW SWITCH LIGHTING PANEL-MULTIBREAKER TYPE G-20 AMP SINGLE BREAKER S SINGLE POLE WALL SWITCH DOOR OPENING

45.,515 Figure 3-9.Inside electrical layout.

SERVICE ENTRANCE

PANELBOARO

SOLID. BRANCH CIRCUIT 2 NEUTRAL BAR

FUSED SERVICE SWITCH

NEUTRAL WIRE (WHITE)

FU SE S BRANCH BRANCH IRCUIT 6 CIRCUIT "4

HOT WIRE"- (BLACK) GROUND CONNECTION

WATER PIPE WALL CE LING SWITCH OUTLETS

82.76 Figure 3-10. Schematic for layout shown in figure 3-9.

55 6 2 CONSTiUCTION ELECTRICIAN 3 & 2

3-11 shows a line circuit portion of a major switchboard circuit. INOPERATIVE STATION Section A shows the telephone set in its nor-' rnal condition. The receiver is on the hook and all lamps and relays associate-i with this section are in their unoperated Section B delineates in bold lines what happens whenapersonatthe calling station removes his receiver from the hook and the LINE hookswitch contacts close. Battery, Bl, sends !CIRCUIT current through the series circuit consisting NO I of line relay LR1, the ring side of the line, the primary winding of induction coil P, the trans- TIPLJI mitter, and back to ground through the tip side of the line. Relay Lill operates, closing the circuitofline lamp LLI, thus lighting the RING lamp. E As you can see from the above sequence of LLI events, intelligent interpretation of schematics and diagrams will permit you to better under- standandservicetelephone communication systems. Ask yourself when you encounter unfamiliar schematics, "What is the sequence of events? What relay energizes coil X or Y or Z? What is the normal current flow? What is supposed to happen?" As you ask and answer these questions, you mill become more knowl- edgeablo about circuit operations and functions. CALLING STATION ELECTRIC APPLIANCE AND EQUIPMENT REP.AIR You may be required to install or repair the electric range or oven in the galley. HDN/ will you go about this task? Obviously, you will obtain the manufacturer's technical manualfor the specific equipment you will be installing or repairing. Figure 3-12 shows a representative wiring diagram of one of those.ranges. What will you do if you are required to install range or oven timers? Figure 3-13 and 3-14 are wiring diagrams for range and oven connections to timers. Notice how use of these diagrams will enable you too install or repair theappliances indicated much more readily than blindly trying to trace out the circuitry fir the appropriate connections.

NAVAL FACILITIES ENGINEERING COMMAND DRAWINGS

73.270 The ConstructionElectricianvery often Figure 3-11. Line circuit portion of switch- works from a drawing prepared by the Naval board.

6 3 Chapter 3BLUEPRINTS, DIAGRAMS AND SCHEMATICS

2 ND HIGH 230-VOLT COILS3 RD LOW WARM 115 VOLTS rip,

; 1 1 115 t

1 IS VOLTS 121,11 yr, IS -230 VOLTS _LH1 NEL/TRAL FIVE-HEAT-RANGE SURFACE UNIT I IS VOLT S HIGH- MFT'ILW- LOW- 1,00 WATTS 6,-1 ..:;! 320 WATTS THREE-HEAT-RANGE SUN Ft.CE UNIT BLACK Gtacx

OVEN APPLIANCE PILO RECEPTACLE

WHITE WHITE

OVEN

LEFT FRONT ICT EAR RIGHT REAR RIGHT FRONT 0 000 0

111..

TC 80 THERMO

15 SW 307 13 SW 700 15 SW 102 25 SW 303 6-POS SHE AT 4-POS 3-HEAT 6-POS 5-Hk AT 6-POS 5-HEAT SURFACE SURFACE SURFACE OVEN SWITCH SWITCH SWITCH SWITCH

BLACK 14

F. NEUTRAL IDENTIFIED BY WHITE INSULATION AND NICKEL TERMINAL

FUSE RECEPTACLE

TO UNE

73.271 Figure 3-12. Range wiring diagrams. 57

6 4 CONSTRUCTION ELECTRICIAN 3 & 2

LEADS TO rBLACK LEADS TO TIMER ,... v-

RED LEADS TO TIMER rRED LTADS TO TIMER RED LEADS TO RED LEADS TO THERMOSTAT OVEN SWITCH WHITE LEAD WHITE LEAD TO TO TIMER

1 LINE rNEUTRAL LEAD LINE LEAD LINE LEAD

h te NEUTRAL LINE LEAD el 1

...b. felk CONNECTOR rd.icL.f, I...v.mo% GROUNDING NEUTRAL STRAP TERMINAL 0 t DISCONNECT AND USE PORCELAIN CONNECTOR CAP WHEN ADDING TIMER

TO LINE

73.272 Figura 3-13. Representative wiring diagrams for range timer connections. FacilitiesEngineering Command. Construc- tion battaLons seldom have the time or facilities for prept.ring a set of blueprints. For this reason, NAVFAC has prepared a series of drawings for use at advanced bases. This series of drawings is entitled Facilities Planning Guide, SINGLE POLE OVEN TIMER Volume I, NAVFAC P-437, and is kept in the 118 VOLT operations or engineering office. These draw- MOTOR OVEN-208 VOLTS THERMOSTAT ings cover most types of major installations. SINGLE Copies are made available toall battalions POLE before they leave the United States. A completesetof drawingsis composed of a number of separate drawings. The specific information which the drawings provide on proper installation of equipment and operating procedures will furnish satisfactory answers to many installation problems. The standard drawings prepared by NAVFAC can save a surprising amount of time in the 118/208 VOLTS THREE erection of a number of similar structures, WIRE SINGLE PHASE N L2 and in wiring them for heating and liE,fliting. For example,, if a series of quonsets are to be erected, use of a standard plan enables the man in charge to put the various tasks on an as- 73.273 sembly line basis, and makes it possible to Figure 3-14. Representative diagram of erect an entirequonset town in less time electric range single-pole oven timer, than it would take to build an ordinary house.

6 5 r,wr ONNet 5( ,NWS. OICS /

ASSEMBLY 30109. Li) t.ILL BUILDING LN,IINNO CIRCUIT -700 W- 7 FOOT -CANDLES PL AN SCti. 1,8(--cr

'hi" floCrli,ES,NotAr ALL "..-errA:11 .....:" --.' AT CE,14C11-5 ON LOOTS/ Go?? 5-.------::-.-.4-..-- - ...... - - .5.-- E., , - 41., -'.... U.- --I-- -.3-- .. -: - Z .----1:- -6.. i.'" 4 1.- 1 I.- 16/ f 6S, iil (D 'ilciCi. CIF C0,7 , 7 !1 j ..7. I OVL 7. .S.A.A. 7 I 13 '. I .4i5t..7_ _,..- - -...r, e 5 0- '' - -0- ''' '- '' -(_)- ''' ''' "" -Cr ,-I4 C \ ------,,T).''. - - . b " 'T." - - -0- ." -.1-'- ts,

,-, ,0E Orl/ 41,5 NOUN !ED CIC Si T ''' THESE AVRL INS / 0------.Z-1 T?, C,RCT ovcr, 90,6trit ------17

ASSEMBLY 30101 di E VEL BUILDING LIGHTING El RECEPTAC, . ECoRCIIrTS- 300 22 FOOT- CANDLES PLAN SCALE ye'. C-0'

pa, TINS ELOCOLITES.MOUNT ALL iLl-P1.74%,(5 C,. LCAE Sr GIP? -I.

-11-' j----- L ; LJ LJ LI LJ .J

LWE. usepIf CIRCLPT fPLY ' 41,.Lo -75-J "tir74-e21 - -8-

P.RoNs, .9..,PPORT rIxrciRES FROM SAME

ASSEMBLY HIGH LEVEL BUILDING UGHTING B RECEPTACLE CIRCUITS- 4N FOOT-CANDLES PLAN scALt vee-0'

Figure 3-15.--40x 100' 6 6 4 ,L 011,1110111,

17100,10101.

" *_. _1

012 4.11 ...a. t

t.;

r po .4.14 30'I3 IL. II , ' 1 P.11. .4,-11 LILL

A- Lt...11% L.

2.1 v." 4 la lel ", 10II0 5C AY, v./1 A. cut Lc 2.1,:11 ...XI!.4. 1111073 t .1 OLX 0. A A- IL 31/0 ;0E.-.-i ;,,00011-s6 FIXTURE 11. '3.171.1.1_1-1, TAIL .J11,11_20,1 tALL-1.

..,02,1_,,,,,,,,, 7.. L i 7 IIALNIA1-0 ' ..4 _x17.5.4.)_e_L,,. 1, 1490 13_LII_10. le '.1 1+011.11211,1 IIlII LI. , _._,...... ,4.1.145.1.1.4.2,-...5.1_ _L ", 1,4,La2 AN La Lis__ SA _.c si /11 t rt- :IN 4: :LE r Of .1 H Ra t 1 I1._ II ...1,12L.141 30 4 SPA R( .1_ 1.1 c!. 11____11 It* _a_ aos ao a F., ass'i ; 34 5C4 5,4R1- 1.14:_so0 r sRs Rso .os I '4.. t 5040( lh041_9 , ,41141 5P4,11- .00 1111/ ;1: : co. 00 t.00 t.

)0101 . , 11/530E 223 AM/ 7: ....NEL PGA.: 51"...TCLIA 1-`'.1_ zc.e, 4 DETAIL _ NO SC 01.1

2Ux RECI-1,4C2E2 - _ IC.4.7,4 o'S'a T ,R 274 PEC(P14C2C5

lCo,,rt, 274 ,, ' --,, 2) 4 4:11,r4141- 5 160111/G 204 ,-- 2,' 4 RI11-01402(5 16,11,V0 204 9 ___...... ,.., 10 4 -.24,1.01 4,1 9

2'0.15 204 I. , -, :'i'.., olSP4C1- ,,I 411 R 4104,15204 53.--, --7.-.7/ Oa 4 54,21 ..... f a .0.1 5304305' .-7 4 5304301 SPAR- 224 7 ,--, , -, /8 20 5304RC

530401 '5 4..1.- ,.. --q1.1 4 52430f 17 ---::, ----.--4 ,,'-' C, - - -h - - 4, 5,41Ir 76 60 3 5,40 1' 75.1.J LAG juPE F4SEDES 1,M 100,10.1711/0130110X Ix ,RPND It DAG NO'S 102E1204. "TT*, 'MINT OF NAVAL IREILITIES ENGINEERING COIRRANO 1028201, . 028206 SEABEE SYSTEMS ENGINEERING OFFICE 5( so 13_,... ._,...-...±1504 54540 1 CO1/I.91JCION .ATIALION CENTER 6/81,1,NEIL Gamma DA, Er.:4 - 22 6 ,L .-Ni.-,_ 2.D 1028323 001A7(00 BAST IUNCTIONAL L01111,3007.1 t.114. 1 594301 rOC 1?- ,.___..._--0412. 4704 53040C DATED 40 X100 RIGID FRAME BUILDING --r-r,;.) ,/,5 t.:' LIGHTING. RECEPTACLEaSERVICE , 1 , ENT RANCE A SSEMBLIE'D EL ECTRICAL STANDARDS

V.L.22, 5i02 000P.IE SCALE /.0.11, 225 4, ;IJEE -04 010 BLDG AD X IDE Moo.1 130091 1 33100.30,31 301N 1109858 COlIC S V./ 69035 011, 1 0, 1

73.367 Igid frame building assemblies. 6 7 =1,M Chapter 3BLUEPRINTS, DIAGRAMS AND SCHEMATICS

However, a single master plan cannot be assembly d:awings show where the main panel used for all buildings. Changes are often necis located, it3size, the material needed to essaxy because of the use of the building and mountit,the number and types of lighting the type of machinery to be installed. Where fixtures, the number of receptacles used, an..1 shops are being erected, th:re will probably Iny special details in its construction. be at least one standaru drawing for each type of shop. In studying the print, notice that each home run (return to panel circuit breaker) is given Figure 3-15 is a standard drawing for a a number. This number indicates what ci-.- 40' x 100' rigid frame building being used for cuit breaker tilts circuit will tie into in the three different types of assemblies. Ali three main panel. The panel is numbered and aach r

H I CONT. CAPACITOR SWITCH LINE

RUNNING START OTOI WINDING WINDING

LINE

73.368 Figure 3-16. Freehand sketch of a single-phase capacitor start motor connected for clockwise rotation.

IJ CENT. CAPACITOR SWITCH LINE

RUN START WINDING WINDING

-4) LINE

73.369 Figure ;1-: 7. Freehand sketch of a single-phase capacitor start motor connected for counterclockwise rotation.

59 68 CONSTT1UCT:ON ELECTRICIAN 3 8i2 circuit identilied for general use and tie-in location shall be checked with maimfacturer's purposes. installation plans." This could call for extra or special materials to install a special piece cf The mounting details shown on the drawing equipment. You should be awal^e of this, because for the incandescent lighting fixture are the when changes are ncessary, the deletionor mounting height above the floor (1,.' 0") and addition should be shown on the appropriate the typeof mounting used.For instance, print to keep them AS BUILT. number 25 (insidethe hex symbol for the incandescent fixture)refers you to number From studying prInts of these assemblies 25 on thu bill of material. The bill of material and with a good knowledge of interior wiring, describes item nunther 25 as a junction box, you should be able to wire up all three of these octagon, 4" x 1 1/2" deep, with 4 knockout assemblies with the least amount of trouble plugs for 1/2 inch connectors. Assembly 30100 and in the shortest time. willneed22 of these, 30101 will need 42, and 30102 will need three. Assembly 30102 will use fluorescent lighting, suspended bya FREEHAND SKETCHES chain 14' 0" abovo the floor. Like the example (number 25), all hardware used is indicated by 3eing able to redraw a circuitcan be very numbers, which refer you to the bill of material helpful and necessary at times. An example of for descriptions and amount. this could be changing the direction of rota-ion of a single-phase, capacitor-start motor which Thebillofmateriallistsall items by runs clockwise. You would want to reconstruct number, description, unit and quantity for each the circuit by ..lrawing the running and starting assembly. The notes on the bottom of this coils according to the existing hookup. Then bill give specia.' instructions that will be useful you would redraw the hookup the way it should when working on the job. For example, note 3 beforthe motorto run counterclockwise. states:"Finished dimensions and equipment (See figs. 3-16 and 3-17.)

60 CHAPTER 4 SPECIAL TOOLS

As a Construction Electrician, you must be PORTABLE POWER TOOLS able to use the special tools andequipment needed in your work. Among these are the portable power tools, such as drills and grinders, the pneumatic In the shop or field, you will be using portable pavement breaker, power hacksaws, powder- power drills, hammers, and grinders. You should actuated tools, air compressors, and earth augers. be thoroughly familiar with the operation and care of these tools and with all applicable safety precautions. Only the portable power tools not coveredin Tools and Their Uses, NAVPERS BATT WON TABLE OF ALLOWANCE 10085-B, are discussed in this chapter. In an NMCB, your portable tools will come from prepackaged kits which are part of the Part I equipment allotted to a construction battalion for overseas deployment. The battalion's tableof Personnel allowance (TVA) takes into consideration a niqn- Weapons and Infantry Equipment ning level of 24 officers and 738 enlisted ;el.' )el NBC Warfare, Radiac, Damage Control, in a wartime deployrnentadanortherntenj ac and Safety Equipment environment. Four men can work out oi each Administrative and General Services prepackaged kit of tools. Part I of the TOA lists Maintenance Tools and Shop Equipment the battalion organic equipment and material. Construct:-T Tools and Kits (See figure 4-1.) Pert II consists 01 equipm3nt Construction Oriented Consumables and suppliescontrolledby COMCBLANT/ Mount-out Material and Containers COMCBPAC. Pie tools used by 'company Clothing and Bedding shops and field crews come under Part I, sec- Medical and Dental tion 6. Communication and Test Equipment Forms and Publications The contents of an electrician's tool it:tre listed in figure 4-2, those of a lineman':, ]it. in figure4-3. Notice that the kits contain only bac t II handtools. (Power tools have to be ('hecked out from thecentraltoolrooxn.)T'iekits for a (20) Civil Ligincui ing Support Equipment battalion's shops and maintenance platoon include (CESE) plumber's kits,refrigeration kits, sheet metal Facilities kits, an electric arc welding kit, and iniscollaneous Collateral Equipment for Facilities equipment (fig. 4-4). As a crew leader or shops (23) Petroleum-Oil-Lubricants (POO supervisor, you willbe responsible for the (24) Provisions checkout,control and inventory, and care and (25) Repair Parts maintenance of these kits. COMCBPAC/ (26) Tactical Support FaciliticL COIVIBLANT Instruction10290.2E coversthe (27) Contingency Support procurement, issue, and care of Illuidtools and power tools; tool custody record cards; power tool preventive maintenance; and the drawing of sample tool kit boxes. Figure 4-1.Battalion TableofAllowance.

7 0 CONSTRUCTION ELECTRICIAN 3 & 2

SOLDER 50/50 ROSIN 3/32 I LB BLOCK AND TACKLE 1/2 F-RP 2 EA SOLDERING GUN ELECTRIC I EA BAG LINEMAN GLOVE 4 EA STRIPPER CABLE F/TYPE NM 4 EA CLIMBERS TREE-POLE WITH BRACE BIT RATCHET 12 1 EA STRAPS AND PADS 4 SE PLIERS DIAGONL CUT 7 1/2 4 EA CLIMBER STRAP AND PAD SET 4 SE FILE AMPAT RD BAST 10 I EA STRAP SFTY NYLON 1-3/4X84 4 EA KNIFE POCKET W/SCDR-SCRPR 4 EA BELT TOOL LINEMAN SZ 36 1 EA FILE AMPAT REG TPR 7 1 EA BELT TOOL LINEMAN SZ 38 2 EA STRIPPER WIRE ELECTRIC 10/18 AWG 4 EA BELT TOOL LINEMAN SZ 40 1 EA BLADE HACKSAW 18T 12LG 2 BD FILE AMPAT FLT SMTH 12 2 EA F_ADE HACKSAW 32T 12LG 2 BD BRACE BIT RATCHET 12 1 EA FRAME HACKSAW ADJ 10-12 2 EA CHISEL COLD 3/4 SAWS NEST KEY-COMPS-NAIL 2 EA 1 SE FILE AMPAT MILL BAST 12 2 EA HOLDER FILE TOOL ADJ JAWS 2 EA KNIFE LINEMANS FLDNG 3 4 EA CHISEL SET BUTT WOOD W/RL I SE BLADE HACKSAW 18T 12LG 1 BD PLIERS SLIP JOINT 11-1/4 LG SMOOTH BLADE HACKSAW 24T 12LG 1 BD JAWS 4 EA FRAME HACKSAW ADJ 10-12 2 EA SCREWDRIVER OFFSET I/4N 5 1/4N OA 2 EA HOLDER FILE TOOL ADJ JAWS 2 EA AWL SCRATCH 3 1-2 4 EA CHISEL FIRMER 2N 2 EA SCREWDRIVER COMM 1/4X4N 4 EA CHISEL SET BUTT WOOD W/RL 2 SE PULLER FUSE 0-100 AMP 1 EA HAMMER HAND ENG 2 1/2 LB 2 EA SCREWDRIVER CABINT 3/16X6 4 EA SCREWDRIVER FLAT TY 3/8X12N 4 EA SCREWDRIVER FLAT TIP MGNTIC 1/8X2N 4 EA PLIERS LINEMAN 8N 4 EA SCREWDRIVER PHILIP NO 3 TIP 6N BLADE 4 EA WRENCH OE ADJ 8N 4 EA SCREWDRIVER PHILIP NO 2 TIP 4N BLADE 4 EA WRENCH OE ADJ 12N 4 EA PLIERS LINEMAN 8N 4 EA WRENCH LINEMAN DBL 4 EA WRENCH OE ADJ 8N 4 EA PLIERS SLIP JOINT ION 4 EA PULLER FUSE 100-600 AMP I EA SCREWDRIVER FLAT TIP 3/8X8N 4 EA PLIERS LONG NOSE 6N 4 EA SCREWDRIVER FLAT TIP 5/16X6N 4 EA SCREWDRIVER CABINT 3/16X8 3/16X8N 4 EA HAMMER HAND CARP 20 OZ RIPPING WRENCH OE ADJ 12N 2 EA FBR GLS HNDL 2 EA WRENCH PIPE ION 2 EA BIT AUGER SHIP 11/16X29 2 EA WRENCH V-GRIP PLIER 8 1/2 4 EA BIT AUGER SINGLE SPUR CAR W/SCREW SCREWDRIVER START 1/4X6 4 EA POINT 9/16X18N 2 EA SCREWDRIVER FLAT TIP 3/8X8N 4 EA BIT AUGER SINGLE SPUR CAR W/SCREW SCREWDRIVER FLAT TIP 5/16X6N 4 EA POINT 7/16X18N 2 EA PUNCH CENTER 3/8X4 I EA BIT AUGER SINGLE SPUR CAR W/SCREW PUNCH CENTER 1/4X3 1/4 NO 2 1 EA POINT 11/16X18N 2 EA HAMMER HAND OUTLET BOX 4 EA BIT AUGER SINGLE SPUR CAR W/SCREW WRENCH SET SOCKT SPINNER 2 SE POINT 13/16X18N 2 EA SCREWDRIVER STUB FLAT TIP 1/4X1 3/4N 4 EA BAG TOOL SATCHEL CANVAS 24X14X6N 4 EA KEY SET SCKT HEAD SCREW 1 SE BAC BOLT NUT W/BELT LOOP I EA DRILL ELEC PORT 1/2 1 EA RULE WOOD FIDG H-DTY 72N 4 EA DRILL SET TWIST 1/16 TO 1/2 BY 16THS I SE TAPE MEASURE CHROME 100FT GENERAL BIT SET AUGER 1/4 TO 1 N I SE PURPOSE 1 EA TAL BOX STL MECHANIC 4 EA TAPE ELEC PLASTIC 3/4 2 RO POCKET ELEC TOOL 4 EA HOOK PULLING STRANDVISES 2 EA TAPE MEASURE FLEX 10FT 4 EA PROTECTOR RUBR GLV 4 PR RULE WOOD FLDG H-DTY 72N 4 EA GLOVE ELEC RUBBER SZ 10 2 PR LEVEL AND PLUMB 9N I EA GLOVE ELEC SZ II 2 PR INDICATOR LINE VOLTAGE 4 FA GLOVE LINEMANS LTHR 4 PR l'Icvmi Eloctric lan's tool klt lltit for four Flguro 4-3.-- LthomarOB tool kit Hut for four !non (80006). num (80007).

7 1 Chapter 4SPECIAL TOOLS

GRINDING MACI BNCH 1X7WHL 2 EA TAPE FISH POLYETHYLENE 100 FT 3 EA TORCH OUTFIT CUTNG-WLDNG 4 EA FLATTER 2 1/2X5 BLKSMITH 1 EA BENDER PP-COND HY 1 1/2-4 1 EA SHOVEL RD PT LG HNDL 10 EA THREADING MACH PIPE-BOLT PORT VISE SHT MTLWKR 9 2 EA 1/8-2PP 1/4-1 BOLT 2 EA VISE WOODWORKERS 12 4 EA BLADE HOLE SAW 2N 1 EA STAKE SHT MTL BLOWHORN 2 EA BLADE HOLE SAW 3/4N 1 EA VISE BENCH 4 1/2N JAWCOMB 2 EA BLADE HOLE SAW 7/8N 1 EA PIKE POLE 14FT LG 8 EA BLADE HOLE SAW 1N 1 EA BENDER CONDUIT 1-1 1/4 6 EA BLADE HOLE SAW 11/8N 1 EA SHOVEL SQ PT D HNDL 4 EA BLADE HOLE SAW 11/4N 1 EA PLATE BENCH MTLWKR 2 EA BLADE HOLE SAW 1 3/8N 1 EA HAMMER HAND BLKSMTH 3LB CROSS PIEN 2 EA BLADE HOLE SAW 11/2N 1 EA BENDER CONDUIT 1/2-3/4 8 EA BLADE HOLE SAW 1 5/8N 1 EA DRESSER WHL ABR W/X CTRS 2 EA BLADE HOLE SAW 1 3/4N 1 EA JACK REEL HAND 4 EA BLADE HOLE SAW 1 7/8N 1 EA HAMMER HAND BLKSMTH SET 1 EA ARBOR HOLE SAW NO 1 5/8X1 1/8N 1 EA TAPE FISH 1/8X100 2 EA ARBOR HOLE SAW NO 2 1 1/4X4 1/2N 1 EA ANVIL BLACKSMITH 200LB 1 EA ARBOR HOLE SAW NO 31 1/4X4 1/2N 1 EA STICK HOT LINE 2 EA GRINDER ATTACH DRILL TWST 1 EA SHOVEL SQ PT LG HNDL 15 EA TRUCK HAND LIFT PALLET TYPE 4000 HANDLING TOOL SHT MTL VACUUM CUPS 2 EA CAP HYD 1 EA STAKE SHT MTL CANDLE MOLD 2 EA TRUCK HAND 2 WHL 500 CAP 1 EA BENDER EMT 'A 5 EA TAIL LINE ASSY SFTY BELT 12 EA BENDER EMT 1/2N 6 EA BELT TOOL LINEMAN SZ-42 20 EA BENDER EMT 3/4N 6 EA COMPRESSOR 15CFM 175 PSI SHOP EMD DRESSER WHL ABR ROTARY 2 EA 208V 60HZ 3 PH 2 EA ATTACHMENT SET SPEED REDC 4 EA HOSE ASSY KIT AIR COMP 15-40CFM SHOP 2 EA SHEAR MTL CUTNG ELEC PORT 2 EA OVEN WELD ELCTRD STORAGE 2 EA SHEAR MTL ELEC 16GA 2 EA SPRAY PAINT OUTFIT W/COMP 1 EA ETCHER ELEC PORT VIBRATOR 1 EA CUTTER TPR JNT ASB CEM PIPE TOOL BOX 18X10X13N MECH 3 EA PRESSURE 3-6 INCH 1 EA CHEST SHT MTL WKR STL 2 EA SAW MITRE BOX 11PT 26 4 EA STEPLADDER FIBERGLASS 12F MITER BOX W/0 SAW 4 EA F/ELECTRICIANS USE 1 EA PUNCH-DIE SET KNOCKOUT 2-2 1/2IPS STEPLADDER FIBERGLASS OF F/1 15/16-2 3/8N HOLE SIZE 4 SE F/ELECTRICIANS USE 1 EA PUNCH-DIE SET KNOCKOUT 1/2-1 1/4IP5 STEPLADDER FIBERGLASS 6F F/7/8-1 11/16N HOLE SIZE 4 SE F/ELECTRICIANS USE 1 EA CUTTER TPR JNT ASB CEM PIPE NON- LADDER EXTENSN 30F 2 EA PRESSURE 3-6 INCH 1 EA STEPLADDER ALUM ALLOY 6FT 5 EA PUNCH-DIE KNOCKOUT 2 1/2IPS F/2 STEPLADDER ALUM ALLOY OFT 5 EA 7/8N HOLE SIZE 3 EA STEPLADDER ALUM ALLOY 12F 1 EA PUNCH-DIE KNOCKOUT 3 I/21PS F/4N INSULATOR HOSE ELEC 4 EA HOLE SIZE 2 EA INSULATOR HOOD ELEC 4 EA PUNCH-DIE KNOCKOUT 3N IPS 1/3 1/2N BLANKET LINEMAN 4 EA HOLE SIZE 3 EA TESTER PORT ELEC TOOL MULTI-AMP 1325001 EA STICK CLAMP HOT LINE 2 EA SCALE BEAM INDICAT 1200LB 1 EA TAPE FISH POLYETHYLENE 50E1 W/RFEL 3 EA METER AIR VELOCITY 0-1000 FPM 1 EA

FlpirJ rvtincollanuouti "B" company linraint (R3002).

7 2 CONSTRUCTION ELECTRICIAN 3 8./ 2

The portable power tools that you use may wear goggles during the drilling operation. Before be powered by electric motors or by air (pneu- connectingthe airhose to thedrill, blow out matic) motors. Whether electric-poweredor air- any foreign matter that may be in the hose. Next rowered, the tools are essentially thesame and connect the hose and drill, and turn on the air the procedures for using then)are the same.at the compressed air outlet. Then ;urn on the The following paragraphs concern the pneumatic drill and test run it. In drilling, first place the drill and pneumatic grinder, probably the most twist drill in the socket. Then adjust the feed widely used portable air-powered tools. Asan screw in the machine to its lowest position and Electrician, you will be required to maintain the place the point of the feed screw in one of the portable pneumatic tools as wellas use them. indentations in the arm. Drill the hole to the required depth. Watch thedrill, and when it PNEUMATIC DRILL beginsto come through, decrease the speed. Hold the drill up by hand so that it will not drop onto the work. The heavy-duty pneumatic drill, shown inview A of figure 4-5, is reversible. Its speedcan be closely controlled by means of the throttle valve PNEUMATIC GRINDER located in the handle. The variable speed feature of this drill makes it particularly useful for heavy-duty drilling in places that are hard to The pneumatic griader, shown in figure 4-6, reach. operates on the same basic principleas the pneumatic drill. It can be equipped with either Another feature of this drill is that it has a grinding wheel or a wire bristle wheel. After a feed screw which can be used in conjunction attachingtheappropriate wheel, perform the with a special type of drill stand called OLDpreliminary steps required to connect the pneu- MAN. This drill stand is shown in part B matic grinder. Always run this machineso the figure 4-5. When you drill a hole using thepneu- grinding surface of the wheol is square with the matic drill with the OLD MAN, makesure you surface of the material being ground.

11.6 Figure 4-5. Ifcavy-duty pneumatic! drill and stand.

64 7 3 Chapter 4SPECIAL TOOLS

11.8X Figure 4-6.Sectional view of a pneumatic grinder.

Pneumatic tools must have thorough lubrica- want to.'walk" away from the point you want tion. The moving parts of a pneumatic tool are to grind. very closely fitted; if proper lubrication is neg- 3. Always stand so that your feet won't slip lected, they wear rapidly and in a short timewhile you are working and so that you are prop- fail to work. erly balanced. Valves and pistons on pneumatic hammers re- 4. Apply the grinding wheel to the work with quire a light machine oil; since the compressedgentle pressure. Sudden forcing may cause the air comes directly in uontact with these parts, wheel to disintegrate. As you complete the work, ithasa tendency to drive the lubricant outease up on the pressure. through the exhaust. 5. With all pneumatic tools, do not allow the airhose to become kinked. When working steadily with a pneuniatic tool, youshould chuck the lubricator regularly to W.en using an electric tool, make sure make certain there is runple lubricant available thatthe toolis properly grounded. Use only and empty the filter assembly when needed. Or. 3-wire grounded cords and plugs. low-pressure compressed air systems that do 7. W;.ienan extension cord must be used in nothavethefilterregulatorruid lubricator addition tothe cord on an electric tool, make assembly installed, you should disconnect the sure the extension cord is .iot energized when airhose every ho...r or so and squirt a few drops thetool plug is inserted in or removed from of light ollinto the airhose connection. If you the extension cord. Use only 3- vire cord and use heavy oil, you will have to clean your tool in cleaning solvent to loosen the gummy sub- grounded plugs. stance. You will then have to blow out the tool with alr, lubricate it with a light oil, and go back PN c PA Eiv ENT BRE\ EER to work. I<::ep your pneumatic tools clean and lubricated and you will have fewer operating A PNEUMATIC PAVEMENT BR ',KEP (fig. trouble 8. 4-7) may be used on construction projec,s to demolish structures made of concrete, bi W!:en operating portable power tools, observe asphalt, and the it if.; also used for general applicable safety precautions. A partial list ofrock brdting. th yttachments, it can be used safe practices follows; for digging and tamping as well. 1. Always wear your goggles when IArking Five attachments for the pavement breaker with these tools. are the moil point, chisel point, tamper, pick, 2. Do not allow tmy of these tools to ..un ot anJ spnclu. (See fig.4-1.) rie moii point is a of hand. The pneumatic grinder especially dev' ) for I 'caking through concrete, stone, or

ti5 7 4 CONSTRUCTION ELECTRICIAN 3 & 2 other dense and abrasive nmteriai, The chisel cases, however, operators have little mechanical point will cut asphalt, frozen ground, or ex- knowledge,soclose supervision is required. tremely hard earth, The tamper is used to compact loose material, Since pneumatic tools are heavy and vibrate alotduring use, they tend to tire out their The spade, shaped like a garden spade, isoperators, especiallythe inexperienced ones. used for digging trenches, preparing footings or The operatorsshould be strong and in good foundations, digging caissons, or general diggingphysical condition. that is too difficult and slow for an ordinary Hold the pavement breaker down while it is hand spade. The pick will dig into frozen ground, in operation, but use only sufficient pressure to guide the tool and keep it in place. Leaning heavily cemented gravel, or other material too hard toon the pavement breaker will only shorten the be penetrated by the spade, stroke of the tool attachment and result in less work being performed. Operation The shank of each attachment used with t'le pavement breaker must be the correct size. Pneumatic tools are simple to operate, andUsing improper shank sizes will reduce the 6:- the average SEABEE 1..an be taught to operate fectiveness of the blow and damage the pavement any of them in a relatively short time, In most breaker.

[PAVEMENT BREAKERI

TaAVETR1

RMSEL POINT1 MOIL PC-TNT

127.267 1.1urf; PzifHn puptizirmt Lreaker rind accessories.

7 Chapter 4SPECIAL TOOLS

Pavement breakers can bestbe operated in andern. In operating, take onlysmall bites (4 to inches behind the working face).If a rnoil point Decomes stuck, usethe second breaker to break the material binding the point.Wien the breaker isbeing usedsinglyand the point becomes stuck, take the pavementbreaker off and use another point to free the stuckpoint. Keep the work rxea clear ofbroken material so that it does notinterfere with efficient operation of the tool. Make sure you are using the rightattachment. Trying todrill holes with the moilpoint will result in breaking the point. T lechisel point issued with the breaker isdesigned for cutting asphalt and soft materials.Ifit is used for breaking concrete, the pointwill be damaged beyond repair. A careless operator canquickly break the tool latch retainer bolt bynot shutting off the tool when the moil pointbreaks through concrete. WLen this happens tile fronthead bounces on the concrete, resulting in abroken retainer bolt. 11.18X Maintenance Figure 4-8. Powerhacksaw. With proper maintenance, apavement breaker can be kept ingood operating condition. It cer-defective hose must be removedfrom service. tainly helps to sharpen thepoints of all attach-Hose should not be laid overladders, steps, ments, and to keep them sharp.Check the airhose or sidewalks insuch a manner as to create a connections to the pavementbreaker often to tripping hazard. W!-,ere thehose is run through make sure no air is escaping.Check to see that doorways, the hose shoul..; beprotected against all nuts and bolts aretight. damage by the door edge.The hose should be laid between the operator'slegs while he is using the pneumatic tool. Safety Precautions Make sure you exercise car working with POWER IIACKSA WS pneumatic pavement breakers orother types of pneumatic tools and accessories.Some general given below. The power hacksaw isfound in all (except the precautions to bear in mind are smallest) shops. It is used forcutting bar stock, The operators of pneumatictools should wear pipe, tubing, or other metalstock. The power goggles to protect the eyesfrom chips and dust, hacksaw, shown in figure 4-8,consists of a base, personal protective devices. a mechanism krcausing the saw frame to re- and use the necessary vise for holding the tools in such a manner ciprocate, and a clamping Lay down pneumatic stock while it is being sawed.The capacity des- that no harm can be doneif the switch is acci- idle tool in a ignationofthis power hacksaw th 4" x4", dentally tripped. Do not leave an which means it can handlematerial up to 4 inches standing position. in width and 4 inches inheight. Shut off and exhaust pressurefrom the line beforedisconnecting thelinefrom thetool. There are three types offeed mechanisms: mechanical, hydraulic, andgravity. Mechanical Tw airhose must ix.;suitable to withstand the 0.025 inch per stroke, pressure required krthe tool. A leaking orfeed ranges from 0.001 to 67

7 6 CONSTRUCTION ELECTRICIAN 3 & 2

Speeds and Coolants

ALLOY STEEL BACK Speeds on hacksaws are stated instrokes per minute (spin). Count only thbse strokes which cause the blade to come in contact with the stock. Speed is usually changed bymeans of a gear r"" shift lever. There may be HICK SPEED STEEL THIN a card attached to your ELECTRIC AELIAD equipment or near it, stating recommendedspeeds for cutting various metals. Tiefollowing speeds, however, can usually be used in cuttingthe metals 11.19X listed below. Figure 4-9. Power hacksaw blade. 136 spm Cold rolled or machine steel,brass, and sort metals. depending upon the class and typeof material being cut, Hydraulic feed normallyexerts a con- 90 sprn Alloy steel, annealed toolsteel, stant pressure, but is so designed that whenhard and cast iron. spots are encountered the feed is automatically 60 spm High speed steel,unannealeci tool stopped or shortened to decrease thepressure steel, and stainless steel. onthe saw untilthe hard spot has been cut through. In gravity feed, weights on the saw Cast iron should be cut entirely dry,but a frame can be shifted to increaseor decrease coolant should be used when all other the pressure of the saw bladeon the material materials being cut. With each type of feed are cut. A suitable coolant for most metalsis a mechanism, solution of water and enough soluble oilto make the blade lifts clear of the work duringthe return stroke. the solution white. The coolant not onlyprevento overheating of the blade and stock butalso serves to increase the cutting rate. Hacksaw Blades Wen you operate the power hacksaw,place the The blade shown in figure 4-9is especiallypipe in the clamping device, adjustingit so that designed for use with the power hacksaw.It is the cutting off mark is inline withthe blade. Next, made with a tough alloy steel back andhigh speed steel teeth, turn the vise lever to clamp the pipein place, a combination which gives both abeing sure that the material is heldtightly, and strong blade and a cutting edge suitablefor high then set the stroke adjustment. Before speed sawing. you start the machine, check tosee that the blade is NOT Hocksaw blades vary in pitch, whichis defined ;ouching the pipe. Blades can be broken ifyou do as the number of teeth per inch. Tie correctnot follow this rule. Feed the bladeslowly into pitch of teeth for a particularjob is determined the work, and adjust the coolantnozzle so that by the size of the section, and thematerial to be it directs the fluid over thesaw blade. Safety cut. Use coarse pitch for wide, heavysections in precautions to be observed whileoperating this order to provide ample chip clearance:For thinner tool are posted in the shop. Readand observe sections, use a blade whose pitch willkeep two them. or more teeth in contact with the workso that the teeth will not straddle the work.Such straddling will strip the teeth. In general,you should select POWER-ACTUATED TOOLS blades as indicated below. A number of different kinds of tools Coarse (4 teeth per inch), for softsteel, cast which iron, and bronze. utilize explosive charges to drivefastening devices are widely used. These toolsare sometimes Regular (6 to 8 teeth per inch), forannealed calledstudguns,stud-typecartridge guns, high carbon steel and high speedsteel. builder's guns, or powder-actuatedguns. Among Medium (10 teeth per inch), for solid brassthe number of different tools,there are two stock, iron pipe, and heavy tubing. basic types in use by the Navy.One type (fig. 4-10)isa high-velocity device in which the Fine (14 teeth per incl.), for thin tubingand sheet metals. fastener is shot down the barrelof the tool by a relatively powertul powder charge.Arother 68 7 7 Chapter 4S PEC IA L TOOLS

ype (fig. 4-11)is a power-assisted hammer- irive tool operating on the low-velocity prin- )iple. The manufacturers of the different types )ftools provide detailed instructions for the safe and effective use of their products so fol- ow their instructions closely at alltimes. The powder-actuated tool in figure 4-10 covers ;he complete range of powder-actuated fastening, providing light, medium- and heavy-duty anchoring of 1/4" and 3/8" headed pins and threaded studs in masonry and steel, (See figures 4-12 133.78 and 4-13 for the proper pins and studs.) The Figure 4-10.Power-Mate stud driver. barrel on this type powder-actuated tool can be changed in a matter of seconds, so as to adapt the tool to either of the kits described in figures 4-14 and 4-15. This can be adifficult the fastener after the piston stops travelling. and dangerous tool to use, so be sure to studyThe depth of penetration varies with the type the manufacturer's manual beforehand. of piston and fastener used. Overpenetration is prevented by the positive control of the L.Etener The power-assistedstuddriver shown inexercised bythe piston and guide disk. The figure 4-11 may be used either with or without hazards of using the high-velocity gun are elimi- the powder charge. When the powder charge isnated by the use ofthis type of tool; special used,it acts as a booster for a ham:ner blow.shields or protective devices are not generally Without a powder charge, the device may be considered necessary. used as an ordinary hammer-drive tool. T ie stud, snown in figure 4-11, is seated, guided, The power-assisted hammer-drive tool may and controlled in the recessed piston. The rim- be used in any position: on the deck, on the wall, fire booster blank, which contains a small slow- in the ow-head. It may be used to fasten almost burning charge of powder, is seated backwardsany type of construction material to any other above the piston and below the ram, which istype. Figure 4-16 shows a wood-to-metal con- hit with the hammer. Rather than shooting the nection.;figure 4-17, a metal-to-concrete con- stud at high velocity, the captive, heavy-mass nection. piston pushes the stud into the work at a relatively low velocity. The piston guides the head of the Figure 4-18 shows some of the other types fastener from the start to the finish of driving. of widely used pins and studs. 'rite tool illustrated A washer or guide disk near the end of thepin in figure 4-11 will accommodate fasteners of up or stud guides the fastener duringoperation. Since to 4-inch overall length. For most jobs you will the piston is captive, no energy is impartedto need two pistons: one for pins and one for studs.

..1:owirovI.

133,78X Figure 4-11.Cutaway view of power-assistedstud driver.

1;9

7 8 CONSTRUCTION ELECTRICIAN38:2

ORDER ORDER HUMBER NUMBER for concrete TANDARDHEAD 311,z 1,,,,,I__ I-.-I 4%71- 3 S-28 s.20 61...... 3.-1.--, 111=1111=111"VI 3 -7--

1",37 XTERNAL THREAD 1% --j.3121- I', S-21 -4-%-4- X-21 -1 It' V4 20N. C. 1-

1v.

--.- ) 13s 1---1/4 ---14-----11/4 S 22 _I__ -1--- X.22 166i4g::: Yl I ..6.**.V4 20 N. C. -4- H.n-1v.1v. 1% t..."% S-23 X H -22 v,. -7-- **". 'A20 N. C.

,, 2' 1Y4 -..---,/, 2 1 -41i S24 X-23 ,144 ...... m.. vA20 N. C.

23/J, s- 2%

11/4 "17'11I'... 2 1-.1-- 11/4 S25 4,,, X.25

1/4 20 N. C. 1

2"Al 2% 11/4 1v4 'ilI 21/2--- ....--...- S 26 t.-- 1/4 1111111111111/MI ----r- XH.25 '..... V4 20 N. C.

1---- 2 4 11/4 1 21/4 .32 S27 X27 , 14, %1 RA li 1--- -1.- v..20 N, C.

7 9 29.121.i Figure 1/4" headed pins and ...hrch. !cd studs.

70 Chapter 4SPECIAL TOOLS

ORDER ORDER NUMBER NUMBER tor steel 3,4 l' TANDARD HEAD i --171-,---"/"4., I r---- L1 1J_. 71 S 60;;;I- 3/41 XH.27 Iiii ai6.v,. 1"- -.....,.20 N. C. 7

2 : KTER NAL THREAD

I---1 --.4-6-11/4 1 i X-71 X41 ilarli; 1.010° ...T._.'m 'A 20 N. C. -----4 1 ..."- v 20 N. C. 1

1Y1 114 ill---01 I. k.--1/4-+- E 1 1 1614664; T X-72 I---10 24 N. C. -I- ..___L___ v.20 N.CTI

NTERNALTHREAD 11/4 1./.. ---i 1/4 r"-- 1v. 11/4 -440- 1/4 F-15 1i_ iY,I -0, X75 liCaNai '..- V420 N. 1024 N. C. 7-- CT

BREAK-OFF HEAD 23/4 1h"l 1 1 r-I-7--i1/4 --E/.1------B21 *1_L

-1- 'A 20 N.CTT

h 2'4,2 11/4 1 1 x .83 B 25 11;1 11,1 -F. I'll.1/4 20 N. C. 7

EYE TYPE INTERNALTHREADH----1.,,. l'i 1/4 1---- .v,, I +______11/4 L 21 .1 F314.r_m... sl,I

1024N. C. T .154Dia. 7

22 CALIBER 25 CALIBER 32 CALIBER STANDARD-Wad STANDARD-Wad STANDARD-Wad LOAD LOAD LOAD ORDER LEVEL WAD ORDER LEVEL I WAD ORDER LEVEL WAD NUMBERNUMBERCOLOR NUMBERNUMBERCOLORNUMBERNUMBERCOLOR 22w3 3 Green 25w6 6 Purple 32w8 8 Brown .72w4 4 Yellow 25w7 '/ Gray 32w9 9 Green 22w5 5 Red 32w10 10 Yellow ;l2w6 6 Purple 25 CALIBER 32w11 11 Red

22 CALIBER SPECIAL-Wad LOAD LOAD ORDER LEVEL HEAD ORDER LEVEL NUMBERNUMBERCOLOR NUMBERNUMBERCOLOR 25c1 1 Gray 22w7 7 Gray 25c2 2 Brown 22w8 8 Brown 25c3 3 Green

29.1 21.2 Figure 4-12.-1/4" headedpins andthreaded studscontinued.

Qit CONSTRUCTION EL2CTRICIAN 3 & 2

I ORDER ORDER NUMBER NUMBER forconcrete ANDARDHEAD 2 2V -..4 1/4 1 v. 2% --a. S-41 S 34 h..---- 7 2% 3 -14 21/4 11 3 S -43 _l_ i S 35 ili 111 T"64 T

31/2 31/4 .. 4 S46 S 38 k..--....- '41 "A.

3% XTERNALI 21/4 31/4 HREAD 6. 1.4.-1% S 47 LL 1Ji... %1 N 52 / .1P_Ir,6 7

-r77k,-- 1 -1-3'4 1'6 =7,---- 3 4 1% -1.. S-48 6.,___..._.__ N 54 . , , v. 16 N, C. 7 LAT HEAD . v y,.H. 1 21: rom...011.3= 1.. .--- 2 --**-- SD15 4, N 55 7 11111Pw ,,..._ Y. -16 N. C. T ,r-----1 4 31/2 r 2 --"'f"--1.6 SD20 i_ Iiimimminfli> YI / / X.45 61 IMPI.PW VI 20 N.C. 7 I'i :YE --MTF1/4 Pi.. rYFE I A ---.11 SD25 Iliiiiiii>14. L-31 IMMIXIV, T..' " .193 D a. 7 forsteel A --.t*--;---1--1% TANDARD 11/4 ------.. IEAD v H--- iv. SD.31 1_L 7.. T 7 2 A XTERNALr , 24 ./. HREAD ---4--1,,,...... _:1_1. S 32 11M11111"44 N.02 7- 6ii _..11ips- 1/4 % 16 N. C, 1

.,, t---vh.,--222-- A S 33 N04 EMIR 117111`.".-il 61, L.% lr N. C.

29.121.3 Figure 4-13.-3/8" headed pins and threaded studs.

72 8 1 Chapter 4SPECIAL TOOLS

K-ICAPTIVE STUD KIT K--2 LIGHT DUTY KIT

K-3 MEDIUM DUTY KIT K-4 MEDIUM & HEAVY DUTY KIT 133.340.1 Figure 4-14.Stud driver kits.

However, if you have studs wtth two different AIR COMPRESSORS thread lengths (such as shown in fig. 4-18), you will n2ed a separate piston for eachthread A compressor is a machine that increases length. There are many other types of fastenersthe pressure of air by reducing its volume. A for special requirements. They may be used incompressor consi.,:s of a driving unit, a com- the hanmier-drive tool if you have the specialpressor unit, aild accessory equipment.The driv- piston that is needed for fastener. ing unit provides power to operate the compressor and may be a gasoline or diesel engine. Com- Powder-actuated toolo should be operated,pressors are governed 11 a pressure control repaired, serviced, and handled only by CE'ssystem adjusted to compress air to a maximum who have been trained and certified by the manu-pressure of 100 pounds per square inch. Iacturer, his authorized representative, or Navy Department certified instructors. Therefore, spe-C011PRESSED AIR SYSTEM cial authorization or licensing is required before you are permitted to use most types of 5tud guns. Never attempt to use one of these tools without LI compressed air system consists of one or proper authorization and instruction.13.::sureniore compressors, each with the necesrmi'y you follow the manufacturer's instructions. Neverpower source, ccntrol of regulation,intalze air use the powder charge in an e;osiveatmosphere.filter, after000ler, uir receiver, and connecting Lastly, remove any defective tools cr parts frompiping, together with a distribution system to service immediately. carry ne air to points of use. 73

8 2 CONSTRUCTION ELECTRICLAN 3 & 2

The object of installing a compressed air isair manifolc.mg ":*119). An air manifold system is to provide sufficient air at the work alarge dm,.-or i-re used to transport area at pressures adequate for efficient operation compressed air Lori on,.- or more compressors of pneumatic tools being used. over a distance wifti a small friction line loss. Many construction jobs require more cubir In construction work, air manifolds are usually feet of air per minute than any one compressor constructed of 6-inch diameter pipe. A pipe of will produce. Terrain conditions often createthis size can carry 1200 cubic feet per minute problems of distance from compressor toop- of air (output from two 600 cfrn air compressors) erating tool. Since the air line hosc issued with at 100 pounds per square inch with less than the compressor c9uses considerable line loss .035 pound pressure loss per 100 lineal feet. at distances further than 200 feet, a system has One or more compressors pump air into the been devised for efficient transmission ofcom- manifold and eventually pressurize itat 100 pressed air over longer distances. This systempounds per square inch; then air may be used

K-1 CAPTIVE STUD KIT .... FREE N.IENBA:1E) 'NADECUATE. PcNER mart:"

/11 K-2 LIGHT DUTY KIT HELPS I,0;2M -HE aLL PURPOSE TC1 rHAT ,c,uP CCNcRETE a ps TEEL WITH r /4 'DIAMETER :TUDS. A 22 CALIBER POWER LOADS -3 MEDIUM DUTY KIT vEs TOP PERFOR11:o4CE rASTENING 3/8' WamE rER STUDS WITH 22 CALIBER PONER LOADS

( -4 MEDIUM AND HEAVY DUTY KIT 'CH 'HE TOI1G1ES, FAr:TENING JOBS' FASTENS 3/8'DIAMETER STUDS WITH E ITHER 22 CA:. IBER OP 32 cal_ IBER POWER LOADS

8 3 133.340.2 Figure 4-15. Purpose of individual stud driver kits.

74 Chapter 4SPECIAL TOOLS

atany point along theInanifold outlet valves and conneeting air 111,1=7; matic tools.

COMPRESSOR OPERATION AND MAINTENANC E -at The following paragraphs will give general A.. instructionson operating and maintaining air compressorunits.One ofseveral types that SEABEES operate and mnintain is the \V?rthing- ton 600-cfm portable compressor (fig. 4-20) which is diesel-engine driven. The complete unit is equipped with sprin6s, tires, and a drawbar. The drawbar is normally located on the compressor end of the chassis. W1'en the unit is coupled to a self-propelled crawler drill supplying air for its tramming motors, this drawbar location keeps the radiator and oil cooler further away from the cloud of dust which the crawler rig can create.

133.79X The compressor unit must be locpteci on a Figure 4-11. Toenailing wood to hollow metal reasonably level area. The design of this unit decking. permits a 15-degree lengthwise and a 15-degree sidewiselimit on out-of-level operation. The limits are placed on the engine, not the compressor. W.en the unit is to be operated out- of-level, it is important: (1) to keep the engine crankcase oil level near the high level mark (with the unit level), and (2) to have the compressor oil gage show nenrly full (with t..: unit on the level). , Itt6ebA dr '1, An instruction plate similar to the one shown in figure 4-21 is attached to the unit. Netice that this plate refers you to the manufacturer's engine and compi.P:- -or manuals for detailed instructions.

I,-; .:" Operating th(- Clutch

. v, $ t The clutchshorld remain engaged at all 11,- times except during engine warmup or tuneup r-V, periods. In this way its compression springs and Shifternv.3chanismare not ..,nder a constant ,l4 strain. The com?ressio- springs hohlthe friction Wsks in the engaged position; the shifter macha- nism forces the disks apart hydraulically against 133.81X the spring compression to disengage the clutch. Figure 4-17. Fastening cnannel to concrete. A built-in safety interlock prevents the clutch 75 8 4 CONSTRUCTION MAX rlift7LNN 3 & 2

I 4" 20 NC "CONICSTUDS - Ii 4" THREAD L ENGTHI NK.DK "CONIC" PINS

ORN:p sruns.1Rt SHONN IN AL- TUAL IL Nil AL IP!I4`, ARk StiONN IN ACTUAL SIZE

, I

1 ti 1 N tt

MU1111)3MMUIrs..111111RINVIAIIIP..".

PI L'1 0=111171171*); 111 rn I'1 _

;u1N0PAROMII"--. M tittlftrAM... - NN Cx 11)1111APORIBBUmmor "K t-

;Trintrittmam-1.....1111041111111101 M w Nh, .15 DK

I 4'. 20 NC "CONIC- STUDS - (I 2- THREAD LENGTH) NK wirm.,111!I ORL'Lk NO ALL STUDS ARE SriOAN IN ACTUAL SI:L m NK Wp...., 1...... -- 1 w a SPECIAL BOOSTERS (.25 CALIBER) NK ---,.,----.-1,..-- ,55 DX2', NK 25 DX 755 DI, w.---1......

N.J DX ORDER NO, COLOR CHARGE 1 75 GRAY REGULAR 710 DX I', NK DX 120 ORANGE MEDIUM 150 BROWN STRONG -735 CX

7.3C DX USE PISTON G-Ny-L 725DX

29.121X Figure 4-18.Stuth; and pins. frombeing engaged or disengaged while the engine is running.

When the engine is stopped, the clutch'Sleeve can be pushed down easily to expose a knurled COMPRESSORS SP.0,110 NAVE APPROXIMAMY knob which is turned to engage and disengage the THE SAME LOADING engine clutch. Never try to move the clutch sleeve UNLOADING PRESSURE. and turn the knob when the engine is running. Nlways shut down the engine before engaging or disengaging the clutch. To disengage the clutch, turn tile knob clockwise as far as it will go. Pressurize the clutch shifter by strcking the hydraulie pump handle. A built-in pressure relief valve prevents over- CIPECK VALVE pressurizing. 4-20Urnpli SERVICE VALVES To engage the clutch, turn t knurled knob counterclockwise three or four turns until tha 115.385 pump handle offers little resis''ce to pumping. Figure 4-19.Methods of manifolding compres- Leave th.3 knob in this position. sors.

76 85 1---;;1)1c1.\1, ToOLs

Starting the Unit 5. With the engine running, check the engine oil pressu .c gage. If no pressure is indicated, ThefolloA ingst ps houldI o taken%% hen turn the engine off. When the oil pressure goes Starting Ow tilgirstliiring eatner; ahove 22 psi, continue to operate the engine and check the low-pressure engine oil switch. The 1. Open service v;11:0;, Inout one qu:,..rter knol, Uns switch should be in the RUN po- not wide open. sitio:

NlYF "Vhe reai-ontoysta rting iththe NOTE: The engine oil pressure gage in- sevice partly Open is that dicates erratically until the engine tii t. inquicker %.alanup of the oil warms up, compressor Oil., 2. Nlake sure the clutch is in engaged 1nt51- 6, open the side curtains on both sides of ton. the engine enclosure and leave them open. Flow of air through the oil cooler and engine radiator 3. 1,ositiontheloi%-pressurc., engine-oil- will be impeded if the side curtains are closed systein salety-c ntrul-knob to ON (fig. 4-22). while the engine is running. 4. Turn the ignition switch to start position. Immediatelyaftertheen;ine starts, release After the engine has run about 3 minutes, the ignition switch.lfthe engine fails to fire check the engine coolant temper'tture gage. PIE,. within 30 seconds, release the ignition switchgage should indicate less than 210° F.If the and allow the starting motor to cool off for agage is showing more than 210° F, SHUT OFF few moments before trying thestarter again. THE ENGINE.

^11

-1_

115.377X Figure 4-20.-- Worthington 600 cfm portable,rotary air compressor.

77 8 6 coNSTRucTION ELECTRICIAN 3 & 2

8. After 5 minutes of operation, close the ser,ice valve and attach the hose or service line of the tool or device to be operated. 9. Open the service valves fully and start the work. After startup, the unit automatically WORTHINGTON provides compressed air at the discharge service CORPORATION valves. Only periodic checking of the gages on the instrument panel is then required. OPERATING INSTRUCTIONS tOINENNI AND COAAPRI,v141 TAANTJ Ai T OR T Alt ID NsTivol 10. When the enitine is started during the day, 10 to,r1 ovATAINs PT /OPE- - %TARING IN.Nt after the first dail-,startup, the above warmup ,IF A IVA '!..! steps may be eliminated.

ON IN UMI Stopping the Unit (.1;AIN lNt Ne A F INt 0/1!so,' 1 V STARTING VVVVVVVVVVVVVVVVVVVVVVVVVVVVSNVVVVVVVVV.W4Sr. ON INITIAL DAILY START OR AFTER PROLONGED SHUTDOWN, OPEN When stopping the unit at the end of lay s 7.= A SFIIVKE VALVE APPROX . TO A:WW COMPRESSOR TO RUN run, take th.) following steps: LOADED FOO S MINUTES TO WARM COMPRESSOR OIL BEFORE PER MITTING THE COMPRESSOR TO RUN UN-OADED, Vt.11? PAAMtA1A.S.SAASSAAAAAAAAA/.AAAAAAAAAAAAAAAAA 1. Close the ser;ice valves and perrniL thr

I IN *ARM WEATHER wilt+ OTTCH TNI.v!"41./ engim3 to run atidle for 5 minutes. This wil: .' IN COLD WEATHER LISF1".R61 L..' 'II AS r,ARECTED ON ITC 111511. L ( T allow the engine coolant temperature to le...el Pi A 7-7.7TAT NMI ITEMI.t.,Atult+E REACHES 12041 STOP ENG,NI off and the entire unit to cool down.

IN I ITREM( CO1I) WEATHER INETROrt ClANIMIN4 ENGIN! ENGINE ) ...,.,,,,,,,.,,,T' IT ANO 2. Turn the ignition switch to the OFZ US( II(P CIIRSCIA SWITETT ON C.,OR STARVING AID PUPG DATINNG GRAN.NG

STEIPP,Nt, RE, 5 MINUTES BEFORE STOPPING ENGINE Cold Weather Starting 1)All T "..C.,4S WITH AN AIR HOSE FROM THE E ATI ' "".. OOT GP E Or CLEANING The following step3shouldbe completed I ..". F 'r P 0450:ATOP CHANGE CAR'P '.rtF :t. ATTE. ENGUNE STOPS during cold weather starting: fP SE APE C'./ST 1. Disengage theclutch. T:ds will permit engine warmup at idling speed.

:T. .5 fr7.ESS/E Pr:C.:CP F.LrEP 2. Start the engine using the heater switeh RED. Ac5 ELE'05NT and priming pump in accordame with the engine -.,,,c-E:GES AT 7:',11 O CHANGE t manual. 3. Warm the engin ,tritil th i. engine coolant temperature reache',1...0° F. Leaving the side .15T_ PESSuPE P S curtains closed fc- a few minutes helps the engine to warm up.

MACE U SA. ROAM0 4. Tarn the ignition switch to OFF. 5. When the engine has stopped, engage clutch and start the engine again with the service valves partly open. B.sure the Jide curtains 115.378X are open. Figure 4-21.Operating instruction plate. 6. When the compressor has ru.a for several minutes and the gages indicate normal operating 8 7 conditions, connect up the tools and go to work. 78 Chapter 4SPECIAL TooLS

T,^LcHLW'E'PHuu;"IvIE TE.H PRIMING PUMP CIHCUI T '?PEAXER O'LL OW PRESSURE ' -CONTROL-KNOB

IGNITION SWITCH

HEATER WORTH! NGTON LAMP

HEAT'sw'

WATER TEMPERATURE C 'AMETEP PRESSURE GAGE REGULATOR LUSE OIL FUEL OIL PRESSURE PRESSURE AIR PRESSURE GAGE GAGE GAGE

115.333X igure 4-22.Instrurnent panel.

Lubricating the 'Unit then enters the second-stage element, a paper cartridge, where more dust is trapped and s.:ol- The lubrication chart in the operator's manual lected. for the particular ,nake and model ol compressor you are operating will show you where the unit The dust bin should be removed by hand and should be lubricated, how often to lubricate, and emptied daily. Some models have a self-emptying what luhricant to use. The frequency will varydust bin that is piped into an aspirator in the depending upon op , atirg conditions. Operatingexhaust pipeline, just beyond the muffler. When under abnorm al c ,ndition requires more frequent the aspirator is used, no alter.ttions are allowed service. to be made to the engine muffle or exhaust pipe. On the side of the air cleaner housing, there CALiTtC,,13i..2ore servicing the compressor is mounted a service indicator. As the paper airsystem or compressor oilcartridge loads up with dust, a red indicator systev. onen the service valvesflag gradually rises in the window. When the to the,nosphere to relieve all cartridge is completely loaded, the window will pressure in the systems. show all red, and the flag will be locked in place. It is time to replace the paper cartridge.Discard Servicing the Air Cleaner the old cartridge and reset the red flag so that the window shows clear. Cleaning used paper cartridges is not recommended. cwo-stage, dry-t2.pe air cleaner, installed angiae Closure at the right rear, Drainage filters the intake air (fig. 4-23). Air is drawn into aIrst-stage element which causes nearly Drain cocks are provided at the bottom of all the dust in theairto drop into a bin. Air the compres-cr suction control and the engine

79 8 8 CONSTRUCTION ELECTRICIAN 3 & 2

speed control. These cocks should 1 left open Never disable pressure gages except when when the unitis sanding parueularl n they are to be removed for good reason. freezing weather. Tliey must 1),; closed before Never kink a hose to stop the air flow. Keep the engine is started. the clamps on the hose tight. Drain any condensate which wa': have accu- \V!,en sLarting an air compressor, check the mulated in the bottom of the oil stc;:itge safety valves, pressure valves, and regulators A drain cock is provided On the p ping ai theto determine that they are working properly. bottom of the left hand oil storage !ari . Open Do .1. tleave the compressor after starting this cock and keep it open as long as water is it unle:;s you have made certain that the control, draining out. Close the coc: quickly len oil uhloading, and governing devices are working sUirts draining. properly. Do not run an air compressor faster than the AIR COMPRESSOR SAFETy speed recommended by the manufacturer. Use only the proper grade of oil recom- G,irecal safety precautica air compres- mended bythemanufacturer, and avoid the :ors ar,., as follows: application of too much oil. Use only oils which have high flashpoints to lubricate the air cyl- sur7the,airati. .akei,- cool and free inders of air compressors. from flammable gases or vapors_ Keep compressors, tanks, and accompanying Do not permit woLd or other damnn utble ma- piping clean to guard against oil vapor explosion. terials to remain in conta t vithtle air dischargeClean intake air filters periodically. pipe. Use only soapy water or suitable nontoxic, InimeJrttely seoure a compressor if the tem- nonflammable solution for cleaning compressor perature of the air disch .rged from any stageintake filters, cylinders, or air passages. Never rises unduly cr ,xceerls 4f F, use benzene, kerosene, or other light oils to clean these parts. These oils vaporize easily and will form a highly explosive mixture under compression. 14, **1 'Pim off the motor before making adjustments It - Dc. and repairs on an air compressor. Before working on or removing any part of a compressor make certain that the compressor is secured Fad cannot be started automatically or by accident, that air pressure in the compressor iS completely relieved, and that all valves 4 between the compressor aad receiver s are closed.

POWER EARTH AUGERS

An earth auger is used to digholesfor placing posts, poles, and explosives charges. It is also used to remove soils for testing. Among other things, the earth auger is very useful in subsurf ace soil explorations for boring holes up to 20 inches in diameter and up to 9 feet in depth. The power earthauger(fig.4-24)isa self-contained, hy dr aulic ally oper ated and positioned earth boring machine. The boring assembly can be operated 115.379X from vertically downward to 45 degrees from Figure 4-23.Air cleaner. vertical. Tae power earth auger is nclinally

80 89 Chapter -IS PEC IA L TOOLS

Wr.1

115.484 Figure 4-24.Power earth auger.

9 0

81 CONSTRUCTION ELECTRICIAN 3 & 2

COOLANT TEMPERATURE GAGE; I AMMETER: NORMAL READING NORMAL READING I60°F TO I80°F. IS ON CHARGE SIDE.

FUEL GA..;E: INDICATES AMOUNT OF FUEL IN TANK.

OIL PRESSURE GAGE: NORMAL READING 40 TO 60 PSI.

TACHOMETER AND TIME TOTALIZING METER: NORMAL ENGINE SPEED 2,400 RPM ALSO RECORDS ENGINE RUNNING TIME 115.485 gure 4-25.Instruments, power earth auger. mounted on the bed of a truck to increase down show the instruments and controls of this earth pr,.ssure and aid in transporting. auger. Bear in mind that the procedure of operation may vary from one earth auger to another, The auger, at full speed in fourth gear, will so make it a practice to check the manufacturer's rotateat less than 150 rpm, or in low gear at manual forthe recommended procedure for not more than 40 rpm. The auger hydraulic valve the auger to be used. levers are placed so that you can observe the boring operations and the engine instruments at the same time. Starting the Auger Engine The earth auger is usually driven by a gasoline engine. The auger assembly consists of the auger, There are certain steps you must take in kelly bar, final drive assembly, and right-angle starting the auger. After performing the routine drive assembly. Operation of the boring assembly prestart checksoftheengine crankcase oil is controlled by the auger clutch which engages level, transmission oil level, fuel supply, battery or disengages the kelly bar. waterlevel,coolant level, and hydraulic oil level, be sure that the proper amount of lubricant, water, and electrolyte is added, as required, OPERATION C)F to bring the specific unit to the proper level POWER EARTH .UGERS or fullmrirk. Placeallcontrols in neutral position and then open the fuel shutoff valve mid I'D give you some idea as to the operation the hydraulic oil shutoff valve. By following Lhe of a power earth auger, information is given step-by-step procedures given in figure 4-27, below on the Texoma Enterprise's earth auger, you should have no difficulty starting the auger Jaques model TJ 254. Figures 4-25 and 4-26 engine.

9 1 Chapter 4SPECIAL TOOLS

>taps for Auger Operation 3. Pull the elevating valve lever to elevate the auger shaft into th3 vertical position and 7lumb as indicated by the elevating spirit level. Followthe procedures bow toplace the 4. Engage 0..9 auger clutch by pressing doNn )oNar earth auger in motion after the engine on the auger clutch shift lever and allow the as beon started: auger shaft to rutate for 5 minutes.

1. Disengage the engine ell tch and shift the NOTE: Do not run the engine faster than idle ;ransmission into fourth gear. until the auger gears are thoroughly warmed up. 2. Engage the engine clutch And run the engine 5. After the auger has been warmed up, dis- a idle speed. engage the auger clutch.

FEED VALVE LEVER USED TO FORCE AUGER INTO GROUND.

ELEVATING VALVE LEVER. USED TO RAISE AND PLUMB AUGER SHAFT TO GROUND. I LEVELING VALVE LEVER: USED TO PLUMB AUGER SHAFT TO GROUND.

LEVELING SPIRIT LEVEL. INDICATES WHEN AUGER SHAFT IS PLUMB FROM I SIDE TO SIDE TO GROUND..,ci TRANSMISSION GEARSHIFT LEVER: HAS4 FORWARD AND 1 REVERSE POSITIONS. IMP. HYDRAULIC SHUTOFF VALVE: USED TO SHUT-OFF HYDRAULIC OIL FLOW.

I rideg"'t ELEVATING SPIRIT LEVELt-NDI: A ES WHEN AUGER IGNITION SWITCH: SHAFT IS PLUMB FROM FRONT TO dEAR TO GROUND. NORMALLY ON TURN OFF TO STOP ENGINE. -STARTER SWITCH CONTROL ROD: PUSH TO START ENGINE., THROTTLE LEVER; NORMALLY OUT AND LOCKED. PULL OUT TO INCREASE SPEED.

AUGER CLUTCH SHIFT LEVER: NORMALLY DOWN, PULL UP TO DISENGAGE CLUTCH. : CHOKE LEVER: NORMALLY IN PULL OUT TO CHOKE ENGINE.

115A86 Figure 4-26. Controls, power earth auger.

83 9 2 C()NSTBUCTI(N ELF,CTEICIAN 3 & 2

fft J.04,1-14

TU'qN ON IGNITION SWITCH

PUSH START SWITCH CONTROL ROD TO CRANK ENGINE AND RELEASE WHEN ENGINE STARTS. mb Mr, 'La017i

IMEIMIXEINa I. PULL THROTTLE LEVER DOWN SLIGHTLY. fa 1 2 PULL CHOKE CONTROL LEVER DOWN SLIGHTLY. I

5 AFTER ENG:NE HAS STARTED ADJUST CHOKE TOMAIN1TAINSMOOTH OPERATION.)

CAUTION DO NOT CRANK ENGINE FOR MORE THEN 30 SECONDS WITHOUT PAUSING AT LEAST ONE MINUTE TO ALLOW THE STARTER TO COnL.

115.487 Figure 4-270 Stkrting the auger engine.

Stopping the Auger Engine shaft can be raised or lowered for transporting, as shown in view B of the illustration. The To stop the auger engine, observe the stepsLEVELING SPIRIT LEVEL is used to plumb given in figure 4-28 after disengaging the engine the auger shaft. clutch and shifting the transmIssion into neutral. After the auger shaft has been placed in the desired drilling position you are ready to begin OPERATING TECHNIQUES drilling operations. This is done by engaging the auger CLUTCH LEVER, pulling back on the Unier ordinary circumstances an auger will THROTTLE LEVER to increase engine speed, be operated as described below. Figure 4-29 and then pushing fcmard on the FEED VALVE shows the auger controls and how tc positionLEVER to 1 wer the auger into the ground as the auger with these controls. With the LEVEL- shown in view C, figure 4-29. ING VALVE LEVER, the auger shaft can be tilted to the right or left as indicated in view A. CAUnON: Do not overspeed the auger. Run With the ELEVATING VALVE LEVER, the auger the engine at slow sp.:ed Ilan the 84 9 3 Chapter PECIA 1.1 O0T,s

textureofthe material can bc SECUHANG A TRUCE-MOUNTED determined. POWER EARTH AUGER Whon the auger is deep enough in the ground When mounted on a t!.i!..k for portable use, toheloadedwithdirt, disengage the!:uger a power earth auger sho,'1,1 :;ecured in the fol- CLUTCH LEVERand pull back on theFEED lowing ivannerPositioi auger for traveling VALVE LEVERto raise the auger from the and stop the auger engine, lie sure to close the hole.Aftertheauger has cleared thehole, fw1 shutoff valve and the hydraulic oil shutoff engage the augerCLUTCH LEVER(fig. 4-29) valve, Drive the truck to the designated securing to rotate the auger and to clear the unit of dirt. area, and position the auger in a safe manner. Remember, as yo.i raise the auger, push the After the truck has stopped, disengage the engine handTHROTTLEforward to lower engine speed. clutch, put the main transmission shaft lever in neutral, engage the truck parking brake, and turn Repeat the steps above until the hole beingthe ignition off. Secure all doors and windows drilled is at the desired depth. before leaving the truck.

3. TURN IGNITION SWITCH OFF.

RELEASE THROTTLE LEVER AND PUSH TO TOP.

2. ALLOW THE ENGINE TO IDLE FOR 5 MINUTES TO COOL ,,EFORESTOPPING.

115.488 Figure 4-28. Stopping the auger engine.

85 9 1 LEVELING VALVE LEVER CLUTCH LEVER ELEVATING VALVE LEVER FEED vALVE LEVER

et' RAISE THROTTLE LEVER

411. TILT LEFT TILT RIGHT

RETRACT LEVELING SPIRIT LEVEL DRILL

Figure 4-23.Using auger controls forpositioning of auger. IALVE LEVER

CLUTCH LEVER 'ALVE LEVER

ALVE LEVER

RAISE LOWER THROTTLE LEVER nu' RIGHT

115.489 Figure 4-29.Usingaugercontrols for positioningof auger. Figure 5-23. Servivar electrical tester. nize:olor codedwhetherBO hethat is theOn user the cana-c quicklycurrent , a-c volt scale, or theohm scale. ecial circuitry (not shown) prevents damage e meter when voltage is applied inadvert- to the instrument when it is on the ohm .This isaccomplished without the use

26,231X 26.232X Figure 5-24. Snap-around probe. Figure 5-25.Line splitter. CHAPTER 5

TEST EQUIPMENT

t Electrician, you will be sl.0 MEASURING INSTRUMENT 01,_:ctrik.:al equipment into PRECAUTIONS rc.;atr eqtlipment, and per- : to..tip,.:prt.ventive maintenance. To help hun using measuring instruments, you must pL,l,these jul;s, many typos of testobserve certain precautions. For example, it is avmlable. Some of these mayespecially important to be careful in using an ai,H u to1,..2 ocil plcx.\, hen analyzed, however, animeter because of its low internal resistance. b..!ot If::s and techniques of operation may lfmistakenly placed across a voltage source, to 5.,Iny)li: hasitcircuits and proce- the meter can be damaged. Always break the dut u Electrical theory underlying the opera- circuit and CONNECT AN AMMETER IN SERIES,

Li,,r0 sumacask. . !st instruments is coveredwith one meter lead going to each point of the .haptei.1 5of Basic Electricity,circuit break to measure an unknown quantity. N lLItt1.U(3-B,\good grasp of this ma- Be ste to deenergize the circuit before making terial will help you to understand not only how or breaking the connections. the mstruments are designed to work, but also When using either ammeters or voltmeters, theE;:portance ot apnlying theoretical analysis ALWAYS start at the HIGHEST meter range. to i;rohleill sok Then drop downtoa laverscale range if necessary. This practice protects the meter frorn Fins chapter describes test procedures and injuryif an attempt is made to read a high value equipment uscd tor investigating a variety ofin a low range. Damagu to instruments can also iiulties. You should be able tc repair vital be minimized ifyou form the habit of placing equipment when yuu follow correct test proce-the range selector switch in the highest range di:reii and the manufacturer's instructions, position after you have finished using the :n- nit: purpose of these instruments is to test strument. and measure accurately certain circuit values OBSERVE POLARITY on all direct cu:.--er or to determine the opal ating condition of the measurements. Take care to connect the p. - electrical circuits, Instrunient accuracy depends tiveterminalofthesourcetothe posityi on its design and how it is treated. terminal of the meter, and the negative terminal of the source to the negative terminal of the The operating energies involved in electrical meter. This ensuresthat the meter polarity measuring instruments are extremely small.The matches the polarity of the circuit in which the instruments themselves are necessarily of deli- meter is placed. cate construction. Special precautions must be Be carefulto avoid dropping a meter or taken to obtain accurate results and to avoid subjectingittoexcessive mechanical shock. injurytotheoperator by mechanical shock, Such treatment may damage the delicate mech- exposuretostrong magnetic fields, and ex- anism or cause the permanent magnet to loBe cessive flow. One of your major responsibili- some of its magnetism. ties is to take care of any instruments assigned Care must be taken to avoid connecting the to you. Instructions and wiring diagrams areohmmeter across circuits in which a voltage furnishedwithinstruments. Such instructionsexists,sincesuch connection can resultifl are either attached to the instrument case or damageto the instrument. TO ENSURE nit cover,oraregiveninseparate inst-uction REMOVAL OF ALL VOLTAGE TO THE EQUIP- books. Theseshouldbe consulted freelyfor MENT UNDER TEST, DISCONNECT THE specific instructions and precautions. SOURCE OF INPUT VOLTAGE BY REMOVING Et.,q llH. r

THE PU\A ER ,L 1 t\ \-- CITURS du sT B E1.)1.,Cii A It6 El)eetornthe ohnimetec prods are comp!, tedii the tercet'. Charges remaining en capa, eers atterhe ap- pliedvoltagehasbeen removed ,I;teetie the instrument severely. Always turr ohmmeters OFF when unished. This will avoid discharge 01the internal battery if the test leads are shorted iteuivertently. Itisimportant that you remembee tot A LOW VulTAGE NI EGGER T,_) TsT I gun 1 nI I VOLTAGE INSCLATiON,.1pplicatiunofhigh voltage may initiate insulation in eakdowe. VOLTAGE MEGGERS should nut be used to test hit voltageinsulation because an inaccuraU: 'AI II Elee reading may re su 1 tfrom the comparatively small output voltagee a iuialile Lonthisin- m can use an anei,eter to me t. sure total strument. Be careful, whether ueing hign or ete Lent through a ciieUit, OF you cal use it tu low range meggers. Dangerous voltages exist :it ewee:emneurrentthruughonlyap:irtofthe meter terminale and 1, r,Ie. circuit.Figure 5-1 illustrates both methode of measurement. In the figure the synilol Al indi- eatee an anmieter which is nieasurie,4 the total BASIC TEST EQUIPINIEVI. currentthrough braneh circuits A,3, C, D, andE.The symbol\ 2indicates an atemeter As a CE, youwill use various types ofwhich is measuring the current through bcanch test equipment. Someetthebasic types 01 circuit B only. test equipment with whichea should be iamiliar Because the functionofan ammeter lEto are described in the following paragraphs, measure current,it must always be conne,2ted inseries with theline,and with the load on the line, It must eevel be subjected to a current higher than Inc rating on the .eeter. Inthe type of ammeter used at advanced bases, the coil through which the measuring current flows is fixed Lo the instrument frame. T magnet is a movable vane of iron or of special alloy, as indicated in figure 5-2. Magnetism induced inthe iron by the current inthe field coil always has the sante polarity as that of the coil, when alternating current flows in the coil, Therefore, when the current reverses inthe coil,the polarityof the magnetism induced in the moving iron also reverses. Tieinstrumentis calibrated in amperes, and rated according toits maximum current- carrying capacity. Because of the fixed relationship inpolarity between field flux and moving vane flux,the instrument could be calibrated for either alternating or direct current. In the latter case, however, the meter could not indicate the polarity of the current. The field coil must supply all the energy necessary to operate the meter movement. Any meter of a given rating, operating on the moving- 73.37 vane principle,requires more power thana gure 5-1.-- Metering current in an entire cir- moving-coil meterofthesama,. xatiniti .,rhe 1h.. '..

that ah. in art., ". (11g, .: rynt,..1) a% 14. ale

.: .,:ts 1:. ...Iscal. 7:i 40 lsbeing 1.1 f, i1,OLd :)-.4RIO

internal tl .." , 1i...de the meter ease. Tlw:, 1.xe,1 OhO0, n.ening that when th meierisinstall,:d In a Lilt:ult., the shunts benottic i:art of the (sir, External s.,"int.:-are hiz,tall,d on the outside ofamete:c:.se,or onthe kiciot a switch- 14Ja1d.rh in gt2,1 torth,.: purpose of in.2reasingtherangeotthe meter. lthough L.) make a(iJusth)ts Ofl meters, there rna',- no an o,:casion whey lave noinstrub...intavailablethatsuits need, and wili have to improvise fri iat ie at hand, Tha shunting method a`)out to be described isnotreallysatisfactory for ananeters oper-- ating on the fixed-coil moving-vane principle. A shuntis ertirely satisfactor, on a moving-coil instrument,toextencitherange up w a r d. A moving-iron element, howayer, is much lase sensitive than a rhuving coil, and would require a greater voltage drop across the shunt. Greater voltage drop causes greater heatin l 1,1to.trdarilmeteri inthe._ shuat. Gre,V.eJ heating former, inducing a voltage in the secondary, causing a current flow in the measuring circuit. This current tends to cancel the existing currentinthe measuring circuit due to the voltage drop across the ground resistance be- CURRENT ADJuST tween the electrodes connected to terminals X ANOR and 1. When the calibrated potentiometer and range switch are adjusted so that the two currents exactly cancel, the galvanomeer will indicate balance by resting in the zero position. The reading on the calibrated dial of the potentiometer, multiplied by the range switbh setting, then gives the value of the ground resistance of the point under test. Representative test setups are shown in figures 5-32 and 5-33. Grounding must be in accordance with the National Electrical Code, published by the Na- tional Board of Fire Underwriters and the jinx tional Electrical Safety Code, published by the 0,1SULATION TEST U. S. Department of Commerce, National Bureau ACCESSORY of Standards, except that grounds and grounding systems must have a resistance of solid earth ground not exceeding the following values: 26.224X Ohms Figure 5-29. MultiA mod ' 1A test set. Generating stations 1 Main substations, distribution sub- An accessorytothe MS-1A tester, used stations, and switching stations for insulation measurements, fits into the ac- on primary distribution system . 3 cessory socket in the test lead compartment (fig.5-29).Wit Iit, insulation measurements Metal enclosures of electrical and from 2 to 1000 megohms with ±5 percent ac- electrically operated equipment curacy can he rn, de. and cable sheaths of connecting cables 3 MODEL lisE,..)GROUND Systems to which portable electrical Electrical.y 'stemsand specific electrical utilization equipment or appliances equipment must be protected from damage or are connected 3 destruction by voltages from other circuits, orlightning. Manmade grounds providethis Secondary distribution systems safety feature. To provide maximum protection, (neutral), noncurrent carrying these grounds must be -hecked regularly. metal parts associated with Figure 5-30 shows the Vibroground, an in- distribution systems, and en- strument specifically designed to checkgrounds closures of electrical equipment quickly and accurately. not normally within reach of other The Vibroground works on a null-balance than authorized and qualified elec- principle. The basiccircuitisindicatedin trical operating and maintenance figure 5-31. The voltage drop developed by a personnel 10 current flowing through the unknown ground resistance is measured by comparing it to aIndividual transformer and lightning portion of the voltage drop developed by that arrester grounds on a distribu- Paine current flowingthrough a calibrated po- tion system 10 tentiometer. The current flowing through the calibrated potentiometer causes a voltage dropEquipment not covered above 10 105 It 5 1DULALIN../1 shock. Insulators, the -forgotten men" of electri- al systenis, are subject to several ills that Transformer Test an make them a potentialhazard unless they re tested periodically.Breakage is probably Deenergize equipment. Di st. ainect theleads he first hazard with insulators. Casually ac-from both primaryar.,, rondary windings. :umulated dirt, grease, or liquids is another. Tests can be made of e!1 the primary or )ccasionally, faulty construction makes a brand secondary winding individu, by connection of lew insulatora source of danger. To test in-the negative lead an associated ground(case, iulators, connect test leads to each end; thenmetal mounting, or manmade ground), andthe est each end to ground (fig. 5-20). lead from the winding under test to theposi- tive lead. Following tests of each winding,it is :apacitor Test a good idea to testinsulation resistance be- tweenthewindings themselves. Connect one test lead to the primary (eitherlead); and the You call usc the Vibrotest megohmmeter to second test lead to the secondary.All of ;heck both insulation resistance and approximate under proper identifying labels, .iapacitanceofcapacitors. When you connect thesetests, Rads to capacitor terminals, observepolarity hould be recorded on a record card. .:arefully. Time your test until the meterpointer If you have transformers withmultiple- stops moving upward, then recordinsulation re- voltage windings, the procedures aboveshould Sistance at highest reading. Dividingtest time,be followed to test all windings to ground,and ln seconds, by 15 will give youthe approxi-each winding's resistance value to everyother winding. mate capacitance, in rnicrofarads,of the capa- clear, dry citor.Ifone pointer has a tendencyto waver Tests should be made during toward the high reading, then drop backdown weather. The temperature and relativehumidity the scale. The capacitor may beleaking, and of the air and general atmosphericconditions further testing is indicated. Be especially careshould be recorded at the time tests are being fulto RELEASE PUSHBUTTONbefore startingmade, if known. Test records should be kept todisconnecttestleads from capacitors, If since they show when trouble is developing as you do not give theVibrotest discharge re-a result of gradual orsudden deterioration of to dissipate the storedthe insulation or because of localleakage. For sistoranopportunity example, a 40-megohm reading on the primary winding of a transformer that has been testing about 500 megohms indicates trouble that should be remediod. Low resistance values may re... quire oil samples to be taken from the transformer to determine whether or not thelow values may be due to deteriorationof the oil.

PHASE SEQUENCE INDICATOR The PHASE SEQUENCE INDICATOR is a device used to compare the phase rotationof an incoming alternator operated in parallel with an alternator already on the line; or todetermine the phase rotation of equipment being putinto use for the first time. The makeuP of it phase sequence indicator is as follows: A tinythree-phase induction motor is equipped with three leads, labeled A, B,and C, au shown infigure5-21. The insulating hoods over the clips are of differentcolors; red for A, white for B, and blue for C. 73.2H2X The rotor in the instrument can be observed that Figure Tenting inritilatorti. through the three PORTS as it turns, so

99 109 notethedirectionofrotationofthe rotor. Now move the A terminal to X, the B tO Y, and the C to Z, and again press the switch. Iftherotor turns in the same direction as before, the phase rotation is the same and the connection can be made X t3 X1, Y to Y1, and ZtoZ1.Iftherotor turns in the opposite direction, transpose the connections of any two of the incoming alternator leads before making the connection. Now move the A terminal to X, the B to Y, and the C to Z, and again press the switch, Iftherotor turns in the same direction so before, the phase rotation is the same and the 73.52 connection can be made X to X1, Y to Y1, and Figure 5-21. Phase-sequence indicator. ZtoZl.Iftherotor tur:13 in the oppositn direction, transpose the connections of any two of the incoming alternator leads before making you can note the direction in which it rotates. the connection. The rotor can be started by means of a momen- Itisnot absolutely necessary that A be tary contact switch; it stops again when you reconnected to the left-hand terminal, B to ow lease the switch. center terminal, and C to the right-hand termip Phase sequence is the sequence or order in nal.This ib a practical method, however, used which the three voltages of a three-phase sys- to avoid the danger of confusing the leads. The tem appear. When an incoming alternator is cut important thingisto ensure that the plume in with a loadside alternator already in opera- sequence indicatorthat was used on v..ibe tion,connections must be made so that thebrought down to X, the one used on to y, phase sequence of the two will be the same. and the one used on Z1 to Z. Reversing any Figure 5-22 illustrates the procedure for two oftheleads will reverse the directioe ensuring this with a phase sequence indicator. of rotation of the rotor. Connect indicator terminal A to X1, B to Yl

SPECIAL TEST EQUIPMENT

Inadditiontothebasic test instruments described in the previous sections, it is neoer sary that you acquaint yourself with varioua INCOMING specialtest instruments. A description of a ALTERNATOR number of special test instruments used by the C E is presented in the following sections.

SERVIVAR ELECTRICAL TESTER The Servivar Electrical Tester is a multi-, purpose electrical instrument designed for re.. sietance,and alternating current and volts. measurements. It is a portable, battery-oPeratO unit conMeting of the basic indicator instrument LOADSIDE- xi Y1 ZI (fig.5-23),an attachable Snap-Around probe ALTERNATOR ALREADY IN for measuring a-c currents (fig. 5-24) anda OPERATION Line Splitter (fig. 5-25). Only one ocale on the instrument is visible 73.53 to the user at any given time. This eliminate* Figure 5-22.Diagram for checking phase se- or reduces confusion and erroneous readings ea quence. common to multiple elude instruments. Tbs scajip- 100 1 1 0 26,230X Figure 5-23.-- Servivar electrical tester. re color coded so that the user canquickly ecognize whether heis on the a-c current cale, a-c volt scale, or the ohm scale. Special circuitry (not shown) prevents damage D the meter when voltage isapplied inadvert- ntly to the instrument when it is on theohm cale. Thisisaccomplished without the use

26,231X 26,232X Figure 5-24. Snap-around probe. Figure 5-25. Line splitter, CONSTRUCTION ELECTRICIAN 3 & 2

fuseb,pircuitbreakers, or other devi r factor that would hitve to be replaced or reset. bined into one instrument and selection is made by another switch. Principles of Operation Adapters The a-c current to be measured is inter- cepted from the conductor in which it is flowing Adapters are available for use on single by transformer actioninthe magnetic pathand three-phase, 3-wire measurements and may that constitutes the Snap-Around probe. A pick-expedite testing procedure. These adapters in.. off coil located inside the probe and around theclude: Model 9815 Type 1 Adapter tor threw. magnetic path surrounding the reference con-phase 3-wire 200/100/50/5-ampere operation; ductor supplies voltage to a full-wave bridgeModel 9815 Type 2 Adapter for single-phase through a resistance network. This voltage varies 2-wire 100-ampere operation; and Model 9835 in magnitude in direct proportion to the current Type 3 Adapter for single-phase 2-wire EA.,- that is being measured. ampere operation.

Probe Precautions The probe has designed to enter into You should remember the following precut.. cramped electrical boxes and to snap around tions when using the analyzers; an individual conductor in a mass of conduc- 1. Always stt switches to the proper set- tors without the need to reposition the othertingb and ranges before connecting the instru- conductors. It operates as a true Snap-Around ment. device that accepts wires up to 0.5 inch outer 2. Always connect theload leads to the diameter, rather than a cumbersome scissorssame current on all three phases of the in-, type jaw that requires a maximum clearance.strurnent and to a high enough range so that The probes are interchangeable with all indi- tht,current indicatedwill be below the full catorsso that additional probes may be left scale deflection of the ammeter. permanently installed in inaccessible locations. 3. NEVER USE THESE INSTRUMENTS FOR The Snap-Around probe features easy thumb D-C MEASUREMENTS. control for quick opening. Retraction is a simple operation. Merely slide the thumb knob back and hold at the desired clearance. (See fig. 5-24.) Connecting Analyzer to Circuits To close, release gently, encircling the wire whose current is to be determined. The three-phase, 4-wl-e hookup in figure 5-27 shows a schematic of external potential and current transformers. Improper connection oath' Line Splitter result in damage to personnel and equipment. Therefore, follow the manufacturer's iestruo- As you know, in measuring a-c current, ittions carefully when connecting analyzers t4) is mandatory that only one conductor be en-circuits. circled. It may not be convenient or possible e.lsure that all cables used for connection.; to split the conductors in a two conductor cableto source or load are of sufficient size to carry so that a current measurement can be made. the currents involved and are connectedse- The line splitter automatically performs thiscurely tothe binding posts and the oiroult function. terminals. Refer to Table 30-13 (Nationnl Electric Code) for information regarding the WESTON MODEL 639 INDUSTRIAL allowable =peonies of insulated copperma- ANALYZER TYPE 3 ductors, for more data pertaining to 0614es BE SURE TO USE THE APPROPMATO The Weston Model 639 Industrial Analyzer CORRECTION FACTOR (bottom of Table 210. Type 3 can be used to measure the complete13) wherever the ambient temperature sumac's load conditionsof any three-phase four-wire86° F. For example, if you plan to ups TRW system when used with proper current and po- conductor, and the ambient temperature at your tential transformers (fig. 5-26). Switches permitstation is UP F, notice that the current ciiriy testing of 60- or 400-hertz power circuits.ing capacity of the size of wire you Iateacl to use

102 112 l'1(\ 1.1 nuciAN 2

14A akib-Aliaraa

a+ CURRENT v- TRANSFORMERS

POTENTIAL TRANSFORMERS 4

VARIOUS TYPES OF CUT OUTFUSES FOR MEASURING CURRENT WITHOUT INTERRUPTINGSERVICE

000 0 0 000 0

ANALYZER DUMMY CARTRIDGE FU E IN USE

TWO POTENTIAL TRANSFORMERS 0 F SUITABLE RANGE HAVING 115 VOLT SECONDARIES CONNECTED FROM NEUTRAL TO LINES 'A° AND C. THREE CURRENT TRANSFORMERS OF SUITABLE RANGE HAVING 5 AMPERE SECONDARIES CONNECTED IN DELTA.

26.40X Figure 5-27. Three-phase, 4-wire circuit connected to three current transformers.

The instrument test relays from 0.1 to 100 1 1 amperes and circuit breakers up to 100 ampere capacity, measuring accurately the time-current 26.31X characteristicsof these devices with a syn-Figure 5-28. Various types of dummy fuses. chronous electronically actuated timer. The MultiAmp (MS-1A) instrument (fig. 5-29) is used primarily in Public Works installations. a comparison is made with the manufacturer's Testing is rapid. It takes but a few minutes specifications. Obviously, any results beyond tbs to know your equipment is properly protected.specified limits will indicate a defective relay The instrument can be used to check the which should be replaced or, Uadjustable, reset overload heaters of small motors. Refer to to meetthe specifications. manufacturer's data sheets or Allowance Parts Use of this instrument will expedite deter.. Lists for the tripping time characteristics formination of relay malfunction, or circuit fault', the particular overload heater. After setting the Assured of relay accuracy, after testing,you Current Adjust knob to t,hat current which is know the cause of difficulty (if 'the relay icespe supposed to trip the device and noting on thetripping) lies within the circuitry other than the Timer the time it takes for the device to trlp, relay and must be sought there.

104 114. former, inducing a voltage in the secondary, causing a current flow in the measuring circuit. This current tends to cancel the existing currentinthe measuring circuit due to the voltage drop across the ground resistance between the electrodes connected to terminals X and 1. When the calibrated potentiometer and range switch are adjusted so that the two currents exactly cancel, the galvanomeer willindi- cate balance by resting in the zero position, The reading on the calibrated dial of the potentiometer, multiplied by the range switbh setting, then gives the value of the ground resistance of the point under test. Representative test setups are shown in figures 5-32 and 5-33. Grounding must be in accordance with the Nationil Electrical Code, published by the Na- tional Board of Fire Underwriters and the liax tional Electrical Safety Code, published by the 01ISUL ATION TEST U. S. Department of Commerce, National Bureau ACCESSORY of Standards, except that grounds and grounding systems must have a resistance of solid earth ground not exceeding the following values:

26.224X hg_j_ns igure 5-29. MultiA mod ' 1A test set. Generating stations 1 Main substations, distribution sub- An accessorytothe MS-1A tester, used stations, and switching stations Dr insulation measurements, fits into the ac- on primary distribution system .... 3 essory socket in the test lead compartment rig.5-29).Wlt Iit, insulation measurements Metal enclosures of electrical and rom 2 to 1000 megohms with ±5percent ac- electrically operated equipment uracy can he nv and cable sheaths of connecting cables 3 110DEL lEstl,..)GROUND Systems to which portable electrical Electrical.y 'stemsand specific electrical utilization equipment or appliances iquipment must be protected from damage or are connected 3 lestruction by voltages from other circuits, srlightning. Manmade grounds providethis Secondary distribution systems safety feature. To provide maximum protection, (neutral), noncurrent carrying hese grounds must be .hecked regularly. metal parts associated with Figure 5-30 shows the Vibroground, an in- distribution systems, and en- strument specifically designed to check grounds closures of electrical equipment luickly and accurately. not normally within reach of other The Vibroground works on a null-balance than authorized and qualified elec- rinciple. The basiccircuitisindicatedin trical operating and maintenance 3gure 5-31. The voltage drop developed by a personnel 10 3urrent flowing through the unknown ground resistance is measured by comparing it to aIndividual transformer and lightning portion of the voltage drop developed by that arrester grounds on a distribu- pone current flowing through acalibrated po- tion system 10 tentiometer. The current flowing through the Palibrated potentiometer causes a voltage drop Equipment not covered above 10 !

RATIO POWER TRANSFORMER O TRANSFORMER SYNCHRONOUS GALVANOMETER,- VIBRATOR ESEC 0 0 ?CD a I PRI. 0 SEC. a RANGE POTENTIOMETER SWITCH WITH CALIBRATED DIAL

t LEVER I SWITCH

BATTERY 0

II GROUND I:REFERENCE 11 REFERENCE II UNDER 1.1 GROUND V GROUND TEST 1.55AX Figure 5-31. Basic Vibroground circuit.

easurement of Unknown Resistances If the resistance of a loop is to be determined, disconnect all equipment from the near Once the instrument accuracy has been veri- end of the loop and connect one wire of the ed,and theresistanceof a loop or otherloop to the binding post Xi and the other wire sistance is to be determined, measurement tolinebinding post X2 (fig.5-35). Be sure in be easily made by referring to table 5-1 thatthe wires connected to the test set are idsettingthe MULTIPLY BY dial to thatclean and firmly secured to the binding posts. tting closest to the estimated value of theHave all equipment disconnected from the far nknown resistance.

2 ow. MIR REFERENCE GROUND GROUND WATER GROUNDS UNDER UNDER SYSTEM TEST 10' 50 10' 60- TEST

26.227X 26.228X igure 5-32. Vibroground test setup for check- Figure 5-33. Vibroground test setup when there ing the resistance to earth of a driven trans- is a well established low resistance reference former ground. ground.

107

7 iMe 5-1. Multiply by Dial Setting When Meas- uring Resistance

STIMATED RESISTANCE MULTIPLY BY (ohms) dial setting

1 elow 10 26.45 1000 Figure 5-36.Connections for ground location, regular Varley and Murray loop tests. 1 ) to 100 100 (2) The equation used to determine resist- )0 to ipoo 1 ance from far end to fault (Xb) equals: 10 Xb A(R + Rb) - BRg 1 A + B sed in Varley tests 9 .where A =numeratorof position of MUL- sed in Varley tests 1 TIPLY BY dial, 4 B =denominator of position of MUL- TIPLY BY dial, 1 r =loop resistance as calculated in 000 to 10,000 1 previous paragraph, Measurement of Unknown Resistance, 10 R =decade dial readingafterbal- D,000 to 100,000 ancing, Rg resistance of good wire from test 100 point to far end, OG,Q00 to 1,000,000 Rb resistance of faulty wire from test 1 point to far end. Three Varley Test 73.340 This test has a definite advantage, especially (1) The equation used todeterminethe re-for central desk testing, over other types of stance from test point tofault (Xa)equals: tests in that the resistance of the test cords rB - AR and the conductors themselves neither need to be Xa A + B kierer equals Rg + Rb(loop resistance).

.C7S11 "" o

26.44 26.46.1 igure 5-35.Connection for measurement of Figure 5-37. Regular Valley loop test circuit, loop resistance. simplified schematic diagram.

109 1.19 Known nor auowea tor in tne calculations. its chief drawback lies in the fact that a good pair (two conductors of any resistance) are needed in additiato the faulty conductor and ground. NOTE: Lead wires and conductors may be of unequalresistance,becausethis method balances out their resistances. The test derives its name from the Varley Loop and from the fact that three such tests (a) "VARLET I" TEST must be made. Howeln.:. each is simple as VARLEY 1 TEST BASIC EQUATION: shown in the diagrams and any tester who can A Rg perform the simple Varley should achieve accurate results here, (See fig. 5-38 (a), (b), and B Rb + R1 (c).) The three tests made are known as "Varley 1", "Varley 2" and "Varley 3", using the con- X 1 nections as shown in figure 5-38 (a), (b), and R (c). Rbow> Calling the rheostat readings at balance Ri, 1.0Xa Xb R2, and 113 respectively, the basic e qua tion s 2 are: lb) "VARLET 2" TEST VARLET 2 TEST BASIC EQUATION: A Rg Rg X,, R, + Rb A litg + Xb B R1 + Rb R2 + R3 X. + R2

Trom which may be obtained the working equations: X = x (R3 - R2) used todetermine a A + B the resistance (Xa) between the test point and the fault. (e)"VARLET 3" TEST A VARLEY 3 TEST BASIC EQUATION: Xb x (R2 - R1) usedto determine A Fig + Rb A + B the resistance (Xb) between the fault.

Rb Xa Xb used to determine the resistance (Rb) A of the full length of x (113 the faulty wire, A + B

These symbols are identified in equation 2 tinder Id) MOCIIFIEO"VARLEY I" TEST Regular Varley Loop Test. NOTE: CONNECTIONS OF POSITIVE PORTION OF BATTERY OISTINGUISH SETWEEN THE In using the three Varley Test, MULTIPLY THREE VARLET TESTS. BY dial ranges 1/1, 1/4, or 1/9 are recommended. Once the range has been selected, it . 26.40.9 must be used on all three tests to produceFigure 5-38. Simplified schematics and blillic accurate results. equations for 'Three Varley tests." 120 110 'KO aetermine tne resistance to tne lama to tenths of an dull, the ratio A/B must be approxi- RQ mately 1/10. The ratio 1/9 and 1/4 are con- . X 1 venient in some models, because their working equations reduce,respectively, to the forms: STRAP R 112 - R3 - R2 R3 - Ri , and Rb -Z.-X Kb a 10 'Xa 10 10 FAULT

R2 - R1 R3 - R2 R3 - 26.46.3 Kb 5 Xa , and Rb - Figure 5-39.Regular Murr ay loop test for 5 5 locating ground. When the total resistance of the loop is more than about 1000 or 1100 ohms, it is impossible R x L to balance the Midge when using the 1/10 or da = 1/9 MULTIPLY BY dial setting. It may then be necessary to use A/B = 1. Then, if the good where R equals the decade dial sum, L equals wire is of lower resistance than the faulty wire, the total loop distance in miles and A equals the bridge cannot be balanced in the "Varley the MULTIPLY BY dial reading (usually set at l." test. The good and bad wires, with their M 10, M 100, or M 1000 for Murray Loop leads, must interchanged as in figure 5-38 (d). readings). while making the "Varley 1."test only. The (b)Resistance-distance method is used after working equations under these conditions are: the resistance X. (from the test point to the fault) has been determined using the formula R2 + 111 R3 - R2 R3 - Kb = Xa and Rb - R x r 2 Xa =R + A ' To avoid the need for interchanging the good where R = total decade dial reading. and bad conductors in the "Varley 1" test, a r = total loop resistance of the faulty pmall resistor may be, connected between the circuit test set and the good conductor. It is used dur- A = numerator of the position of MULTI- lag aU three tests. Any reasonable value of PLY BY dial. resistance may be used which is large enough The result obtained from the above calculation to msite the resistance of the good conductor is then substituted in higher than that of the bad one. Its value need Xa not be known since it is automatically eliminated da = by this method of test. 1/2 resistance per loop mile,

Murry Loop Test For and should agree with the result calculated by Locating a Ground the direet computation method. To use the Murray loop test for locating a CABLE REPAIRMAN'S TEST SET ground, a good wire should be available (fig. 4.48) in addition to the grounded wire. A sim- The cable repairman's test set, 1-51.(fig. plified schematic is shown in figure 5-39. Re- 5-40) is used to pinpoint the location of sable move SU equipment from both ends of the circuit faultsaftertheapproximate location of the fault has been obtained by the use of the Wheatp and locate the fault using the manufacturer's stone Bridge or some other method, The test inatrucUons and either of the following methods: set can be used to locate shorts, grounds, (a)Direct computation, for solving da, the crosses,split pair., wet spots, and similar distance from the test point to the fault, when troubles in a cable. IT CANNOT BE USW TO Iota mileage of loop is known. LOCATE OPEN CIRCUITS..

111 121 Chapter 7.---SilOPWOHI:

this measurenvmt by 3,1416 and yo..i get a circumference of18.85 inches. Divide thisinto 1200 and you gc63.66 rpm thich roimis off to 64 rpm. Insulating mica protruding from,'Iteslots between the ommutator bars can cause wear, streaking, and breaking of the brushes. Remove this high mica by undercutting it to a depth of between 3/64 and 1/16 inch below the level of the commutator bars with a power-driven flexible shaft undercutter, after first remiwing the brushrigging.Ifa power-driyen toolisnot available, use a slotting tool, or else make a cutter by rem.lying the teeth from e. hacksaw blade and forming one end. The straiOlt end, taped, will serve as a handle. Figure 7-8 shows properly and improperly undercut commutators. Do not use lubricant, and do not cut too deeply. After remwing the high mica, smooth out all burrs and polish the comtmitator with a commercial burnishing stone or hardwood block shaped to the curvature of the armature. The block is pressed hard against the surface of the 77.74 Figure 7-7. Truing commutator by turning. commutator while the machine is running. Poor h3lance in an armature can cause commutator failure. Detach the armature from the Because there is a certain give, or elastic-machine, and rest the shaft ends on V-blocks. ity,to the support, a heavy cut may result in For a ball-bearing-supported armature, let the the cylindrical shape of the commutator beingbearings remain on the shaft, and check the impaired.Again,a heavy cut can cause the commutator withthe shaft on V-blocks. The turning tool to twist the com mutator bars, and surface on which the V-blocks rest mist be to make deeper cuts at one end than at the other. perfectlylevelin every case. To check for Take light cuts, therefore, even though more concentricity,usea dial gage mounted on a cuts will thus be necessary. brush holder with the contact tip of the gage contacting the top of the brush and rotate the The lathe must be capeble of turning the armature. part to be ground at exactly its rated speed; if Commutators with peripheral speeds of ap- the cutting is done at a lower speed, any slightproximately 5500 fpm should be concentric to unbalance will cause the commutator to turnwithin 0.001 inch. For commutators with pe- eccentrically, when run at rated speed. The usual ripheral speeds of about 9000 fpm, the allow- cutting speed is 100 ft per m;n (fpm), which is able tolerance is only 0.0005 inch. 1200in.per min (ipm). The feed should be about 0.01in., and the depth of the cut should not exceed 0.01 In. 4picidakich4 The procedure for changing fpm to revolu- tionspermin (rpm)is as follows. First determine the circumference in inches of the commutator by measuring with a cloth tape, or by measuringthediameterand multiplying by 3.1416. Divide the result into 1200 to obtain the number of rpm required for a cutting speed of 100 fpm. 73.229 For example, suppose you have an armature Figure 7-8. (A) Commutator r erly undercut; witha 6-inch commutator diameter. Multiply (a! Commtator improperly undercut.

183 193 CONSTRUCTION ELECTRICIAN 3 Sz2 11".

where thebrushesride.If a nonuniform or bluish colored surface appears, improper com- I 4 TO 3fl STICK RIVET CANVAS mutation conditions are indicated. Periodic in- INCH THICK spectionsand propercleaning practices will keep commutator and collector-ring troubles at a minimum,

Cleaning 1.54.1 Oae of the most effective ways of cleaning igue Canvas wiper. the commutator or collector rings is to apply a canvas wiper whilethemachine isrunning. The wiper can be made t,y wrapping several A check should be made on the air gaps at layers of closely woven canvas over the end of commutator poles, and at main poles, to deter- a strong stick between ane-fourth and three- mineIfthereis any wear or misalignment. eighths Inch thick (fig. 7-9). The canvas may be You take the air gap measurement by setting a secured with rivets If they, in turn, are covered reference point on the armature (or rotor), and withlinentapeto prever.t the passibility of revolving it to measure four points on the stator their contacting the commutator. When the outer (or the field frame) with reference toit. An layer of canvas becomes worn or dirty, it is equally satisfactory method isto choose your removed to expose a clean layer. Tne wiper Is reference point on the stator or field frame,most effective when used frequently. On large and revolve the rotor or armature to measure generators, it may be desirable to use the wiper four points on the la:ter with reference to the once each watch. When using the wiper, exer- stator point. cise care to keep from fouling moving parts of Correct tension an :le commutator Is usu- the marhine. The manner of applying the wiper allydeterminedatthe time of manufacture. to a commutator is illustrated in figure 7-10. Tightening the commutator will not align the When machines are seeured, a toothbrush bars in their original position, and if the com-can be used to clean out the commutator slots, mutator becomes too tight, some of the bars and clean canvas or lint-free cloth may be used may buckle. Making ringbolts and loaknuts too for wiping the commutator and adjacent parts. tight may result in pressing the V-ring through In addition to being clean-d by wiping, the com- t'ie mica Insulation, thus short circuiting themutator should be periodically cleaned with a bars. vacuum cleaner or blown out with clean, dry air. After being used approximately two weeks, A fine grade of sandpaper, No. 00, may be the commutator of a machine should develop a used to clean a commutator that is only slightly rough,butnot outoftrue. SandpaperingiE uniform, glazed, dark brown color on the places recommended foi reducing high mica, and for finishing a commutator that has been ground or turned.The sandpaper, attached to a wooden block shaped to fit the curvature of the commu- \RIVETS COVERED tator,is moved slowly back and forth across WITH LINEN TAPE the surface of the commutator while the machine is running at moderate speed. Rapid movement or the use of coarse sandpaper will cause scratches. Emery cloth, emery paper, or emery stone should never be used on a commutator or collector ring.

COLLECTOR RINGS 1.54.2 Collector rings (slip rings) require the same Figure 7-10. Using the canvas wiper on a coi- carefulattentionas the commutator. Out-of- mutator. round conditions of the rings may be corrected

1184 194 Chapter 7SHOPWORK in the same manner as for commutators, except for the fact that crocus cloth is used to apply a mtrror-like finish following any turning, grinding, or sanding operations. Pitting can develop because of the electrolytic action on the surface of collector rings caused by current flow.It may occur in only one ring,but will be general over the whole ring area. This condition can be corrected by reversing the polarity of the rings evely few days. Reversing the polarity of the d-c field of a 3-phase generator willnot affect the phase rotation of the generat9r. Field current must not beleft on while a r!achineis secured because it will cause spot pittingand burningof the rings beneath the brushes.

BRUSHES

The brushes used in electric motors and generators are one or more plates of carbon, bearing against a commutator, or collector ring (slipring)to provide a passage for electrical currentfor an external circuit. The brushes are held in position by brush holders (fig. 7-11) mounted on studs or brackets attached to the brush-mounting ring, or yoke. The brush holder studs or brackets, and brush-mounting ringcom- prise the brush rigging. A d-c generator brush holder and brush-rigging assembly are shown in figure7-12.The brushriggingisinsulated from, but attached to, the frame of the machine. Flexible leads (pigtails) are used to connect the brushes to the terminals of the external circuit. 73.165 An adjustable spring is generally provided to Figure 7-11. Brush holder and brushes. mMnth.in proper pressure of the brush on the commutator in order to effect good commutation. Any defect in the brush riggings or malad- justment of the spring tension can impair thetrouble. Brushes are manufactured in different proper contact between the commutator and the grades to meet the requirements of the varied brushes. types of service. Tne properties of resistance, ampere-carrying capacity, coefficient of friction, Maximum commutation is achieved when the and hardness of the brush are determined by the correct grade brushes are set in the holders maximum allowable speed and load of the ma- withallowableclearance and the appropriate chine in which it is used. spring tension applied to maintain the correct pressure for the particular type brushes. Use the grade of crush indicated in the technical manual. Normally, similarly sized and graded brushes of any manufacturer on the Correct Brush Type Qaalified Products List may be substituted. In certainspecializedequipment, however, only Tne correct grade of brush and correct brush one grade of each of two different brush manu- adjustment are necessary to avoid commutation facturers is pertnItted for any machine.

185 193 CONSTRUCTION ELECTRICIAN 3 & 2

Care Replacement must be preceded by cleaning alldirt and other foreign material from the Brushes should nr)ve freelyh.! their holders brush holder. but should not he loose enough to vibrate in the holder. Where brush springs are of the positive gradient (torsion, tension, or com7ression) type and Brushes should he replaced when they are are adjustable, they should be adjuted as the worn or chipped to such an e:.:tent that they will brushes wear, lu order to keep the brush pres- not mAve properly in their holders; or are worn sure approximately consant. Springsofthe to within 1/8 inch of the !metallic part, or more coi:ed bar constant pressure type and certain than 50 percent of the original length of thesprings of the positive gradient type are not brush. adjustable except by changing springs. Brush

Ar/L!" TING I N

BRACKET

BRUSH HOLDER ;aft'

STUD

BRUSH

PIGTAIL

77.70 Figure 7-12. Brush holder and brush-rigging assembly.

186 196 Chapter 7----SliDPWORK

correction factors into consideration, the actual pressure will be a few percent lower in the case of brushes operating in the leading position and a few percent higher In the case of brushes operating in the trailing position. All brush holders should be thesame distance from the corn matator, not more thanone- - SPRING BALANCE eighth inch, nor less than one-sixteenth inch. The toes of all brushes on each brush stud PIGTAIL LEAD should line up with each other and with the edge of one commutator segment.

SPRING The brushes should be evenly spaced around the commutator. To check brush spacing,wrap astrip of paper aroand the commutator and mark the paper where the paper laps. Remove BRUSH the paper from aie commutator, cut at the lap, and fold or mark the paper into asmany equal partsas there are brush studs. Replace the paper on the commatator and adjust the brush TAKE SPRING REAOING COMMUTATOR OR holders so that the toes of the brushesare at WHEN SLIP OF PAPER COLLECTOR RING MAY BE DRAWN FROM the creases or marks. BETWEEN BRUSH AND COMMUTATOR Seating 77.72 Figure 7-13. Measuring brush tension. Accurate seating of the brushes must be assured where their surfaces contact thecommu- tatof. Sandpaper and a brush seater are the best pres3ure should be in accordan.3e with the manu- tools to accomplish a true seat. factLrer's tec"/ i m9nua1. Peessures as low as 1-1/2 po., las per square inch of contactarea Allpower mast be disconnected from the may be speciiied fo l. large mcchines and as high machine, and every precaution must be taken as 8 noands per squure inch of contact area may to ensure that the machine will not be inad- be specified for s-nall machines. Where tech- vertently started before and whenever using sand- nical manuals arenot available, a pressure paper toseat the brushes. The brushes to be of 2 to 2-1/2 pound=, per square inch of contactfitted are lifted, and a strip of fine sandpaper area is recommnnded for whole number horse- (No. 1) approximetely the width of thecommu- power and whole number ki.T.owatt machines, and tator,is inserted(sand side up) between the about twice that pressure for fractional horse- brushes and the commitator. With the sand- power and fractional kilowatt machines. paper held tightly against the commutator sur- faceto conform withthe curvature and the To measure the pressure of brushes operat- brushes held down by normal springpressure, ing in box type brush holders, insertone end of the sandpaperispulledin the direction of a strip of paper between the brush and commu- normal rotationofthe machine(fig.7-14). tator; use a small brush tension gage (suchas When returning the sandpaper for another pull, the 0- to 5-pound indicating scale carried inthe brushes must be lifted. This operation is General Stores under Stock No. GS5670-583- repeated until the seat of the brush is accurate. 0063) to exert a pull on the brush in the direc- Always finish with a fine grade of sandpaper, tion of the brush holder axis as shown in figure No. 0. A vacuum is required for removing dust 7-13. Note the reading of the gage when the pull while sanding. After sanding, the commutator is just sufficient to release the strip ofpaper so and windings must be thoroughly cleaned tore- that it can be pulled out from between the brush move all carbon. dust. and commutator without offering resistance. This The brush seater is compounded of a mndly reading divided by the contact areamay be con- abrasive rrir 'erial loosely bonded, and is formed sidered to be the unit operating pressure. Taking in the shape of a stick about 5 inches in length.

187 197 CONSTRUCTrox P.ECTIUCIAN 3 & 2

For niachines having a num7)er of poles equal to two times an odd number, will obviously not be possible to stagger all the brushes in accordance with the correct method shown. Stag- ger :tll but the odd pair of positive and negative brushes in accordance with the correct method, andthe odd pair as shown in view B of figure 7-16.

Setting on Neutral

When a machine is running without load and with only the main-pole field windings excited, the point on the comm.,:tator at which minim.= ENn LO VIEW voltage is induced between adjacent commutator bars isthe no-load neutral point. This is the best operating position of the brushes on most 1.52 commutating-pole machines. Usually, the brush Figure 7-14. Method of sanding brushes. studs are doweled in the proper position, and the correct setting is indicated on a stationary partof the machine by a chisel mark or an The brush seater is applied to the commutator arrow.In some cases, commutation may be while tne machine isrunning, and every pre- improved by shifting the brushes slightly from caution should be taken to prevent injury to the the marked position. person applying it. The brush seater is touched lightly, for a second or two, exactly at the heel The correct neutral position can be found by of each brush (fig.7-15). If placed even one- the use of: fourth inch away from the heel, only a small part of the abrasive will pass under the brush. 1. Tne mechanical method. Pressure may be applied to the brush by setting 2. Tne reversed rotation method. thebrushspring tension at maximom or by pressing a stick of insulating material against 3. The inductive kick method. thebrush. The dustisremoved during the operation, and the machine is thoroughly cleaned Tne mechanical method is an approximate afterwards in the same manner as for sandingmethod. Turn the armature until the two coil brushes. sides of the SAME armature coil are equidis- Brushes should be staggered as shown in fig- tant from the centerline of one MAIN field pole. ure 7-16 to prevent grooving of the commotator. The commutator bare to which the coil is connected give the position of the mechanical neutral. Use of the reversed rotation method is pos- BRUSH BRUSH sible only where it is practicable to run a ma- SEATER chine in either direction of rotation, with rated BRUSH load applied. This method differs for motors and HOLDER HEEL generators. For motors, the speed of the motor COMMUTATOR OR COLLECTOR RING is, at first, accurately measured when the field current becomes constant under full loadPt line TOE voltage with the motor running in the normal DIRECTION OF ROTATION direction. Then, the rotation of the motor is reversed, full load is applied, and the speed is again measured. When the brushes are shifted so that the speed of the motor is the same in both directions,the brushes will bein the 1.53 neutral position. Generators are run at the same Figure 7-15. Using the brush seater. field strength and same spee in both directions,

188 198 Chapter 7SII0PWORK

-NNW UNII

000 PAIR

77.71 Figure 7-16.Correct method of staggering brushes.

and the brushes are shifted until the full-load Tne rotating element of an electric m.--,,tor terminal voltage is the same for both directions or generator may subject a ball bearing to any ofrotation.To ensure accuracy,a reliable one or a combination of three loads radial, tachometer must be used to measure the speed thrust, and angular. Radial loads are the result of the machines for this method. of forces applied to the bearing perpendicular to the shaft; thrust loads are the result of forces The kick method should be ased only when the applied to the bearing parallel to the shaft; and other methods are inadequate and the conditions angular loads are the result of a combination of are such as to warrant the risks involved, and radial and thrust loads. Because the load carried then only when sufficient resistance is connected by the bearings in electric n-iotors and generators in series with the field coils to reduce the field is almost entirely due to the weight of the ro- current to approximately 10 percent of normaltating element, itis apparent that the method value.

BALL BEARINGS Rolling, antifriction bearings are of two types: ball and roller bearings. Basically, all rolling bearings consist of two hardened steel rings, hardened steel rollers or balls, and separators.

The annular, ring-shaped, ball bearing is the RADIAL ANGULAR THRUST type of rolling bearing used most extensively CONTACT in the construction of electric motors and generators used in the Navy. This bearing is further A divided into three types dependent upon the load itis designed to bear (1) radial, (2) angular 77.66 contact, and (3) thrust. Examples of these three Figure 7-17.Representative types of ball bear- bearings are shown in figure 7 17. ings.

189 199 CONSTRUCTION ELECTRICIAN 3 Sz2 of mounting the unitisa major factor in de- noise in the bearing. A good method for sound termning the type of bearing enriloyed in its testing is to place one end of a screwdriver or construction. Ina vertically mounted unit, the steelrod against the bearing housing and the thrust bearing would be used; while the radial other erd against the ear. If a loud, irregular bearingis common to most horizontal units. grinding, clicking, or scraping noise is heard, trouble isindicated. As before, the degree of The preventive maintenance of ball bearings reliance on the results of this test depends on requires periodic checks of bearing woar, and the experienceofthe person conducting the adequate lubrication. te st.

Wear Checking a motor or generator shaft can give a good indication of the amount of wear, asshownin figure 7-18. View A illustrates Measuring air gapsto determine bearing thatif the motor shaft has vertical movement, wear is not necessary on machines equipped with worn bearings are indicated. View B illustrates ball bearings because the construction of the motor or generator end-play movement and is machine is such as to ensure bearing alignment. corrected with bearing shims. Ball bearing wear of sufficient magnitude as to be readily detected by air-gap measurements would be more than enough to cause unsatis- Bearing Installation factory operation of the machine. The easiest way of determining the extent Representative techniques for bearing removal of wear in these bearings is to periodically feel are shown in figures 7-3 and 7-4. Four acceptable the bearing housing while the machine is running methods for installing bearings exist. These are to detect any signs of overheating or excessive called the arhor press, infrared, oven, and hot- vibration, and tolisten to the bearing for the oil methods. Tne technique you use will depend presence of unusual noise. The indications thus upon the equipment available. obtained are comparative, and caution mist be exercised in their analysis. ARBOR PRESS METHOD.If available and adaptable, and proper precautions are taken, an When testingforoverheating, the normal arbor press can be used. Place a pair of flat running temperatureofthe bearing must be steel blocks under the inner ring or both rings known before the test can be reliable. Rapid of the bearing. Never place blocks under the outer heatingof a bearing isindicative of danger. ring only. Then line up the shaft vertically above While a bearing temperature uncomfo2table to the bearing, and place a soft pad between shaft the hand may be a sign of dangerous overheat- and press ram. After making sure the shaft is ing, it is not always so. The bearing may be all started straight in the bearing, press the shaft rightifit has taken an hour or more to reach into the bearing until the bearing is flush against that temperature; whereas, serious trouble can the shaft or housing shoulder. be expected if that same temperature is reached within the first 10 or 15 minutes of operation. INFRARED METHOD. Abearing can The test for excessive vibration relies to a be heated using an infrared oven to expand the great extent on the experience of the person inner ring for assembly. The bearing should not conductingthetest. He should be thoroughly be heated above 200° F. This method ensures familiar with the normal vibration of the ma- uniform heating all around the bearing. chine in order to be able to correctly detect, identify, and interpret any unusual vibrations. OVEN METHOD. Alternatively, bearings can Vibration, like heat and sound, is easily tele- be heated to expand the inner ring for assembly graphed, and thorough search is generally rein a temperature-controlled furnace at a tempera- quired to locate its source and to determine its ture not to exceed 200° F. The bearing should not be left in the furnace beyond the time necessary cause. to expand the inner race the desired amount, Ball bearings are inherently more noisy in since heating for an excessive period of time normal operation than sleeve bearings, dis,Jussed would giverise to the possibility of deteri- later, and this fact must be borne in mind by oration of the grease with which the bearing personnel testing for the presence of abnormal is prelubricated. 190

200 Chapter 7SIROPWORK

the entrance of foreign materials. Both should be tightened evenly. Any "V" grooves in the housing lip shouldbefilled with grease which will act as an additional seal to protect against entrance of dirt.

ARMATURES A Preventive maintenance of an armature con- 73.303 sists of periodic inspections and tests to deter- Figure 7-18. Ctlecki ngmoto ro rgenerator mine its condition, and proper cleaning practices shafts. (A) Vertical movement;(13.: End-play to preserve the insulation. movement. Frequent checks most be made of the condition of the banding wire that holds down the FIDT-OtL NI TUOD.A fourth method used windings of the d-c armature to see that the in installing bearings is the hot-oil methoti,which wires are tight, undamaged, and have not shifted consists of heating the bearing in oil at 200° F' (fig. 7-19). At the same time, the clips securing until expanded and then slipping it on the shaft. the wires should be checked to see if solder 1,as Tbis motho.:1 is aot desirable and should not be loosened. When repairs are required, banding- used unless absolutely necessary. wire size, material, and the method of originai assembly should be duplicated as far as possible. Note: When pressing a bearing onto a shaft, Only pure tin most be used for soldering band- pressure mast be applied to the inner ring, but ing wire. when pressing a bearing into a housing, pressure must be applied to the outer ring. Periodically, all end windings should be inspected and cleaned (fig. 7-19). Allow sufficient Beforethefinal assembly has been com-clearance between theend windings and end pleted,theentireunitshould hethoroughly brackets or any air deflecting shields to pre- checked for alignmemt. vent chafing or other damage. In cases where shop overhaul is not feasible, air-drying var- The bearing should be paciced with the proper nish may be applied to the windings by brush lubricant and the cleaned bearing housing should after they have been cleaned and dried. be half filled with the same lubricant. The housing must be properly assembled and care must be Risers must be inspected periodically to de- exercised to prevent om'ssion of bearing parts,termine the condition of the solder that secures lubricant seals, grease pipes, plugs, and fittings. the windings to the segments (fig. 7-19). All dirt These parts mast be securely assembled to and lint should be removed by thorough cleaning complete the housing closure and pfotect against to ensure that cooling pas sages will not be clogged. It may be necessary in the case of generators to do this each time the machine is secured. Cleaning Is easier when performed while the BANDING WIRES machine is warm.

END WINDINGS Winding Identification

It is important for you to be able te dentify armature windings because the type niast be determined in order to understand the trouble indications and to make the necessary repairs. Your complete understanding of LAP, WAVE, PROGRESSIVE, and RETROGRESSIVE windings 5.143 isvital. Furthermore, your understanding and Figure 7-19.A d-c armature. applicationof terms such as PITCH, COIL

151 201 CONSTRUCTION ELECTRICIAN 3 &I 2

PITCH, and SIMPLEX, DUPLEX and TRIPLEX connections will enable you to perform your jobs quickly and efficiently.

LAPAND WAVE WINDINGS. Armature windings, irrespective of how the elements are Or\ri© I@ placed on the armature core, are generally classifiedas LAP or WAVE windii.gs.The classification designates the method of connect- SLOT 7 ing the ends of the elements, or coils, to the commutator (fig.7-20). If the ends of the coil are co mected to adjacent commutator segments, or to segments that are close together, the coil A SINGLE TURN LAP COIL is designated as a lap-connected coil, and the winding is a lap winding (view A of the figure). 01 the other hand,if the ends of a coil are connected to commutator segments approximately two pole pitches apart, the coil is designatedas a wave-connected coil, and the winding is a wave winding. (See fig. 7-20, view B and fig. 7-21.)

PITCH. Bothlapand wave windings are placed on the armature core so that the two sides of an element occupy slots that are influ- enced by adjacent poles of opposite polarity, and the emf's generated in the two sides add B SINGLE-TURNWAVE COIL together. In other words, if the left side of a coil momentarily occupies a position wrier the 111.1 center of a north pole, the right side of the Figure 7-20. Classification of armature wind- same coil will occupy a position under approxi- ings. mately the center of an adjacent south pole. The distance between the centers of two adjacent poles is the pole pitch. The span of one coil should be equal or nearly equal to one pole

POLE PI ha-- POLE PITCH

r Is I I

A LAP COIL g WAVE COIL

Figure 7-21. Full-pitch coils. 111.2

192 202 Chapter 7SHOPWORK pitch.Ifa coil spans exactly one pole pitch, 7-23. A PROGRESSIVE WINDING (view A) pro- thewinding is FULL PITCH (fig.7-21), andgressesinaclockwise direction around the ifa coil spans less than one pole pitch, the armature when traced through the winding from winding is FRACTIONAL PITCH. COIL PITCH the commutator end. In other words, the wind- isrecordedand identified by the numher ofing progresses clockwise from segment (bar) slots spanned by the coil in the armature (fig. through the coil to segment. 7-22). Progressive wave winding and retrogressive lap windings are very seldom er1ountered because NUMBERING. Usually d-c armature wind- of the inherent undesirable features, such as the ings ai e two-layer windings in which each slot end connections of coil groups crossingover each contains two coil sides of a single-coil t:ype of other, added weight, and longer leads. Tnerefore, winding (fig. 7-20). Thus one side of the winding with few exceptions lap windings are progressive element is placed in the top of a slot, and the and wave windings are retrogressive. other sideisplaced in the bottom of another slot. It is immaterial which side of the element A RETROGRESSIVE WINDING (view B of is placed inthe top or bottom of the slot. Infig. 7-2) progresses in a counterclockwise di- practice (observing the armature from the com- rection around the commutator end, mutator end) the right side of the coil is usually placed in the bottom of one slot and the left side MULTIPLEX WINDINGS. Windings may also is placed in the top of another slot. The coil sides be classified and connected in SIMPLEX, DU- are arbitrarily numhered so that all TO? coil PLEX, or TRIPLEX. A simplex lap winding is sides have odd numbers and all BOTTOr.4 coilone in which the beginning and ending leads of sides have even numbers (fig. 7-20). This sys- a lap would co:l are connected to adjacent com- tem 7ielpsto place the coils properly on the mutator bars. Duplex lap winding leads are con- armature. nected two bars apart, and triplex lap winding leads are connected three bars apart. PROGRESSIVE AND RETROGRESSIVE WIND- Progressive and retrogressive simplex lap INGS.Lap and wave windings can be progres-windings are shown in figure 7-24. As you can sive or retrogressive, as illustrated in figure see, the progressive lap winding is one in which the current flowing in a coil terminates in the commutator bar clockwise adjacent to the starting bar as you view the armature from the com- PITCH I AND8 mutator end. A retrogressive simplex lap winding PITCH I AND 6 is one in which the current in the coil terminates inthebqr counterclockwiseadjacent P ITCH to the I AND 4 starting bar. Simplex progressive and retrogressive wave windings are shown in fis-ure 7-25. Compare these with the lap windings shown ir figure 7-24. When you have to identify armature 'windings, you might think it will be complicated. Use of an organized test procedure will enable you to distinguish the 111 types. Test Procedures

There are many armature testing techniques. One method is to use a low-reading ohmmeter to indicate variations in the resistance readings 73.132 as the test probes are shifted around on the Figure 7-22. Progressive and retrogressive commutator. If a low-reading ohmmeter is not windings. available, a milliammeter connected in series

193 203 CONSTRUCTION ELECTRICLAN 3 &2

L AP WAVE A PROGRESSIVE

RETROGRESSIVE

111.3 Figure 7-23. Meaning of coil pitch in armature winding.

A SLOTS OF CORE

BEGINNING LEAD BEGINNING COMMUTATOR LEAD END LEAD BAR

COMMUTATOR BAR

73.230 Figure 7-24.--Simplex lap windings. (A) Progressive; (B) Retrogressive.

194

'2 0 Chapter 7SHOPWORK

COILs reading decreases because the resistance be- A IN SERIES-z, tween the probes has increased. With one probe stationary and the other probe contacting each segment in succession around the cominut:lor, the armature indications will decrease stealily until the test probes are directly opposite each other, and then start I casing steadily as the other half of the windir,v t sted. These indi- 231 13 2112 3 cations are obtainedt of the method of COMMUTATOR BARS connecting the coils to .orrunutator, which is determined by the type vinding. A simplex lap winding is the only winding that gives these COILS IN SERIES indications. SIMPLEX WAVE. An important rule to remember for all wave windings is that the ends of each coil are connectec commitator segments that are approximately two pole pitches apart. Using the test procedure described previously, the maximum ammeter reading Is indicated when 1.11=1 JI the test probes are connected across that portion 11 12 23 the winding in which one coil shunts the re- COMMUTATOR BARS ffiaining portion of the winding. Hence, in all wave windings the maximum reading will be indicated when the probes are placed on commutator seg- 73.231 ments that are approximately two pole pitches Figure 7-25. Four-pole simplex wave windings. apart. The minimum ammeter reading will occur (A) Progressive; (13) Retrogressive. when the probes are placed on segments approximately one pole pitch apart. With one probe stationary on segment 1 (fig. wIth a rheostat and a 6-volt battery can be used 7-28)and the other probe moved around the (figure 7-26).

SIMPLEX LAP. A schematic diagram of a simplex lap winding is illustrated in figure 7-27. With the test probes placed on adjacent segments. the ammeter will indicate a maximum been Ase the resistance of only one coil shunts th(remainder of the winding, and the resistance alried to the test circuit is at minim.im. Move one tei':,t probe to the next segment, and the ammeter

111.6 Figure 7- 26.Test c 1 rcul t for measuring a rma- 111.7 tu re. Figure 7-27. --Schematic of simplex lap winding.

195 205 CONSTRUCTION ELECTRICIAN 3 & 2

coil that has some turns shorted, the resistance of one turn of the coil will be very low, and the voltage generated in that turn will cause a aigh- c.irrentflow,resultingIn excessive heating, which will cause the insulation to burn. If the armaaireisreadilyaccessible,the short- c:rcuited coil can be detected immediately after stopping the machine because the shorted coil willbe much hotter than the others. In idle machines, a short-circuited coil may be identi- fiedbythe presenceofcharredinsulation. An open armature coil in a running machine is indicated by a bright spark, which appears to pass completely around the comm.tator. When the segment to which the coil is connectedpasses under thebrushes,the brIshes momentarily complete the circuit; when the segment leaves the brushes, the circuit is brok-n, causing a spark to jump the gap. Eventually, it will definitely locate itself by scarring the comm gator segment to which one end of the open coil is connected. 111.12 Figure 7-28. Portion of 6-pole, L,implex wave When a ground (-Pours in an armature coil of winding. a running machi,le,will cause voltage fluctua- tion as the groutLied coil segment passes from brush to brush during rotation of the armature. comm itator from r4egment to segment (2, 3, 4, Two grounded coils result in the same effect ns and so for), the ammeter readings steadilya short circuit across a group of coils. ON' .- decrease until the proms are approximately one heating will occur in all of the coils in the group pole pitch apart, and then the readings steadily and burn out the winding. Grounded coils in idle increase until the probes are approximately two machines can be detected by measuring insula- pole pitches apart. tion resistance. A megger, or similar insulation measuring device, can be connected to the com- If the probf is ci reled around the remainder mutator and to the shaft or frain_ of the machine of the commutator, the readings will decreasein order to properly measure the resistance of and then increase once for each pair of poles. the insulation of the coils. In the identification of a 6-pole, simplex wave winding there will be three successive decreases Locating Troubles andincreasesinthe meter readings as the commutator IScircledonce. Similarly,in a 4-pole simplex wave winding there will be two Usually d-c armatui'e troubles are confined successive decreases and increases in the meterto one coil or group ofcoils, and if not readily readings. Thus, a simplex wave winding can be apparent, the segmentsto which they are con- readily distinguiShed from a simplex lap winding nected can be locatedby a bar-to-bar test or by measuring the resistances of the armature use of a growler.

HAR-TO-BAR TEST. A low voltage, d-c T rouble Indications source, such as a storage battery, lighting circuit, or welding set, In required for this test. S91/1".: 'Lrmatu retroubles may beletcctoc1 Tne machine mustIx) disconnected from lts while making Inspectior.F1 of running machines. normal power supply before the test is made and Heat and the odor of burning insulation may allexcept one pair of brushes lifted from the indicate aFlhO rt-clrealted armature coll. In a commutator. Me voltage is applied across the 20(i 196 Chapter 7SHOPWORK

one positive brush holder and an adjacent nega-

PHANTOM tive brush holder. Connect the low-voltage po- REAL tential to these brushes and adjust the current, if aeed be, so that the readings obtained with the millivoltmeter will be roughly one-third to one- half full scale. The current must not exceed one-fourth that normally carried by one set of

DIRECTION brushes. The voltage drop between two adjacent OF POTAT ION com,nutator barsismeasured with a milli- A voltmeter. The armature is held in a fixed position, and the meter leads are moved from one 77.75 pair of adjacent bars to the next until a test has Figure 7-29. Real and phantom grounds in bar- been made of all the pairs of bars included be- to-bar test. tween the brushes (fig. 7-30). The armature is then turned to bring different bars between the brushes, and these bars are tested. Tnis is re- + and - brush through a resistance, lamp, lamppeated as necessary to test all around the com- bank, or rheostat. A low-reading voltmeter ormutator. In a simplex winding, an open coil is millivoltmeter is necessary for taking meas- located where the meter reading is a maximum, urements. and a shorted coil where the reading is a mini- To locate a ground in a d-c armature coil, m im. one lead of the voltmeter Is connected to the For most armatures the windings will be shaft, and, w!th the armature in a fixed position, free from eault if all the voltage readingi are a the other leadis touched to each comar:tator small fraction of the voltage between the blushes bar in turn. If there is a ground, two or more and are equal within the limits of measurement. barswillindicatepractically zero readings. However, in some cases, a duplex winding may Some of these will be real and others will bebe encountered. This type of winding is indi- phantom grounds(fig.7-29, view A. All such cated when the readings are only a small frac- bars should be marked with chalk. The armature tionof thevoltage between the brushes and is then rotated a few degrees and tested again. follow each other in a regularly repeating pat- The real grounds will remain in the same bars tern such as 0, R, 0,R,O,R, and so on, where while the phantom ones will shift to other bars. R is a reading different from zero. When this For example,in view B of figure 7-29, the happens, a further test must be made by meas- phantom ground has shifted from bar b to bar c, uring the voltage drop between alternate bars while the real ground has remained in bar a. 1 and 3, 2 and 4, 3 and 5, 4 and 6, and so on. If The ground will be in a coil connected to the these readings are equal within the limits of bar, showing arealground with the lowest measurement, the winding will be free from faults. voltage reading. When an open circuit is present, the volt- To locate an open or short circuit in a d-c meter reading across one pair of adjacent bars armature, remove all brushes except those ofwill be approximately equal to the voltage between the brushes, and zero readings will be obtained on several pairs of bars on each side of the pair with the high reading. The open- circuited coil will be connected to one or both of the bars in the pair with the high reading. Should the voltmeter readings taken between adjacent pairs of bars increase or decrease in magnitude and be alternately plus and minus, a duplex winding is indicated. A further test by measuring the voltage drop between alternate bars is then necessary to locate the open circuit. When a reading approximAing the voltage between the brushes is thus obtained, the open-circuited coil 77.76 will be connected to one or both of the bars in Figure 7-30. Testing for an open coil. the pair with the high reading.

397

2 0 7 CONSTRUCTION ELECTRICIAN 3 8.1 2

When a short circuit is present, the interpretation of the indication given by readings between adjacent bars or between alternate bars (duplex windings) depends I pon whether the armature hasalapor a wave winding. In an armature havingalapwinding, a voltmeter reading considerably lower than the others will indicate a short-Gtrcuited coil is connected between the pair of bars that shows the low reading. A short-circuited coil 7n an armature with awave winding will cause low readings to be obtained on as many pairs of bars as there are pairs of poles, and the short circuit will be in a coil connected to bars in these pairs. The best method for locating the ends of a faultycoilina wave-wound armature isto separate the coil from the rest of the winding in the following manner. In a 6-pole machine, a short-circuited coilin a wave-wound armature would be indicatc.4 at three positions during the test. These positio:is should be marked with chalk. When the riser ,,;onnections on these segments are lifted, six coils will be isolated from each other and the rest of the winding. The shorted coil is located by comparing the resistances of the six cons, and it wnl have less resistance than the others. A

GROWLER TESTS. A growler (fig.7-31) can be used to detect and locate grounds, opens and shorts in small armatures. The device consists of a con of wire wound around an H-shaped, larrCnated iron core. The lamnations on top are cut out to hold the armature under test between the two poles of the growler. When an alternating current is applied to the coil, an ern` will be induced in the armature coils by transformer action. To test an armature for grounds with the growler, place the armature on the poles of the growler and energize the coil from a 115- volt source. Connect one lead of an a-c milli- voltmeterto the armature shaft and use the other lead as a probe, contacting each commutator segment one at a time in sequence (fig. 7-31, view A).If there are no grounds in the winding, no reading will be indicated on the meter because the commutator is insulated from the haft.If there is a ground in the winding, a < icling will be indicated on the meter for all 2.92 good coils (view 13 of fig.7-31). No reading on the meter indicates that the grounded coil Figure 7-31.Growler. is connected to this segment. elLa 0 8 198 Chapter 7SHOPWORK

To test an armature for shorted coils with the growler, place the armature on the growler and turn on the current. Hold a hacksaw blade directly over, and along the length of, the top ''viillIgrilferfill111111751r8r111111. slot. If the coil in this slot is shorted, the blade 3 will vibrate rapidly and cause a growling noise. If the blade does not vibrae, it is an indication 4 that no short exists in the coil. Test eacth slot (5, ,?) in sequencebyturning the armature so that the slot to )e tes,ed is on top. To tept a simplex lap or wave armature for opens wi n the growler, set up the armature on 6 the growler in the usual manner. Test the top two adjacent seginents with an a-c millivclt- 7 --=:= meter. Turn the armature and continie tes`j the two top adjacent segments. A reading wii: be indicated on the meter of all segments tILA are connected to good coils. No reading on the 10 meter indicates an open coil between the two 41.0 segments.

Emergency Repairs 1. FibEr horn 6. Wedge driver 2. Steel ,,iot drift or 7. Lead drift Emergency repairs can be effected by cutting tanpcL tool 8. Rotation indica- out a short-circuited or open-circuited armature3. Lear' ',1ter tor coil. Tnis will permit restoration of the machine 4. Hack._ aw bladeP 9. Wire scraper to service until permanent repairs can be made. 10. Wedge inserter However, permanent repairs should be made as 5. Saw soon as possible. Tne coilis cut out by disconnecting both ends of the coil and installing 111.17 a jumper between the two risers from -which Figure 7-32.Armature rewinding handtools. thecoil was disconnected. The coil itselfis then cut at both the front and rear of the arma- 2. Steel slot drift, or tamping tool, for driving ture to prevent overheating of the damaged coil. A continuity test from one end to the back ofthe coils to the bottom of partly closed slots. the coil will locate the turns of the faulty coil. 3. Lead lifter for lifting the coil leads from If a pin or needle is used to puncture the insu- the commutator risers. lation for this test, insulating varnish can be used to fill the tiny hole in the event the wrong 4. Hacksaw blades for removing the fiber coil is pierced. All conducting surfaces exposed wedges that hold the coils in the slots. by the change in connections should be insulated 5. Saw for undercutting the commutator mica and all loose ends should be tied securely tobetween the segments. prevent vibration. 6. Wedge driver for driving the fiber wedges41, out of the slots. Handtools 7. Lead drift for cutting off the leads at the The handtools used in rewinding armatures risers. are relatively few and simple. In fact, they ere 8. Rotation indicator as an aid to determine usually handmade by Construction Electriciann the proper connections of the windings. engaged in this work. Figure 7-32 shows the 9. Wire scraper for removing the Insulation following tools: from the ends of the coil leads. 1. Fiber horn for shaping the coil ends after 10. Wedge inserterfor driving the wedges the coils are placed in the slots. into partly closed slots.

199

911Q CnNSTRUCTION ELECTRICIAN 3 & 2

Stripping After the coil is partly raised, drive a tapered fiber wedge between the top and bottom :oils within the slot to finish raising the top coil from Beforestripping an armature, record all theslot. After stripping the armature, remove available winding data on an arrmture data card, all dirt, grease, rust, and scale by sand blasting. as shown In figure 7-33, for use in rewindingFile each slot to remove any burrs or slivers and for future reference. and clean the core thoroughly with compressed air. Immerse the cleaned armature core in a After recording the initial winding data, per- varnish and bake in accordance with the steps form a bar-to-bar test to determine if the winding in table 7-1, using a dilute varnish (20 percent is lap or wave and record this information on solution) of the same type of varnish to be used the armature data card and proceed to discon- after winding. nect and remove the coils. This treatment preventsthe formation of During this process, accumulate the winding oxides and forms a base for the adherence of data the.:t was impossible to obtain before strip- the final varnish treatment. pIng the armature. Remove the banding wires by filing them in two places. If banding wires are not used, remove the wedges in the slots. Winding ArMature Coils A simple means of removing the wedges is to place a hacksaw blade, with 'he teeth down, on Formed coils are wound on a coil-winding the wedge. Tap the top of the blade to set the machine and pulled into the desired shape on teeth in the wedge and then drive out the wedge the forming machine. The shape of the coil is by tapping the end of the blade. determined by the old coil. The two wires forming the leads are taped with cotton or reinforced Next, unsolder the coil leads from the com- mica tape. The binder Insulation, consisting of mutator and raise the top sides of the coils the cotton or glass tape, is applied to the entire distance of a coil throw (distance between the coil surface. two halves of a coil). Tne bottom side of a coil is now accessible, and the other coils can be The coilis now sprayed with a clear air- rem/Ned one after the other. Exercise care to drying varnish (grade CA), which conforms to preserve at least one of the coils in its original MIlitarySpecification, M1L-V-1137. After the shape for use as a guide In forming in the new varnish has dried, the coil ends are tinned to coils. Next, record the wire size, number of ensure a good connection to the commutator. turns in a coil, and type of insulation on the coils and in the slots. Preformed windings should be used on large To raise the coils without damaging the insu- armatures, butitis more practical to wind lation, use a small block of wood as a fulcrum small armatures by hand. End room is very resting on the armature core and a steel bar orlimited, and windings must be drawn up tightly piece of wood as a lever. to the armature core. Figure 7-34 shows the method of winding an armature by hand. One armature in the figure is small enough to be hand-held. The other, too heavy for this, rests K W H P R P M Volts Amps on a support. Cycle Type Frame Style

Temp Model Serial Phase Placing Coils in Slots No of Sluts Ears Coils/Slot

Size Wire Coil Pitch

Center of Eons Before assembling thecoils Center of Slot to insulatethe Center of Mica armature core. This step is of extreme im- Commut a tor Pitch ijIflhjiflfliUuliffifll* portance;if the a;:mature contacts the coils, Lap Wave you will have to do your work over. Clean the core slots and ends, and true up the laminations. Use fish paper or fuller board for insu- 111.18 lation, and let it extend 1/4 in. beyond the slots, Figure 7-33. A d-c armature data card. to prevent the edges of the laminations from

200 2 1 0 Chapter 7SHOPWORK

Table 7-1. Varnishing procedure Typicaltreating schedule.The following treating schedule may be used as a guide in processing electricalwindings. The baking time and temperature may vary depending on the type and grade of varnish used and the size of the winding being processed: Armature coils, armatures, stators and field coils

Class A, Class B and Class H end higher Class F systems temperature systems Step 1: Prebaking Put into oven at 110°C (230°F). Hcld Put into oven at 1 50°C (302°F). Raise at temperature for 4 hours. Cool to temperature 50°C (1 22°F).per hour to approximately 50°C (1 22°F). a maximum of 200°C (392°F). Hold at temperature for 4 hours. Cool to approximately 50°C (1 22°F). Step 2: Dipping Immerse coils or wound apparatus in Immerse coils or wound apparatus in 40°C (104°F) in varnish until bubbling varnish for not over 5 minutes. ceases. Viscosity shall be held between Varnish types or grades shall not be 150 to 250 centipoises. Thin Class A, mixed. Viscosity shall be held between Class B varnish with mineral spirits 1 25 to 225 centipoises. Tain with to maintain viscosity. Use xylene for xylene to maintain viscosity. Class F varnish. Step 3: Draining Drain and air dry for 1 hour. Rotate Drain and air dry for 1 hour. Rotate wound apparatus to prevent pocketing wound apparatus to prevent pocketing the varnish. the varnish. Step 4: Wiping After draining but before baking the After draining but before baking the metal surfaces of the armature, the metal surfaces of the armature, the bore of the stator and the pole faces bore of the stator and the pole faces of the field structure must be wiped of the field structure must be wiped v.ith a cloth moistened with solvent. with a cloth moistened with solvent. Step 5: Baking Bake in a circulating type, forced- Put into a circulating type, forced- cAhaust, baking oven at temperature exhaust, baking oven at temperature of 1 50°C (302°F) for 6 to 8 hours. of 200°C (39 2°F) for 2 hours. Step 6: Cooling Remove from oven and cool to Remove from oven and cool to approximately 50°C (1 22°F). apprwdmately 50°C (1 22°F). Step 7: Second treatmentRepeat steps 2 (immerse for 1 m!.nute), Repeat steps 2 (immerse for 1 (dip in opposite 3, 4, 5, and 6. minute), 3, 4, 5, and 6. direction). Step 8: Third treatmentRepeat steps 2 (immerse for 1 minute), Repeat steps 2 (immerse for 1 (dip in original 3, 5, and 6. minute), 3, 5 (baking additional 8 direction). hours at 230°C (446°F)) and 6.

111.82 CONSTRUCTION ELECTRICIAN 3ez 2

73.233 Figure 7-34. Winding armatures by hand. injuring the coils. Figure 7-35 shows a method to the riser and allow it to flow down and around of insulating the slots. the lead and into the wire slot, and then remove the iron. The groun 1 insulation, consisting of flexible rrica wrappers or layers of reinforced r&ca Tne ordinary soldering iron cannot supply tape, is applied to the coil sides that lie in thesufficient heat fast enough to perform a satis- slots. The formed coils are next placed in thefactory soldering job on a large armature. slots, the lower side first and then the upper Therefore, apply a soft flame from an acetylene side, until all the cons are inserted and the torch to the outside end of the comirrotator seg- winding is completed. Be certain that the coil ments to the riser ends where connections are pitch is correct. A strip of rigid laminate, type made. Tin the coil ends (to be connected to the GME-MI,.-P-15037, is placed in each slot be- commutator risers)withthesoldering iron. tween the lower and upper coil sides, and a sim- Next, tin the slots in the commutator risers ilar strip is placed at the back and front of the armature where topand bottom sides cross eachother.If the slots have straight sides, they are filled up with a strip of rigid laniinate, type GME-MrL-P-15037, on the tops of the coils FISH so that they can be held down by the banding PAPER wires. In some armatures the slots are shaped so that fiber wedges can be driven in each slot DRIFT from 4)ne end to hold the coils in place. STICK Before soldering the coil ends to the com- PEG TO HOLD mutator segments, test the winding for grounds, INSULATION TIGHr Afill111111111" WHILE WORKING opens, shorts, and ead coils. Exercise care NEXT. SLOT (when soldering) to prevent solder from falling allt0141111111111,xiativer. or running down the back of the commutator, as lb* 0010" FISH PAPER OR this would result in a short circuit. Tip the FISH PAPER TREATED armature so that the solder will not flow down .1464446".1111.1111r.FABRIC the back of the commutator. Place the tip of the soldering iron on the commutator near th riser and wait until the Iron heats the riser 73,232 sufficiently to m:qt the solder. Touch the solder Figure 7-35.--Continuous strip method of insulating slots. 202 212 Chapter 7---SHOPWORK with heat from the torch. Then -nake the con-Insulating Materials nections while applying the flame to the outside endofthe commutator segments. Wrap the Current-carrying conductors require insula- winding in asbestos tape for protection (whention for various reasons. An understanding4of making thecommutator connections) becausethe different types of insulation used will be of too much heat can damage the winding insula-help to you in the repair of electrical equipment. tion. The completed armature winding is checkedThe different classes of insulation materials electrically for continuity and for shorted turns.are listed in table 7-2. To prevent centrifugal force from throwing There are certain conditions when the re- the coils outward, wind a band of high-gradewinding of Ciass A and B insulated motors with steel piano wire on a strip of leatheroid, Class H insulation becomes necessary. This is isplacedaround the armature and over Ate coils about 2 inches from the edge of the core.done to prevent a recurrence of insulation break- This is done either before or after the armaturedown and ultimate failure. Here are examples has been dipped and baked. of such conditions:

It is preferable to place the banding wires on 1. Where the location ambient exceeds the the armature while the windings are hot becauseequipment design ambient (usually 50° C). theinsulationshrinks when heated, is more flexible, and can be pulled down tightly mach 2. Where excessive moisture (usually con- easier than when the armature is cold. Whendensate) is present and the windings are exposed. the first banding wire is wound on the armature, 3. Where the service life of existing equip- small tin clips, with insulation under them, arement is shortened by overload, heat, moisture, inserted underthewire. When the required number of turns has been appiied, the ends ofor a combination of these factors. these clips are turned up over the wires to hold them tightly side by side. Tne clips are then Siliconeinsulationisnotacure-allfor soldered with a tin solder, and a thin coat ofmotor and generator failures. Before deciding solder is run over the entire band to secure theto use silicone insulation the installation should wires together. be checked to determine the cause of failure. Misalignment of bearings, mounting bolts dis- The end windings are secured, if necessary,located, a bent shaft, failure or inoperativeness by groups of wire wow-1J on insulating hoods toof overload devices or similar causes may have protect the coils. On the commutator end, stripsinitiated the failure rather than the insulation of thin mica with overlapping ends are usuallyitself. placed on the commutator neck and held by a few turnsofcord. On large armatures, banding Consideration must be given to the condi- wires are sometimes placed over the lam;natedtions to which the windings will be subjected portionofthe armature. The lamiaations onduring winding, varnishing, and drying out or these armatures have notches in which the band-baking. Class A, B, and F materials are gen- ing wire is placed. erally tough and will take a lot of abuse. Class H inJ N materials are considered somewhat fragile and should be handled with care In order Ifit is necessary to rebuild a commutator, use molding micanite to insulate between thenot to damage the reffin film. spider and the commutator. Commutator mica isused asinsulation between the segments. After the commutator is assembled, it is heatedVarnishing and tightened with a clamping ring. Prior to varnish treating, the windings or If shrink rings are provided, they are notcoils should be prebaked to remove all moisture. put on until the commutator has been tightenedThe winthngs or coils should be left to cool to (while hot) and the banding wires tightly placeda temperature not less than 10° C above room around it.If defective, small commutators aretemperature prior to immersion in varnish. The usually completely replaced. windings or coils should remain in the varnish

203 213 CONSTRUCTION ELECTRICIAN 3 & 2

Table 7-2. Classes of insulation

MATERIALS REQUIRED CLASS CLASS OR TRERMA L INSULATION MATERIAL COMBINATION OF LIFE SYSTEM MATERIALS

A 105 Cotton, silk, and paper when suitably impreg- 105°C nated or coated, or when immersed in a dielectric liquid such as oil. 130 M:ca, glass fiber, asbestos, etc., with suitable 130o C bonding substances. 155 Mica, glass fiber, asbestos, etc., with suitable 155°C bonding substances. 180 Silicone elastomer, mica, glass fiber, asbestos, 180°C etc., with suitable bonding substances such as appropriate silicone resins. 200 Mica, glass fiber, asbestos, etc., with suitable 200°C bonding substances.

11.132 until bubbling ceases. After dipping, the windings 500° Fforhigher temperaturt- windingri and or coils should be allowed to drain and then aremust be of sufficient cape city to maintain taese baked at the prescribed temperature for the time temperatures at a full exhaust rate of two air shown in table 7-2. Do not dip and bake m:u'e changes per minute. than three times. The baking ovens must be rated Separatedipand storage tanks should be at 350° F for Class A, B, and F windings and provided for the silicone varnish, because silicone varnish is not compatible with other varnishes. No solder joints should be used on the tanks as solder may gel the varnish. Aft The d-c armatures should be dipped with the commutator end down to seal behind the commutator neck. The commutator can be wrapped to prevent varnish buildup. When draining, have the commutator upright. If the assembled winding cannot be immersed, it can be slowly rotated ina horizontal position in a shallow pan to allow the varnish to flow into the winding in- terstices(fig.7-36). All winding parts should be well soaked during the immersion. At least two complete revolutions should be made, each revolution taking about 10 minutes. In the baking operation allowances should be made for the time necessary to bring the armature up to temperature. If possible, d-c armatures should 5.143 be baked with the commutator end up. Figure 7-36. Applying insulating varnish to ar- The completed armature is now placed in a mature windings. lathe and a very light cut taken over the surface

204 214 Chapter 7--SHOPWORK

of the commutator and over the face and side of severe strain, at some point of the winding. For the commutator risers to make the assemblyexample, to m:,ke a high-potential test on a re- perfectly true. Next, the commutator m'ca shouldwound armature, short circuit the commutator be undercut so that the carbon brushes will not segments by wrapping one or more turns of bare be danwged by the high mica. wire around the commutator and apply the high- potential test voltage across the common con- You m-st remTrnber that all armature stator nection of all the commutator segments and the and field windings must be checked for shorts, grounded armature shaft. grounds, and opens after each step of beingwound, The high-potential test volt ge is obtained formed, taped (if necessary), installed, connected,from a 60-hertz a-c source that should have a dipped, and baked. capacity of 1 kilowatt. When making a test, increase the voltage as rapidly as possible with- High-Potential Tests out exceeding the correct value, as indicated on

A high-potenti' est is made by applying T able 7-3. Minimum Direct-Current Generator (between insulated rts) a test potential that is and Motor Insulation Resistances for High- higher than the rated operating voltage. High- Potential Tests potential tests are frequently used in ;:onnection with the repair or reconditioning of naval equip- Insulation Resistance in ment ashore. Megohros at 25°C,1 Circuit After Reconditioning Tne purpose of the test is to break down the in Shop. insulation if it is weak, thereby in13.,..:ating defective material and workmanship, and permitting Complete armature 1 replacement prior to actual use. circuit2 Armature alone 2 The application of each ,,,gh-potential test Armature circuit 2 tends to weaken insulation even though it does less armature2 not produce actual failure at the time. Also, the Complete shunt 2.5 use of high-potential tests requires special equip- field circuit2 ment 'ind safety precautions. 1The figures given are for machines rated at When making high-potential tests on elec- 250 volts or less. For machines having a rated trical equipment that has been reconditioned or voltage, E, greater than 250 volts, multiply all rewound in a shop, keep from com'ng in contact figures given in the table by E/250. with any part of the circuit or apparatus. Never touch the winding after a high-potential test 2Small machines usually haveone of the has been made untilit has been connected to shunt field leads connected internally to the ground to remove any static charge it may have armature circuit. To avoid disassembly in such retained. cases, the complete arm atuxe circuit and complete shunt field circuit may be measured without A high-potential test should not be made on breakingthisconnection.Ifnecessary,the a d-c generator or motor until after the re-armature can then be isolated by lifting all conditioning or rewinding is completed, includingbrushes. theapplication of varnish, and the insulation (a) Withthe brushesleftin place, the resistance has been measured and found to becomplete armature circuit will include armature, higherthanthevalue in the last column ofarmature circuit, and the permanently connected table 7-3. shunt field circuit. The values given in the table for the complete krmature circuit will apply. All leads to the circuit being tested should (b) With the brushes lifted, the armature be connected to one terminal of the source ofcircuit less armature and the complete shunt test voltage. All leads to all other circuits andfield circuit will be mea8ured. The values given all metal parts should be connected to ground.in the table for armature circuit less armature No leads are to be left unconnected for a high-will apply. potential test as this may cause an extremely 111.83 205 215 CONSTPUCTION ELECTRICIAN 3 t4z 2 the voltmeter. Tne full voltage should be main- removed, (2) weight of the coil without the tape, tained for 'I .mi-nute. The voltage should then be (3)sizeof wire, and(4)type of insulation. reduced at a rate that will bring it to one-quarter of the corn value or less in not more than 1.'11:: two general classes of coils are (1) shunt 15 seconds. field coils, which consist of many turns of fine wire and (2) series and commutating field coils, which consistof fewer turns of heavy wire. FIELD COILS SHUNT COILS. The equipment for rewindin shuntcoils includes a lathe or suitable face Preventive maintenance of field coils requires plate, which can be turned at any desired speed, periodic inspections and to determine the and an adequate supply of the proper size wire condition of the coil. Coils should be cleaned pn- wound on a spool, which can be supported on a riodically to remove any foreign particles whie' shaft so that it is free to turn. Friction should might have collected on them. be applied to the spool to provide tension on the wire. A coil form having the exact inside di- The insulation on field coils should be testedmensions of the coil is secured to the lathe or periodically todetermineitscondition. A face plate. The form for shaped field coils can resistance-mcasuring device may be used for be made from a block of wood shaped exactly to this parpose. If a ground is detected in the field the required size and provided with flanged ends circuits (shunt, series, and interpole)of.' a d-c to hold the wire in place (fig. 7-37). One of the m2.chine, the circuits must be disconnected from flanges should be removab1,1 30 that the finished each other and tested separately to locate the coil can be taken from the forming block. groundedcircuit.Thenallthe coils in that circuit must be opened and tested separately to The wire is now wound from the spool onto locate the grounded coil, which can be repairedthe forming block for the required number of or replaced as necessary. turns. The turns must be evenly spaced, one against the other, until the 'winding procedure 7( an open circuit develops in the field wind- is completed. The turns of the completed coil ing' of an a-c or d-c generator that is carrying are secured by tape, and the wire leading to the a 'load, it will be indicated by immediate loss of spool iscut, leaving sufficient length to make leadand voltage. An open in the shunt field theexternal connections. The completed coil A 'ridingof an operating d-c motor may be must be checked electrically for continuity and indicated by an increase in motor speed, exces-for shorted turns. sive armature current, heavy sparking, or stalling of the motor. Wnen an open occurs in the field circuit of a machine, it must be secured immediately and exam'ned to locate the faulty circuit. The open circuit will usually occur at the connections between the coils and can be detected by visual inspection. An open in the coils generally causes enough damage to per- m't detection by visual inspection.

Rewinding Field Coils

The old field coil is rernoved from the pole piece and,if spare coils are available, a new oneisinstalled.If a new coil m.st be made, record all pertinent coil data as the old coil is stripped down.

Tnis data should include the (1) dimcnsions 77.81 of the coil, both with the tape on and with the tape Figure 7-37. Coil form ror field coils.

206 216 Chapter 7SHOPWORK

The coil is now prebaked and varnish treated. When varnishi.reated, the finished field coil should withstand a high-potential test of twice the rated excitation voltage +1,000 volts.

SERIES AND COMM UTATING COILS. Series and commutating field coils are frequently wounC with strap (rectangular) or ribbon copper instead of round wire. These coils have only a few turns thatare woundinasingle turn per layer. A series coil wound (with ribbon copper) on edge is illustrated in figure 7-38. It is mcre difficult to bend the copper ribbon, but it has an advantage inthat both terminal leads protrude on opposite sides of the coil. Thus, the connections can be made very easily' compared to the strap-wound coils, which have one coil end at the center and the other coil end at the outside of the coil. The strap-wound construction requires leading the inside coil end over the turns of strap in the coil. After the winding is completed, the ...lollis 77.80 testedelectric ,llyfor continuity and shorted Figure 7-39. Testing polarity of field coils. turns. It is then prebaked, inished, and tested for polarity, grounds, opens, and shorts as described previously, at e?-11 stage in turn. and its polarity determined. A small magnetic compass may be used to determine the polarity J1 a field coil by holding it several inches away Compass Aids from the coil along its sods (fig. 7-39). A small battery is connected to the coil leads, and if the south icompass needle points toward the center Before installing a new or repaired coil, itof the coil, the face of the coil nearest the com- should be tested for shorts, opens, and groundspass will be a north pole. Tnis will indicate that the coil should be placed on a north pole in the same position it was in during the test, and the field current should flow through the coil in the same direction. To protect the armature, the same precxl- tions that were observed during removal oi the coil must be observed when installing it. All of the shims originally removed from the pole piece must be in position when it is replaced. With thecoilin position in the machine, it should be temporarily connected to the other coils in the field circuit and a compass and battery again used to check its polarity. For thistest,connect the battery to the proper fieldleads and check the polarity of all the coilswith the compass (fig.7-39). Adjacent poles must be of opposite polarity. If need be, polarityof the new coil can be reversed by reversing its leads. When the polarity Is correct, the coil is connected, and the pole-pieces bolts 77.84are tightened. Air gaps should be rnear,ured to Figure 7-38. Edge-wound seriescoil. ensure uniformity.

207 217 CONSTRUCTION ELECTRICIAN 3 & 2

phase. Then, each circuit in the grounded phase isopened and tested to locate 'the grounded circuit.Finally, the endb of each coil in the grounded coi' are located. Shorted coils are identified readily if an internal growler is used. Tnis iastrument has an attached blade which is run over the stator coils (fig. 7-40). Transformer action causes a growling noise when a shorted coil exists. Itis most important to keep an accurate record of all the pertineot data concerning the winding on the stator data sheet, as shown in 1110VAC figure 7-41. If possible this information should POWER SUPPLY be obtained before stripping;if not, it can be obtained during the stripping oreration. 73.147 An a-c stator is stripped in the same manner Figure 7-40. Testing a three-phase stator for as a d-c armature. Exercise care to preserve shorted coils. one coilin the original shape to provide the dimensions for the new coils if spare coils are not available and it is necessary to rewind them. ALTERNATING-CURRENT STATOR COILS Be certain to measure the end room of the coils before they are removed from the slots. Record Alternating-current stator windings require this distance on the data sheet and be sure that the same careful at-tent:0n as other electrical the new coils do not extend beyond this distance windings. For a machine to function properly, from the ends of the slots. The winding should the stator windings must be free from grounds, be preheated in an oven to soften the varnish short circuits, and open circuits. Frequent tests and thus facilitate stripping. The end connec- andinspectionsarenecessarytodeternvne tions, preferably at the lead end, are then cut thecondition of the windings, and they nrost and the coils removed from the slots by pliers be kept clean to preserve the insulation. or a screwdriver. A shortcircuitinthestator of an a-c After the stator is stripped, inspect the lam- machine will produce smokeflame, or the inations for alignment and especially for sharp odor of charred Insulation. 'r"machine must be secured immediately.

Open circuitsina-c stator windings can Make sometimes be found by visual inspection because the open is usually the result of damaged H.P. R.PM. Volts Amps. connections where the coils and circuits are connected together. Should visual inspection fail, Hertz Type rrome Style resistance measurements between the phase terminals will reveal the presence of open-circuited Temp. Model Serial Phase coils.The coil ends in the faulty phase are tested with an ohmmeter to locate the open- circuited coil. When the open circuit is in an No. of Coils No. of Slots Conrwction inaccessiblelocation andcannot be reached for repairs, the machine .;an be repaired for Size Wire No. of Turns No, ot Groups emergency use by cutting out the faulty coil. Cails/Group No. of Poles Pitch of Coil Grounds in a-c stator windings can be de- tectedwith a megger or similar resistance- measuring instrument. Both ends of each phase 111.65 are opened and tested to lo2ate the grourded Figure 7-41. Stator data sheet.

208 218 C ha pter 7--S110PW0111: burrs drotruding from the end laminations. The statorshaald be cleaned of alldirt, grease, INSULATION PLACED ON TOP rust, and scale. The stator, similar to the d-c OF SLOT TO PROTECT WIRE rmiture,isthenvarnish-dipped and baked, FROM SCRAP(NC IRON CORE using a dilute varnish of the same type that is used after winding. The windings of stator coils are usually pre- Is? SLOT wound and preformed (formed coils) on a ma- //' 2nd SLOT chine. The size and shape of the oils are best determined from the coil that was removed from L .1 the stator intact. After the coil is wound, it is tied in several places to hold the turns together. BOTTOM SIDE The two wires forming the leads are tapedor OF COIL sleeved with glass braided sleeving. The excess insulationis removed from the free ends of each coil, whichLre then tinned. The individ- FIRST COIL OF1,k, -)ING IN PLACE ual coils are then checked electrically for continuity and for shorted turns.

TOP SIDE NOT IN SLOT Placing Coils in Slots

Tne coils to be inserted in open slots have the entire surface taped, and the coil sides are placed in eac'a slot intact. Tne right side of the coil, which occupies the bottom ' alf of the slot, is inserted first (fig. 7-42). The free end coming Ist ...<1.NE SIDE from this side is known as the bottom lead of 2nd COIL IN SLOT the coil. The left side of the coil, which occupies the top half of another slot, remains free. Con- tinue by placing the right side of the second SECOND COIL OF WINDING IN PLACE coil in slot 2 adjacent to slot 1. Tne remsining coils are inserted in this mariner until the slots 111.66 spanned by a complete coil pitch each contain Figure 7-42.Flacing sides in slots. the right aide a coil. The left side of each coil remains out of the slot until the bottom half of the slot is occupied by the right side of a coil.should be completed before any coils are in- Continue around the stator, and then insert theserted in the stator to allow for this extra in- left side of each coil on top of the right side of sulation. a coilseveralslots away, depending on the coil pitch. After the stator coils are all in place, force the coil sides down in the slots by placing a Before inserting the side of the second coilpiece of soft wood or fiber on top of the coils in a slot, insulate it from the first coil's sidethrough the slot opening, and gently tapping on already in the slot. This is done by placing ait. When the coils are securely in the slots, strip of insulation over the bottom coil. insert the slot wedges to hold the coils in place. The wedges consist of flat melamine laminates Be certain that each coil side extends beyond machined to shape. the slot at both ends and does not press against the stator core at the corners. The phase insu- When all the coils have been inserted in the lation consisting of varnished2am1'ricis placed stator slots, the ends insulated, and the slot between the phase groups because of the highwedges driven in place, there will be two free voltage existing between phases. The computa- ends for each coil(tor and bottom) from one tions indicated under interconnection of phases side of the stator wir, The free ends must

209 219 CONSTRUCTION ELECTRICIAN 3 & 2

Aster twisting the ends together, check the Indlvidual groups to determine that the proper niher of coils have been connected together tach pole-phase group and that they have the proper polarity. Tnen solder the twisted connections and cut off the ends so that the soldered stubs are about three-quarters of an inch long. Insulate the stubs with cotton tape or reinforced mica tape. If the distance to the bearing brackets (frame of the machine) is small, bend the insulated stub in between the coils so that they do not come in contact with the frame when the stator is assembled in the machine. In practice, the coils that comprise the pole- phase groups are usually gang wound. Gang wound coilseliminate the need for stubbing, because the coils are wound with a continuous length ot wire. 111.67 Figure 7-43. Three-phase 4-pole winding for a 36-slot stator. Polyphase Stator Troubles be connectedto form a series of groups of In troubleshooting rewound and reconnected coils. polyphase stator windings, you are likely to find that the trouble is a short in a pole-phase group you can compute the number of coils in aor an entire phase, or that a winding is open group by dividing the number of coils in the circuited. statorbythenumber of pole-phase groups. For example: if the stator haf'q slots and 33 SHORTED POLE-PHASE GROUP, An entire coils, and if there are 4 poles and 3 phases, you pole-phase group may be shorted in a polyphase will have 3 coils in series in each group. The stator.Such a defect is usually indicated by number of poles multiplied by the number of excessive heat in the defective part. The trouble phases gives the numer of pole-phased groups. can be readily located by a compass test. To conduct a compass test, excite the stator windings To connect the pole-phase groups together,with a low-voltage, direct current that will set you should have a diagram simlar to figureup the poles in the stator (fig. 7-44). When the 7-43. Mirk with arrows the direction of the windings are excited, a compass is moved around current flow through each pole-phase group. theinside circumference of the stator core. The current flow tst reverse in direction forAs each pole group is approached, the polarity eaclisuccessive group so that there will beis indicated by the compass. There should be alternate north and south poles. the same number of alternate north and south Inarranging thesecoilsintopole-phase poles in a 3-phase winding. groups, start by bending (forming) the inside lead of the first coil in toward the center and In a 3-phase, wye-connected winding (view A, then connect the outside lead of that coil and the fig. 7-44), test each phase separately by impress- inside lead of the next coil together. Connecting the d-c voltage successively on each of the the outside lead of the last coil with the inside phase leads and the midpoint of the wye connee- lead of the next coil and bend the outside lead :xi.If there is no trouble in the winding, the of this coil away from the center. Repeat this ,.0,unass will indicate alternately north and south procedure for each of the pole-phase groups each pole-phase group around the stator. If all around the stator. D3 not solder the con- a complete pole-phase group is shorted, the com- nections at this time. pass needle will not be deflected at this point.

210 220 Chapter 7S HOPWOR K

voltage successively on each of the phase leads A A and the midpoint of the wye connection. If there is no trouble in the windings, and if the impedance of the winding of each phase is thesame, the ammeter will indicate approximately thesame value of current for each of the three phases. If one phase is shorted, the ammeter will indicate a higher current readi, crfor this phase D-C than those of the other two phases because the SOURCE impedance is less.

WYE CONNECTION DEVA CONNECTION In testing a 3-phase delta-connected winding A (fig.7-45, view B), open each delta connection and test each phase separately. As in the wye- connected winding, the shorted phase will be 111.76 indicated by a much higher current reading on Figure 7-44.Compass test for shorted pole- the ammeter. phase groups. OPEN CIRCUITS. An open circuit in a 3- In testing a 3-phase delta-connected winding phase winding can be readily located bymeans (viewB offig. 7-44), open one of the delta of an ohmmeter. Intesting a 3-phase wye- connections and apply the direct current to the connected winding (fig.7-46, view A), connect winding. The current will flow through the three the ohmmeter leads across each of the phases phases in series. If the pole-phase groupsare to locate the defective phase. When the ohm- connected properly, the compass will indicate peter leadsare placed on terminals A and alternate north and south poles around the stator C, no open circuit (a low reading) is indicated. frame. As inthe wye-connected winding, a However, when the leads are placed on termi- shorted pole-phase groupis indicated by no nals C and B, and then on terminals B and A, deflection of the compass needle. an opencircuit (a highreading) is indicated inbothpositions,thus denoting an open in SHORTED PHASE. When an entire phase of phase B. After the defective phase has been a 3-phase winding is shorted, the defect is most located, test each stub connection of the pole- readily located by a balanced-current test made phase groups with the ohmmeter until the open with an industrial analyzer. coil is located. This test can also be made with an ammeter In testing a 3-phase, delta-connected wind- and low-voltage a-c source. In testing a 3-phase ing (fig. 7-46, view B), it is necessary to open wye-connected winding (fig. 7-45, view A), test one delta connection to avoid shunting the phase each phase separately by impressing the a-c being tested. Test each phase separately until

CLOSED CIRCUIT CLOSED CIRCUIT

A-C z SOURCE t ItOPEN- o 3

WYE CONNECTION DELTA CONNECTION

A WYE CONNECTION DELTA CONNECTION

A 111.77 Figure 7-45. Balanced current test for shorted 111.78 phase. Figure 7-46. Ohmmeter test for open circuits. 211 221 CONSTRUCTION ELECTRICIAN 3&I 2

Single Phase Capacitor Split Phase LII

H.P. Hz Type Style

R.P.M. Volts Model Ser. No.

Malcom Amps Frame Cap MFD Rotation facing shaft Clockwise Counter-Clockwise fl i No. Pole, INo. Slot, SIOlor Dimnsions No. Coils Turns inside No. Coil Winding S. Typo Per Pole PIO Pole Coil Spon Wire Wire Circuits Extension inside Diometer -- nethr. Punning ollo _ Depth Iron Storting Phind Slot

Running I 1 I 1 1 Ili Slot No. I 1 I 2 3 1 4 II 5 6 7 8 9 10 11 12 13 14 15 1 16 1 17I18

Starting I 1 I I il I I

111.65 Figure 7-47. Single-phase motor data card. the open is located. After the faulty phase is help you in reviewing the theory of operation located, test each stub connection of the pole-of single-phase motors. phase groups, as in the wye-connection, until the open coil is located. Stepsinanalyzing motor troubles should proceed ina logical sequence to determine If the windings are parallel, it is necessary what repairs are required for reconditioning the to open each parallel group and test each group motor; (1)Inspect the motor for defects, such separately. as,cracked end bells, bent shaft, broken or burned wiring; (2) check the motor for bearing troubles; (3) test the motor for grounds, opens, MOTOR AND GENERATOR and shorts (see armature and 3-phase stator MAINTENANCE sections).If rewinding is required, record the necessary data on a motor data card (fig. 7-47). There are many applications for single-phase motors in the Navy. They are used in interior communication equipment, refrigerators, fans, CENTRIFUGAL SWITCHES drinking fountains, portable blowers, portable tools,and in many other applications. Single phase motors are considerably cheaper in frac- Burnt starting windings and defective cen- tional horsepower sizes, but above 1 horse-trifugal switches are frequently the causes of power the 3-phase motors are less expensive. inoperativesingle-phase motors. Figure 7-48 The use of single-phase motors also eliminatesshows the two major parts of a centrifugal the need of running three wire service to sup- switch. The centrifugal switch is located inside ply small loads. the motor on the rear end bell. It is used to In Basic Electricity, NA VPERS 10086-B, chap- disconnect the starting winding after the rotor ter 17, there isa section devoted to single- has reached a predetermined speed, usually 75 phase motors. A check cf this section wouldpercent of the full load speed. The action of the

212 222 C ha pte r 7S11OPWORK

have been made, is for appropriate voltages at MOUNTS IN MOUNTS the terminal block. The next check is for grounds, END BELL ON ROTOR shorts, or opens. Check to see if the rotor revolves freely. If the rotor turns freely when no voltage is applied, but locks when energized, you will know that the bearings are worn enough to allow the iron in the rotor to make contact ii with the iron in the pole pieces.

CAPACITOR MOTOF

STATIONARY CONTACTS The capacitor motor is similar to the split- phase motor except that it has a capacitor installed either on top of the motor, on the end of 73.130 the frame, inside the housing, or even remote Figure 7-48. Two major parts of a centrifugalfrom the motor. switch. A capacitor-start motor does have a centrifugal switch for removal of the starting wind- centrifugal switch is as follows: The contactsing when the rotor has reached 75 percent of its on the stationary part of the switch (the sta- rated speed. The capacitor-run motor does not tionary part is mounted on the end bell) arehave this switch. The starting winding stays in closed when the motor is not in motion and the circuit continuously. completes the circuit through the starting winding. When the motor is energized and reaches The procedure for repair and troubleshoot- approximately 75 percent of full load speed, the ing capacitor motors is the same as it is for rotating part of the switch (mounted on the rotor) the split-phase motor except, of course, for the is forced by centrifugal force against the sta- capacitors. Before applying the leads of a ca- tionary arm, thereby breaking the contact andpacitor, disconnect the power and be sure to disconnecting the starting winding from the cir-discharge the capacitor terminals. Upon com- cuit. The motor is then operating on the runningpletion of the tests, BE SURE TO DISCHARGE winding as an induction motor (fig. 7-49). THE CAPACITOR TERMINALS. Replace the ca- When a motor is overloaded, the speed slows pacitor,if tests indicate a defective capacitor, and allows the centrifugal switch to energize the with an identically rated capacitor. starting windings, then the motor speeds up enough so that the centrifugal switch opens the starting circuitagain.This constant opening and closing of the starting winding circuit will cause the failure of the winding. The condition of the switch must be checked periodically to determine that the switch contacts are clean and that all moving parts function properly. Stalling while starting or failure to start may indicate a faulty centrifugal switch. If this happens, power to the motor must be secured immediately or the starting winding will soon overheat and burn out.

SPLIT-PHASE MOTORS 73.131 To analyze troubles in a split-phase motor,Figure 7-49.Connectionsofasplit-phase the first check after the obvious physical checks motor.

213 223 CONSTRUCTION ELECTRICIAN 3 & 2

3-PHASE MOTORS The windings in a 3-phase induction motor consistofcoils, groups, and phases. For the 4-pole motor (the most common type), there are 36 slots and 36 coils. These coils Are placef! three coils to a group, three groups to a pelf-. Each of the three groups in a pole constitutes aphase.Phases arelettered A, B, and C. Coils or groups of coils can be connected 3 in various ways, such as series delta, parallel 8 delta,seriesstarand parallel star. Figure r5 7-50 shows a star-connected motor, with series connection for higher voltage in view A, and parallel connection for lower voltage in view

73.144 Figure 7-51. Delta-connected motor. (A) Se- ries; (B) Parallel.

B. Most 3-phase motors are connected for dual voltage with nine leads brought out to the terminal box on the motor, so that the coils can be connected in parallel for the low voltage or inseries for the higher voltage. The choice between star or delta connection therefore depends on the voltage available from the power source. 4-5-6 CONNECT AND Figure 7-51 shows a delta-connected motor, INSULATE withseriesconnection for higher voltage in view A and parallel connection for low voltage 73.143 in view B. Figure 7-50. Star-connected motor.(A) Series; Checking for trouble in a 3-phase motor fol- (B) Parallel. lows the same procedure as that used for a 214 224 Chapter 7---SlIOPWORK single-phase motor, exceptthatthe 3-phase Wiping with a clean, lint-free, dry rag (such motor has more coils to check for grounds, as cheesecloth) is effective for removing loose shorts, and opens. dust or foreign particles from accessible parts First isolate the trouble as to phases, then of a machine. When wiping, do not neglect such open the connections in the particular phase to parts as the end windings, mica cone extensions separate the groups and check again. When the at the commutator of d-c machines, slip-ring faulty group has been located, open the connec- insulation, connecting leads, and terminals. tions of the three coils in the group to locate the faulty coil. For an emergency connection, The use of suction is preferred to the use of this coil can be cut out in the same manner compressed air for removing abrasive dust and as described for cutting out a coil in the arma-particles from inaccessible parts of a machive ture. because it lessens the possibility of damage to insulation. If a vacuum cleaner is not available With a 3-phase motor, one fuse can open and for this purpose, a flexible tube attached to the the motor will keep running (with less power and suction side of a portable blower will serve as more current). When the motor stops, it cannot asatisfactorysubstitute. Always exhaust the start again with the opened fuse in the line. blower to a suitable sump or overboard when When a fuse opens, replace all three fuses withused forthispurpose.Grit,iron dust, and fuses known to be good, and test the old fuses copper particlesshould be removed only by later on a fuse-testing circuit at the electric suction methods whenever possible. shop. To ensure that all possible trouble points have been covered, it Is a good idea to follow a Compressed air must be clean and dry when usedforcleaningelectrical equipment. Air troubleshooting checkoff list. pressure up to 30 pounds per square inch may be used on motors or generators. A throttling valve should be used on air lines that carry GENERATORS higher pressure than is suitable for blowing out a machine. Before the airblast is turned You should review the information regarding on the machine, any accumulation of water in generators presented in Basic Electricity, NAV- the air pipe or hose must be thoroughly blown PERS10086-B.Any time you are required to out,and both endsof the machine must be work on any generators, be sure to consult the opened to allow a path of escape for the air and appropriatetechnical manuals. Theselista dust. The use of compressed air will be of variety of difficulties you may encounter, some small benefit if the dust is not suitably removed possible causes, and repair methods. from the machine. The most suitable method is to attach a suction blower to an opening in the CLEANING MOTORS opposite end from the air jet to remove the AND GENERATORS dirt-laden air. The use of solvents for cleaning electrical The importance of keepingallinsulation equipment should be avoided whenever possible; clean must be emphasized. Dust, dirt, and for- however, their use is necessary for removing eign matter (carbon, copper, mica, and so on)grease and pasty substances consisting of oil tendtoblock ventilation ducts and increaseand carbon or dirt. Alcohol will injure most resistance to the dissipation of heat, causing types of insulating varnishes aLti should not be local or general overheating.If the particles used for cleaning electrical equipment. Solvents are conducting or form a conductingpaste through containing gasoline or benzine must not be used the absorption of moisture or oil, the windingfor cleaning purposes under any circumstances. may be eventually short circuited or grounded. Carbon tetrachloride is not to be used because Abrasive particles may puncture insulation; iron of its extremely high toxicity. dust is particularly harmful since the dust is agitated by magnetic pulsations. Approved Solvents The four acceptable methods of cleaning motors and generators are wiping, use of suc- Inhibited methyl chloroform (trichloroethane), tion, use of compressed air, and use of a solvent. FSN GM6810-664-0388,is one of the principal

215 225 CONSTRUCTION ELECTRICIAN 3 & 2 approved solvents for cleaning electrical equip- Precautions ment but liberal ventilation must be provided byexhaust fans or portable blowers ifthis During the use of any solvent the following solvent is used for more than a few minutes. precautions must be observed: In the rare cases when means of ventilation are impractical, an air line respirator or oxygen Guard carefully against fire. breathing apparatus (OBA) must be used if exposure to the solvent vapors is for more than Use vapor-proof or watertight portable lights a few minutes. if supplementary lighting is required..

Inhibitedmethyl chloroformis very cor- Havefireextinguishers available for im- rosive in its action on metal and may prove mediate use. injurioustocertaininsulation.Before using any solvent, apply it to a small area or sample Prevent possible sparks caused by one me- of the insulation to be cleaned. If it injures the tallic object striking another. insulation,donotuseit.Clean freshwater, preferably warm or hot, may be used as an If a rpray or atomizer (not normally used emergency substitute for inhibited methyl chloro- for routine cleaning) is used, ground the nozzle. form. Water should be used only as an emergency substitute and the equipment must be thoroughly Avoid saturation of the operator's clothing dried after any application of water. with the solvent. Do not spray inhibited methyl chloroform on Provide liberal ventilation by means of ex- windings. It will collect in pools and do more haust fans or portable blowers. harm than good. The solvent should be applied by moistening a lint-free cloth with the fluid When using inhibited methyl chloroform or and lightly rubbing the surfaces to be cleaned; trichloroethylene, protect against breathing the repeat the process if necessary to loosen the fumes (a chemical cartridge respirator such as dirt.After wiping the insulation with solvent a gas mask will not prevent suffocation since it should be thoroughly dried with a clean lint- the vapors from these solvents displace air and free cloth. oxygen).Cleaning should be done under the observation of someone familiar with artificial Inhibited methyl chloroform is detrimental to respiration. good commutation and should be kept from coming in contact with the commutator or brushes of Do not apply solvents on hot equipment or d-c machines. in the presence of open flames. The chlorinated solvents form highly toxic phosgene gas on con- Inhibited methyl chloroform should never be tact with open flame. used on hot equipment as the accelerated evap- ioration will increase the toxic hazards. No less than two persons should be assigned to cleaning operations in a single compartment. Trichloroethylene (FSN G6810-184-4794) is another approved solvent widely used in a vapor process for degreasing metals. It should not be General signs of fume.poisoning by chlori- used for cleaning electrical insulation because nated hydrocarbons include headache, nausea, of its strong solvent action on these materials. mental confusion, and in some instances a kind The toxic effects of trichloroethylene are sim- of drunken behavior similar to that caused by ilarto those of inhibited methyl chloroform. alcohol. When any of the above symptoms are Dry cleaning solvent, type II (FSN W6850- observed, the person should immediately be re- 274-5421), is an approved safety type solvent. moved from the toxic atmosphere to fresh air The fire and health hazards of this solvent have or a well-ventilated space. been minimized. The efficiency of this solvent is somewhat less than the previously discussed Wear rubber gloves when constant contact of chlorinated solvents but the hazards to personnel approved solvents is unavoidable. The solvents are also reduced. dry out the skin and cause it to crack and bleed.

216 226 Chapter 7.---SITOPWORK

GENERAL MAINTENANCE ialet and outlet oil piping flanges (for force feed bearings). Special attention should be taken to The essential points in the maintenance of ensure that this insulation is not damaged or that electric generators and motors are: keep insu- conducting paths around this insulation are not lation clean and dry and of high resistance, keep inadvertently provided. For instance, care should electrical connections tight, and keep machines be taken when painting machines furnished with in good mechanical condition. insulated pedestals not to paint over the insulating Keepall small pieces of iron,bolts, and shims, washers, and oil piping couplings. Bearing tools away from themachines. Where it iscurrents, if of sufficient magnitude, will rapidly necessary to do any soldering, make sure thatruin a bearing. These currents are caused by no drops of solder get into the windings and that electromotive force generated in the shaft and there is no excess of solder on soldered jointsstructural parts of a generator unless it is which may later break off due to vibration andcarefully designed and constructed to minimize fall into the windings. their occurrence. An insulated bearing (or pedestal) breaks the circuit and protects the bearings Do not disturb the commutator clamping from damage so long as the insulation is ef- bolts on d-c machines. Interference with these fective. may make it necessary to turn or grind the commutator to restore it to service. Inspect all electrical connections (particu- Otherboltsand mechanical fastenings onilarly terminals and terminal board connections) both the stationary and rotating members should at frequent intervals to make sure they are tight. be tightened securely when the machine is in- Loose connections result in increased contact stalled, checked after the equipment has run for resistance and increased heating which may re- a short time, and thereafter checked at regular sult in breakdown. Use locknuts, lockwashers, intervals to make sure that they are tight. Par-or other means to lock connections which tend ticular attention should be given to the boltsto become loose because of vibration. Inspect used to clamp any insulation. soldered terminal lugs for looseness or loss of solder,and tightensolderless terminal lugs Lf an inspection of a rotor shows that there isoccasionally. When electrical connections are looseness of keys, bolts, or other fastenings, a opened,cleanalloilanddirt from contact check should be made for evidence of damagesurfaces beforereconnecting.If thecontact due to this looseness. Such looseness may result surfaces are uncoated copper, sandpaper and in worn dovetail keys, damaged windings, or clean immediately before joining. If the contact broken dovetails on the end plates. Two or three surfaces are silverplated, do not use sandpaper. drivings (with a punch and hammer) usually will Use silver polish or a cloth moistened slightly ensure the tightness of the keys, but they should with an approved solvent. Coat the finished joint be checked regularly. with insulating varnish. Steel bolts for making electrical connectionsshouldbezinc- or The banding wire on d-c armatures should cadmium-plated. Make sure that exposed elec- be checked at regular intervals to make sure trical connections are adequately insulated to that it is tight. protect against water and moisture and injury to personnel. This applies especially to exposed The outboard bearing on some generators connections at terminal straps extending outside (both a-c and d-c) is electrically insulated from the frames of propulsion motors and generators. the frame; or the bearing pedestal is insulated from the base and the bearing oil piping to prevent theflow ofshaft currents through the Lubrication bearing. In the former case, insulation is accomplished by means of a shell of insulating material installed between the bearing shell and IMPROPER GREASING PROCEDURES ARE the bearing housing.In the latter case, the A FREQUENT CAUSE OF DAMAGE TO bearing insulationisaccomplished by using ROTATING ELECTRICAL MACHINERY PRO- insulating shims under the pedestal and insu- VIDED WITH GREASE-LUBRICATED BALL lated holding down bolts and dowels. Also in- BEARINGS. The trouble is generally caused by sulated couplings are provided in the bearingforcing an excessive quantity of grease into the

217 227 CONSTRUCTION ELECTRICIAN 3 & 2 bearing housing, with either one or both of the PLUG USED TO REPLACE THE GREASE CUP following results: AFTER GREASING IS ALSO CLEAN. Some electric motors and generators may 1. Grease is forced through the bearing hous- be equipped with oil-lubricated ball bearings. ing seals and onto the windings and, in the case Lubrication charts or special instructions are of d-c machines, onto the commutators wheregenerally furnished for this type of bearing and it causes deterioration of insulation, and even- should be carefully followed by personnel main- tuallyresultsin taining the equipment. In the absence of other grounds or short circuits. instructions,theoil level inside the bearing 2. The excessive quantity and pressure of housingshouldbemaintained approximately grease in the bearing housing result in churning, level with the lowest point of the bearing inner increased temperatures, rapid deterioration ofring. This will provide enough oil to lubricate the grease,and ultimate destructionofthe the bearing for a considerable operating period, bearing. but not enough to cause churning or overheating. One common method by which the oil level is maintained inball bearings is the wick-fed The following instructions apply to equip- method. In this method, the oil is fed from an ment except oil-lubricated bearings, synchros, oilcupto the inside of the bearing housing and similar devices where friction must bethrough an absorbent wick, which also filters maintained at an absolute minimum, and equip- the oil and prevents leakage through the cup in ment for which approved lubrication charts or the event momentary pressure is built up within other specific instructions are furnished by the thehousing. A representative wick-fed, oil- Navy. Except for the equipment to which they do lubricated ball bearing is shown in figure 7-53. not apply, the following instructions should be carefully observed in order to avoid failure of elebtrical equipment because of improper greasing practices: Motors and generators provided with bearings that should be lubricated with grease are BALL now normally delivered from the manufacturer B ARING with the grease cups removed from the bearing GREASE housingsand replaced with pipeplugs. The CUP grease cups are delivered with the onboard re- GREASE pair parts or special tools. It is recommended FITTING thatgrease cups(fig.7-52)beattached to electric motors and generators only when the bearings are being greased. When the grease cup is removed from the bearing housing after a bearing has been greased, the hole which remains should be plugged with a suitable pipe plug. When this procedure is used, the grease cups should remain in the custody of responsible BEARING maintenance personnel and can be stored in the HOUSING workshop or toolroom. This procedure is par- DRAIN ticularlyadvantageous when the motors and PLUG generators maintained by a particular group of maintenance personnel need only relatively few different sizes of grease cups. This procedure should also be followed for motors and generators which have been supplied with grease cups attachedtothe machine. CARE SHOULD BE TAKEN TO MAKE SURE THAT A GREASE CUP IS CLEAN BEFORE IT IS USED TO ADD 77.68 GREASE TO A BEARING AND THAT THE PIPE Figure 7-52.Grease-lubricated ball bearings.

218 028 Chapter 7SHOPWORK

2. Wipe the outside of the grease fitting and drain the plug free of all dirt. 3. Remove the bearing drain plug, and make sure the passage is open by probing with a clean screwdriver or similar implement.

4. Remove the pipe plug on top of the grease pipe (open the grease pipe by probing as above). Select the proper grease cup, empty and clean out the grease cup (top and bottom). Install the bottom portion of the grease cup on the grease pipe. 5. Fill the bottom portion of the grease cup with clean grease, fill the top portion (cap) of the grease cup only half full of grease.

6. Thread the half filled cap of the grease cup onto the fully filled bottom of the grease cup and screw it down as far as it will go (by 77.69 hand). Keep the machine running continuously Figure 7-53. Wick-fed ball bearings. while adding grease.

7. Repeat steps(5)and(6)above until The frequency with which grease must be clean grease begins to emerge from the drain added depends upon the service of the machine hole. andthetightnessofthe housing seals, and should be determined for each machine by the engineerofficer.Ordinarily,theadditionof 8. Continuetorun the machine and let grease will not be necessary more often than grease nm out of drain hole until drainage stops once every 6 months. When a bearing housing is (normally about 30 minutes). Remove the grease too full of lubricant, the churning of the grease cup and replace the pipe plug. generates heat which in turn causes deterioration of the grease. Under these conditions the 9. Replace the drain plug. grease separates into oil and minute abrasive particles , becomes increasingly stickly, and tends 10. If a grease gun must be used, remove to seal the bearing against fresh lubricant until thedrain pluginthe bearing housing while theresultingfriction, heat, and water causegreasiag and use extreme care to avoid insert- failure of the bearing. ingtoo much grease or applying more than just enough pressure to get the grease into the Greasing Procedures housing. Bearings which normally operate at a temperature of 194F (90° C) or below should be High Temperature Grease lubricated with grease in accordance with Mili- tarySpecificationMIL-G-18709,Stock Nos. W9150-235-5544 and W9150-235-5564. Bearings which normally operate at a tem- To avoid the difficulties caused by an ex- perature above 194° F (90° C) should be lubricated cessive amount ofgrease, add it only when with a silicone grease in accordance with Military necessary. Grease is added according to theSpecification MIL-L-16719A, Stock No. W9150- following instructions: 257-5358. Machines which require this special grease have a caution plate stating "USE HIGH 1. Run the machine to warm up the bear- TE MPERATURE GREASE" which is attached near ings. the grease fitting by the manufacturer,

219 229 CONSTRUCTION ELECTRICIAN 3 & 2

SLEEVE BEARINGS and two measurements approximately 900 apart at the less accessible end. If these two do not A SLEEVE bearing is a type of sliding bear- differ greatly from the mean of the measure- ing employed in electric motors and generators. ments at the other end, the air gap is reason- These bearings are used in large equipment, ably uniform at both ends. such as turbine-driven ship's service genera- torsand propulsion generators and motors. 2. Take several measurements at one end of The bearings taay be made of bronze, babbitt, the machine in accordance with the procedure or steel-backed babbitt. described above, and average these to obtain the average air gap, or obtain the average air gap Preventive maintenance of sleeve bearings from records of preceding measurements. The requires periodic inspections of bearing wearaverage air gap is one-half the difference be- and lubrication. tween the inside diameter of the stator (or field pole arrangement) and the outside diameter of Wear the rotor (or armature), and is not affected by bearing wear. Procure a long, narrow strip of Large motorsand generators are usuallysteel. The thickness of the steel strip should provided withagage for measuring bearingbe 20 percent less than the average air gap for wear. Bearing wear on sleeve bearing machines average air gaps smaller than 0.040 inch; it not provided with a bearing gage can be obtained should be 10 percent less for average air gaps by measuring the air gap. It is usually not nec- larger than 0.040 inch. Test the air gap by try- essary to measure air gaps on machines whiching to push this strip all the way from one end have ball bearings because the construction ofof the air gap to the other. This test should be the machine is such as to assure bearing align- made at four points 90° apart, if possible, and if ment. Bearing wear of sufficient magnitude tonot, at a number of points (not less than three) be readily detectable by air gap measurements spaced at approximately equa, intervals around would be more than enough to cause unsatisfac- thecircumference. The test can be repeated tory operation of ball bearings and would bewith a slightly thicker strip if a closer estimate detected in this way. is needed. Air gaps on a sleeve bearing machine not provided with a bearing gage should be meas- Itis more important to have uniformity of ured at each end of the machine. Air gaps canair gaps at all points than to have the gap con- be measured with an air gap feeler. This is aform exactly to the specified limits. If the air machinist'l feeler gage with a blade long enough gap at any of the places tested differs from the to reach into the air gap without removing the average air gap by more than 20 percent for end bracketsof the machine. Before makingaverage air gaps smaller than 0.040 inch, or by the measurements, clean the varnish from a more than 10 percent for average air gaps larger spot ona pole or tooth of the rotor. A spot than 0.040 inch, the bearings should be realigned, shouldalso be cleaned at the same relativerepaired, or replaced. Usually an inequality of position on each field pole of a d-c machine.air gaps which is not greater than specified For a-c machines, at least three and prefer- above will not cause unsatisfactory operation. ably four or more spots spaced at equal inter- If,however, trouble is experienced, such as vals around the circumference should be cleanedvibration or excessive noise which cannot be on the stator. The air gap measurements shouldtraced to any other cause than unequal air gaps, be taken between the cleaned spot on the rotoritis advisable to realign, repair, or replace and the cleaned spot on the stator, turning the bearings to equalize air gaps, even if the meas- rotor to bring the cleaned spots on the rotorured inequalities are within the limits given. opposite each of the cleaned spots on the stator. If one end of the machine is accessible only Lubrication with difficulty, either of the following procedures may be used: Every precaution should bc taken to keep the 1. Take several measurements at one end inoil and bearings clean and free from water or accordance with the procedure described above, foreign particles.

220 230 Chapter 7SHOPWORK

Do not add oil while the machine is running.

This affords an opportunity for oil mist or spray OIL SLINGER ACCESS to escape from the bearing housing and be blown (DEFLECTOR RING) COVER on the machine windings.

BEARING Bearings having an overflow gage should be filled until the oilis about one-sixteenth inch from thetcpof the gage. If the machine is equipped with an oil filter gage, the gage should

be filled to the manufacturer's oil level ark, OILER or (if no mark is available) the gage should be RING betweer two-thirds and three-quarters fullat all times. Be sure that the gage glass and piping tothe gage are clean or the glass will give mt.RETURN TO SUMP OIL false indications of the oil level. If the bearing RESERVOIR has neither an overflow gage nor an oil filter gage, fill to a level so that the oil ring dips into oil to a depth of about half the shaft diameter. 77.239 Figure 7-54.Diagram of an oil-ring lubricated bearing. When the bearing and bearing housing are in good condition, there should be no loss of oil. If the proper oil level cannot be maintained without Oil Rings and Dearing Surfaces adding oil, it is probable that oil is leaking from the bearing. Be sure the oil sight gage connection to the bearing is tight. Much of the oil that An opening is provided in the top of the bear- le-Ks out of a bearing is drawn into the machine ing for checking the condition of the oil rings by the cooling air and sprayed onto the windings and bearing surfaces (lig.7-54). Periodic in- where it causes oil soaked dirt to collect. Thisspections are necessary to make certain that condition tends to cause insulation failure. Ifthe oil ring is rotating freely when the inachine o'.1leakage is suspected, carefully clean and is running. With the machine stopped, the bear- chalk the shaft outside the bearing, the outsideing surfaces should be inspected for any signs of the bearing housing, and the parts of the rotor of pitting or scoring. adjacent to the bearing. If the machine is throwing oil, discoloration of the chalk will so indicate after a short run. This test will not be dependable Trouble Analysis unless the chalked part is perfectly clean at the beginning of the test.If leakage is found, the labyrinth seal in the bearing housing should be The earliest indication of sleeve bearing mal- corrected to make it effective. Another possiblefunction normally appears as an increase in the source of leakage is from the vent with which operating temperature of the bearing. This in- some labyrinths are provided. Made sure that crease is due to the heat generated in the ex- any such ventisnot stopped up and that it tremely sensitive oil film separating the rotating terminates in still air of atmospheric pressure journal from the bearing surface and is governed where there is no current of air over the ventby the slipping or shearing of the oil molecules. that will suck oil out of the bearing housing or When the bearing is operating satisfactorily, oil vapor out of the vent into the machine. Such the film temperature remains stable; but when oil leakage is often due to overfilling the bearing the equilibrium of the oil film is interrupted, or trying to fill the bearing through the vent. rapid and sharp changes occur in the temperature of the oil film. Oil is supplied under pressure from a central system to sleeve bearings Bearing oil should be renewed semiannually. in some large generators. Drain the oil off by removing the drflin plug, then flush the bearing with clean oil until the drained Thermometers are usually inserted in the oil flows clean. discharge line from the bearing as a means_ of 221 231 CONSTRUCTION ELECTRICIAN 3 & 2 visually indicating the temperature of the oil as itleaves the bearing. Thermometer readings are taken hourly on running machinery by operating personnel. However, a large number of bearing casualties have occurred in which no temperature rise was detected in thermometer readings,and,in some cases, discharge oil temperature has actually decreased. Therefore, ADAPTER after checking the temperatureat the ther- 2 POLE 3 POLE mometer, a followup check should be made by RUBBER MOLDED TWIST LOCK feeling the bearing housing whenever possible. WITH FINGER GRIP Operating personnel must thoroughly familiarize themselves with the normal operating temperature of each bearing so that they will be able to recognize any sudden or sharp changes in GROUNDED PLUG bearing-oil temperature. Many large generators are provided with bearing temperature alarm contactors which are incorporated in the alarm 5.I3A system. The con;actor is preset to provide an Figure 7-55. Attachment plugs. alarm when the bearing temperature exceeds a value detrimental to bearing life. If bearing malfunction isindicated,the affected machinery Any unusual noise in operating machinery should be secured as soon as possible. A motor may also indicate bearing malfunction. When- withoverheatedsleevebearingsshould be ever a strange noise is heard in the vicinity of unloaded, if possible, without stopping the motor. operating machinery, a thorough inspection must stopped immediately, the bearing may seize. be made to determine its cause. Excessive vi- The best way to limit bearing damage is to keep bration will occur in operating machinery with the motor running at light load and supply plenty faulty bearings, and inspections should be made of cool, clean oil until the bearing cools down. at frequent intervals in order to detect its presence as soon as possible. The temperature of sleeve bearings and the outer races of ball bearings should not be allowed Portable appliances and devices that are to to exceed the following values: be connected to receptacles have their electrical cords equipped with plugs (fig. 7-55) that have prongs which mate with the slots in the outlet 1. Sliding contact (sleeve) bearings-82° Creceptacles. Equipment connected by a cord or (180° F). plug should be grounded in accordance with the National Electric Code, article 250-45. A three- 2. Rolling contact (ball) bearings on class Aprong plug can fit into a two-prong receptacle or B insulated motors-90° C (194° F). by using an adapter. If the electrical conductors connected to the outlet have a ground system, the lug on the lead wire of the adapter is con- 3. Roiling contact (ball) bearings on class nected to the center screw holding the rezep- insulated motors-150° C (300° F). tacle cover to the box. Many of these pluge are permanently molded to the attached cords. There are other types of cord-grips that hold the cord The permissible operating temperature is too firmly to the plug. Twist-lock plugs have patented high to be estimated by sense of touch. Tempera- prongs that catch and are firmly held to a mating ture measurements are needed to determinereceptacle when the plugs are inserted into the whether a bearing is overheated. A thermometer receptacle slots and twisted. Where the plugs securely fastened to the bearing cover or housingdo not have cord-grips, the cords should be tiod will usually give satisfactory measurements. Awith an Underwriter's knot (fig. 7-56) at plug thermometer should not binserted into a bear- entry to eliminate tension on the terminal con- ing housing; it may break and necessitate dis-nections when the cord is connected and disassembly to remove glass and mercury. connected from the outlet receptacle.

222 232 Chapter 7SHOPWORK

thermostat, starts the circulator and also energizes the stack switch.This closes the line-voltage circuit to the circulator and the low- voltagecircuit acrosstheterminalsofthe stack switch. The stack switch, when energized by either the relay or the operating immersion controls, starts the oil burner if the stack has cooled,returningthehelix-operated contacts to the starting position. The oil burner runs until the thermostat is satisfied. The thermostat then turns off the relay which stops the circulator and simultaneously breaks the low- voltage circuit across the terminals of the stack switch, stopping the oil burner operation. When the operating immersion control used to maintain summer-winter (domestic hot water) senses 5.1313 thedrop in the boiler water temperature, it --56.The Underwriter's knot. energizes the stack switch as required. It breaks the low-voltage circuit across the relay terminals when the water temperature reaches its cutout setting. This operation does not affect the unit's DOMESTIC OIL BURNERS, WINDOW hot-water circulator. AIR-CONDITIONERS, AND LARGE APPLIANCES Forced Warm-Air System When you are assigned to "13" company or A thermostat senses the need for heat in a Public Works electric shop, you will be involved the room and energizes the stack switch which with troubleshooting and repair of various types closes the low-voltage circuit across the ter- of heating units, window air-conditioners, and minals of the switch (fig. 7-58). When the stack appliances. Your knowledge of wiring diagrams switch is energized by the thermostat, it starts and schematics, along with a good understanding the oil burner, if the stack has cooled, returning of locating grounds, shorts and opens in a cir-the helix-operated contacts to the starting po- cuit, will be of prime importance. .Ation. The oil burner runs until the thermostat is satisfied and turns off the stack switch, which opens the low-voltage circuits across the ter- OIL BURNERS minals to the stack switch or until the bonnet temperature reaches its present high point. The electrical portion of an oil burner inThis causes the safety limit control, which is almost any type of automatic oil heating instal- part of the fan-and-limit control, to turn off lation contains motors, relays, and thermostats. the unit. The sequence of operation will vary with the As soon as the combustion unit increases type and application of each oil burner. The the bonnet temperature enough to ensure that manufacturer's manual willfurnish you with warm air will be forced out of the residence this needed information. Examples of two types registers, the fan side contacts of the fan-andof operations follow. limit control starts the blower. The blower continues to function until the bonnet temperature Forced Hot-Water System is reduced to its cutoff setting. There are basically three components in an A thermostat senser the need for heat in the oil burner ignition system: room and turns on the relay, closing the low- voltage circuit across the terminals of the relay 1. Thestep-uphigh-voltagetransformer (fig.7-67). The relay, when turned on by the which steps up from 116 volts line on the primary 223 " 3 3 CONSTRUCTION ELECTRICIAN 3 & 2

4 TO THERMOSTAT ----- CLOCK I METER 1

DAY-NITE: I HOT II b STACK SWITCH "j L TRANSFORMER s -rj L

OW 2 I

RELAY 4"--0 0 0$ LINE SWITCH OPERATING LIMIT 2 DUAL IMMERSION CONTROL FUSE

GROUND

BURNER _CCIRCULATOR MOTOR MOTOR

HOT

IGNITION LOW VOLTAGE TRANSF')R M ER LINE VOLTAGE 73.392 Figure 7-57.Oil burner circuit, forced hot-water system.

side of approximately 10,000 volts on the sec- In other types of systems, the spark remains ondary side. on during the entire firing cycle. 2. Ignition wires or bus bars which are a 0 point of contact for the high-voltage source to This spark occurs on the zips of the two reach the electrode assembly. properly positioned electrodes, and the high- voltage transformer provides the electricity to 3. The electrode assembly which consists ofproduce it. It must be strong enough to bridge a combination of insulated porcelain and steel the correctly set gap between the electrodes. electrodes for spark which isLlE,ad for ignition. Setting the electrode gaps will vary with each unit. Manufacturer's instructions will be pro- This system provides the spark or lightoff vided for each burner. required to ignite the fuel oil as it enters the combustion chamber. The spark must be correctly positioned to provide immediate ignition AUTOMATIC WASHERS to the prepared fuel. It cannot be delayed, weak, or off-target. These and other defective conditions can resultin odor,dirt, inconvenience, and The main electrical parts of an automatic possible hazard. Some units are designed sowasher are: timer, water temperature switch that the spark remains on for just a short pe- or mixing valve, limit switch, door safety switch, riod after providing initial ignition or lightoff.water level control, and main drive motor. The 224 234 Chapter 7SHOPWORK timer is the most involved of all these parts.depending on the manufacturer. The final spin Figure 7-59 showsa wiring diagram of theuses no water, so the clothes will come out electrical parts controlled by the timing device. damp dry. The time cycle in figure 7-60 is for a typical top load washer. The sequence of operation for ELECTRIC DRYERS the regular cycle is as follows: The fill cycle turns on the mixing valves. The machine fills with water until the timer advances to wash. The main electrical parts of a dryer are: The wash cycle starts the two-speed motor onelectric heating elements, thermostats to control low and works the agitator until the cycle is heat, a motor to turn the main drum assembly, complete. There is a pause between the wash and a timer to select cycle operations. Most and spin rinse cycle. The spin rinse turns thedryers have a cutoff switch on the door which motor on high speed and a clutch device engages stops the dryer when the door is opened. Many the water pump to spin out the wash water. dryers have a 40-watt ozone bulb to help con- Fresh water is also sprayed into the machine ditionthe r.This bulbrequireseither a during this cycle. The machine stops at the endballast coi a ballast bulb. Both high-limit of the spin cycle and fillsagain. The entireand low-lirna operating thermostats are used processisthen repeated except for rinsingin dryers to control the air temperatures that insteadof washing. There will be variations pass through the clothes. These are located in

TO THERMOSTAT METER CLOCK DAY-NITE s I

I I HOT b6

STACK SW ITCH L-T--r" TRANSFORMER I I i

30 S RELAY 0 os LINE SWITCH I 3 OPERATING 2 LIMIT DUAL IMMERSION CONTROL FUSE

GROUND

BURNER QCIRCULATOR MOTOR MOTOR

HOT IGNITION LOW VOLTAGE TRANSFORMER LINE VOLTAGE

73.39$ Figure 7-58. Oil burner circuit, forced warm air systum.

225 2 3 5 CONSTRUCTION ELECTRICIAN 3 & 2

LI MOTOR VIBRATION PROTECTOR L2 DISC. LIMIT SWITCH IN SHIP- 23a MENT

LINE SWITCH RED-BLACK

SAFETY -SPIN

RED-BLACK DOOR SWITCH N.O.

YELLOW-RED T 0 14 WASH 330---Ea® RINSE WATER WATER VALVE EP=1----? II TEMPERATURE PINK 9) 21 WASH 072-\-- 22 RINSE 0-Ei L9) PINK-BLACK16 0 71 PINK-GREEN VIOLET

MOTOR CONTROL

BRAKE BRAKE SOLENOID BROWN SOLENOID

SPIN AGITATE

'AGITATE SPIN

YELLOW-BLK.,

AGITATE SPIN TMo WHITE

PUSH-OFF 0 PULL-ON '-' 0 29 WHITE-GREEN

236 73.394 Figure 7-59. Wiring diagram showing electrical connections from timer to otherelectrical parts.

226 Chapter 7SHOPWORK

thermostats in the figure operate as follows: The single-throw thermostat is in series with REGULAR CYCLE TIME(MIN.)GENTLE CYCLE TIME(MIN.) the heating element and has only one set of FILL 4 FILL 4 contacts, which open and close in response to WASH 2-10 WASH 3 the temperature at the bottom of the water- PAUSE I PAUSE I SPIN 2 SPIN 2 heater tank. The double-throw thermostat con- SPIN SPRAY I SPIN SPRAY I trols both the upper and lower heating elements. FILL 3 FILL 3 The switch closes the circuit in the upper heat- _OVERFLOW RINSE 4 OVERFLOW RINSE 1 ing unit whenever the water temperature in the DEEPWAVE RINSE I DEEP WAVE RINSE I top of the tank becomes lower than the thermo- PAUSE I PAUSE I static switch setting. When the top part of the SPIN I SPIN SPIN SPRAY I tank reaches a preset temperature, the switch SPIN 5 opens the contacts to the upper unit and, by a 20 MIN. toggle action, closes the contacts to the lower TOTAL 34 MIN.TOTAL unit. The lower unit comes on and remains on until its preset thermostat is satisfied. 73.395 Figure 7-60. Time cycle foran automatic washer.

LI L2 WHITE BLACK the exhaust housing and can be easily checked RED during operation by a voltage check. The tester CONTACTS will indicate a voltage each time the contact CLOSEWHEN is opened. Safety thermostats should show con- TIMER IS SET tinuity between terminals at normal room *em- TIMER TIMER A perature. Holding a small flame close under it MoToR CONNECTOR BLOC K should cause it to open, indicating an open cir- ) cuit acrossitscontacts. Dryer timers are fairly simple to troubleshoot. Some timer drive motors and switching mechanisms can be replaced, but in most cases it is more practical 6-44-1 TEMPERATURE- *--.1 CONTROL to replace the timer. Figure 7-61 is a wiring THERMOSTAT diagram for an electric dryer. DOOR/ SWITCH ri'SAFETY OZONE \A/THERMOSTAT LAMP ELECTRIC HOT-WATER HEATERS I LLU- HEATING MINATING ELEMENT LAMP An electrichot-water heaterisa metal water-storage tank with one or two electric heating elements, thermostatically controlled to heat water in the tank. It is a simple device and BLACK YELLOW GREEN among electrical problems that may arise are: no power, defective thermostat, thermostat out of calibration, or defective heater element. DRUM The hookup of a hot-water heater will vary MOTOR with the size and application of each unit. Where MOTOR RUNtHNG power consumption is a problem, a hot-water 'MOTOR STARTING heater may be piaced on a timeclock and taken out of the system during maximum power consumption periods(fig.7-62). Most unitsat advanced bases will be hooked up without a 73.396 timing dev:r..3as shown in figure 7-63. The Figure 7-61.Schematic of an automatic dryer.

227

`2, 3 7 CONSTRUCTION ELECTRICIAN 3 & 2

RANGES

The electric ranges you will be workingon # I wil vary in size and style but will all basically work the same. Surface heating elements work off a selector switch which changes the voltage and resistance value of the element, givingyou #2 DOUBLE-THROW a variety of heating temperatures. Figure 7-64 THERMOSTAT shows how this is accomplished. Oven elements 1 work off a thermostat to control heat temperature and a timing device for automatic shutoff as shown in figure 7-65. In troubleshooting, start by checkingto ensure proper voltage to the unit, then checking out each element and control device. The heating element, though ruggedly constructed, might becomeopen- circuited. This can be checked out with an ohmmeter. Normal resistance is somewhat less than 100 ohms. If elements are opened, replacement isnecessary.Iftheheating element checks normal, but the unit doesn't heat up, the controls should then be checked. Voltage measurement isthe most reliable test for a switch. When turned off, the measurement across the switch

UPPER HEATING TIMER UNIT

TERMINAL BOX 0 0 I 'SINGLE-THROW 0 THERMOSTAT

LOWER HEATING UNIT

73.398 HEATING Figure 7-63. Wiring connections foran electric water heater having two heating units. II5V terminals should read full line voltage, 120 or SINGLE THROW 2nV THERMOSTAT 240 volts. When the switch is on, the reading should be zero across the terminals. Any voltage reading across the terminal of a closed switch indicates a fault. Replacing a faulty switch 73.397 involves the disconnection and reattachment of Figure 7-62.Wiring diagram for a limited- many wires. A sketch or identifying tags should demand, time-controlled, hot-water heater. be used to ensure the correct relocation of 228 238 Chapter 7SHOPWORK

SWITCH SWITCH 0 SWITCH o SWITCH POSITION POSITION POSITION POSITION NO. 1 NO. 2 NO. 3 NO, 4

OUTER JsuRFAc OUTER Ir OUTER HEATING 1 ELEMENT HIGH HEAT MEDIUM HEAT LOW HEAT SIMMER 73.399 Figure 7-64. Surface heating element with four-heat switching. wires. Oven thermostats control temperature and are factory calibrated for that unit. Some units can be recalibrated but most must be replaced. When replacement is necessary the exact type ie preferred; however, universal type replacements areavailable. The manufacturer's in- PILO;LAMP structionsthat come witha thermostat will THERMOSTAT give you the exact method for installing and calibrating the device. SE' C TOR ++ non& TIMER Faulty wiring isthefinalcheck. Unless IIII- IP RED SWITCH RED arcing damage is evident, test a wire by dis- rE) LI connecting both ends from thecircuit; then JI L20 check it with an ohmmeter. A good wire checks RED 0 ohms; a faulty one, infinity pc) . Replacement IBLACK BLACKL2 of a faulty conductor should be made with asbestos- RED covered heater wire. Solder is not used because BLUE it will melt; spade-tongue or quick-connect ter- BLACK minals are used instead. BROIL

BAKE UNIT HERMETIC COMPRESSOR APPLICATION ti UNIT BLACK

Hermetic compressors contain the motor and [ 1 compressor in a sealed unit. The motor and compressor work off the same shaft; therefore, no shaft seal or belt drive is required. This 73.400 arrangement provides a more compact assembly Figure7-65. -Oven heating circuit with two and takes up less space, heating units.

229 239 CONSTRUCTION ELECTRICIAN 3 & 2

thestarting relay coil to close ,tscontacts. The current passing through the starting coil ,- COMPRESSOR MOTOR induces an out-of-phase, magnetic field in the stator and starts the motor. As the motor speed increases, the current in the running winding STARTING RUNNING is reduced. This drops the value of the current in the starting relay and opens its contacts, taking the starting winding out of the circuit. The motor continues torun on the running winding as an induction motor. L OVERLOAD PROTECTION is provided bya bimetallic strip in series with thecompressor windings (fig.7-67). Should the current in the STARTING RELAY motor windings increase to a dangerous value, 1 the heat developed by the current passing through the bimetallic overload willcause its contacts RELAY to open circuit. This will stop the motorbefore COIL any danger occurs. When the bimetallic strip cools, it will return the contact to the closed STARTING position. CONTACTS WINDOW AIR-CONDITIONERS

HOT A basic electrical system for a window air- conditioner consists of a hermeticcompressor 73.401 Figure 7-66.--Schematic wiring of acompressor-motor and starting relay.

Almost all household refrigerators, window STARTL air-conditioners, and ice cube machinesyou will IR be working on have hermeticcompressors. CONTACTS OVERLOAD Compressor motor sizes will vary, depending on application and capacity of the system. The HEATER compressor motor consists of a starting and running winding. The runningwinding is energized dufing the con-II-Arne cycle period, whereas the starting winding is er.trgized only during the starting period, bt;cance additional starting torque is reouired in sing1,;-phauo units. PUSH ON RELAY STAIcIN!(..; 1'LAYare used at the moment of starting.(figIrc -66). When the electrical COMPRESSOR circuit is c:ott.,)te.a. by 'a control device calling for the system to operate, currentpasses through 73.402 the starting relay coil and running winding. The Figure 7-67.Wiring diagram of acompressor- high current drawn by the running windingcauses motor with overload protection.

230 240 Chapter =7SHOPWORK

BLACK LI CABLE LP IAN BLACK LI MOTOR MAIN WHITE SWITCH RUN RED Irt: AUX MAIN Al 581:_:./DOT YELLON oe' YELLOW BLACK AUX. MAIN*? BLACK BR)WN 2 WHITE COMPRESSOR BLACK FAN MOTOR RED BLACI, TERMINAL BOX STARTING RELAY CAPACITOR RELAY HERMOSTAT VERLOAD 1 /ORANGE 7I 4 EXT 5 BLACK OVERLOA START COMPRESSOR CAP WHITE 12 WHITE

73.403 SWITCH POSITION CONTACTS CLOSED Figure 7-68. Air-conditioner diagram with one OFF NONE fan motor and hermetic compressor. FAN LI TO 2 HI-COOL LI TO 3 a 4 MED-COOL LI TO 2 a 4 LO-CDOL LI TO Ia 4

1_6 73.405 L I L2 Figure 7-70. Window air-conditioner with starting and running capacitors.

8 FAN MOTOR

with thermal overload protection, starting relay, starting capacitors, running capacitor (on some models), motor thermostat, and unit control switch STARTING (on-off and fan speed). Hermetic compressors, CAPACITOR thermal overloads, and starting relays have been prev!ously discussed. LI Se ( S ISR The choice of starting or runr.ing capacitors of air-conditioners depends on the type and sib,. STARTING START of unit. The thermostat or temperature contro;, WINDING RELAY stops and starts the nornpressor in response to room temperature. Its principle of operation will be discussed later in this chapter. OVERLOAD RUN WINDING 8 In studying figures 7-68 and 7-69, you 2 I C R notice a starting capacitor is used. These o. pacitors are of the electrolytic type and are us0.1 73.404 in motor starting windings to effect an increm Figure 7-69. Schematic wiring diagram of the in starting torque. Starting capacitors ar3 in- air-conditioner in figure 7-68. tended for short andinfrequent compressor 231

2 4 1 CONSTRUCTION ELECTRICIAN 3 8z 2

TROUBLE POSSIBLE CAUSE POSSIBLE REMEDY

UNIT WILL NOT RUN BLOWN FUSE CHECK FOR AN ELECTRICAL SHORT AT WALL RECEPTACLE. BROKEN OR LOOSE WIRING REPLACE FUSE. LOW VOLTAGE CHECK VOLTAGE. VOLTAGE SHOULD BE WITHIN 10% OF THAT SHOWN ON THE UNIT NAMEPLATE. DEFECTIVE UNIT STARTING SWITCH CHECK VOLTAGE AT SWITCH. IF MERE IS PROPER VOLTAGE AT SWITCH, BUT NO CONTINUITY THROUGH IT, REPLACE SWITCH.

FAN RUNS, INOPERATIVE THERMOSTAT IF TURNING THERMOSTAT TO ITS COLDEST SETTING DOES BUT COMPRESSOR NOT START COMPRESSOR (AND ROOM TEMPERATURE IS WILL NOT OPERATE ABOVE 750), BUT SHORTING ACROSS ITS TERMINALS DOES, CHANGE THERMOSTAT. LOOSE OR BROKEN WIRING CHECK UNIT WIRING AND WIRING CONNECTIONS AT THE UNIT S CARTING SWITCH AND AT THE COMPRESSOR. STARTING CAPACITOR FAULTY CHECK STARTING CAPACITOR (IF USED). (IF USED) RUNNING CAPACITOR FAULTY CHECK RUNNING CAPACITOR. RELAY FAULTY (IF USED) CHECK RELAY (IF USED). OFF ON OVERLOAD OR OVERLOAD CHECK FOR OVERHEATED COMPRESSOR OR FOR FAULT DEFECTIVE OVERLOAD. LOW VOLTAGE CHECK VOLTAGE.

UNIT BLOWS FUSES SHORTED OR INCORRECT CHECK UNIT WIRING. UNIT WIRING SHORTED STARTING OR RUNNING CHECK CAPACITORS. CAPACITOR SHORTED OR STUCK COMPRESSOR CHECK COMPRESSOR. COMPRESSOR STARTING CHECK FOR LOW VOLTAGE. CHECK STARTING CAPACITOR DIFFICULTY AND RELAY. INCORRECT FUSE CHECK FUSE SIZE.

73.406 Figure 7-71.Troubleshooting chart for window air-conditioner.

starts. Any operating fault that would cause a Fan motors are usually of two types: split- starting capacitor to remain in the circuit for phase capacitor motor or shaded-pole motor. The more than several seconds could cause its fail- number of fan motor leads will vary, depending ure.Internallyshorted capacitors will causeon the type of motor used. Shaded-pole motors starting trouble and blown fuses; with open- wilt have either two or three leads, depending circuitedstarting capacitors, the compressoron whether the speed winding is incorporated may not run. Running capacitors are used inin the motor, or if a reactor is used to reduce some systems. They are heavy-duty, oll-filled the fan speed.Figure 7-70 shows a circuit capacitors that can remain in the circuit con-with starting and running capacitors. The fan tinuously. Running capacitors also increase start- motor speed is controlled by the motor windings. ing torque and :educe the running amperage by The unit control switch may be a rotating control increasing the power factor. dialorpushbuttontype,depending on the 232 242 Chapter 7SHOPWORK

TEMPERATURE CONTROL CONTACT RELAY COIL E

OVERLOAD HEAT ER 81 DOOR RUN LIGHT CONTACT SWITCH

LINE VOLTAGE

LIGHT START

RELAY L_ CONTACT COMPRESSOR MOTOR 73.407 Figure 7-72. Basic refrigerator wiring diagram. manufacturer. Switching positions such as thosetemperature, the thermostat opens, stopping the shown in figure 7-70 are given in tho manufac- compresso r. turer's instructions. Knowing the switch position Other refrigerators have automatic defrosting, makes troubleshooting the system easier. internal forced-air fans, and panel heating elements. The automatic defrosting can be accom- Troubleshooting charts can be found in most plished by several different methods, depending manufacturer's manuals. These charts are in-on the manufacturer. One method is shown in tended to provide quick reference to the cause figure 7-73. The electric timer clock is preset and correction of a specific fault.(fig. 7-71). to defrost the system every 12 hours. During, this period the freezer fan motor is stopped and HOUSEHOLD REFRIGERATORS the heaters placed around the cooling coils are energized. This cycle lasts about 10 to 18 min- The electrical wir!ng of household refrig-utes, depending on the size of the unit. Most erators may differ considerably from unit to refrigerators have the wiring diagram on the unit, depending on compressor protection, method back of the unit. You should studyit before of defrosting, and extra design features. The troubleshNting the electrical system. simplest form consists of a motor-compressor, Learning the sequence of operation of both light switch, and temperature control (fig. 7-72). the mechanical and electrical components (such as the defrost timing device) will save you time Thetemperaturecontrolor thermostatic and needless disassembly of internal components, switch operates on the expansion and contraction such as heaters placed around cooling coils. Take of a gas-filled bulb. As the temperature in the a few minutes to study each job; it will save time box rises, the gas expands, closing the contacts in the long run. Troubleshooting guides in the on a toggle switch. The hermetic compressionmanufacturer's manual are a big help. The more comes on and the refrigeration cycle begins.you work on a system, the easier it willbe- When the box temperature drops to a preselected come to recognize possible causes of trouble.

243

233 CONSTRUCTION ELECTRICIAN 3 & 2

NOTE: CONTACTS SHOWN IN POSITION AT 115 VOLTS AC. START OF REFRIGERATIoN CYCLE. 60 CYCLE

BUTTER vomovon, HEATER

REFRIGERATOR

REFRIGERATION SOLENOID THERMOSTAT

INTERIO LIGHTS It30- DOOR SWITCH rrerv-v-m____ ( S.P.D.T.) BALLAST PURIFYING LAMP 1\ REFRIGERATOR FORCED AIR FAN

\\\\\ \\\\\\\\\\\\\\\\\\\\\\\\ CHAPTER 8 INTERIOR WIRING

At any Navy base, the electrical system con- and standards, the military has established its sists of three parts: the po'.ver plant that sup- own MILITARY STANDARDS (M1L-STD's) and pliestheelectrical power, thedistribution MILITARY SPECIFICATIONS (MIL-SPEC's). In system that carries the electrical current frommany cases, these requirements are more rigid the generating station to the various buildings,than their civilian counterparts, so that com- and the interior wiring systems that feed theponents can withstand the test of severe en- electrical power to the appliances and equipment vironmental and usage conditions. within a building. As defined here, interior wiring begins at the NAVF AC SPECIFICATIONS point where the distribution systems service leads are connected to the wiring from within CE's are also required to follow the spec- the building and extends through each circuit ofifications issued by the Naval Facilities Engi- the building's interior wiring to the last fixtu-:e neering Command (NAVFAC) whan performing installation. any work involving electrical apparatus, distri- The interior wiring system must meet two buting systems, and wiring. NAVFAC specifica- essential requirements: it must be safe for per- tions, however, are all-inclusive E.nd advise you sonnel and the appliances it serves, and, further, of those /specifications (MIL-STD, federal, or m. stbe capable of serving these appliancescommercial) you must use for particulal appli- properly for as long as necessary. cations. In this chapter, we will discuss your responsibilities in meeting various code and spec- Remember thatspecification., whether ification requirements and a variety of techniques military or civilian, are updated periodically for installing, repairing and maintaining interior and you must check to see that you use the wiring. mret current ones. SPECIFICATIONS AND REQUIREMENTS NATIONAL ELECTRICAL CODE All Navy electrical installations ashore must The NATIONAL ELECTRICAL CODE (NEC) conform t-fa rigid standards and specifications. is prepared and published every 3 years by the As a CE, you must be aware of the requirementsNational Fire Protection Association. Its pur- set by three sources: the Federal Government, poseisto safeguard personnel and buildings which putsout military standards and spec-and their contents from hazards arising from ifications(MIL-STD's and MIL-SPEC's);the the use of electricity. Naval Facilities Engineering Command (NAV- FAC), which writes NAVFAC specifications; and How does this code minimize the dangers the National Fire Protection Association, whichmentioned above? Briefly, the NEC provides: vepares and publishes the National Electrical Code. various methods of wiring and descriptions of materials, MILITARY STANDARDS AND SPECIFICATIONS techniques for wiring design and protection, Although variousindustry and government requirements or general and special equip- agencies have developed many specifications ment, 235 CONSTRUCTION ELECTRICIAN 3 & 2

special conditions and occupancy information, and BRAID BRAID avarietyof tablesand examplesfor TIN calculations. TIN 44,* This wealthof information provides Con- COPPER WIRE COPPER WIRE structionElectricians with astrictly-to-be- RUBBER observed guide that experience has shown will RUBBER minimize electrical hazards to personnel and buildings. Study the NEC closely and learn it RUBBER-COVERED well.Itwill prove useful to you throughout your career as a Construction Electrician. As you advance inrate, you may be required to teach courses on its contents. COTTON BRAID STRANDED INTERIOR WIRING MATERIALS VARNISHED CAMBRIC Every wiring job calls for its own particular type of material. Whether to use rigid, flexible, CAMBRIC-COVERED or thin-wall conduit might be a decision you will have to make. Use the information provided here to become familiar with installation re- COPPER WIRE. COPPER WIRE quirements. Learn to use the proper cable, conductors, and conduit in the correct place. Make sure you are familiar with methods of TWO AYERS OF COTTON bending,joining,andinstalling thevarious PLASTIC materials; and learn to select the proper fittings IMPREGNATED WITH PARAFFIN and accessories that you will need in installing materials. As you are referred to the NEC BELL throughout this discussion, look up the articles PLASTIC-COVERED indicated and get acquainted with the NEC book. It will be your guide on acceptable and safe 73.301 procedures. A good ConstructionElectrician Figure 8-1. Single conductors. takes pride in doing a neat, safe and proper job. Stranded conductor has the advantage of being COND UC TORS more flexible than solid conductor, making it more adaptablefor pulling through bends in Electrical conductors generally consist of conduit. drawn copper or aluminum formed into a wire. Conductors vary in diameter. Wire manu- They provide paths for the flow of electric current facturers have established a numerical system and usually have insulating material (fig. 8-1) called the American Wire Gage (AWG) standard. encasing the metal. The insulation material is Table8ofthe NEC and page 127 of &lig provided to minimIze short circuits andto Electricity, NAVPERS 10086-B, show how this protect personnel. Atmospheric conditions, volt-numerical system eliminates the necessity for age requirements, and environmental and oper-cumbersome circular mil or fraotional inch ating temperatures are factors considered in the diameters when describing wire sizes. Notice selection of the type of insulating material for a that the wire gage numbers Increase from 1 particular job. through 18 as the diameter of the wire decreases. Single Conductors Size, Number, and Ampacity A conductor may coasist of a single solid The wire size most frequently used for interior wire or combination of a number of solid wires wiring is No. 12 AWG, used as a solid copper oon- (stranded) which are not insulated from each ductor. Table 310-17, column 2, of the NEC shows other and share in carrying the total current. the allowable ampacity of a single conductor in

236

2 4 6 Chapter 8 INTERIOR WIRING free air, No. 12 AWG (for types RUW, T, and TW insulation) to be 25 amperes. However, the minute that conductor is not alone in free air, andis placed in a raceway, cable or direct FILLER burial, you can see, by referring to Table 310-16, thatits ampacity is reduced to 20 amperes, ARMOR RUBBER COVERED provided that not more than three conductors are RUBBER WIRES in the raceway or cable. What happens if more COVERED WIRES PAPER than three conductors are in the raceway conduit, or cable? The following informationindicate3 COTTON COVERED BRAID the reduced ampacities for a variety of numbers METALLIC NONMETALLIC of conductors in such a situation. ARMORED CABLE SHEATHED CABLE ( BX ) Percent , rmal Number of ing conductori RUBBER LEAD 4 to 6 COVERED WIRE 7 to 24 25 to 42 60 LEAD 13 and over 50 SHEATHED CABLE

Suppose, now,that you have four tosix RUBBER No. 12 wires in a conduit. The allowable current- COVERED WIRES carrying capacity would be only 80 percent of RUBBER TAPE normal, or16 amps.'2o ensure a current- RUBBER RUBBER carrying capacity of 20 am?s, you would have to PAPER use No. 10 wire, which has a normal current- FILLER capacity of 30 amps, 80 percent of which is 24 WIRE amps. NINSULATED The type of wire used to conduct current from WIRE outlet boxes to sockets in the lighting fixtures is LEAD ARMOR called fixture wire. It is usually size 16 or 18 FABRIC AWG, stranded for flexibIlity. GALVANIZED STEEL TAPE CABLES LASPHALTIMPREGNATED JUTE A cableisan assembly of two or more ARMORED PARKWAY SERVICE ENTRANCE conductors insulated from each other with an CABLE CABLE additional insulating or protective shield formed or wound around the group of conductors (fig. 73.302 8-2). A cable that contains two No. 12 wires Ftgure 8-2. Multiconluctor cables. is known as 12-2;ifit contains three No. 12 wires,itiscalled 12-3. If a cable has twoconductors, insulated with rubber or thermo- insulated No. 14 wires, as well as an uninsu- plastic,with paper orjute insulation wound lated grounding wire, it is referred to as 14-2over the rubber or thermoplastic, and an over- with ground. This cable would contain one blackallbraid covering the combined conductors. and one whiteinsulatedwire. Ifit containsThis type of cable is still found in many places three insulated wires, the third wire isred. either withorwithout abare (uninsulated ground wire. Now, Romex cable is required to Nonmetallic Sheathed Cable have a ground wire. A ground wire is used to ensure the grounding of all metalboxesin the Nonmetallic sheathed cable is usually called circuit,and alsofurnishes thegroundfor Romex, its trade name. It is the cable shown in grounded type convenience outlets. the upper right-hand corner of figure 8-2. At Romex isavailable in sizes 14 to 2 AWG one time, this cable cons.ited of two or threewith 2 or 3 conductors. Sizes 14, 12, and 10

237 047 CONSTRUCTION EL'TRICIAN 3 & 2

are solid wires. Sizes 8 to 2 AWG are stranded fished in walls.It must be secured to boxes conductors to a cable. Romex must be securedwith a squeeze-type connector. Itiscut with atintervalsofnot mcre than 4 1/2 ft and afine-tooth hacksaw, and a fiber bushing is within 12in.ofeach outlet box of fittings, installed .3 veal- the conductors at each cut. except where finished in walls. BX coms in sizes from 14 to 2 AWG and in Innaval installations Romex is used pri- cables containing 1, 2, 3, or 4 conductors. The marily for temporlry wirk, 3uch as on Quonset armor r)nthe cable furn!shes a Jontinuous huts.Civilian contractors,however,useit ground ween boxes, extensivelyfor resiclmtial wiring.The NEC doesnot permit Its use a3 service entrance Flexible Cord cable, in com.nercial garages, in theaters built for more than 200 spectators, !n storage battery A flexible cord is made up of two or more ropms, in any ha2ardous l^cation, or embeddedconductors, each insulated from the other, and in concrete. All connections in Roinex must be usuallyfine-stranded.Flexible cordis usee made at junction or outlet boxes, and saueezefor such purposes as the connection of portable type connectors must he Ised for sPcuring the lamps, tools, and applw.nces; for elevator cables; cable to boxes. and for the connection of stationary equipment in which connections must be frequently inter- In most installations where Romex is per- changed. It m.,st not be used as a substitute for mitted, a ground wire must be used with the fixed wiring;or run through holes in walls, cable to furnish a continuous ground through- ceilings, or floors; or run through doorways, out the circuit. This ground wire is fastenedwindows, or similar openings. It may not be under a scr.ew in each outlet box to which che attachedtobuilding surfaces or concealed cableisconnected. Another way to secure the behind building walls, ceilings, or floors. ground wire is to wrap it backward over the braidin a close wrap and under the Romex Finally, flexible cord may be 1. :ed only in clamp.This makes a very good bond. When continuous lengthsmeaning that sp.:Ices or taps using grounding type duplex receptacles, the in it are forbidden. ground wire can be fastened under the green grounding screw. Insulation

When making bends in Romex, the radius of Electrical conductors areavailable with the bend should be not less than five times the various k;ndsofinsulation such as rubber, diameter of the cable. thermoplastic, varnished cambric and asbestos. Paper, glass, silk and enamel are also used to BX Cable insulateconductors, but with must less frequency than those previously mentioned. BX. an armored metalliccable,isalso used on naval installations for temporary wiring The NEC recommends insulations of various but, unlike Romex, its use in civilian installa- kinds for use in dry, damp, and wet locations. tionsisrestricted. Most city building codes A dry location is one which may become only restrict the use of BX to oil burner control temporarily subjectto dampness or wetness. circuits and the like. A difficulty with BX is the A damp locationrequires mo:sture-resistant fact thatit tends to ground after installation.insulation because It is subject to a moderate Small metal burrs on the armor can, becauE degree of moisture. Underground installations, of vibration, penetrate the insulation ani caussthose in concrete :31abs and masonry, those in a ground. The trouble and expense involved indirect contact with the earth, and those subject clearing a ground behind the wall covering, after to saturation with water or other liquids are a building is finished, can be easily imagined. considered wet locations. Just as humidity affects the choice of insulation for cables, temperature BX, like Romex, must be run continuous isalso a factor to be considered. Different from box to box, with no splicing allowed be- insulations have different maximum temperature tween boxes. It mist be secured at intervals ratings.Check the NEC to be sure you are not greater than 41/2ft and within 12 in. using the appropriate insulstion for the location from each outlet box or fitting, except where and temperatures in which the conductors will

238

"g.. 4 8 Chapter 8INTERIOR WIRING operate. Some examples of the composition of insulation. However,itis not satisfactory for insulation, the locations in wIlich they are used, damp or wet locations, and is limited to a maxi- and their maximum temperatures follow. m of 300 volts.

Type RH is a heat-resistant compound which RIGID CONDUIT will stand higher temperatures than type R. The maximum temparatLire for RH is 167° F. It is Rigidsteelconduit may be either black- used in dry locations. enamel finished,sherardized(zmc-coated by heat), or galvanized. Black enamel and sherard- Type RHW is a moisture-resistant rubber ized are not used much in the Navy, because compound for use where the wire may be subject these types deteriorate in damp locations ol to wet conditions. The temperature when exposed to the elements. The galvanizeu rating is167° F. RHW is used in both wet and type can beinstalledoutside,inside,or dry locations. em`)edded in concrete, even in wet locations. Type RUH is a very high grade rubber com- W!en conduit is installed in concrete, it must pound, consisting of 90 percent grainless rubber be embedded in the concrete, not in a cinder known as latex rubber. This type is often u..4ec bed below it.In some overseas locations, the fordirectburialin dry locations. Maxirmirn conduit mast be given a good coat of red lead temperature rating is 140° F. or asphalt paint as a preservative against corrosion caused by beach sand in the oncrete Common g aries of thermoplastic insulation and/or cl-le 11s in the soil. are type T,ype TW, and type TA. Type T is suitable only for dry locations with maximum Rigid c ,tt comes in 10-ft lengths, threaded temperature of 140° F. Type TW is moisture- on both ends, each length having a coupling on resistant. Again maxim im temperature rating one end for joining lengths together. Sizes range is 140° F. Type TA is a thermoplastic-asbestos from 1/2 in. to 6 in. in diameter. compound which combines the characteristics of type T and type TW, and has a maxim= Cutting and Threading temperature rating of 194° F.Its use is restricted to switchboard wiring. The use of rigid conduit involves a good deal o`. cutting and threading of lengths. It is best to Thermoplastic insulation has the advantages cut with a hacksaw or special conduit cutter. An of long life, toughness, and a dielectric strength ordinaryrevolving wheel pipecutterleaves (that is, a capacity for insulating) equal to thata heavy Inside ridge that is difficult to remove ofrubber.It requires no protective covering andtendsto jam thepassingthroughof over the Insulation. conductors. Always ensure that you make a cut at right angles to the axis of the pipe. Varnished cambric insulationis,in most respects, midway between rubber and paper in Alter the pipe iscut to the proper length, insulating quality. It is more flexible than paper use a reamer to remove all burrs from the butnotasflexible as rubber. Its dielectric insideof the sawed end. T-ie coadult should strength is greater than that of rubber, but not be held in a vise during cutting and reaming. as great as that of impregnated pape,.. Var- ifa regular reamer is not available, a large nished cambric insulation is not adversely af- rattail or half-round Zile can be used to remove fected by ordinary oils and greases. It is made burrs. However, no matter what burring tool in two types: the standard with a black finish, you use,you must get a smooth inside finish and the heat-resisting with a yellow finish. It to allow for passage of the conductors. is used on motor leads, transformer leads, airl high-voltage cables. Its use is restricted to dry The next step is thread-cutting on the cutoff locations. end. For the smaller pipe you use a ratchet- typediethat turns directly with the handle. Asbestos insulation 'las, as the nams im- On larger pipe you use a die with a mechanical plies, the highest capacity for resisting heat. advantagethat is, one on which the die makes Consequently,itis used for temperatures be- onlya part of a revolution when the handle yond the maximum limits set for other types of m&':ces a complete revolution.

239 CONSTRUCTION ELECTRICIAN 3 & 2

A conduit-threadingdie,like a plumber's die, makes a tapered thread, so tha; a coupling starts rattle: loosely but binds hard as it is set up. This tight connection serves two purposes: (1)it makes a watertigit joint, and (2) it makes 0FACTORY-MADE a good electrical connection for a continuous HEAD FOR HICKEY ground throughout the length of the conduit. To ensure a tight connection when it is impossible toscrew a pieceof pipe into a coupling, a special type of split coupling called Erickson CONDUIT coupling is used. Itis 8onT1.1that simflar to a las water-pipe union, but is used without gasket or ground joint. Manual Bending In any conduit job yoa will have to imake bends of various shapes, such as right-angle or 90- degree bends, offsets, and saddles. For smaller 20" pipe this is done with a bendIng tool which is comm_Inly called a hickey.

The procedure illustratedir.figure 8-3 is recommended as one method of making a right- angle bend in a length of 1/2-inch conduit using a hickey. If a 90-degree bend is to be made in a length of conduit at a distance of 20 inches from one end, the electrician must: 1. Mark off 20 inches from the end of the I conduit. 2. Place the conduit hickey 2 inches in front of the 20-1nch mark and bend the conduit about 25 degrees. 23 -1 3. Move the bender to the 20-inch mark and bring the bend up to 45 degrees. 0 STEPS IN MAKING A 900 BEND

4. Move the bender a13out 1 Inch behind the CONDUIT 20-inch mark and bring the conduit up to 70 degrees. 5. Move the hickey back about 2 inne.s 0 SADDLEBEND behind the 20-Inch nark and bring the bend up 73.304 to 90 degrees. Figure 8-3. Bending rigid conduit with a hickey. When bending conduit beyond 90°never make a sudden, sharp bend which may cause flattening the pipe is matched with the chalk diagram as of the pipe. Make a bend in a series of gradual the bendisformed. Conduit in excess of 1 movements. Bend a small amount; then move inchisusually bent by a hydraulic bender. the bender a short distance and bend again. Miscellaneous conduit bends such asthe Hydraulic Bending saddle bend shown in figure 8-3 can be made more accurately if the contour of the bend is A hydraulic bender speeds conduit and pipe drawn with chalk on the floor and the bend in installations b y means of a powerful force,

240 250 Chapter 8INTERIOR WIRING applied smoothly to the pipe, resulting in accurate bend:3 without kinks or damage. A portable hydraulic bender may be operated by a suitable electric motor, or mInually by Q) STEEL CONDUIT PIPE a hydraulic hand pump, A bending ram assembly which can be quickly disconnected completes zimmulilmilfil% -.mmoomummo the unit. For a single conductor whin is not IMINM11111111111111111 IM110111111111111 lead-covered, the bend must have a minimum radius of six times the inside diameter of the %WNW-01011.4 pipe;forlead-covered conductors the radius ofa conduit bend must be at least 10 times the inside diameter of the conduit. Figure 8-4 ® CONDULETS illustrates what is meant by the radius of bend. OUTLET CONDLJIT BOX Making a quick, neat bend is a job that requires WALL a lot of practice. 1111111111:10.1'14,11IINI: Fittings LOCKNUT BUSHING LOCKNUT I )/if BUSHING There are two types of fittings for conduit: the standard size outlet box (fig. 8-5, view 2) DEAD-END CONDUIT IN OUTLET BOX andthejunction orpullbox.The standard outlet box fittings are classified as type F and 73.409 are used normally in exposed installations for Figure 8-5. Rgici conduit and fittings. receptaclesor switches. The junction or pull box fittings are used to provide intermediateBoxes to be used in wet locations mist have points in long conduit runs for pullthrough ofthreaded hubs which theconduit is screwed wire orjunctionsforseveralconduit runs. into.Other accessories are shown in figure Conduit fittings are not permitted in concealed 8-6. The threaded coupling is furnished with installa'.dons where they will not be accessible. each length of rigid 2ondu:t. Standard conduit Boxes used withrigidconduitaresupplied elbowsare manufactured for use where 900 with removable knockouts. Bushings and lock- bends are required. Unions permit the opening nuts are provided for attachment of the conduit ofaconduitatany point without sawing or to the boxes, as shown in figure 8-5, view 3. break;ng the conduit run. Condulets are a convenient way of making bends, especially in conduit which will be exposed to the eleme_its. However, a condulet must never be concealedin a wall or elsewhere, because the cover must always be accessible. Coni.ilets may be used to reduce the number of bends madeina run of conduit.The NEC specifies not more than four 90-degree bends between pull boxes (NEC. article 370-18) but a condulet may be used in p!ice of a pull box. 14 The LB condulet shown in figure 8-7 is very RIGID-CONDUIT BEND convenient for sharp zorners. The LB condulet A-RADIUS OF BEND can be opened at the back to allow the wire to be pulledwithout b!nd,ng against the coniiit B-LENGTH,STRAIGHT PORTION wall. Be sure that covers are set on securely. C-OFFSET TO OUTSIDE For condulets exposed to the elements, place a gasket under the cover to ensure that it is watertight. 73.17 Neatness is a must in bending, conduit work, Figure8-4.Dtmnsiori 1 niultbend. and any other electrical work. Belds which are

241

1 51 CONSTRUCTlON ELECTRICIAN 3 & 2

electrical work. This conduit, as its name im- plies, hasathinner wall than rigid conduit but has the same cross sectional area as rigid 0 CONDUIT COUPLING conduit.Itis available in sizes from 1/2 inch to4inchesindiameter.Allcouplings and connectionsto boxes are threadless and are elther the clamp or comp7ession type. Some common types are shown in figure 8-8. The compression type is waterproof. The Indent and setscrew types are not waterprool. Extreme care /mist be used when bending metallic tubingtoavoid kinking the pipe or (2)CONDUIT ELBOW reducing the inside area. The thin-wall conduit bender (fig. 8-9, view 1) has a cast steel head which is attached to a steel pipe handle approximately 4 feet long. It is used in the field to form thin-wallconduitintostandard and offset bei:ds. Benders are made for each size ofconduit and mast be used only on those sizes for which they are designed. (3)CONDUIT UNION 73.410 Figure 8-6.Rigid conduit accessories. not uniform :letract from the appearance of the job.The method of securing conduit depends on its size and type. A one-hole strap is the type f fastener most frequently used. The manger of fastening depends on the material to which itis fastened. Hollow walls require toggle bolts: coocrete or block walls require a lead anchor set in a drilled hole; steel construction requires a bolt set in a drilled hole.

ELECTRIC METALLIC TUBING (TIEN-WALL OR EMT)

Thin-wall conduit is a metallic tubing which COUPLING INDENT THIN-WALL CONDUIT can be used for either exposed or concealed TYPE FITTINGS

BOX CONNECTOR COUPLING COMPRESSION TYPE FITTINGS

73.18 73.411 Figure 8-7. LB condulet. Figure 8-8. Thin-wall conduit and fittings. 242

2 5 2 Chapter 8INTERiOR WIRING

of more conductors than can be used in the same size of rigid metal conduit but does make wire dulling easier. PVC CONDUIT

90 BEND Rigid polyvinyl chloride (PVC) conduit has 0 been developed by msny m9.nufacturers. Some of the advantages of PVC conduit are: the light handling weight, high corrosion resistance, ease of installation, leakproof joints and easy wire pulling(due to the mirror-like walls). Refer BENDING GROOVE to NEC, articles 347, 514-8, and 515-5 for 0 BENDER installation requirements. Joining PVC

11" Permanent joints are made quickly in PVC conduit by cutting the conduit with a handsaw or hacksaw and removing the burrs with a pocket- CONDUIT knife. The surfaces to be joined are wiped clean TAKE-UP and a light coat of solvent cement is applied totheinsideof thecoupling or fitting and 0 BENDING 11-INCU STUB outside of theconduit.After the conduit is inserted all the way into the fitting, it is given a quarter turn to ensure good distribution of the 73.412 cement. Any excess is wiped off. Figure 8-9. Bending thin-wall conduit. A variety of threaded P VC fittings is avail- To bend conduit, first place the conduit on a able from manufacturers. Their use is covered level surface and hook the end of the bender inarticle 370 of the NEC. Installation ut,ing under the conduit's stub end. Then, with the the solvent-welding technique described in the bending groove over the conduit and using aprevious paragraph, however, is preferred be- steady and continnis force, while firm'y hold-cause thejointsare water- and N,oporproof. ing the conduit and bender with the body, push down on the handle and step on the foot step, Bending PVC bending the condilt to the desired angle. Takeup height is shown In figure 8-9, view 4. You can Bending of PVC conduit is accomplished very cut thin-wall conduit using a 32-teeth-to-the- easily by application of heat from a hot-air, inch hacksaw ',lade, keuptng the cut at right cold-air blower to a section of PVC rigid conduit. angles to thet.A.E: the pipe. Gradual pressure is applied to form the bend desired. When the desired curve is achieved, INTERMEDIATE METAL CONDUIT the cold air from the blower is then applied to set the b.end. Be sure to compensate for any Intermediate metal conduit is a conduit withspring back. Remember, too, that PVC conduit a wall thickness less than rigid metal conduit should be bent on a radius at least 10 times but greater than that of EMT. It uses the same its diameter. standard fittings as rigid metal conduit and has the same general application as rigid metal FLEXIBLE CONDUIT conduit, except thatitmust not be used in hazardous locations. Its lighter we_ght makes Flexible conduit (also called Greenfield) is for easier handling and lower labor units (es-composed of aspirally wrapped metal band timates) than rigid conduit. Because it has thewound on Itself and interlocked so that it makes same outside diameter as rigid metal conduit a cylindrical metal flexible tube of high mechan- of the same size, it has greater interior cross icalstrength.Greenfield can be used in lo- sectional area. This does not permit the usecations where rigid conduit is not adaptable. It 243

2 5 3 CONSTRUCTION ELECTRICIAN 1 & 2 iseasilyfished,reqiIresno elbow fittings, carry a number of conductors from the panel and comes in diame,ters from 1/2 inch to 3to the trough and smaller conduits branch out inches. from the trough to the various circuits. The trough can also be used for feeders from the The only fittings required for G-eenfield areentrance switch to the panelboard. An example sqneezetypefittings for connecting the pipeof how wiring troughs are used Is shown later to boxes. (See fig. 8-10.) A fine-tooth hacksaw when service entrances are discussed. should be used for cutting, and again the cut should be square. BOXES Greenfieldisavailableintwo types: the A box is a container, set flush or nearly standard unfinished-metal type, and a moisture- flush with the wall, floor, or ceiling, into which resistanttypecalledsealtite,which has anthe outlet, receptacle, or switch will be inserted outside jacket of latex or plastic. The moisture- and fastened. A 4-in,octagon box used for resistant type is no: intended for general use, ceiling outlets is show,' in view A of figure 8-11. but only for connecting motors or portableThis boxis made with 1/2-in.or3/4-in. equipmentin damp or wet locationswhere knockoutsthat is, indentations which can be flexibilityof conlections is desired. It mustknooked oat to make holes for the admission be used with connectors approved for the pur- of conductors and connectors. View B shows a pose. 411/16-in,square box used for heavy-duty Installation, sue% as for a range or dryer re- The standardme::.alGreenfieldisused ceptacle. It is made with knockouts up to 1 in. prImrIly forconnecting motors mounted on in diameter. The box in view C is a sectional slidingbases.Itis also used for equipmentor gem box used for switches or receptacles. which cannot be easily wired with rigid con- By loosening a screw you can remove a side dult and requires conduit which can be fished panel, so that two or more boxes can be ganged in walls or between the floor above and ceil- (combined) to install more than one switch or ing below. It is seldom used in wet or hazard- receptacleata location. View B illudtrates oislocationsexcept as expressly permitted a utility (called a handy) box, made with 1/2- by the NEC. or 3/4-in. knookoats and used principally for open type work. The box in view E is a 4-in. WIRING TROUGHS square box with 1/2-or 3/4-in. knockouts, used quite often for switch or receptacle installation. Wiring troughs are useful in any location It is equipped with plaster rings having flanges where a large nurns)er ofconduitsentera of various depths, so that the box may be set panelboard. One large conduit can be used to in plaster walls of various thicknesses. Besides the boxes shown, there are special boxes for switches° when you have more than two switches at a location. These are called conduit gang boxes, and they are made to ac- 0 PLAI N ® PLASTI C-COVERED comintxlate 3, 4, 5, or 6 switches. Each size has a cover made to fit. A celing box may be fastened to a wooden header set between theceiling joists, or it may be fastened to a bar hanger as shown in figure 8-12.

0 COUPLI NGS FOR® COUPLI NGS FOR 0 BOX CONNECTOR The NEC requires that outlet boxes be 1 1/2 FLEXI BLE-STEEL FLEXI BLE-TO- in. deep, except when the use of a box of this CONDUI T RIGID CONDUI T depth"willresultin !njury to the building structure or is impracticable," in which case 73.413 a box not less than 1/2 in. deep may be used. Figure 8-10.dreenfield flexible condait and Switch boxes range in depth from 1 1/2 in. fittings. to a maximum of 3 1/2 in. The 2 1/2 in. depth

244

.5. L1 Chapter 8INTERIOR WIRING sa." .

73.15 Figure 8-11. Type3 of outlet, receptacle and switch boxes. Is the most widely used. The 1 1/2 in. depthfinished wall surface. Wall outlets are to be boxes are used when two boxes in two dif- located the followirg distances above finished ferent rooms happen to o.m.? back-to-back In !low surfaces: duplex receptacles, 12 in.; toggle the wall separating the rooms. switches, 48 in.; wall fan receptacles, 78 in.; overcounter receptacles, 46 in, ,_11 these me.as- Nonmetallic boxes are made of plastic 1/1F."- urements are from the finishcd floor surface terial and are used with nonmetallic-sheathed to the middle of thereceptacle. The usual cable. Many types are available with mountingway to mz'unt a wall borc in a frame wall is on brackets or nailsfor installing directly on a wood header inserted betv.oen studs. timbers in buildings. These boxes are of one- piece construction and cannot be ganged, but For exposed wiring installed in a building readymade 2-gang and 3-gang boxes are avail- after completion of the wall fin'sh, the pro- able.Coanectors arenot needed at the boxcedure for securing boxes varies according to but the cable must be supported within 8 in.the wall or ceilingsurface material. Boxes of the box on new work. are fastened to a wooLl surface with wood screws; for plasterboard or plywood, toggle bolts are better; for concrete you must &ill holes for To locateoutlet,receptacle,andswitch setting lead anchors. boxes you follow the electrical floor plan. As- sume you are working on a new building In which RECEPTACLES all wiring will be c000ealed by wall, ceiling, or floor covering. The NEC requires that the out- Receptacles used in interior wiring are dis- side edges of outlet and awitch boxes without cussed below in the order of their frequency of flush plates NOT be recessed more than 1/4 use. in. below the surface of the finished wall. Boxes A convenience oatlet (fig. 8-13) is a d.iplez having flush plates mu3t not project beyond the receptacle with two vertical or T-slots and a 245 2 5 a CONSTRUCTION ELECTRICIAN 3 Ea 2

sources, break the center tab between the two screw term'nals on each side. Then, wire the same as you would single outlets. Most floor receptaclesaresinglereceptacles with two vertical or T-slots. A rangereceptacle(fig. 8-14) may be a surface type or a flush type. It has two slanted contacts and one vertical contact, and is rated at U) imps. Receptacles for clothes dryers are similar, but are rated at 30 amps. Range and dryer receptz:.eles are rated at 250 volts, and are used with three-wire, 115/230 volts, two hot wires and a neutral. A receptacle for use with an air-conditioner taking 230 volts is mode with two horizontal slots and one round contact for the ground.

SWITCHES For interior wiring you usesingle-pole, 3-way, or 4-way toggle switches. Most of the switches you use will be single-pole, but oc- casionally you will have toinstall a 3-way system, and on rare occasions a 4-way system. Stillanother system of switching, called the 73.16 low-voltage system, is coming into use. Figure 8-12. Ceiling outlet box onbarhanger. A single-pole switch is a one-blade, on-and- off switch which may be installed singly or in multiples of two or more In the same metal box.(Boxes were explained earlierinthis chapter.) In wiring a single-pole switch, connect the colored wires to the two contacts on the switch, the switch being always in series with the hot wire. Figure 8-15 shows a single-pole switch circ;ilt.

CENTER TAB MAY BE BROKEN OFF TO ISOLATE THE TWO SCREW TERMINALS 73.28 Figure 8-13.Duplex convenience outlet. round contact for the ground. This ground is connected to the frame of the receptacle, and is grounded to the box by way of the screws that secure the receptacle to the box. When you desireto have the two outlets 73.29 on a receptacle supplieoy two separate power Figure 8-14. Range receptacle. uLi '1 Chapter 8 INTERIOR WIRING

HOT WIRE

NEUTRAL

NEUTRAL WIRE LIGHT ()URGE re-T

-11. 1 SINGL E POLE 72 SWITCH 3 4 4 wAY SWITCH

SWITCH SWITCH ( A ) 73.24 CA) Figure 8-15. Single-pole switch circuit. TOGGLE UP Ina 3-way switchcircuit there are tw%) NEUTRAL positions, either of which may be used to turn LIGHT SOURCE a light on or off. The typical situation is one HOT in which one switch is at the head of a stair- way and the ther at the foot. Figure 8-16 shows how the circuit functions. t 12 3 4 Terminals A and A' are the common ter- 2 4 WAY SWITCH CE9 minals, andswitch operation connects them 0SWITCH either to B or C and B' and C', respectively. ( ) Either switch will operate to close or open TOGGLE DOWN the circuit, turning the lights on or off. 73.26 By tracing the circuit in figure 8-16 from Figure 8-17. Four-way switch circuit. the source, you can see that the hot wire goes to the 'first switch, through the closed switch (B)isin the UP position and contact is made blade to the other switch by way of the traveler, from point 4 to point 3. The hot wire continues and through this switch to the light. By changing on through the traveler to switch (Ai, and through the position of either of the switches, the cir- position 2 (which is closed) to the light. cuit Is broken. Suppose, now, that you want to turn the light A 4-way switch is an extension of a 3-way offa': 4-way switch (B). By putting the toggle circuitby the addition of a 4-way switch inin OFF (down) position you change the switch serieswiththe:Ivotra paler wires.Figure blades from ppint 1 to 2 and to 4 to points 1 8-17,view A shows how a 4-way circuit isto 4 and 2 to 3. (See fig. 8.7view B.) If you wired. By tracing this circuit from ihe source now retrace the circuit from switch (B) to you observe the hot wire connected to switch switch(A), you willfindthat it goes from (C) passing through position 1, which is closed. ppint 4 to point 1 on switch (B) and through The hot wire continues to point 4 on the 4-waythe traveler to switch (A), where the circuit switch (B). At thts time the toggle on switch is broken by the blade in open position. Most 4-way switches have a wiring diagram on the switch body. Some, however, have the diagram on tile carton the switch is packed in. SOURCE This diagram must be presPrved. If it gets lost you will have to use an ohmmeter or Cr_JOT TRAVELERS batteryto trace the movement of the blades -9 C' SWITCH when you change the position of the toggle. 73.25 Note that 3-and 4-way switches may be Figure 8-16-- Three-way switch circuit. usedassingle-poleswitches,and 4-way 247 257 CONSTRUCTION ELECTRICIAN 3 Sz 2 switches may be useas 3-way switches. Some There isnonecessity for 3-way or 4-way activities may install all small-wattage, 4-way switches, because the switches are connected switches for all lighting circuits, to reduce their inparallel,and the movement of the switch inventories.However, 3- and 4-way switchestoggle in cne direction pulls the relay one way are usually larger than single-pole switches (orfthecircuit)and energizesthelight. A and take up more WI: roam. The size of a movement of the toggle in the other direction switch depends on its ampacity (rated maximum pulls the relay the opposite way (into the circuit) amperage). The ampacit, and maximum allow- and breaks the circuit. able voltage are stamped on the witch, and must be considered when ordering eauipment EXPLOSION-PROOF FITTINGS for the job. In locations specified by the NEC (articles Low-voltage wiring is a switching system 510 through 511)as explosion-hazardous, you which employs a transformer and low-voltage must install explosion-proof fittings. Locations relay. A low-voltage conductor (three No. 18 are classed by number in descending order of AWG wires)isused from the outlet to thedanger: class 1, division 1, highly hazardous; switch box instead of conduit or homex. Someclass1,division2, slightly less hazardous; systems use a master transformer to reduce and so on. the voltage from ?.10volts to 6 voits, but one system_seaa combination transformer.(A As an example of explosion-proofing; in a relayisa protective device which opens a gasoline filling station the pump island is classed circuit when currentinalineexceeds the as class 1, division 1. All condlits in this area ratedvalueof therelay at the outlet box.)must be sealed with a special sealing fitting, A combination transformer ensures that onlyand on rioaduit for lights above the pumps the onelightis affected in case of transformersealing fitting must be located at a height of failure. not leas than 4 ft above the driveway surface. No ;unction boxes (explained in NEC article The transformer-relay comlAnation is in- 370-18) or condulets may be used in the pump stalledintheoutlet box for the light beingarea. Conduilts running from pumps to panels controlled, with the transformer inside the out- in the bulding mist be sealed not less than let box and the relay protruding outside through 18 in. above the building finished floor to avoid a knockout, as shown in figure 8-18. fumes from the gasoline pumps. An approved seal must also beinstalled on any conduit In the low-voltage system c.s many switches entering or leaving a dispensing pump or other as are required can be installed for any given enclosure on the pump island. light, or a master switch can be installed to turn on as many as eight lights simultaneously. Inside the building of a gasoline station the class 1, division 1, space extends 18 in. above the floor. Space above the 18-in, level is classed TO LIGHT NEUTRAL as class 1, division 2. 110 VOLTN je.TO SWITCH Paint spray booths are listed as class 1, 6 VOLT division 1, and therefore all fixtures, exhaust fans, air compressors, or other electrical ap- plianceslocated insuchbooths must be TRANSFORMER explosion-proof, as well as all switches, con- venienoe outlets, and :motor starters. Figure 8-19 shows an explosion-proof fluorescent lighting fixture for installation in a SOURCE paint spray room. In this fixture the fluorescent 'Foos110 VOLT tubes are sealed in a larger glass tube. The foar tube seal ends can .be seen in the figure. 73.27 The ballast (explained in NEC article 410, part Figure 8-18. Low-voltage relay and trans- P) is enclosed in the container above the tube former. seals. -48 258 Chapter 8INTERIOR WIRING =111, 111111

Figure 3-20 shows an explosion-proof incandescent lightingfixture;figure 8-21, an explosion-procy: on-anJ-off switch for lighting. Wnen the interior wiring system has been completely installed, make an overall inspection to be ure that good installation practices have been observed and all connections are correct. While making this check, don't forget neatness. Make surethat ground connections are tight and that ground wire is protected against injury. Be sure that all connectioas in entrance switch and panel-boards are tight. See that all metal noncurrent-carrying parts cf portable equipment are grounded.

INSTALLING THE SERVICE The term "service" means, in general, the electrical system which brings the power from the pole or other point on the powerline to the point in the building from which it is distributed to the building circuits. 73.19 Figure 8-19. Explosion-proof fluorescent fixture.

73.20 73.21 Figure 8-20. Incandescent explosion-proof fix-Figure 8-21. Explosion-proof an-and-off light- ture. ing switch.

249 2 59 CONSTRUCTION ELECTRICIAN 3 & 2

The service for a building consists of two SERVICE ENTRANCE CONDUCTORS parts: the service conductors and the service equipment. The service conductors are divided Service entrance conductorsinthe Navy into service drop conductors and service en- aresingle conductors runinrigidconduit; trance conductors. Ty) SERVICE DRO? CON- incivilian construction they may consist of DUCTORS are run from the pole to the building. an approvee type of service entrance cable. The SERVICE ENTRANCE CONDUCTORS cou- Conductors also must have rubber or thermo- nect the drop conductors at a point outside theplastic insulation, except that a grounded con- building and must be run in rigid conduit to the ductor may be un;nsulateeifthe maximum service equipment inside the bulding. voltage toground of any conductor does not exceed 300 volts. The service equipment consists of circuit breakers, switches, and fuses. This equipment The NEC specifies No. 6 AWG wire as the islocated near the point of entrance of the m!alm.Im size conductor to be used for service supply conductors to a building, and constitutes entrance, exczvt that in special cases and by the main control and means of cutoff for the special permission, No. 8 wire may be used. electrical supply to that building. For a Navy man, special permIssion means thatof higher authority. In civilian wcrk (in most civilian communities the NEC nas been SERVICE DROP CONDUCTORS incorporated into the building laws) means thatofthe community's 'building inspectors. Service drop conductors may consist of an Table 1 of the NEC indicates the maximum approved multiconductor cable or they may be number of conductors of a given size to be used opensingleconductors.Ineither case they in rigid conduit for new work. Let's assume you mast have thermoplastic, rubber,orother are going to use No. 6 wire with Type THWN weatherproof insulation, except that a grau .ded insulation. Using three wires (the norml number conductor may bc uninsulated if the maximum for service entrance) you see that you can use voltageto ground of any conductor does not 1-inch conduit. The conduit mast be continuous exceed 300 volts. The current-carrying capacity from the weatherhead (point where the wires of the service drop conductors must be suf- enter the conduit) to the entrance switch except ficientto ensUre that ample current for thewhen a condulet (fig. 8-22) is used in place of prospective maximum load may be conducted a oend. without a temperaturerisetoa point high enough to damage theinsulation.Obviously, The conductors must be continuous from the the conductors mist also have adequate mechan- weatherhead outsidethe building to the con- ical strength. The NEC specifies No. 8 AWGnections in the entrance service switchmean- wire as the minimum size, except that in special ingthat no splices between these points are cases No. 12 may be used. allowed. However, a connection is permitted, Table 8-1. Circuit conductor wire sizes for various motors

MOTOR SINGLE-PHASE AMPSWIRE SIZEAMPS ATWIRE SIZE:s-PHASE AMPSWIRE SIZE HP AT 110 V (AWG) 220 V (AWG) AT 220 'V (AWG)

3/4 14 12 6.9 14 , 16 12 8 14 3.5 14 1 1/2 20 10 10 14 5 14 2 12 14 6.5 14 - 5 28 8 15 12 71/2 40 6 22 10 10 27 8 15 40 6

250 260 Chapter 8INTERIOR WIRING

4 WIRE SERVICE DROP TO POLE

73.8 Figure 8-22. Service entrance with condulet. when properly enclosed, where an underground service conductor enters a building and is to be extended to the service or meter in another fo7m of approved service raceway or service cable. 73.10 When the service is run underground, the Figure 3-23.-- Entrance switch marked to show conduit must be continuous from the pole or open (OFF) and closed (ON) positions. underground vaulttotheservicesw!tch.If the conduit enters the building through a con-for the circuit breakel: i;ype. A circuit breaker crete floor, a conduit coupling must be :nstalled Is a protective device which automatically opens in the conduit line with the top of the coupling the circuit, rather than burning out like a fuse, flush with the finished floor surface. The ad-when the am7erage exceeds that rated for the vantage of thisis that spare conduits can be circuit breaker. installed in the concrete floor and a plug screwed However, the NEC recommends a minimum into the coupling, making a fit:ch job. Also, if size of 100-amp service for Individual residences. the wiring were to be renv.ved for some reason, An exceptioti '6 that where not more than two the open conduit could be removed from ibe 2-wire branch circuits are installed, a 30-amp coupling and a plug screwed into the same. entrance swItch may be used. No overcurrent device ine.y be inserted in a grounded conductor except a circuit breaker ENTRANCE SWITCHES which will simultaneously open all conductors of the service. EVERY ungrounded conductor A service entrance switch provides a means must be provided with overcurrent protection. of disconnecting the service conductors from the Switches used fo.: entrance equipment must supply source. It may consist of a single man-be of an approved type. An approved type is ually operatedswitch or circuit breaker. Itusually a quick mal.e-and-break type with an must te marked to show whether the contacts interlocked cnier which can't be opened when are in an open (OFF) or closed (ON) position,the switch isin the ON position. The service as illustrated ,in figure 8-23. conductors must be connected to the discon- The neutral conductor must not berun necting device by pressure connectors, clamps, straight through the service switch, without a or other approved means; a solder lug or other means ofdisconnection. Therefore, a screw typeofsolderedconnection cannot be used. or boltedlug on the neutral terminal block should be provided for disconnecting the neutral DISTRIB UTION PANELS conductorfrom theinterior wiringsystem. The NEC sets a minimum size for entrance A panelboard ir defined by the NEC as "a switches at 60 amp for the fuse type and 50 amp singleanel or group of panel units designed for

251

2 6 1 CONSTRUCTION ELECTRICIAN 3 & 2 assembly in the form of a single panel including buses(buses and busways are explainedin articles 354 and 384-21 of the Code) and with or without switches and/or automatic overcurrent protective devices for the control of light, heat, or power circuits of small individual as well as aggregate capacity, designed to be placed In a cabinet or cutout box and placed in or against a wall or partition and accessible only from the front." As a Construction Elect' You will be concerned mostly with the breaker panel for both light and power. (See fig. 8-24.) The t-eaker panel uses a thermal unit built into the switn. The breaker is preset at the factory to opr:- automatically at a predeterm;ned ampere setting. It may be reset to the ON position after a short cooling-off period. Lighting panels are normally evipped with 15-amp single-pole automatic circuit bre:Lters, while the dower panels may have 1- 2- or 3-pole automatic circuit breakers with a capacity to handle the designated .oad. Figure 8-25 shows a typical layout for an entrance switch, lighting panel, and power panel. In most buildings the entrance switch and 73.11 panelboards can be mounted close to each other. Figure 8-24. Lighting panel.

PLYWOOD BACKBOARD 4

:N.

"'Z Ii

TO MOTORS AND CONVENIENCE OUTLETS.

73.12 Figure 8-25.Representative layout for entranoe switch, lighting panel, and power panel.

262 262 Chapter 8INTERIOR WiRING

Whenw:ringabuildingthathas been built NEUTRAL WIRE previously, the best way to mount the switch and panelsis to mount a sheet of plywood for a To understand the purpose of a neutral wire, backing board. The board should be large enough bear in mind that the path traveled by elec- toaccommodateallofthuequipment, be atricity is always from She source around the minimum of 3/4in.thick,and be securelycircuit and back to the source. As the current fastenedtothe wall with wood screws, leadfollows this path, it energizes the fixtures and/ anchors, or toggle bolts, depending on the type or appliances that are connected into the circuit. ofwall. The switch and panels can then beYou can see, therefore, how essential it is to fastenedto the backboard with wood screws. ensure current return. If you are working In a newly constructed Generally speaking, the fixtures can be con- building where only the framework has beensidered as resistances in series with the hot erected,it will be a simple matter to arrange wires. In a balanced circuit, one hot wire carries for a concealed installation. One point to re- the current to the load, while the other carries member is that there are two types of switches it back to the source. and panels. The recess or flush type has a front flange that extends beyond the edges of The neutral wire ensures current return in the cabinet to cover the rough edges around the an UNBALANCED circuit, as shown in figure cabinet where the finish wall has been cut. Also, 8-26. Here there are two hot wires and a neutral. theflushtype switch as a front control forThere are three lamps connected across one hot operating the switch. The surface type switchwire and the neutral, and five lamps connected and panel has a front cover that does not extend across the ther hot wire and the neutral. These 'oeyond the sides of the cabinet, and the switch lam::s occasion a current flow of approximately may be side-operated or front-operated. 1 ampere per lamp. It follows that the flow is 3 amps in one phase and 3 amps in the other In locating panels, yoa must follow certain meaning that the circuit is unbalanced, with an basio requirements. The panels must be placed unbalanced loadof5minus3,or 2 amps. where service and maintenance canbeeasHy If each phase carried three lamps, the cir- performed; they should not block any passage cuit would be balanced. But because there are that is supposed to be open; they must not be in two extra lamps in one phase, the neutral wire a place where they mightbeexposed oorrosive must pick u:pthe extra load and return it to fumes ortodampnvom; anl'theyshould be located as near as possible to the center of the the source. electrical load. Why must the neutral have the same size as the hot w!res? In this case, with all the lamps The circuits controlled at the panelboard m ist on,it must handle only 2 amps, whereas th be clearlyindicated.List them numerically, hot wire in phase B must handle 5 arms. If from top to bottom, with the odd numbers onthe lamps in phase A wre all turned off, the the left. Pt.C.,thislist (called a catalog) in the neutral would have to handle the full 5-amp slot provided forit,as shown in figure 8-24. return from phase IL If possible, provide for extra circuits in the A motorinacircuitusually causes an new panel to accommodate future additions. unbalancedcircuit. A motor operating on 220

PHASE "A" 120V (1-100W (100W CLi)1100%, 209V NEUTRAL 120V wow yloow (1-1)loow (i)ioow PHASE "B"

73,14 Figure 8-26.-Use of neutral wire in unbalancedmutt.

253

(3 `..3 CONSTRUCTION ELECTRICIAN 3 & 2 volts single-paase does not have a nrtral wireunderground water system. If an underground to aid the balance. Therefore, when a motor ofwater system isnot available, driven grounds thistype is connected across two phases, the are used. Grounding systems are further dis- other phase should be given enough extra lighting cussed in chapter 9. load to balance the load as nearly as possible. Perfect balance Is possiblein theory, but not LOCATING AND INSTALLING in actual practice. CONDUCTORS With a 4-wIre system, one neutral wire can When the service switch, panelboaius, and be used for three circuits, proiided the threeconduits have been installed, you are ready to are conaected to oppoGing phases. Never usepull in the wires. The electrical print or plan one neutral wire for two circuits connected to shows the Lumber of wires to be palled into the same phase. each individual conduit. Remember that there must always be a neutral wire in any lighting The NEUTRAL wireinawiring system or convenience outlet circuit. -nust not be confused with the equipment ground wire. The neutral wire should have white or Lighting fixtures and convenience outlets are light grey Insulation; the equipment ground wire, cormected between a neutral and a hot wire, if insulated, will always have green insulation. with the wall switches connected in series with However, an equipment ground wire ma: bs. un- the hot wire. Any solid color except white or insulated. green can be used for the hot wire, except that in switch leg wiring using cable, the return leg In a 4-wire system (fig.8-27), one of the must beblack.The neutral wire is always wires is alwsys a neutral wire, but in a 3-wIre white, and equipment grounds always green, if system there may or may not be a neutral wire. insulated. The accepted wire color code is in In a 3-wire system you may have a 3-phase NEC article 210-5. circuit(3live or hot wires), or you msy hav, a single-phase circuit (2 hot wires and a neutral). Wires are pulled throughconduit with a narrow steel tape called a fish tape. Fish tapes GROUNDING come in various thicknesses; on most Jobs you will use the small 1/8 by 1/16 in. size. The two types of grounds used are tiv".., system ground and the equipment ground. The system Startthistape through the conduit athi ground consists of grounding the incoming neutral outlet box or panelboard, as the case may be, wire as well as the neutral wires of the branch and kee.p pushing the tape until it emerges at circuits.The equipment groundconsistsof the next opening or outlet box. You secure the grounding the metal parts of the :service en-wires to a hook on the fish tape by removing trance, as wl as the service entrance conduit.about 3 in. of insulation from the wires and The equipment groundilso includes grounding bending the bare wires over the hook. Make switchboard frame3, motor, and simlar equip- afew wraps of frictioa tape over this con- ment. nectioa, to prevent the wires from slipping off andtoprovideitsmooth pulling surface. In The usual method of grounding is to attach Rome casetyou may ham to put talo or a lubricant called pulling compound on the wires. the grounding wire to a cold water pipc of theNever use oil or grease for this purpose, because these subrit:i aces will deteriorate the in- 3 PHASE 4 WIRE CIRCUIT sulation.

I I?UV Pullthe tape anO wires back through the 1:!()v conduit.If paseible, have a man at the point ;,() V where the wires enter, to keep out kinks or twists.Where wires pass through an nutlet ()ti v box without being tapped, pull enough wiAt to continue on through without malting a ROWS, to eliminate extra splices in the box or cconing. 73.13 Wien the wires have been pulled in threurit- I.' wire 3-27. r-wl re system. oattheconduit nyeem, oonnect the proper

264 264 Chapter 8IN TERIOR WIRING wires to the various fixtures and outlets. Do inbasements orattics is best protected by any necessary splicing at the same time. During running the wire alongside joists or rafters. splicing, remember that white wires connectWhere wires run across these timbers, you can to white, except for Romex cable switch runs, run them through holes bored in the timbers. and other colors to the same colors. In splicing However, figure 8-29 shows how wire can be joints, always be sure the joint is well soldered run across timbers on a running board. and taped with rubber or friction tapeor, in some places, yai may use a plastic electrical Flexible cords on portable equipment must tape which does not require a cover of friction never be subjected to mechanical strain. They tape. must be kept as short as possible. All cords must be 3-wire, with the third wire grounding Another way of insulating splices is to usethe equipment on one end and terminating at an insulated wire connector, called a wire nutthe grouiding screwina 3-wire grounding (fig. 8-28, view A). You screw this device nto attachment plug. the bare end of a conductor. Wire nuts do not requiretapeiftheconductorendsare cut MOTOR BRANCH CIRCUITS short enough to prevent them from extending outside the nut. As a CE you will frequently have occasion towirein,connect,andservice motors of A wire nut isbut one type of solderless varioussizes and voltages. A motor branch connector.Another typeisshovriInfigure circuit consists of the following elements: cir- view 13 o: figure 8-28. It grips the wires like cuit conductors, overcurrent protective devices, avise,producing such good metal-to-metal means for disconnection, controller, and motor contact thatitis unnecessary to use solder. running protection. Apply the connector to the wires, and then cover the joint with tape. Of course, you must pre- The circuit coniuctors are the wires from pare thewire ends just as you wo,ild for a panelboardtomr.,tor.Overcurrent protective soldered splice. devices protect the motor, controls, and wires against any overloadscaused by grounds or When Installing Homex or BX, make sure shorts. The means of disconnection separates the conductors do not come in -..otitact with metal motor and controls from electricity source when pipes, and see that they are supported properly, adjustment, maintenance, or repair work is being with no sag between supports. Exposed wiringdone. The controller starts, stops, and reverses

SCREW

HEXAGON SOCKET SMALL WIRE TERMINAL

SPLIT BOLT IN!'JLATED SPLIT COLT CCPANECTOR TEST CLIP

73.306 Figure 8-23.Cable and wire connectors. 266 263 CONSTRUCTION ELECTRICIAN 3 & 2

every case the disconnecting device must be one which opens all ungrounded conductors in- stantly. It may also open the grounded wire, provided that it opens all wires simultaneously. It m ist disconnect both motor and controller, and may be installed in the same case with the controller. For portable motors, the attachment plug andreceptacle are sufficient means for disconnection. For stationary motors of 1/8 hp or less, the branch circuit overcurrent device is sufficient. Motor controllers may be manual07auto- matic. For smaller motors a general-purpose switch or circuit breaker may be used. For larger motors and three-phase motors, automatic controllers give better service. An automatic controller can be remotely controlled pushbutton, and formachinerymotorsthe RUNNING BOARD pushbutton can be installed convenient to the operator's station. This type of connection can also be used to interlock different motors, as ina system of conveyor belts. Figure 8-30 shows an interlocking system for three motors. Motor 1 must be running before motor 2 can STRAP EVERY 4IS. be started, and motor 2 must be running before B X CABLE motor 3 can be started. Overcurrent protection devices may be fuses or circuit breakers, used to p:rotect the con- 73.23 ductorsagainst overloads of current greater Figure 8-29. Wires run across timbers on a than normal starting current. Theee devices also running board. protect the m:Itor controller, which cannot}, amperage higher than that which is norn, I. the motor. Motor mining protection ts provided the motor. by overcurrent prote:itive devices which protect motor,controls,and wires againstdamage If fuses are used, one must be n In caused other than by grounds and shorts each ungrounded wire of sufficient a iy t,o The circuit conductors may be feeding current to a motor of less than 1 hp. or to one with hp in the hundreds. The type of insulation used will depend on moisture and temperature conditions, and also on the danger or. mechanical injury. The aize of conductor will be determined on the basis of 126 percent of the full-load current of the motor. Table 8-1 gives you an idea of the wire size for a given motor hp and a given voltage. The disconnecting :neans for most motors is elther a motor circuit sw" oh or an air circuit breaker. It must be 7 .ated within 50 ft of 73.31 and visible from the motor, anc1 must be et:pipped Figure 8-3O.Interlocking controls for throe with a device for locking in OvF position. In mr tors.

4 Chapter 8 INTERIOR WIRING allow for motorstart.ingcurrent. A device 3. You can use either a soldering copper or other than a fuse must be capable of openinga direct flame to sweat the Golder to a splice. all ungrounded wires feeding a circuit. Small-sized wire is best soldered with a copper. Large-size requires a blowtorch or an alcci,o. MOTOR overload protection is required to torch. protect against overload caused other than by a short or ground in the motor branch circuit. Always remember in soldering that you will After a motor has come up to full speed, andnever get the solder to stick unless the bj,lice is operating at its normal rated amperage, the Itselfishot enoagh to melt the solde To equipment driven by the motor, because of adetermine when the splice is hot enough. temporary overload or some ther cause, mayever, hold the solder to the side of the.lice require more power than the rated hp of the OPPOSITE the soldering copper. When the t; ilder motor. To deliver this extra power, the motormelts, the splice is hot enough, and the voider must consume greater-than-normal amperage. will then flow into every crack and hidderIpace. This type of overload can be safely carried for Figure 8-31 shows wrong and right of a short interval, but if it continues too long the soldering a splice. motor will be damaged. Refer to chapter 7, Basic Electri';ity, NAV"- For example: Suppose something causes a PERS 10068-B and Tools and Their Uses, 01AV- fuseina three-phasecircuitto7a1ow. The PERS 10085-B for further information ..,.igarding motor will try to continre running on a single soldering and splicing. phase.Thiswillcausea much higher than normal amperage to flow through conductors and controller. However, a motor current protection device in the motor or controner will REPAIRS AND MAINTEN open all conductors to the motor. Maintenance of buildingsisnecessary tc Automaticcontrollers have such a deviceprevent fire and electrical hazardr a 1 by builtinto the controller. Some small motors have overload devicesbuiltintothe motor. INTERIOR WIRE SPLICES The way you 8pl1ce or "oin corpluctors I.J- gether is one indicaton of your c7anpetency as an electrician. An electrical system Is only a3 good asIts worst splic-:. A good splice must have the same mechanical strength and electrical conductivity as the w.res it joins together. A spliced wire must be as good a conductor as WRONG a continuous wiy.L.).

The best 'trig practice is to run continuous SOLDER wires from th6service box to theoutlets. UNDER NO CONDITIONS SHOULD SPLICES BE PULLED THROUGH CC.Y4D:JIT. SPLICES MUST BE PLACED IN APPROPLIATE ELECTRICAL BOXES. iv:lowing observations appV 0 electrical r Adoring:. 1. Soldering asplicehelpstoprotect it RIGHT from corrosion. 73.261 2. Rosin is the only flux used in sultlo.ringFigure 8-31. Right and wrong ways of solder- oleotrlcal connections. ing a splice.

257 41 RI IA LP I CONSTRUCTION ELECTRICIAN 3 & 2 defective wiring and equipment. The information below provides guidance for the maintenance of interior electrical systems of 600 volts or less. This includes such components as wiring, disconnecting devices, overcurrent protective devices,panelboards, feeders and illumination. WIRING SYSTEMS

Loose wires, poor connections, bare con- ADAPTF; duntors,defectiveconven'enceoutletsand switches, defective attachment cords, and other unsafe conditions should be checkedforand corrected when inspecting interior wiring. Rigid steelor aluminum conduit should be used in hazardous areas or where mechanical protection PLUG of wiring is necessary. The type of wiring provided should be in accordance with Navy spec- 73.413 ifications and the National Electrical Code. Figure 8-32. Plug fuse with tamper-resisting base. DISCONNECTING DEVICES also practically impossible. Circuits supplying Panel connections made by bolts, screws orelectric motors are subject to the momentary clamps should be tightened.Loose or poorhigh current required for motor starting and connections are trouble sources and present awhich blows the ordinary fuse providing normal fire hazard. Properly made connections seldom protection.Timelag fuses are used on these loosen unless subjectedtosevere vibration. circuits. These fuses are available with regular screw bases or tamper-resisting screw bases. Partially closed switches may result in burned The internal construction of the timelag fuse contacts.Switches should be closed with oneis shown in figure 8-33. The heavy fuse link rapid motion so the blades are thrown com- does not open quickly on motor starting currents. pletelyinto the clips or jaws of the switch. An overload heats the thermacontrol inthe If the switch is tight or the contact is too stiff, ruselink causing thesolder to softenand monoxide grease on the blades will help close release the spring at the end of the fuse link the switch. (fig, 8-33. view 1). Since motorstarting currents do notlabclong enough to melt the solder, FUSES the timelag fuse does not open. In case of a short circuit, however, the fuse link blows just as an Fuses commonly foundin interiorwiring ordinary fuse (fig. 8-33, view 2). panels are plug fuses or cartridge fuses. Plug fuses are ratedim 1 to 30 amperes. The base Two kinds of cartridge fuses, ferrule and contactisthe bane alze as a medium-size knifeblade,are shown in figure 8-34. Knife- lamp. This type of fuze has a clear mica window bladecartridge fuses with nonrenewable, re- to show the fuse link or some other means ofnewable and timelag features are shown in indicatingdefective fuse link. A disadvantage of the ordinary plug fuse is that a penny or strip of metal may be placed in the fuse receptacle and held in place with a blown fuse to complete the circuit without giving fuse protection. One type of tamper-resisting base fuse uses an adapter that screws into the fuse receptacle and locks into place (fig. 8-32). The fuse, in turn, screws intotheadapter.The adapter and fuse plug prevent using a 16 to 30 ampere plug fuse in a() to15 ampere adapter, limiting the possi- 73.414 bility c.r overfusing. Bridging a defective fuse is Figure 8-33. Plug fuse with time lag.

268 268 Chapter 8INTERIOR WIRING

SODI200/0 60% 60% 73.415 Figure 3-34. Cartridge ft:9es. figure8-35.The checklist below should be followed when installing or replacing cartridge fuses and blocks:

1. Check the fuse block to make sure the clips are making full contact with the fuse (fig. 8-36). 550/0 55% Improper contacts cause fuses to overheat and may blow at less than rated current. Any pro- 73.417 longed overheating oald destroy the fiber case Figure 8-36. Poor contact between clips and and take the spring tension out of the clips. fuses.

2. Replacetheclipsthat have lost their spring or use clip clamps (fig. 8-37).

3. If the inside of the clip is not bright and clean, brighten it with emery cloth.

iN.L.',1-t:naqmAgWY;4,

73.418 NONRENEWABLE FUSE Figure 8-37. Clip clamps. 4. If the fuse dIes not require considerable pressure to insert it into the clips, insufficient contact pressure is present. Remove the fuse and draw clips together. If enough contact pressure isnot obtained, replace the clips or use clip clamps. RENEWABLE P-USE 5. To test for the degree of contact, insert the fuse in the clips ani try to insert a thin strip of paper between the clips and the blade or ferrule. If paper can be inserted for a short distance, contact is insufficient and the condition must be corrected. TIME LOG 6. Poor contact at any point on thefuseblock 73.416 isjust as bad as poor contact in thefuseor Figure 8-35. Knifeblade cartridge fuses. clips. Be sure the lugs are properly soldered

269

2,6 9 CONSTRUCTION ELECTRICIAN 3 & 2

to wires or cables, that the bolts holding theair gets into the contact surface and heating lugstothefuse block are drawn tight, andof the fuse causes oxidations, resulting in dis- that the screws holding the clips to the :use coloration of surfaces. No matter how much a blocks are tight. Any excessive heating causedfuse is heated,little oxidation occurs if good by poor contactistransmitted to the clipscontact exists. and fuse, destroying the spring tension of the clips and the fiber tube of the fuse. 2. When only one end of the fuse has a badly oxidized contact surface, poor contact positively 7. Check the fuse blocks to make certain thatexistedattheend where thediscoloration the clips are straight and in line. If the fuseoccurred. Oxidation of the bottom contact on a blades aretwisted diagonally or bent out ofplug-type fuse indicates poor contact because line, the condition caused by damaged or mis- the fuse was not screwed down tight. aligned clips has not been corrected. 3. If the washer or end ring on a ferrule- A block having one straight and one bentcontact fuse is burned or partially melted, the clipisnot improved by a fuse with one blade cap was not screwed down tight. twisteddiagonally.Contactin bothclipsis ruined because the twisted blade must be pushed 4. Charred ends of the fiber tubes on non- over, causing both blades to be set into the renewable or renewable fuses always indicate clips at an angle. poor or inadequate contact (see fig. 8-38). The poor contact may be enused by abuse or lack A block with one clip out of line does not of proper attention to fuse clips and fuse blocks. permit enough contact even though the blades When only one end of the fuse is charred, poor may bebentoutof line, because the angle contact existed at the charred end. of one blade is not in line with one of the clips. Ifthefuseispushed into such clips,little 5. Charred ends of the fiber bar of a re- contactIsobtained,because the bent blade newable fuse always indicate poor contact even must be pushed over to getitinto the clip, though the fiber tube is not already charred. causing both bladestobesetat an angle.If poor contactiscontinued, the fiber tube is also sure to char. In replacing a blow:i fuse, keep in mind tue following pointers: 6. Figure 8-39 illustrates fuse links blown under four differentconditions. The first is I. Do not put in a new fuse until the source a result of poor contact; the blow is between of trouble is located and corrected. thereduced portion a.nd the end of the link, The second is a normal blow when contact was 2. Do not replace a blown fuse with one of good;thethirdis also normal, indicating a higher rating before determining the carrying lightoverload.The fourth shows the result capacity of the circuit. Using a fuse too large of heavy overload or short circuit. does not give adequate protection. 7. Figure 8-40 shows blown links in non- 3. Do notinsert fuses on a live circuit renewable fuses. When break occurs in center, becausethecircuit may arc. Arcing causes a burr on the ferrule or terminal, which prevents good contact in the clips. 4. If the inside of the clip or contact of the fuse is not bright and clean, brighten it with emery cloth.

In caseofablownfuse, a check of the following conditionswillaidyou in locating the source of trouble:

1. Portions of the fuse making good ccntact 73..119 will be clean and bright. When contact is poor, Figure 8-38. Charred fiber tubes.

260 270 Chapter 8INTERIOR WIRING

73.420 Figure 8-39. Fuse links blown under various conditions. 73.422 Figure 8-41.Blown link in plug fuse. tripped breakers. An unbalance occurs when one side of a 3- or 4-wire circuit has a greater 73.421 load than the other(fig.8-42). This can be Figure 8-41. Blown links in nonrenewable readily checked by using a clamp-on ammeter fuses. and taking ampere readings when the circuits are loaded.Unbalance can be correctedby a good contact isindicated. Break at one end changing part of the connected load from the is usually caused by poor contact. overloaded side to the lightly loaded side. If this isno': practical, part of the load may be 8. A plug-fuse link blown as shown in fig- transferred to another circuit, or a new cir- ure 8-41 indicates a poor contact and is usu- cuit installed. ally accompanied by discoloration of the bottom contact. The blow should come at the center or upper portion of the link. WIRE 1 FOUR 100- WATT BULBS

OVERLOADS An overload o3curs when the electric load becomes greater than the safe carrying capacity of the wiring or apparatus. Itis usually indicated by frequent blowing of fuses or tripping 2 TWO200-WATT BULBS of circuit breakers and abnormally hot wiring WIRE or equipment. When an overload appears likely, RIGHT. CORRECTLY BALANCED 400 WATTS ON EACH CIRCUIT the load should be checked with an ammeter WIRE 1 ONE100-WATT BULBS to determine the actual ampere load. An ap- iNEUTRAL parent overload may be caused by a partial 00 ground on the circuit. Partial grounds should CNJ be located by ohmmeter or insulation resistance CNJ c\o0 0 0 testing equipment. When an ov)rload Is found, part of the load should be transferred to another circuit or the wiring should be increased WIRE 2 SEVEN 100-WATT BULBS in size to provide adequate capacity. WRONG: CIRCUI1 NOT BALANCED. LOAD BALANCE 100 WATTS ON FIRST CIRCUIT, 700 WATTS ON SECOND An unbalanced load may result in heating c' the wiring and panelboards and blown fuses a. Figure 8-42. Load balancing. 73.423 261 CONSTRUCTION ELECTRICIAN 3 & 2

OPEN CIRCUITS An open circuit exists when oneor more conductorsinacircuitarebroken, burned open, or otherwise separated. Part or all of thelights will be out and the equipment will not operate even though the fuse has not blown nor the circuit breaker opened (see fig. 8-43). CHECK CHECK HERE HERE When an open circuit occurs, chock at the least energized outlet on the circuit for broken or loose connections. If a defective connection MOTOR is found, repair and splice it out or installnew STARTER wire as necessary. CHECK CHECK HERE HERE If the trouble is not visible, usea test lamp totrace the circu't back to the source (fig. 8-44). MOTOR HERE NOTE: For 110-volt motors, usea single CONNECTOR bulb rated from 110 to 130 volts. For 220-volt CHECK INSIDE motors, use one 220-volt bulb or two 110- to RECEPTACLE 130-volt bulbs in series. SHORT CIRCUIT OR GROUND

A short circuit results when two barecon- MOTOR ductors of different potential come in contact with each other. If a hot conductor is making contact wAh some metallic part of the wiring system, such as the conduit (fig.8-45) or a motor frame connected to ground, it is called a ground. A high resistance ground may cause 73.425 current flow without opening a breaker or blow-Figure 8-44. Usinga test lamp at various ing a fuse. points ina motorcircuitto locatea line break. To determine the cause andlocationof trouble in a building wiring circuit, protected open, the circuit is grounded. If the lamp ourns by plug fuses, the following procedure issug- with the neutral closed and goes out when the gested: neutral is opened, a short circuit is indicated. Make surethecircuitis not overloaded. If a short circuit exists, leave the 200-watt Then remove theblownfuseand screw a lamp in the fuse receptacle to prevent the flow 200-watt lamp into the fuse receptacle. If theof excessive current. If the trouble is not dis- lam3 burns atfull brilliancy with the neutralcovered bya quick visual inspection, pull out the plugs of all portable equipment on the cir- OP f:,4 cuit and turn off all wall switches. If the short LAMP', fiukrIN,7, I I LAMP; OUT circuit 1E3 cleared during this isolation process, the lamp in the fuse receptacle willgo out or glow dimly. Do not leave the 200-watt lamp in the receptacle fqier insulating the defective device. Leaving the lamp inthe receptacle will create a low voltage condition. If certain 73.424loadsfor example, mctors areconnected, Figure 8-a13. Open circuit with part of lights they could be seriously damaged by the low out. voltage. 262

47 2 Chapter 8INTERIOR WIRING

BARE WIRE METAL CUNDUIT TOUCHING CONDUIT

GROUND

"411-, .111F ..1111

FUSE BLOWS GROUND

73.426 Figure 8-45. Wire grounded by conduit. If the 200-watt lamp in the fuse receptaclewatts, and light output. Many incandescent lamps continues to burn after all the load is discoluected, are available with life ratings considerably in install a test lamp in the nearest convenience excess of ordinary general service lamps. Some outlet on the circuit. Open the circuit at various have ratings of 5,000 aours or more and some outlet points and observe the lamp. When theeven are guaranteed to burn for 5 years. Use faultysectionof the circuit is disconnected,of these lamps is not recommended because the test lamp will burn dimly. the initial cost is comparatively high and the extendedlifeis gained by reducing the light LIGHTING SYSTEMS output. There are, however, a few rreas where itis necessaryto use bulbs witn a long life. Each lighting installation is designed to pro- Typicallocations include high ceiling audito- duce a specific level of illum;nation adequate riums, exit lights, stairwells, and marker lights for those working in the area. The amount of on towers or fire alarm boxes. For these areas, illumination initially provided starts to decline donot use a spec.al rated lamp. Do use an almost as soon as it is put in opei ation. This ordinary general service lamp whose voltage reduction is caused by dirt on the lamps andrating is higher th-n the circuit voltage, e.g., luminaires, a decrease in lamp lumen output, 130-volt or higher lamps tor 120-volt circuits. and dirt on the room walls and ceilings.Il- By operating the lamp below ,ts rated voltage, lumination shauld be sufficienttoeliminate thelifeisincreased at a sacrifice in light eyestrain, maintain a high level of production, output. For general use, the lamp voltage rating and promote safety and employee morale. nearest theavailablelinevoltage should be used. Incandescent Lamps There are many kinds of incandescent lamps Lightingfixtures are designed for a par- especially designed for placement in variety of ticular lamp eize and type. Many fixtures, how- situations; for exemple, under severe physical ever, were installed in military buildings longconditions (been as vibration or extreme tem- beforethemanufacturers started producing peratures),in inaccessible locations or when higher and higher wattage lamps in ever 'smaller speciallighting effects are desired. Some of envelopes. Consequently,itis possible to usethese typesofincandescent lampS and their much higher wattage lamps than the fixtureuses are: or the circuit can handle adequately. Excessive heat of h'gher wattage lamps can damage the INSIDE-FROSTED LAMPS are used in most sockets,increasefailurerate,and overload fixtures designed for incandescent lamps. The thecircuits.Personnel are cautioned to usefrosted finish reduces lamp brightness and glare. onlythe lamp size(inwatts) recommended CLEAR LAM?S are used in fixtures where forthefixture rather than a higher wattage controlofthelight is required (such as in lamp that may physically fit. reflectors having polished reflecting surfaces and in enclobed gles or reflectors of pris- Incandescent lamps comein a variety of matic glass), particular where concentrated light 'voltage ratings. For most applications, the lamp irrequired, as in high narrow bays. voltage rating nearest the available line voltage ccntrol should be selected. Under this condition, the reflector equipment of the diffusing globe larni3willproduceitsratedvaluesof life,type, where the lamp protrudes through the

263

2 7 3 11=01 CONSTRUCTION ELECTRICIAN 3 & 2 bottom of the fixture, requires WHITE BOWLand a life twice that of regular general service LAMPS. The white bowl reduces the surface incandescent lrmps. They depreciate at a lower brightness and glare from the working surfaces. rate than the general service lamp. The lamp costis considerably higher, however, than a SILVERED-BOWL LAMPS are used prin-general service lamp, and a special fixture is cipallyforindirectlighting and in reflector requi red. equipment. The fixture parts should not touch the lamp as the thermal expansion may cause Fluorescent Lamps the bulb to crack and fail prematurely. There are two principal types of fluorescent REFLECTOR LAMPS, with thereflecting lamps,instant-start and rapid-startpreheat surface inside the lamp are, in effect, a fixture lamps. Both have practically the same physical in themselves. The lamps can lose their ef- dimensions but different internal construction. fectiveness due to the collection of dust andThe type of circuit in which th e lamp should dirt on the exterior. be used is etched on the end of the lamp. The rapid-start preheat lump operates satisfa,torily PROJECTOR LAMPS are installed in indoor with either the preheat or rap:d-s?art circuits. and outdoor display lighting fixtures. They employ It has a very short lamp life in an instant-start a self-contained reflector but have advantage over cdrcuit. The instant-start lamp operates satis- the reflector type since they are suitable forfactorily with an instant-start ballast, burns out extreme temperature conditions and provide more the ballast in a rapid-start circuit, and does accurate light control. not lighiin a preheat circuit. Preheat lamps dominated the field for rally years but are no HEAT AND DRYING LAMPS, available with longer considered a major type. They continue built-in reflectors or with separate reflectors,to be in use, however, particularly in fixtures are an inexpenshe answer to a requirement fo:.using lamps smaller than 40 watts. A typical Instantaneousinfraredenergy. The reflectorpreheat circuit is shown in figure 8-46. Other bulb keeps theinitial cost to a minimum andexamples of circuits for the major types are providesa new reflecting surface with each readilyfound in current manufacturers' pub- new lamp. lications. An example of some circuits is shown In figure 8-47. The 4-foot rapid-start lamp is HARD-GLASS LAMPS, inade of special glass the preferred lamp for most applications. with highresistanceto thermal shock, are effective where rain, splashin g. liquids, insects, Fluorescent lamps are available in a varizty snov.', fixture parts, or hot metallic spray may of colors for decorative use as well as numerous touch the glass bulbs. shades of white for general illumination. The predominant white shade recommended for most VIBRATION SERVICE LAMPS are available officeareasis Cool White. Other shades of that withstand excessive vibration which cannotwhite used for various purposes include Day- be eliminated by flexible fixture mounting. light, Deluxe Cool White, White, Wavm White, ant.,Deluxe Warm White.Daylight and Cool Where the lamp will be subjected to shock, White provide a crisp, cool, business-like at- such as the endofa drop cord or nearmosphere and the warm whites find application machiner: youwill want toselect ROUGH in.restaurants, homes, theaters, and similar SERVICE ',AMPS. With filament supports, these areas. Colored materials will appear more favor- lams can withstand severe shocks without fail- able -under a fluorescent light that containsa ure. high component of the same color. Blue back- grounds improve with the cool whites and day- nfigh-cost replacement areas such as towers,light.Deluxe warm whiks flatter reds while industrial high bays, theater marquees, halls,white and warm wh.ms strengthen oranges and anistairwellsarelightedwith LONG-LIFE yellows. LAMPS. Fluorescent lamps require ballasts to limit QUARTZ-IODINE LAMPS offer a very con- the current andto supply proper voltage to centrated sou'.) of incandescent light with ex- start and to operate the lamps. For general cellent light control characteristics, good color,lighting purposes, the ,ballests also contain a 264 274 Chapter 8INTERIOR WIRING

FIXED BULB FILLED

ELECTRODE WITH INERT COILED ELECTRODE co, i GAS WITH MATERIAL Wt-'(...1 GIVES OFF FRL BI -METAL wHEN HEATED STRIP MERCURY a ARGoN GLOW GAS IN TUBE INSIDE OF TUBE STARTER COATED WITH PH OSP H OR

PIN BALLAST CONTACTS SINGLE LAMP ALUMINUM CIRCUIT CASING STARTER ARC STREAM TAKES PLACE BETWEEN ELECTRODES AFTER STARTER CONTACTS CONTACT STARTER HAVE CLOSED, THEN OPENED STUDS SOCKET ELECTRODE - - - --ARC STREAM LAMP-A. ELECTRODE

GLOW CAPACITOR TOCUT RADIO INTERFERENCE SOCKET SWITCH

BALLAS--rk IRON CORE CHOKE TO 115 V. 1_10010001001) AC LINE .411 L J 73.427 Figure 8-46.Preheat fluorescent lamp and circuit. capacitor to improve posp)r factor. The currentcoating. Long average life(16,000 hours and National Electrical Code requires that all indoor up) is a primary characteristic of most mercury fluorescent fixtures (except those with simplelamps. There will be a different economic life reactanceballasts)must incorporate ballasts for mercury lamps at each installation depending with therma: protection. The thermal protctor on lamp mortality, power cost, equipment and isolates the ballast (and fixture) from the circuit wiring costs, frequency of replacement and cleanin the event of overheating. As a result, damageing of lamps, and other factors. Mercury light- from fires and from leaking compounds should ing is one of the most economical means of be reduced. There are small fuses available lighting high- and medium-bay industrial areas, that can be installed in the fixture to provideparticularly in areas where color rendition is this protection for existing ballasts. notcritical.Small wattage lamps have been introduced, and it is anticipated that future designs will see a more widespread use of these in low- Mercury Lamps ceiling nonindrstrial areas. While the lamp bases are the same size as incandescent lamps, mercury Mercury lamps(fig.8-48)have the best lamps must never be used to replace a burned- maintained light output because the electrodesout incandescent lamp because a ballast must operateat a relatively cool temperature re- be used with mercury lamps. An objectioaaole sulting in less evap3ration of the metals andcharacteristicof mercury lamps is the time oxides. The clear mercury lamp has a betterrequired to reignite (several mlnutes),fter a lumen maintenance than those with phosphor momentary loss of power.

265

0 r7 CONSTRUCTION ELECTRICIAN 3 &

BALLAST

4 -J

A ONE LIGHT, 4 0 WATT, 115 vOLT B TWO LIGHT, 4 0 WATT, 115 VOLTFLUORESCENT CIRCUIT FLUORESCENT CIRCUIT

BALLAST

II (ELLOW

oowwwws".(Vvs,m BLUE 0vvvvvws,"^"Aryvv BLUE

LAMP

-J Lii LAMP

LAMP

CTHREE LIGHT, 40 WATT,115 VCLT FLUORESCENT CIRCUIT

Figure 8-47. Representative fluorescent circuits. 73.35 Metallic-Vapor Lamps Ietallic-vapor lamps resemblemercury- vapor lamps in appearance and havesimilar uses. The initialefficiency andcontrol are better with metallic-vapor lamps thanwith mercury-vapor lamps. In regard to disadvantages, the rate of depreciation is much greater with metallic than with mercury, the cost is higher, and the life expectancy is shorter. High-pressure sodium-vapor lamps are used for highway interchanges, parking lots,and 73.428 high-baaindustrial areas. They are the most Figure 8-49. M..,31.cury lamp. efficient of the light sources in general use

266 2 7 6 Chapter 8INTERI011 WIIUNG in number of lumons produced ;)er watt of elec- INCANDESCENT LAMPS. Line voltage higher tricity.. The relative cost is high, the life ratings than the maximom lamp range will increase the are not well established, and 1 vecial ballast lightoutputbut will shorten lamp life.IAne isrequired. The color isslightly yellowish,voltage below the minimum range will extend lamp life but will reduce light output approxi- Overall Illumination mately 3 percent for each 1 percent in voltage drop. Walls,ceilings,and surroundings are an important part of the overall illumination sys- MERCURY LAMPS. Line voltage higher than tem since they redirect light to the workingthe maximum lamp range will shorten lamp and area.The most efficientlightingsystem is ballast life.Line voltage below the m;nimmu obtained when the fixtures are new and when range wYll reduce illum'nation and may Nmse the walls, ceilings, floors, and furnishings ofuncertain starting. the room are colored with a high reflectanc color. Lighting is, however, only one of many LAM? GUIDES. Tne most common troables factorsthat make up the whole envIroament,encountered with lamp equipment, the piobable While the highestlighting efficiency may be causes, and the suggested solutions are co.itained maintainedinacompletely white roo,n, the in table 8-2. psychological effect of such surroundinge, on the occupants may be less than harmoni.:,..41The use of color In the surroundings, evenfit :,1AINTENANCE means sacrificing lighting efficiency,Isnec- essary forthewell-being ofthe occupants. Ceilings should have the lightest color, pre- Lighting has a great influence on the quality ferably an off-w:Lite. Shiny surfaces should be and quantity of work as well as a direct bearing avoided as they result in glare. M mentioned on employee morale. The necessity for periodic earlier, lighting levels start dropping immedi- attention to the lighting system cannot be over- ately after the installation of the fixtures. Lampemphasized. To prevent progressive deteriora- burnouts and lamp depreciation contribute to tionofthe system, regular maintenance and this but the principal cause is the accumulation prompt repair of any deficiency are essential. ofdirt.Itisnot uncommon to find lighting levels 1/2 the initial values after only a year Maintain t1 required illum'nation intensity or so of operation. The lighting maintenanceby keep:ng lamps, fixtures, and reflective areas program inust include cleaning and painting ofclean and in good repa:r; replacing defective the walls and ceilings in addition to the fixture lamps; and keeping the voltage steady. cleaning schedule. It ir well-- nown that dirt absorbs and masks TROUBLESHOOTING LAMPS light. The progressIve decre. se of light caused by accumullting dirt renders periodic cleaning aslightsources are designed to operate of lighting equipment a neoeseity. The frequency most efficiently and economically at their ratedof cleaning depends largely upon local condi- voltages, special emphasis should be given to tions. Fixtures in air-coaditioned and air-filtered using lamps to suit the voltage of the circuit. rooms. may require cleaning only once a year. Operation within the normal operating range In an atmosphere whichisheavy with dust is desirable, because both overvoltage and an- and fumes, cleaning every few weeks may be dervoltage operations have a determined effect necessary. on the life; efficiency, and economy of the light source. The effect on lamps operated over or The cleaning schedule for a particular in- under their rated voltage range is as follows:stallation should be determined by light ineter readings after the initial cleaning. When sub- FLUORESCENT LAMPS. Line voltage higher sequent foot-candle readings have dropped 20 than the maximum of the ballast range will to 25 percent, the fixtures should be cleaned shorter, lamp and ballastlife.Line voltage again. Readings should be made with the light below the minimum rAlt will reduce illumi- meter at the working surface with the meter nation and may caus .,.uncertainstarting ofreader in the position of the operator or person fluorescent types. using the working surface.

267

2 7 7 CONSTRUCTION E1CCTRICIAN 3 & 2

Table 8-2.-- Lighting .naintenance chart

INCANDESCENT _ {-, , , y I y I A i ',..

1-, Hu 'Ho, -` I- LC,.:.LL AMP, OR L 000 ,Lf-tIII7OELE N I ILOITEN IN SOOKF T, OP _I CORE TERMI- Ii. ' ly: E.ONNE rI IoN'. NA L:, oR REPAIR WIRING 1 ,,o,\,,,,,I A GE MA TSH L AMP PAT 346 10 I. INE VOLT AGI

INURE ASE I. INF_ VOLTAC;E. IIGR) Lamc, IFt utGri VOL TAGE . C .'II L[I CPA,..KET, MA TC LI L AMP RA TING 10 1 INE VOLTAGE

,IN INOORREC I. . .0.,`. ^P ,-", ANC) REDUCE VOLT AGE. REPLACE

. E.SSIVE ViElk . II, LAMP RE "LACE WITH LAMP OF PROPER RA 1 ING.Os!:. ".HOCIN-AB3OPPING DEA :E...

, AM, opt A. A.,./ WA TER CONTACTS LAME' HuLEE, OR H,-,E_ INCL,ZSED. VAPORTIGHT LUMINAIRE E- H0LEI TJUCHE SI lIMINA IRE WA TER VAPOR IS PRESENT. SEAL ,DINT WHERE CONDUIT STEM ENTERS LUMINAIRE . 0SE CORRECT-SIZE LAMP. STRAIGI-E.;':E '',OCKE T FLUORESCENT -- --- ',MPT,'M possIBLE CAUSE REmED) DOE5 NOT ;TART -AMP PINS NOT CONTACTING, OR SEAT LAMP FIRMLY AND CORRECTLY. RE- OH F.l ASHES -'. AND LAMP WORN OUT. OR STARTER PLACE WITH TESTED LAMP. REPLACE DEFECT!VE. OR LOW LINE VOLT- WITH TESTED STARTER. CHECK WITH AGE, OR FAUL I :N CIRCUIT OF VOLTMETER, CHECK WIRING AND LAMP LuMNA IRE HOLDERS. CHECK BALLAST. E.._"TE. A F: ASHING ,_AM" L3LUALLL L:INDICA rEs END ..:E LAMP LIFE LAMP PLICKERs, ARC DEFECT WHICH OCCURS IN ROTH TURN LUMINAIRE ON AND OFF SEVERAL w GC-LES, SoitRLS OR NEW AND OLD LAMPS TIMES. A LL OW A NEW LAMP TO OPE"- F JrIERS ATE A FEW hrluRS FOR SEASONING. RE- MOVE LAMP AND SHAKE ONE END DOWN. REPLACE LAMP IF FLICKER PERSISTS. IF FLICKER IS REPEATED IN NEW LAMP REPLACE STARTER. LAMP STARTS SLOWLY LOW LINE vOLTAGE OR SLOW CHECK WITH VOLTMETER. REPLACE Nos/.I.tart ii aleli STARTER STARTER.

SHORT LAMP LIFE II LOW LINE VOLTAGE. OR LAMPS CHECK WITH VOLTMETER. IrLtearl,, latlarrs do TURNED ON AND OFF TOO aw indicale at rrage. OFTEN. , xrcup:ome /ail a '(eritfeu Ithadred Am.,. other,1,4.1 1000 6000hours.) RACIO INTERFERENCE mAY ORIGINATE FROM OTHER OPERATE RADIO WITH FLLIORESLENT SOURCE RADIO TOO CLOSE TO LAMPS TURNED OFF. MOVE RADIO 9 LAMP-AERIAL LEt.D-IN NOT TO 10 FEET FIRCM LAMP. SHIELD SHIELDED. LEAD= I AND GROUND SHIELD. INSTALL FILTER RADIO OR LUMP AIRE. NOISE FR:Ai EA LLAST IF QUIET NECESSA,)Y, TAKE SPEC!? - PRE- (nn't expect perfect CAUTIOS IN LOCATING BALLAST. IF arrIce I UNIT VERY NCWY, RL'LACE BALLAST. MERCURY LAMP SYMPTOM PR,13ABLE CAUSE REMEDY

LAmP FAILS TO START LAMP LOOSE. TIGHTEN IN SOCKET. LAMP BURNED OUT. REPLACE. LOW VOLT,AGE. INCREASE LAMP VOLTAGE BY CHANGING TRANSFORMER TAP. WIRING FAULT. CHECK WIRING. 1 IGHTEN CONNECTIONS LOW TEMPERATURE. LA,!PS MAY NOT START WHEN TEMPERA- TURE IS BELOW 32° F. FLUCTUATING VOLTAGE. CHECK LINE VOLTAGE. Momentarydips of 10 perreru, or more, often cause light to go out.) LAMP FREQUENCY GOES WIRING FAULT. TIGHTEN CONNECTIONS. CHECK WIRING. OuT SEPARATE LIGHTING CIRCUITS FROM HEAVY POWER CIRCUITS. ANNOYING STROBOSCOPIC CYCLIC FLICKER. WHERE THERE IS A 3-PHASE SUPPLY, EFFECT CONNE,7T LUMINAIRES ON ALTERNATE PHASES. ON SIN.3LE-PHASE, ADD IN- CANDESCENT LUMINAIRES TO THE SYSTEM. 7 8 268 Thapter 8 INTERIM WIRING

Lighting equipment should be washed, not Neglected lamp outages reduce illumination. just wiped off with a dry cloth. Wa Ailing re- If burned-out lamps are not promptly replaced, claims 5 to 10 percent more light than dry wiping illuminationrivaydroptounsafe foot-candle undreducesthepo3sibility ofmarringor levels in a short time, due to outages alone. scratching t.he reflecting surface of the fixtures. In some cases it may be satisfactory and mr., economical to cleun lamp surfaces and fixture To clean rem( vable glassware, reflectors, and interio-,13 only at the time of relamping. Each diffusinglouvers, immerseinasolution of activity most determine whether cleaning is syntheticdetergent cleaner and scrub with a tobe accomplished byelectrical,self-help, soft brush or sponge. When incrustation ts notor custoial service personnel. removedby scrubbing, use No. 0steel wool Burned-out lamps are replaced on reque, to remove dirt film. Rinse in warm clear water To prevent reduced illumination fror;amp out- and dry with a clean cloth. ages:

CAUTION: Do not immerse lamp base or 1. Instruct employees to report burnouts as electrical connections in the cleaning solution. they occur. 2. Replace blackened Dr discolored lamps even Glassware, reflectors, and diffusing louvers though they are still burning, Discoloration inthat cannot be removed should be cleaned as dicates the lamp is nearing !.i%en] of its useful follows: life. Wipe with a :noist cloth or sponge, using a 3. Replace fluorescent lamps ri as they solutionof synthetic detergent cleaner. Whenbegin toflicl,er. A burned-out lu. ,Li a live incrustation isnot rem.lved by sponging, use circuit may cause damage to star..eiA ballast. No.0steel wool to rempve dirt film. Care Blackening at the ends of the tube a:',11-, to should be taken to ensure that shreds of steel t,he base indicates that the lamp ic ,7;t: end wool do not touch the pin contacts or get into of its useful life. the lamp socket. Wipe off excess moisture with a clean cloth. Clean fixture holders and stem 4. In general. replace with the rame typ; hangers with a moist sponge or cloth dampened wattage, and voltage as that of the litnrc reinoved. with synthetic detergent cleaner and wipe dry. Iffrequent burnouts occur, vo/tage iating of Enameled, chrome, aluminum, or silver-plated lamps may be too low. Lamps oE higher wattage reflecting . surfaces that caanot be adequately than called for on lighting design plans should nct cleaned and polished should Ix.: replaced. be used.

" 7 0

269 CEAPTER 9 CENTRAL POWER STATIONS

Since the days of Farad iy,electricity has Table 9-1. Family of Engine-Generators been generated at various power sources. Water- falls, coal, and oil have been used as sources for the colvelsion of their energy into elec.- ALTERNATING CURRENT At present, hydroelectric, steam-turbine, or FREQUENCY 63-HER iZ intema: co ni,ustion engine genet-ators at central power stations generate electricity economically VOLTAGE 120/208 and efficiently I:,ecause of their physicalproximity 120 12"208 2.40/416 to their .-ources of power or custorne:s. Stewn tirbi.iegeneratorsareutilized on PHASE larger Navy shore int,tallations where the prime 1 1 & 3 3 nurpJse of t'ae steam is for heating, or aboard steam-driven ships. WIRES 3 4* 4 Larg...:diesel engines are the kinri inost of you w:11 encounter other than the portable sets FUEL G D G D C, D ci.scussed in this chauter. Maintenance and repair of the intcrnal combustion type are relatively KW easy comparedt.3 the hydroelectric and steam RATING turbine generators. Today nuclear power is looming as a source of electricity. As time goes on, more and more 1.5 X of the electrical energy supplied in the United 3 X States will originate from nuclear power. 5 X 10 X Especially selected CEs are sent to nuclear 15 At Xt reactor schools for special training in nuclear 30 XtXt power generation. CEs operate these plants in 45 certt.:n shor ,... installations forthe Navy. Thorough Y kncv ledge f electricaltheory and practical 50 X Xi- .lity are prerequisites for selectionfor training 75 Xt t. the nuclear power field. Study this book and 100 Xt oL er training material thoroughly if you want to 150 Xt be clnsidered for such training. G -GASOLINE DRIVEN. C -DIESEL DRIVI:01.

As 7 Construction Electrician you will help t -THESE GENERATORS TO PRODUCF EITH-P in the ,callation, operation, maintenance, and 50- OR 60-HERTZ. repair of advanced-base generating equipment. * -PANEL CONNECTIONS PERMIT, AT RATED This equipment is portable and ranges in size KW OUTPUT: 120/208V 3-PHASE 4 -V,IRE, from 1.5 kw to 600 kw. In time of war or national emergency, portable generator equipment will 120V 3-PHASE 3 -WIRE, 120V SINGLE PI-.ASE normally be used at temporary overseas bases. 2-WIRE, 120/240V SINGLE PHASE 3-WIRE. Even in peacetime, portable equipment may be used remote bases. 26.163

2 8 0 1Chapter t -CENTRAL POWER STATIONS

At large, more perm; neW activLies over- nothave timeto set up a centrally located seas, you may have duti asso(Ia: i with the generatingstation.Instead,youwillspot a Installation of large electr'cA power systems. portable plant at each im-dortant location requiring power. Table 9-1lists some of the standard Generating equipment installedat advanced alternating current generators available. These bases is simple, rugged, and reliable. It is alsostandard generators are capable of meeting the flexible in that power can be supplied even after power requirements of advanced bases. part of the plant is darnarzed. It is up to you to take advantage of thes(: cha..acter 7 tics by learning how to install, operate, maintain, and repair DIESEL AND GASOLINE the components of thisekA.r'... plant andits ENGINE SETS distribution system. Roth gasoline and diesel engines are useful You can learn how !)y :,:)plyir,-; the fundamentals as prime movers for generators. Diesel engines of electricity and eleetro -,ics and by observing a are used to drive the larger generators (15 kw few simple rules aad wor1;ing nractices. and higher) because, they are highly reliable in operation, havealowfuelconsumption per horsepower per hour, reduced fire hazard, lower GENi:EATOR EQUIPMENT maintenancecost and longer useful life than the gasoline engine. Gasoline engines are more an over-' as be ie is first established,suitable to supply power and light on an inter- el?ctric power L needel in a hurry; you will mittent or emergency basis. Their initial cost is

AMMETER VOLTMETER EN GINi

CONTROL BOX

3ENERATOR

TOOL AND SPARE ACCESSORY PARTS BOX BOX

73.306 Figure 9-1. --Gasoline engine generator,

271 " 8 1 CONSTRUCTION ELECTRICIAN 3 ea 2

AMMETER

VOLTMETER

GENERATOR VOLTAGE REGULATOR CONTROL 040 err %Nosy Of

-41111._

RECEPTACLES

TERMINALS

TOOL BOX

26.64 Figure 9-2. Representative 1.5-kw., 120-volt, 60-hertz, portable generator set. much less than that of Liesel engines, but main- GENERATORS tenance costs are higher arid their useful life Os short. The 1.5-kw output gener:qor delivers 120 volts single-phase at a frequency of 60 hertz. The one cylinder engine driven generator in Itis a very versatile and widel:used small figure 9-1is about the simplest you'll find in generator because its output is adequme for the an advanced base. It will handle loads up to communications and lighting recr....Jments for 1.5 kilowatts. A starting rope wrapped arounduse in the field. Figure 9-2 shows a 1.5-kor the flywheel is used to start the engine in thegenerator mounted on a base with handl,to same manner as that for small outboard ormake it transportat:e ty two men. Th.:simplicity power lawn motors. of operation is evidenced by asi, gle control consisting of a field rheostat or voltage-regulator Some gasoline-driven generators used by the control to permit adjustment of the vo"tage output. Seabees supply as much as 10 kilowatts of a-cRepresentative 10- and 60-kw generators are power. These may be used as emergency standbys illustrated in figures 9-3 and 9-4. fn.a small central power station. They are skid-mounted, andifequipped with weather- The electrical loads to be supplied, power, proof metal housing, are designed primarily as voltage,phase, frequency and duty cycle re- portable sets for outdoor operation. quirements govern the selection of generating

272 282 Chapter 3 CENTRAL POWER STATIONS equipment.Probableloaddeviation, probable percent or higher.If the load is mare than a life of the installation, availability of fuels, and few hundred feet from the power source, a high availability of skilled personnel are other im- voltage distributioa system is required. portant factors. If several generators are to serve primary Electrical plants at advanced bases serve a distribution systems, they should generate the varied load of lighting, heating, and power equip- same voltage to avoid need for voltage trans- ment, most of which demand power day andformation. The number of phases required by night. The annual load factor (the ratio of average the load may differ from that of the generator. power to peak power) of a well-operated active As loads can usually be divided and balanced base should be 50 percent or more with a power between phases, most generators of a?preclaole factor(explainedlater in the chapter) of 80 size are wound for three-phase operation.

MANUAL COMPARTMENT

CONTROLS 144.4i

AIR CLEANER

RECONNECTION PANEL

TOOL COMPARTMENT GROUND STUD

26.243 Figure 9-3.R ep r esenta ti ve 120/208-volt, three-phase, 4-wire, 60- hertz, portable generator set.

273 t) Q CONSTRUCTION ELECTRICIAN 3 & 2

COOLANT RELAY Fl L LE R BOX

STAT C EXCITER ALTERNATOR OVERSP ED GOVERNOR HYDRAULIC GOVERNOR LECTR IC GOVERNOR OIL TANK CONTROL UNIT

S LAVE RECEPTACLE AUXILIARY FUEL CONNECTION

FUEL SELECTOR 01 L VALVE DRAIN FUEL BATTERY 0 I L PUMPS COMPARTMENT FILTERS 01 L FUEL FILLER FILTERS

26.244 Figure 9-4. Generator set, left front, three q larter view.

CONTROL PANELS Every generator set at an advanced base must ha-e a control panel which may or mu not be a built-in part of the unit. The size of the panel A generator must be set up immediately when and the number and type of controls mounted an advanced base is first occupied, to provide therem will depend on the size of the generator power for temporary lighting, communications, unit and the type of equipment for which the station and other services as needed. If the base is to must supply power. be a permanent one, a central power station For an initial, temporary unit the panel or must be established for control and distributioncontrol board contains all the necessary meters, of electric power toall spaces and services switches, and other devices. For a permanent which are to be located at the base. central power station with two main generators,

274 0 84 Chapter9CENTRAL POWER STATIONS the control panel is a combination of two boards, The air-beater switch is turned off after the one for each main generator unit. This assemblyengine has started.Itis common practice to is known as "switchgear." preheat the large diesel engines for cold-weather Figure 9-5 shows the control panel for a starting.Inone preheating method, an AIR- portable single-generator uuit. Figuie 9-6 .-,hows HEATER PUMP is used in conjunction with the the control ooard of a single generator ina air-hvater switch. Operating this pumpcauses central powerstation.Figure9-7shows theoil t .;low under pressure from the air-heater switchgear unitfora central power stationunit spray nozzle. The ignition system in the containing two diesel-electric plants. air-heater unit ignites the oil spray. The heat The functions of the controls identified infrom this miniature oil burner warms the ingoing figure9-5are given below. charge of air. The STARTER SWITCH controls the starting The ELAPSED-TIME METER indicates the motor.Pushing the starter switch completes num;-)er of hours the engine is in operation. You the circuit between the battery and the starting will record the reading of the elapsed-time meter motor. inthe log.Itis used to determine when the The THFOTTLE normally controls the amount .angine is ready for maintenance or lubrication. of fuel fed into the cylinders of the engine and The OIL-PRESSURE GAGE indicates the therefore controls the speed of the engine. Mostengine oil pressure. A quick look at this gage of the advanced base generating units are equipped tells you the condition of your lubricating system. with a GOVERNOR. The governor is an automatic The normal operating pressure averages about throttle that maintains a constant engine speed by 30pounds per square inch. counteracting changes in load. Thus, the frequency The WATER-TEMPERATURE GAGE indi- output of the generator is kept constant. cates the temperature of the cooling water in The AIR-HEATER SWITCH controls the cur- the engine. The water temperature should read rent to an ignition system in the air-heater unitI60-185°F under normal operation of nonpres- installedintheengine.The air-heater unit suri zed systems. preheats the ingoing charge of air to the cylinders. The BATTERY-CHARGING AMMETER indi- This unit is used only for cold-weather starting. cates the amount of current sent over to the

METER A-C SWITCH VOLTMETER ELAPSED TIME METER

BATTERY CHARGING AMMETER

FIELD RHEOSTAT

VOLTAG FIELD REGULATOR SWITCH RHEOSTAT

VOLTAGE REGULATOR MAIN WITCH

VOLTAGE REGULATOR SWITCH

AIP HEATER FREQUENCY L,WITCH METER THROTTLE

73.53 Figure9-5.Cogtrol panel for singl.) diesel-driven generator unit.

275 o 410 CONSTRUCTION ELECTRICIAN 3 & 2

.S'YNCHRONIZINGLAMPS

AMMETER N Y INOI TO A WATTMET R AmAi R

vle',1144,

ELAPSED TIME METER SOHERTZ 60 HEFerz

VOLTAGE COOUNG FAN MOTOR A -IA RING REGULATOR AY UNIT 31121i.:

VOLtAlle SYNchRONIZINO AMMETER VOLTMETER REGULATOR SW,ITC.:_41, SWITCH SWITCH SWITCH ,_:,...A14XTIrKgE

GOVERNOR MOTDA CONTROL SWITCH MEE poze , rfkerz.1 EN DISCONNECT ITCH

CxCITER FlEuu RHEOSTAT'AV..'4, FIELD SWITCH r -

, 73.64 Figure 9-6. Control board of a single generator in a central powerplant. battery from the charging generator. It akoarmature. In the ON position, the exciter field indicates the amount of current being delivered is connected to the exciter armature. Since the by the battery on discharge. exciter supplies current to the alternator-field coils, the field switch also controls the alternator The FIELD SWITCH controls the output ofoutput. Before the engine is stopped, the field theexciter.In the OFF position, the switchswitch is thrown to the OFF position. This disconnects the exciter field from the exciteraction disconnects the exciter field and at the

276 286 Chapter 9 CENTRAL POWER STATIONS

same time shunts a FIELD-DISCHARGE RE- The VOLTAGE REGULATOR alsoserves to SISTOR across the exciter-field coils. Thefield- controlthe voltage.It makes your generator dischargeresistor absorbs any high voltages watch an easy job. Without the voltage regulator which might result from the quick openingof the it would be necessary for you to changethe field circuit. field-rheostat setting each time the output voltage of your generator unit varied from itsnormal The FIELD RHEOSTAT is a manuallycon- value. The voltage regulator does this foryou trolled variable resistor that is placed in serieb automatically. Like the field rheostat, the voltage with the exciter field.It controls the voltage regulatorisavariable resistance in series output of the exciter. The value of the exciterwith the exciter field. The resistance isvaried voltage detel.mines the amount of excit current automaLl,:allybyacontrol unit. The control flow.i.o: in the alternator field coils. Theamount unittakes changesin generator voltage and of en:iter current, in turn, controls thevoltage converts them to changes in mechanical motion. outpuC the alternator. Thus, when you adjust The changes in mechanical motion will increase the'ie:drheostat,the result is seen as anor decrease the voltage regulator resistance. increase or decrease of the voltage output ofIn this manner the output of your generator is your generator unit. kept at a constant value.

MIt Alt

73.65 Figure 9-7. Switchgear unit for central power station.

277 2 8.7 CONSTRUCTION ELECTRICIAN 3 & 2

The VOLTAGE-REGULATOR SWITCH in the and distribution points thatis,they receive ON position puts the voltage-regulator unit tothe power generated by the system, and dis- work. With the switch Ln the OFF position you tributethesame to the distribu on circuits must use the field rheostat to adjust the voltageleading to the various points of consumption. output of the generator unit. The VOLTAGE-REGULATOR RHEOSTAT is SWITCHBOARD CONTROLS a small variable resistor mounted on the voltage- regulator It is in operation only when the The switchboard instruments should include voltage regulator is in the circuit. The setting an indicating wattmeter to avoid the necessity of the voltage-regulator rheostat determines thefor making numerous ammeter and voltmeter value of voltage kept constant by the voltagereadings to compute power output.If records regulator. must be kept on generator efficiency, a watt- hour meter is also needed. The A-C VOLTMETER indicates the voltage Remember that the voltmeter measures the output of your generator unit. When you adjustvoltage of the bus, not that of any one generator your field rheostat or voltage-regulator rheostat contributing to the bus voltage, :Immeters, how- you will be watching the a-c voltmeter. It will ever, should be connected in series with at least tell you when you have reached the generator's one leadof the output of each generator. If rated voltage output. only a single ammeter is available for measuring The A-C AMr:113TER indicates the currentthree-phasecurrent,itmust be switched to output of your rne...-ator unit. Any overload or the different phases. unbalancing of a line can be spotted with this A group of lamps connected across the bus, i nstrument. and with a cent point grounded, provides a The METER SWITC", is necessary because this particular unit is a three-phase generator. Each position of the switch puts the a-z..voltmeter and the a-c ammeter in a different leg of the three-phaseline. Thus you are able to read the voltage acrossny two legs and the current in any one leg. The OFF position of the switch disconnects the am:neter and voltmeter cc :npletely. file FREQUENCY METER me'3sures the frequency (hertz) of the voltage generated by the alternator. The SYNCHRONIZING LAMPS are used when the generator unit is being paralleled with another generator. The MAIN SWITCH opens or closes the circuit between the generator and the load. Re- member that it doesn't shut the engine off. In most cases the main switch will have a built-in CIRCUIT-BREAKER. This device will automatically open the main switch whenever a continuous overload current appears on the line. All of these meters, switches, and controls mounted on the face of a panel board or switch- gea r unit either control or are r.ontrolled by other equipment located behind the board. For k-STATOR. B-REVOLVING FIELD. example: the ontput cables from the generator are brought to the back of the switchgear and D-POWER RECTIFIER. E-MAIN HEAT SINK. connectedtotheline terminals of the main switch. The load terminals of the main switch are connected to the bus bars. These bus bars 73.337 are bar conductors whi ;IIserve as collection Figure-9-8. Field excitor. 278 288 Cnapter 9CEN1'RAL POWER STATIONS

types which required movable mechanical parts incl electrical contact points.

OPERATION THEORY 00 150° 3000 360° OF SRCR GENERATORS VOLTAGE WAVEFORM AT HEAT SINK (E) Residual magnetism in the field poles (fig. 9-8) will allow the generator to produce approxi- mately3 to 5% of rated voltage. Two of the three phases are tapped to provide a-c for the field excitation. Two power rectifiers (D) change thisto d-c and are mounted on the main heat sink (E). The direct current from the power rectifiers is fed through brushes and slip rings to the field windings (B) and adds to the residual magnetism to increase the output voltage. Since the generator voltage would increase without control in the circuit as shown, a method oflimitingandcontrollingis required. The field rectifier (F) in figure 9-9 mounted on an auxiliary heat sink (H) maintains field current flow when the excitation voltage drops to zero

A-STATOR B-REVOLVING FIELD D-ROWER RECTIFIER. E-MAIN HEAT SINK. F-FIELD RECTIFIER H-AUXILIARY HEAT SINK. J-CONTROLLED RECTIFIER.

73.338 Figure 9-9. Field rectifier. practical meansfordetecting any accidental ground.

STATIC CONTROLS In today'sfieldgenerating plant you will be operating and maintaining Statically Regulated ControlledRectifier (SRCR) geneiators. They vary in size and manufacturer, and require less maintenance, are more compact and lightweight, 73.339 and give better voltage regulation than the older Figure 9-10. Controlled rectifier. 279

LI 8 !) CONSTRUCTION ELECTRICIAN 3 & 2

NO LOAD FULL LOAD

0° 1500 300° 3300 GATE SIGNAL FIELD FIELD SCR 0 4 SCR BLOCKI NG -4BLOCKING VOLT. VOLT.

+ AVERAGE CURRENT +AVERAGE CURRENT 0 73.340 Figure 9-11.Field current. for 600 of fieldrotation. This current flow is VOLTAGE CONTROL CIRCUIT due to the collapsing magnetic field which represents stored electrical energy. The voltage buildup relay (L) in figure 9-12 appliesa positive voltage to the gate of the The silicon controlled rectifier(J)in the rectifier (J) and turns it on when the generator field circuit(figs.9-9 and 9-10) provides the is being started. The closed contacts apply the means of controlling field current, henceoutput positiveheat sink (E) voltage to the gate of voltage. This rectifier will not conduct until a the SCR. positive voltage is applied to the gate terminal The buildupresistor(BR)isa piece of (G).It has to be turned on every cycle since nichrorne wire on tie relay socket base. the 60° time that the voltage is zero turns it Blocking diode (BD) protects the rectifier offat the end of every cycle. The pulses of(J) from failure in case the power rectifiers current form an average value of current which (D) short. maintains the generator at rated voltage. The relay contacts open when the generator reaches 60%of the rated voltage. The regulator The field current is turned on during each assembly (X) controls the rectifier (J) after the cycle (fig.9-11). At no load the silicon con- voltage builds up. trolled rectifier (SCR) allows little current to Regulator Assembly (X) turns on the rectifier reach the field. At full load the SCR allows (J)every cycle (60 times per second) to allow a larger current to reach the field. field current to flow. The amount the regulator assembly allows current to flow depends on the generator load. The regulator assembly changes WARNING the amount of field current flowing by turning on the rectifier (J) sooner oi later in the cycle. When a statically regulated controlled recti- The regulator assembly contains a voltage fiergeneratorisrunning, donot touch the level sensing circuit and a SCR triggering circuit. aluminum heat sink assembly on the back of theThe triggering cir3uit does the actual triggering chassis as it is electrically charged. The recti- of the SCR but the voltage level sensing circuit fier may be damaged if metal contact is madetellsthe triggering circuit when to turn the between the heat sink and the generator frame. SCR on.

280 290 Chapter 9 CENTRAL POWER STATIONS

The voltage level sensing circuitin figure 5. Voltage droop transformer (T) providesthe 9-13 which feeds a signal intothe regulator additionalcontrolcircuit voltage required to assembly (X), contains the following parts. produce the desired voltage droop whenoperating in parallel. 1. A voltage level potentiometer (N) provides a means of adjusting the voltage level. The 6. Voltage droop potentiometer (U)controls voltage level is changed by adjustingthe amount the amount of voltage droop added to the of voltageapplied to the regulator assembly regulator. through the isolation transformer (P). By sensing the generator field current,the regulator gain control(S)holds the generator 2. Sensing reactor (M) makesthe regulator voltage constant as the engine speed droopsfrom circuit indeperden1 of generator frequency.The no load to full load. The generator field current regulator responds no.v at the samerate as the produces a voltage droopacross the regulator engine governor. gain resistor(R) and the gain control isin parallel with the resistor. 3. Isolation transformer (P) isolatesthe reg--- The noise suppression assembly (V)elimi- lator assembly from the reEt of thegenerator. nates the radio static produced by the generator. The noise suppressor has coils in serieswith 4. Filter choke (Q) increases the. stabilny the lines and capacitors connected to ground.An of the regulator assembly by smoothingout the additional surge suppressor is connectedacross voltage that the voltage sensing circuitsends the field rectifier (F) to protect it fromshcrt to the triggering circuit. high voltage pulses.

T2 :TOT3:I VOLTAGE SENSING

X CIRCUIT TRIGGERING CIRCUITS

D D

' 2-2" PIECES OF NICHROME

A-STATOR F-FIELD RECTIFIER BD-BLOCKING DIODE B-REVOLVING FIELD H-AUXILIARY HEAT SINK BR-BUILDUP RESISTOR D-POWER RECTIFIER J -CONTROLLED RECTIFIER X-REGULATOR ASSEMBLY E-MAIN HEAT SINK L-BUILDUP RELAY

73.341 Figure 9-12.Voltage buildup relay. CONSTRUCTION ELECTRICIAN 3 &I2

10 jvv\/__CWN YEL 16 X RED 9 0 % Or' VOLTAGE DROP 9 15

24 22 78°6 40

25 23

C2- FU FU

14 F- 12A 11

-74;AKCDi KC D KC

5 I BD BR

I 3 4

13 CW AAA, S A- S TATOiq L-BUILD-UP RELAY U-VOLTAGE DROOP TRANSFORMER B-ROTATING FIELD M-SENSING REACTOR V-NOISE SUPPRESSION ASSEMBLY D-POWER RECTIFIER N-VOLTAGE LEVEL POTENTIOMETER X-REGULATOR ASSEMBLY E-MAIN HEAT SINK P-ISOLATION TRANSFORMER Y-CONTROLLED RECTIFIER HEAT SINK F- FIELD RECTIFI ER R-REGULATOR GAIN RESISTOR SS-SURGE SUPPRESSOR H-AUXILIAR' HEAT SINK S-REGULATOR GAIN POTENTIOMETERFU-FUSE J-CONTROLLED RECTIFIER T- VOLTAGE DROOP TRANSFORMER KC-KL1P-CEL VOLTAGE SURGE SUPPRESSOR

73.342 Figure 9-13.SRCR control.

The fuses (EC) are extremely fast blowing Instrument Transformers to protect the circuit from high current. The voltage and currents delivered by a gen- The klip-cels(KC)reduce voltage pulseserating system to the bus bars are too high for across the rectifiers. The voltage pulsescould safe operation of most of the switchboard appa- occur when large loads are disconnectedfrom ratus, particularly the switchboard instruments. the generator. Instrument transformers, therefore, are mounted 282 292 Chapte 9 CENTRAL la)\\ STATiHNS on the back of theswit(hbc)arci ;oldonnected The secondary should always be grounded at to the bus bars. Their purpoe is to step (town one terminal, to eliminate static from the meas- the voltages and currentsfedto instruments, uring instrument, and also to protect personnel. relays,voltageregulators,andthelike. Again there is an important safety precaution: the use of transformers, swit,..thboard apparatus NEVER SHO1T-C1HCtiT THE SE CONDAll y OF can be ;nsulated from the high-voltage circuit, A 1)0 TI A Tlt A NS FOR m E H. yet receive enough power to indiL!;ite ;iccurately the voltage, current, and power in the circuit. nchroscopes Transformers used toreduce high current The SYNCHROSCUPEisa phase relation values to the small values required to operatemeter connected so;isto measurethe phase ammeters, or to operate current coils in other instruments, are called current transformers. Transformers whichreducehigh voltagesto smaller voltages required to operate voltmeters or the potential coils of other instruroents are known as "voltage" or "potential" transformers. The primary winding of a current transformer may consist of a few turns around a laminated iron core, or it may, in some cases, consist of the bus bar or cable carrying the line current. The primary winding isalways connected in series with the line. The secondary winding consists of several turns of relatively small wire wound around a laminated core. It is the secondary, of course, thatis connected to the ammeter or other instrument or switchboard device. The current rating of the secondary on pLactically any current transformer is5 anme 2S, rega- -s of the current rating of the prinv.ry. The secondaryofacur:-enttrarioriTer should never be open-circuited while the primary is energized. An open-ciicuited curren: transformer might develop several tao,isandN across the secondary, where there would he only a few millivolts(a millivoltis 0.001volt) if the secondary circuit were closed. This high voltagemight well cause severe, even fatal, shock to the operator. It would in any case break down insulation and destroy the transformer. Hence the invariable rule: NEVER OPEN THE SECONDARY OF A CURRENT TRANSFORMER WHEN IT IS CONNECTED IN THE CIRCUIT. Potential(voltage) transformers have a low current rating. The low side of the transformer is usually wound for 110 volts, and the ratio of turns on onesidetoturnson the other is TO RUNNING TO INCOMING determined bytherating of the high-voltage ALTERNATOR ALTERNATOR side. The primary is connected across the voltage source to be measured, and the secondary is connected to the meter or other instrument or device. The current through the potential trans- 73.54:55 former depends on the load of the meter or other Figure 9-14.--D1al face and wiring diagram of a device. This load is always constant. synchroscope.

283 293 coNSTE iON 11 LLCFRICIAN 3 & 2 ,=.1=1 relation between generator voltage and bus bar is slow, toward EAST ifit fast. The amount voltage when an additional generator is twing put of differencen frequency isi nclicated by the on the line. speed of travel.

With a synch roscope you determine (1) whether BRUSIILESS GENERATORS the frequencies of the alternators are the same or different,(2) whether frequency is constant Figure9-15 showsan elementary ciralit foranappreciable tinv2, and(3)whether or diagram for a brushless generator system. Elimi- not die voltages of both generators are in phase nation of brushes, slip rings, and commutators thatis, whether they reach maximum value at is accomplished by placing a rectifier assembly, the same time. generatorfieldand exciter armature on the rotor. Figure 9-14A shows the dial of a synchro- In the brush type of a-c generator (fig, 9-16), scope, figure 9-14B a wiring diagram of thethe field current is trairs,ferred from the rotat- instrument. Coils A and P are connected to the ing part of the machine to the generator field by incoming generator through a potential trans- the use of commutator, brushes and collector former. Coil C is connected to the bus line. rings. Much time is spent on the maintenance One pointer holds a fixed position at the top of of these components. the dial as shown in figure 9-14. The moving Brushless type rotating exciters (fig. 9-17) elementisattachedtothesecond, movable eliminate the necessity for commutator, collec- pointer.Ifthe frequencies are the same, this tor rings and brushes by applying the a-c output pointer takes a fixed position. With any slight oftheexciter armature tosilicon rectifiers variation in frequency, however, it will begin to connected in a bridge. The d-c rectified output traveltoward SLOW if the incoming generator isthenapplieddirectlyto the field. Since

GENERATOR FIELD RECTIFIERS (ON ROTOR)

EXCITER FIELD (STATOR) OUTPUT LINES (PHASES) EXOTER GENERATOR ARMATURE ARMATURE GENERATOR FIELD ROTOR) (ROTOR)

jm X

RHEOSTAT EXCITER FIELD RECTIFIERS

EXCITER FIELD SUPPLY

73.307 Figure 9-15. Brush type rotating exciter.

284 294 Chapter 9 CENTRAL POWER STATIONS Nall=1111. 'NONNI

PRIME 1 MOVERI

COLL ECTOR FIELD OF RINGS GENERA TOR

73.3G8 Figure 9-16. Hasic brushless generator. all these components are mounted on the rotor, no need exists for brushes, commutator or slip rings, making the entire unit compact, simple, and free of sparking. Maintenance is thus reduced. 26.248 Figure 9-18. Towing and lifting slings. GENERATOR INSTALLATION POWER AND VOLTAGE In setting up the generator try to place the REQUIREMENTS equipment near points of large demand, to reduce thesizeof wirerequired,to hold the line The power and voltage requirements of the losses to a minimum, and to afford adequate load will normally determine the size of the voltage control at the remote ends of the lines. generator to be used. For example, electrical Generators must not be closer than 25 feet to equipment rated at 120 volts, single phase with a load, because of noise, fire hazard, and air a combined power load of less than 1500 watts circulation. can be adequately handled by a gasoline- or Moving the generator may be accomplisheddiesel-driven power plant with a 120-volt, 2- by lifting or pulling (fig. 9-18). The generator wire output rated at 1.5 kw. If the power demand set comes equippet.: with a lifting sling usuallyof the equipment is greater than 1.5 kw, but stowed in the skid on the side of the unit oppo- does not exceed 4.5 kw, a generator rated at site the operator's control panel. 5 kw, 120 volts, with a 2-wire output can be used. The selection of voltage is affected by the size,character, and distribution of the load; length, capacity, and type of transmission and I PRIME 1, ,-- ROTATING distributioncircuits;and size,location, and I MOYER / ELEMENTS connection of generators. Practically all general purposelightingin the United States and at United States overseas bases is 120 volts. The lighting voltage may be obtained from a 3-wire,

3 - PHASE FIELD OF 120/240-volt, single-phase circuit or a 120/208- EXCITER GENERATOR ARMATURE volt, three-phase, 4-wire circuit. Some small SILICON RECTI FIER motors can be supplied by direct current or ASSEMBLY single-phase alternating current at nominally 120 volts. Large three-phase, a-c motors, above 73.309 5 hofsepower, will generally operate satisfac- Figure 9-17. Brushless type rotating exciter. torilyatany voltage between 200 and 240.

285 CONSTRUCTION ELECTRICIAN 38./2

Demand E:ictor VOLTAGE CURRENT IN CIRCUIT WITH NO INDUCTANCE

Electrical loads are generally measured in CURRENT IN CIRCUIT terms of amperes, kilowatts, or kllovoltamperes. WITH INDUCTANCE In general, electrical loads are seldom constant for any appreciable time, but fluctuate constantly. The connected load is the sum Df the rated TIME capacities of allelectrical appliances, lamps, TIME motors, and so on, connected to the wiring of OF the system. The maximum demand load is the L AG greatest value of all connected loads that are in operation over a specified period of time. 26.245 The ratio between the actual maximum de- Figure 9-19.Inductance mai:es current lag mand and the connected load is called the demand behind voltage. factor. If a group of loads were all connected to the supply source and drew their rated loads at the same time the demand factor would be voltage,as illustrated in figure 9-19.If the 1.00. There are two main reasons why the de- voltage and current curves start together, reach mand factoris usually less than 1.00. First, maximum at the same time, and pass through 0 all load devices are seldom in use at the same together, the circuit has a power factor of 1 time, and even if they are, they will seldom or 100%. reach maxim im demandatthesame time. A power factor of 1 or 100% means that no Secondly, some load devices are usually slightly time lagexistsandthat watts equals volt- larger than the minimum size needed and nor- amperes. A 50 percent power factor means that mally draw less than their rated load. watts are only 1/2 the volt-ampere product and that twice as much current is required to produce Power Factor a given amount of power, compared with 100 percent power factor. Power factor (PF) is a ratio or percentage The power factoris illustrated in figure relationship between watts of a load and the 9-20 which shows a railroad car being pushed by productofvoltsand ampPres necessary to a locomotive. If the locomotive were on the same supplythatload. Watts (W), the measure oftrack pushing directly from behind it, all the actual power, is the product of volt and ampere force woulu be useful work. However, if the valuesat any one instant. Volt-amperes, the locomotive is on a parallel track as shown, the measure of volts (E) and current (I) on the line, amount of force may be the same, but the actual is the product of the units, regardless of theirpush on the car is not the same because some time displacement. These productsare alsoforce tends to push the car sideways off the referred to as true power (watts) and apparenttrack. The power output from the locomotive is power (volt-amperes). divided between actual work and the lost force. In other words, real power is less than apparent Power factortrue power power. The situation is similar to that of an apparent power electrical circuit where time lag exists and the watts real or true power is less than the apparent volt-amperes E x I power. For single-phase circuits RAILROAD W= ExIxPForI-E x PF CAR SIDE For 3-phase circuits, the constant 1.73 must PUSH be introduced into the equation. Therefore, LOCOMOTIVE USEFUL MOTION E x PF x 1.73 Inductanceinacircuit lowers the power 26.246 factor by causing the current to lag behind the Figure 9-20. Illustration of power factor.

286 296 Chapter 9 CENTR.A POWER STATIONS

Power loads from drive motors and constant- Installationspecifications are available in current regulators reduce the power factor mostthe manufacturer's instruction manual that ac- because they require large amounts of reactivecompanies eachunit.13e sure to use them. powerintheiroperation. Reactive rower is Consulting your I3uilder about these specifica- appa rent power used by inductive loads, that tions may help cut installation costs and solve is, inductance in a circuit. Other appliances, such piping problems. as welders, may also require reactive power. Loads, such as electric heaters and heating ap- The following hints and suggestions will also pliances, that are due to resistance only do not be helpful. affe:t the reactive power. 1. Consider ventilation when installing the units inside a building. Every internal combustion SHELTERING GENERATORS engine is a IIEAT engine. Although heat does the work, excess amounts of it must be removed if Although advanced base portable generators the engine is to function properly. This can be are designed to be operated outdoors, prolonged accomplished by setting the engine's radiator exposure to wind, rain, and other adverse con- grill near an opening in the wall and providing dltions will definitely shorten their life. If theanother opening directly opposite the unit. In generators are to remain on the site for anythis manner, cool air can be drawn in and the extended period oj time, they should be mounted hotairdirected in a straight line outdoors. onsolidconcretefoundationsand should be These openings can be shielded with adjustable installed under some type of shelter. louvers to prevent the entrance of rain or snow. There are no predrawn plans for sheltersIn addition, when operating in extremely cold for a small advanced base generating station.weather, the temperature in the room can be The shelter will be an on-the-spot affair, thecontrolled by simply closing a portion of the construction of which is determined by the equip-discharge opening. Additional doors or windows ment and material on hand plus your ingenuity,should be provided in the shelter if the plants common sense, and your ability to cooperateare installed in localities where the summer with men in other ratings. Before a Builder cantemperatures exceed 80°F at any time. getstarted on the shelter, you will have to furnishinformation,suchasthe number of 2. Be ,rre to provide enough working space generators to be sheltered; the dimensions of around each unit for repairs or disassembly and the generators; the method of running the generator load cables from the generator to the busfor easy access to the generator control panels. bar ard from the bus bar to the feeder system outside the building; and the arrangement of the 3. Do notallow carbon monoxide gas to exhaust system. collect in a closed room; this gas is extremely poisonous.Discharge theengine's exhaust to Large generator units may have, connected the outdoors by extending the engine's exhaust orattachedtothem, engine equipment thatpipe through the wall or roof of the building. requires extra space and working area. Included Support the exhaust pipe and make certain that in this equipment are: air-intake filters, silencers no obstruction or too many right angle bends for air intake and exhaust, fuel and lubricatingare used. Also, whenever possible, arrange the oil pumps, tanks, filters and strainers, startingexhaust system so that the piping slopes away gear,isochronous regulating governors with from the engine. In this way, condensation will overspeedtrips,safety alarm and shutdown not drain back into the cylinders. If the exhaust devices, gages and thermometers, turning gear, pipe should have to be installed so that loops or and platforms, stairs, and railings. traps are necessary, a drain cock should be An even larger and more complete power placed at the lowest point of the system. All plaat may require separate equipment, such asjoints must be perfectly tight, and where the amotor-driven startingair compressor andexhaust pipe passes through the wall, care must air storage tanks; motor-driven pumps for jacket be taken to prevent the discharged gas from water and lubricatingoil cooling, or heat returning along the outside of the pipe back into exchangers with raw cooling water pumps and the building. Exhaust piping inside the building lubricating oilcoolers;and tanks,including must be covered with insulation capable of with- day-fuel storage. standing a temperature of 1500°F.

287 CONSTRUCTION ELECTRICIAN 3 & 2

ELECTRICAL INSTALLATION througiiout the system, with size 1/0 AWG used for the main ground and for the branch cables. As a CE your prime concern will be with the electrical installation. You will have to insure The preferred grcund is a buried metallic the generator is in good work\ rig order, grounded water piping system. In the absence of such a properly, connected for the proper output voltage, piping system,adriven solid metal rod, a and protected against overloads and shorts when driven metal pipe,oraburied metal plate tied to the load. can be the ground. The ground rod must be at least5/8inchin diameter, the ground pipe at least 3/4 inch. Both must be driven into the GROUNDING earth to a depth of 8 feet or more. The ground plate must have a minimum st rface area of 2 The metal cabinet in which each power panel square feet and be buried at a minimum depth is mounted, and the neutral bus in the switchgear of 4 feet. The rod, pipe, plate, or piping system unit,must be grounded. However, there are is bolted or clamped to the ground lead (one many metal noncurrent-carrying parts of theend of a No. 6 AWG coprer wire). The other distribution system that must be grounded asend ofthislead is connected to the ground well. It is the custom, therefore, to draw up a stud on the generator set. plan or system which will ensure grounding of all metal parts, such as the bases and frames The usual method is to install the preliminary of motors and generators, the steel tanks of dis-featuresofthegrounding system during the tribution transformers,switchgear apparatus, early stages of base construction. Cables must and any other metal parts which might permitbe laid and ground- rods driven before the con- development of an electrostatic field. crete foundations and decks are poured. When the power plant has been installed, the branch Figure 9-21 shows a representative grounding cables are connected at one end ta the equipment plan. The dotted lines represent grounding cables. and at the other end to the main belt of cable The letter "R" denotes the locations of drivenencircling and running through the station. This ground rods. The letter "A" indicates points main cable is earth-grounded at frequent inter- atwhich branch cables are connected to thevals throughout its run (see letter "R" points in equipment. Bare stranded copper cable is used fig. 9-21).

tvAPORATOP EVAPORATOR

C GROUND CONNECTION TO LUB. OIL CT BUILD.NG STEEL a TANK STARTING ABIRECEIVERS AWN/ -7 To-T-4 'Tr tc, x. 1.11

J AIR COM - F 575 KVA DIESEL PRESSOTIS ][CiniZIDIO GENERATOR N91 A MAIN 9ELT o BARE STRANDED t EKE iv. ::gRETI Ti9 ccf: CABLE

ALL 0RANC.HES TO BE .6 RARE COPPER EXCEPT AS OTHERWISE NOTED I 1 375 KvA DIESEL GROuNn METAL C.,A0 N ERATOR N9 3 TEST TO WATER 1 SWITCH GEAR sURRET I RACK 3 KVA

EINE -RANSFORMERS 1 G41I:* Cc II , ,It',1 'CIC II- _a240.2Ark14A WATER ..q --IL SUPPLY LINE 1.1.19 OIL TANK 7POWER PAN LETTERS A. 9. C rEiC INDICATE GROUNDiN0 OETAiLS, EVAPORATOR THIS DRAvv,NO

PLAN OF GROUNDING SY:, E SCALE VS-- I

73.66 Figure 9-21. Representative grounding plan for advanced base power plant.

288

1 9 8 Chapter 9 CENTRAL POWER STATIONS

_Ada

Vi?

t, s A

711111111.,/,

1,71111_,

salto

73.67 Figure 9-22. Equipment and material used for Cadweld process.

One way to connect branch cables to mainbranch cables, at the point of connection. The cables and the main cables to ground rods is by lower part ofthismold has cavities which the use of "ground clamps." However, metalreceive the items to be joined. The upper part clamps tend to corrode, and corrosion causes has a cavity into which first a metal oxide is high resistance (ground resistance must be less poured, and next a starting powder which, upon than 1 ohm). To overcome this problem, thebeing ignited, burns at very high temperature. metal must be cleaned thoroughly and the con- The starting powder is ignited by a spark from nection made very tight. Periodic inspectionsa welder's flint lighter. The resulting reaction of the connections must be made to ensure that in the starting powder melts the metal oxide, resistance to ground does not develop. which flows from the upper recess in the meld A thermit weld process, called the Cadweld into the lower, cools and hardens there, and process, is used on Navy installations to elimi-thus fuses the items to be connected together. natethe problem of developing resistance in Because thereaction occurs quickly and groundclamp connections. No outside source ofwith high thermal efficiency, the process is power or heat is required for this process. The ideallysuitedforjoining copper conductors. equipment includesa mold which is clamped Normally the weld is completed 10 seconds after over ground rod and cable, or over main and the powder is ignited. The short heating process

289 '2 9 9 CONSTRUCTION ELECTRICIAN 3ez 2 helps protect long conductors against insulation of 10coil leads. Each coil lead is identified damage dueto prolonged exposure toheat. by a number stamped on a metal band. Figure 9-22 shows Cadweld equipment and material used to weld a ground conductor to a In a dual-voltage, three-phase generator a ground rod. A is the mold, B is the clam? which voltage is generated in each set of coils, when holds the mold in position, C 'he cartridgethe prime mover is operating at rated speed. containing the powdered met. '.e and theThus, by connecting theexternalcoil leads starting powder, and D is a weld:,iiIntlighter. together in different combinations, you can change Figure 9-23 shows some welds made by thethe voltage output of the generator. The chart Cadweld process. in table 9-2 gives the exact data needed to make these connections for both thre,J-phase and single- GENERATOR CONNECTIONS phase voltage outputs. Let'stake a specific example. Suppose it When installinga power plant that has abecomes necessary to obtain 220 volts single 220/440-volt, 208/416-volt or other dual-voltage phase from a three-phase, 220/440-volt gener- alternator unit, you must connect the armature ator.Checking table9-2 you find that coil coil leads properly to produce the voltage re- leads T2 and T8 are to be connected together quired by the equipment. Take a look at figure and then in turn, connected, through the main 9-24.It shows a dual-voltage alternator unitcircuit breaker, to one of the two load cables. that has been disconnected and removed from a Simrarly coil leads T3 and T9 are to be secured three-phase diesel-driven power plant. The stator and connected, through the main circuit breaker, or stationary armature coils and core are mounted to the other load cable. Leads T5 and T6 are in the frame of the generator. The a-c voltages connected together as common point. Terminal generated in tne coils .are brought through anlugs on theen;.;of each coil lead provide an opening in the pedestal of the frame by meanseasy means of bolting them together. Just be

11111411.11-.

73.68 Figure 9-23. Welds made by Cadweld process.

290 300 Chapter 9CENTRAL POWER STATIONS

-\ GENERATOR FRAME

COIL LEADS STATOR CORE tit

STATOR COILS

COIL LEADS MARKER-LEAD IDENTIFICATION

26.72 Figure 9-24. AlterrvItor coil leads.

Table 9-2. Connections for Three-Phase Generators

REQUIRED VOLTAGE CONNECT LINE LEADS ( ", 01" TO- CONNECT TAPE INDIVIDUALL4

14 10 I? 440-VOLTS, INFfl1,11ASI 12 I', 10 1H 16 10 T9 127/220-VOL TS, TIIRI I. 12 MID I H .. VIAND 19 .. t 4,15, 16, AND 10 FOR NI 11114AI .

220-VOLTS, SINGLI1'HASI, 11 AND 1'9 . HAND 19 .. I', f 6

220A40-VOI IS, SIN(,I I It 12 AND 19, 11i IS 10 16 PHASI 1-WIRI. NI 011/A1 440N01 I I I'MASI-,1 12 1(ri 2-WIR1 10 It

26.169

291 301. CONSTRUCTION ELECTRICIAN 3 & 2 surethatthe connections are thoroughly in- amperes. The first thing you will want to check, sulated with a wrapping of rubber tape followed then,isthe fuse rating in the main switch. by a wrapping of friction tape. Table 9-2 indi- Youwillprobablyfindthat for the original cates that leads T1, T4, T7, and TO are not220-volt, 264-ampere setup, the generator was usedforsingle-phase service. Therefore, toprotected by a 275-ampere fuse. To protect the finish the job, you should individually insulategenerator for its new current rating (132 am- each of these four leads with rubber and frictionperes), you must replace the 275-ampere fuse tape.Figure 9-25A shows you how the con- with one having a 150-ampere rating. nectionsappear on thestator coil diagram. Another thing to consider when reconnecting Figure 9-2511 shows the appearance of the actuala generator is the switchboard ammeter instru- connections. ment thatrecordsthe current output of the unit. Since it is impractical to use an ammeter RECONNECTING GENERATOR LEADS capable of carrying the full-load current, instrument transformers are used. An instrument When you reconnect generator leads to meet transformer reduces the current value to one certain load conditions, you change not only thethat may be safely measured by the ammeter. voltage outputofthe generator but also its Usually, the instrument transformer is designed current rating. These voltage and current changesto reduce the full-load current to a secondary will have an effeet on the operational charac- current of 5 amperes. In turn, the ammeter, teristicsof the switchboard controls and in- which isconnected to thetransformer's struments. Thus, before the generator can be putsecondary, is designed to produce a full-scale intooperation, other changes must be made. deflection with an input of 5 amperes. Since the For example, suppose you have to reconnect ratio between the load current and the current a75-kw, three-phaf3e, 220 volt, generator so intheinstrument transformer secondaryis that it will have an output voltage of 440 volts.practically constant, the ammeter scale can be In the original setup (220-volt output), the genera- calibrated to read a true value of load current. tor was capable of carrying a full-load current of Now, In the example being used, the generator 264 amperes. Changing over to 440 volts, how- had a full-load current of 264 amperes when ever, reduces itsfull-loadcurrent to 132 connectedfora220-volt output. That meant

14 A111,1 P 11111 1o1/ 1,1/1'.11,(11i11.1 I A/ ol1,,100, U /11 131141 14 1 oi,i I Af

II /or 11MP, o MAIN ihr ',if mut Amt

26.73 ro 9-2f)..220-volt, ffingle-pharm connoctionft.

292 302 Chapter 9 CENTRAL POWER STATIONS

CURRENT TRANSFORMERS

_CONNECTION DIAGRA

LEADS FROM STATOR COILS

GROUND CONNECTION

26.75 Figure 9-26. Representative changeover block showing generator and load connecting points. that the instrument transformer induced 5 am- types of voltage regulators they all respond to peres of current in its full secondary winding VARIATIONS IN RATED LINE VOLTAGE. How- when 264 amperes flowed in the line and, as ever, the line voltage is not applied directly a result, the ammeter had a full-scale deflection. to the regulator unit. A potential transformer is On reconnecting the generator for 440 volts, used to reduce the line voltage to a standard however, you reduce the full-load current to 132 value thatis safe for the regulator. The ratio amperes. Unless you alter the instrument trans- of primary voltage to secondary voltage must former connections, full-load current will pro- remain constant if the regulator is to function duceahalf-scaledeflection of the ammeter properlywithin the limits of the generator's which results in a false reading. In this case, rated voltage. Therefore, when the output voltage you must move the instrument transformer wind- ofthe generatorischanged, you must also ing connection from the full-winding position to change the tap connections on the primary of the mid-tap position. However, most switchboard the potential transformer. ammeters have another calibrated scale which Now comes a likely question. To make these makesitunnecessarytoapply a correction changes must you actually dive into the maze of constant when the current range is changed. wiring behind the generator's switchboard and Another possible change in the generator's move leads from one terminal to another?Gen- switchboard wiring concerns the voltage regula- erally no. In a few cases you may have to change tor, whose main purpose is to keep the generated the leads. Most manufacturers have provided a voltage within certain limits regardless of chang- means tosimplifythechangeover from one ing load conditions. Although there are many voltage output to another.

293 303 CONSTRUCTION ELECTRICIAN 3 & 2 1111

One type of changeover device in advanced base generators is shown in figure 9-26. Called FEEDER TO SECTION"A" FEEDER TO a CHANGEOVER BLOCK, it is mounted on the SECTION "B" rearofthegenerator's switchboard (control cabinet). The terminal studs that protrude from the changeover block serve two purposes they MANUAL FEEDER provide a disconnect point between the load SWITCHES cables and the generator coil leads, and they BUS BAR present a convenient means of altering the ope;- PROTFCTOR ating characteristics of the generator'scom- SHIELD ponents without changing the positions of the wires.Noticethateach of the 10 generator stator coil leads is attached to a correspondingly num")ered terminal stud. Rearrangement of the coil leads becomes a simple process of inter- NOTE INTERNAL CIRCUIT BREAKERS MUST BE LOCKED connecting the terminal studs in a definite pattern GROUND ROD CONNECTION by the use of CHANGEOVER LINKS. IN OFF POSIiION BEFORE ANT FOR NEUTRAL AND WORK IS DONE ON GENERATOR CONTROL BOXES Wnen in position on the coil lead term;nal studs,the changeover links also contact othei 26.76.1 studs that are connected to components, such Figure 9-23. Representative ous bar instana- as the current transformers and the potential tion. transformers. Thus, the outputs of these components are also changed automatically. Con- nection diagrams on a nameplate attached to the A newer type of chauzeover board with its changeover block provideinformation on the instructions is shown in fipiTre 9-27. positions of the changeover links for specific Remember that you are r. spons:ble for the voltage outputs. proper operation of the genera tir g unit. There- fore proceed with caution on any reconnection job. Study the wiring diagrams of the plant and follow themanufacturer's instructions to the letter.Before you start the plant and throw MOVE CHANGE BOARD DOWN the circuit breaker, double-check all connections. FOR 120/ 206 V (MATCH ARROWS) BUS BAR There are a number of reasons why sometimes you must use a bus bar when settingup a portable generating station. For one thing, you may not be able to get a generating plant that has sufficient capacity to meet the total power demand of the electrical load. In this case, then, use two or more generating units and collect 20/208 their paralleled outputsat one central point (the bus bar). Or, you may discover that the electrical equipment in the advanced base is scattered in such a manner as to require the use FOR vOLTAGE RECONNECTION, LOOSEN MDUNTING of feeder (branch) lines that can be controlled NUTS (12) AND MOVE CHANGE BOARD UP OR DOWN from a central source. Again, the bus bar is TO ALINE ARROWS INDICATING DESIRED VOLTAGE. the answer. INSTALL CHANGE BOARDI NEW POSITION AND A representative advanced base generating TIGHTEN MOUNTING NU T stationusinga bus bar is shown in figure 9-28 (circuit breakers are enclosed in the generator). Be sure that disconnectsare inserted in the 26.250 installation as shown in figure 9-29. The two Figure 9-27.Reconnection panel. generators are leveled on a concrete pad that 294 304 Chapter 9CENTRAL POWER STATIONS

built over the rack. The canopy will help ensure uninterrupted service and protect operating personnel. GENERATOR LOAD MANUAL SAFETY CONTACTORS DISCONNECT SWITCH Improving Power Factor From your study of basic electricity, you learned that power factor can be improved in parallelcircuitsby aiding capacitors of the propersizein parallel with the load at the N points where improvement .:, needed. How much capacity to adu will generally be figured out for you by someone in operations LOAD or the comnany offic, . CONTACTORS Generally thein -7,t,..ifectivt.location for installation of individuq: ci-pacitor as close to the inductive load as :.ossible. This provides maxirhum power facto,i;orrection from the capacitor back to the source of power. Capacitors shouldbeinstalled where the temperature of the air does not exceed 104° MANUAL SAFETY (40° C). They should always be well ventilated DISCONNECT SWITCH because they always operate at full load and N Li L2 L3 generate heat which must be ren Most power capacitorsare p ,,vided with 26.76.2 fuses which provide protection case of an Figure 9-29. Schematic of bus bar installation. internal short circuit. An accepted method of wiring capacitors is illustrated in figure 9-30, where a separate service switch is used. is sloped for drainage. The electrical output of Capacitors can be mounted on the floor, each generator is transferred underground to the wall or ceiling, depending on the floor space bus bar by four single-conductor cables. The and equipment layout. Most come equipped with bus bar itself consists of four cables stretched mounting brackets, so that they can easily fit between two 4- by 4-inch posts. A secondary into these places. rack mounted on each post serves as an insulating AN IMPORTANT SAFETY PRECAUTION IS support for the bus bar cables. Two switches, THAT A 5 MINUTE WAITING PERIOD MUST one for each feeder line, are mounted above BE OBSERVED BEFORE ANY WORK IS DONE thebus bar. A wooden platform provides an ON A DISCONNECTED CAPACITOR. Since a insulating medium for operating personnel. disconnected capacitor may retain its electrical charge and have full line voltage across its Whether or not the schematic of your busterminals, these terminals must be short cir- bar installation looks exactly like figure 9-29,cuited and grounded before any work is begun. the point to remember isthat the equipment should be properly secured and supported, and where necessary, properly insulated. The size of PREPARING TO OPERATE THE wire will depend on the load current. The switches GENERATOR SET that control the output to each feeder line can be either fused knife switches or circuit breakers. After setting up a portable generator set, Be sure that the current rating of the fuses oryou must do some preliminary work before trip elements will provide adequate protectionplacing it in operation. against excessive overloads or short circuits on the feeder lines. Also that the switch blades INSPECTING THE GENERATOR or breaker contacts are capable of carrying the rated current and voltage of the feeder lines. First make a visual overall inspection of In addition, protect the switchgear and bus barthe generator. Look for broken or loose elec- from the weather by having a weatherproof canopy trical and hose connections, and for loose bolts

295 305 CONSTRUCTION ELECTRICIAN 3 & 2

the proper grade of oil and lubricant. A lubri- SOURCE OFPOWER cation chart in the instruction manual furnished with each generator will show the proper grade of oil to use at the operating temperature. Re- gardless of the air temperature, be sure touse an antifreeze solution in the proportions recommended in the instruction manual for the MAIN DISCONNECT generator. SWITCH The fuel tank should be tine'', with clean fuel oil, strained if necessary. Prime movers of advanced base electric power generators are started by starting units which obtain their power from botteries. If your prime mover is equipped with a battery (or batteries) you have another servicing job to do. Batteries are usually shipped without theelectrolyte, but with the plates ina dry-charged condition. Thus, TO LOAD SEPARATE it is necessary to fill the battery with electro- CAPACITOR lyte. Usually, the electrolyte is shipped right with DISCONNECT thegenerator and isof the correct specific SWITCH AND gravity. OVERCURRENT If you must prepare your own electrolyte, PROTECTION however, consulta mixing chart (table 9-3). Inthiscase, use the specific gravity value recommended in the instruction manual.

CAUTION

'NIDIVIDUAL BE SURE TO ADD THE ACID TO THE WATER S-L-O-W-L-Y, STIRRING CON- PMENT FUSES STANTLY AND THOROUGHLY.

DISCHARGE Table 9-3. Electrolyte Mixing Chart RESISTORS

USING 1.835 USING 1.400 SPECIFIC SPECIFIC 73.343 GRAVITY GRAVITY Figure 9-30. Capacitor installation withover- SPECIFIC ACID ACID cu rrent protection. GRAVITY DESIRED PARTSPARTSPARTSPARTS OF OF OF OF and capscrews. See that the set is properly WATER ACID WATER ACID grounded. Check the wiring diagrams in the instruction manual furnished with the generator, .400 3 22 .. toseeifany wire connection is suspected .345 2 1 1 7 of being improperly connected. Any faults that .300 5 2 2 5 are found should be corrected immediately. .290 3 9 20 .275 11 4 11 20 SERVICING THE PRIME MOVER .250 4 3 4 .225 11 3 1 Servicing the prime mover is the next step .200 13 3 13 10 in the process of placing the generator inopera- tion. Be sure that the crankcase is filled with 26.164

296 306 Chapter 9CENTRAL POWER STATIONS

After the electrolyte has been prepared, again the alternator. Generally, you should take the see the instruction manual for the recommended following steps: filling procedure. If the manual is not available, follow this general procedure: First, add elec- 1. Find all the electrical connections by re- trolyte to each of the battery's cells until theferring to the generator's connection diagrams level of the electrolyte is visible in the fillerand see that the connections are tight. neck or at least 3/8 inch above the separators. The temperature of the electrolyte when placed 2. Seethatthecollector rings are clean in the cells should be between 600 and 90° F. and have a polished surface. IT SHOULD NEVER EXCEED 90° F. Chemical reaction resulting from addingelec- 3. Check collector brushesto make sure trolyte will cause the battery to heat. Cool itthey have no tendency to stick in the brush artifically (cooling fans) or allow to stand atholders,that theyare properly located, and least 1 hour before placing it in service. thatthepigtailswillnotinterfere with the You will probably notice at the end of the brush rigging. cooling period that the level of the electrolyte has dropped due to the electrolyte soaking into 4. Check the collector brush pressure, making the plates and separators. Before placing the sure it agrees with the pressure recommended batteryinservice restore the electrolyte toin the manufacturer's instruction manual. Cal- its proper level. Remove any electrolyte spilled culations for brush pressure may be made, using on the battery, using a cloth dampened with aa spring scale (to measure the spring tension) solution of bicarbonate of soda and water. and the formula: Although the battery can be placed in service 1 hour after fillingit with electrolyte, do so PresEmre Tension (in pounds) only in an emergency. If at all possible, give (psi). Brush width x Thickness (inches). the battery an initial light charge. Iftheinstruction manual isnot available Example: orifitdoesnr,tgive the battery charging procedure, proceed as follows: Manufacturer's recommended Charge the battery at a low rate (about 5 tension = 40 ounces(2.5 amperes) until the voltage and specific gravity, pounds) corrected to 80° F, remains constant for at least Brush width = 1/2 inch 5 hours. If the temperature of the elect! 3lyte Brush thickness = 1-1/8 inch reaches 125° F redttce the charging rate o, stop the charge until the battery cools. NEVER 'E r,-Substituting those figures in the formula above, MIT THE TEMPERATUR7 TO EXC't,'"*. I° F. 2 5_pounds= 4.4 psi During charging, replenish any luoby Pressure 0.'5x 1.125 evaporation. After the battery has been charger nilent it into the starting system of the prime mover SERVICING AND as indicated by the wiring diagrams accompanying OPERATING PROCEDURES the generator. On large generatorsyoushould check the You must always check the appropriate in- area ventilation; the fan cover must be opened struction manual for specific operating and serv- and latched in that position. There must be no icing procedures.The following information, cover or obstructions over the main diesel en- however, is general and applicable to the gen- gine exhaust stacks, or over the radiator section. erators you may encounter. The bypass shutters or doors may be closed Make sure that the fuel you are going to use toshortenthe warming-up period, and roof is not contaminated with dirt or water, and that hatches and side louvers MAY be opened for allequipment (cans, funnels, and/or nozzles) additional ventilation, if requrred. for transferring the fuel to the engine fuel tank isclean. Dirty fuel clogs the carburetor and SERVICING THE GENERATOR fuel lines. Water in the fuel often keeps an engine from Just as important as the preparation of the starting and damages the injection pumps and prime mover is the inspection and servicing of nozzles of diesels. In cold weather, especially,

297 307 CONSTRUCTION ELECTRICIAN :3 & 2

e #4e2i

...... , ..44:,04, ,Cttro,r

SPEED CONTROL KNOB J ?."',"'1,.1.1, , ' ' ENGINE SPEED (R.P.M.)"

, lir-I PERA:fING LEVER s. COOLING WATER TEMPERATURE

FUEL OIL PRESSURE

TAR N A R PRE E AWr'777"1 s'Y LuTCATEkriiic OIL ST TINAIR LEV

73.58 Figure 9-31. Diesel engine, showing controls andgages.

298 308 Chapter 9CENTRAL POWER STATIONS fuel tanks should be kept full to minimize con- Figure 9-31 shows the controls and gages of densation of moisture in them. a diesel engine that drives a large generator. BE SURE THE FUNNEL IS IN DIRECT CON- The STARTING AIR LEVER controls a vaive TACT WITH THE TANK when fuelisbeing which admits starting compressed air to the transferred, to eliminate the possibility of an engine'cylinders. TheENGINE OPERATING explosion. LEVER controls engine speed while starting, Damage due to dirt can be eliminated or stopping, or in an emergency. The SPEED CON- minimized by changing the air cleaner at ap- TROL KNOB controls engine speed during normal propriate intervals. If the oil feels gritty whenoperation. Figure 9-32 shows details of the engine checking its level, change it and the filter too. operating lever. If your generator set requires water for its The speed contr-1 lever controls engine speed cooling system, be sure to keep it filled. Re-during normal opciation through a governor. member, that in freezing temperatures, anti-In starting, the governor is made inoperative freeze must be added. so that the operator can control engine speed Check the battery electrolyte level period- during starting by manipulating the engine op- ically and add water if required. When available,erating lever. To render the governor inop- distilled waterispreferable to plain water. erative, you set the PAWL-ACTUATING LEVER Coat the battery terminals with a light coating(fig. 9-32) in the position where it points away of corrosion-preventive grease after connections from the engine. After the diesel engine starts, have been tightened. you turn the pawl-actuating lever toward the engine. Before you start the diesel engine, see that OPERATION OF POWER STATION the circuit breaker and the field switch on the Once the central power station has been established, the various base activities should be able to count on a continuous and adequate flow OPERATING of electric current to supply the needs of the LEVER HANDLE living and working spaces. As a Construction LATCH LEVER Electrician who has worked on the installation of the power distribution system, you will have a SPEED INDICATOR AWL ACTUATING good overall working knowledge of this system. LEVER However, you should also know how to operate and maintain the equipment in the power gen- TEL-TALE erating station. PLATE VERNIER You can help yourself to the required know- KNOB how by studying the general operating and maintenance procedures in this chapter, by referring toelectrical plans and diagrams relating to tasks involved, and by consulting the instruction manual furnished with each piece of plant equipment. STARTING AN A-C GENERATOR

Thefollowing description of the steps in starting an a-c generator is a general description only. For a particular generator you follow the step-by-step instructions for starting given in the manufacturer's manual. It is assumed that the generator is driven by a diesel engine which is started by air pressure (some diesels are started by an electric starting motor and batteries or by a gasoline engine which 73.59 is cut off after the diesel engine starts runningFigure 9-32. View of diesel engine operating on its own fuel). lever, showing details. 299 309 CONSTRUCTION ELECTRICIAN 3 & 2 111=11, 4IM generator switchboard are in the OFF position. voltmeter selector switch is set to permit the This step ensures that no load exists on thea-c voltmeter to indicate the desired measure- generator.Next, set the pawl-actuating lever ment. for manual control (away from the engine), and Turn the handle of the exciter field rheostat latch the engine-operating lever in the INJ FULL counterclockwise as far as it will go, so as to position (fig. 9-32). put maximum resistance into the shunt field of The LATCH LEVER shown in figure 9-32 the exciter. releases(bysqueezing)theengine-operating Throw the field switch to the ON position, lever for movement to a different position, andthus making excitervoltage available to the locks the same in the new position when thegenerator field. At the same time watch the latch lever is released. a-c voltmeter and ensure that it records a low The VERNIER KNOB of figure 9-32 is used reading. to control speed adjustment when you are oper- Turn the exciter field rheostatknob clockwise, ating the engine under manual speed control, thus decreasing exciter field resistance, and as in an emergency. increasing exciter field voltage and excitation Pull down on the starting air lever (fig. 9-31). current in the generator's field winding. This This will admit air to the cylinders, which will will cause output voltage to rise. Watch the a-c inturn set the pistons in motion. The engine voltage meter, and turn the rheostat knob until shouldfire within 10 seconds; when it does, the rated voltage is reached. release the starting air lever. Check the frequency reading on the frequency Immediatelyafterthe engine fires, checkmeter. Increase or decrease the engine speed the LUBRICATING OIL PRESSURE GAGE (fig. until you read normal frequency (in this case, 9-31). If it does not indicate oil pressure within 60 hertz). 10 seconds after the engine fires, stop the engine Turn the voltage regulator switch to the ON at once by moving the engine-operating lever or AUTOMATIC position, thus placing the volt- to the INJ STOP position (fig. 9-32). age regulator in control. Then check the volt- If lubricating oil pressure is satisfactory, meter to ensure that it still reads rated voltage turn the pawl-actuating lever toward the engine value.Ifthevalue has changed,adjust the and move theengine-operatingleverto thevoltage ngulator rheostat until the voltmeter GOV RUN position. Engine speed is now con- again reads rated value. trolled by the governor. Release the interlock on the circuit breaker, Make sure you know the engine speed re- thus closing the generator circuit and energizing quired to maintain the required voltage output. the bus. With the generator now connected to Assume thatto produce a 60-hertz voltage, the external circuit, the a-c ammeter will indi- the engine must make 600 rpm. Check the rpm cate the current drawn by the load. indicator and if it does not read 600 rpm, turn Check the current in each phase by switching the SPEED CONTROL KNOB in the appropriate the ammeter. Recheck the voltage across each direction until the engine speed indicator reads phase. 600 rpm. Recheck the lubricating oil gage for proper SYNCHRONIZING GENERATORS loll pressure; also check the FUEL OIL PRES- SURE GAGE for proper fuel oil pressure, and the The load power demand may often reach a COOLING WATER TEMPERATURE gage for point where it cannot be satisfied by a single proper water temperature (fig. 9-31). generator. In this case, it becomes necessary to "nut in" or "parallel" another generatorthat PLACING GENERATOR ON THE LINE is, add another generator to the bus. You CANNOT parallel by simply starting the engine of a reserve Your generator is now running, but it is notgenerator and place this generator on the line yet "on the line", that is, not delivering power by throwing the main switch. You must go through to the distribution system. Before you set about a procedure that concerns four important events; putting the generator on the line, make sure that (1) The incoming generator voltage must equal you know the locations of the various switchboard the bus voltage. (2)It must have the same controls, and that you are Wei' to operate them frequency and (3) must be in phase with the smoothly and in proper sequence; check to seebus voltage.(4)All phases must be connedted thatthevoltageregulator switch is in OFF in proper sequence. This procedure is called (or MANUAL CONTROL) position, and that the synchronizing or paralleling generators.

300 310 Chapter 9 CENTRAL POWER STATIONS

To adjust frequency,you adjust the speed and L3 will glow with maximum 'prilliance and in rpm of the prime moverthereby ensuring L1 will be dark. that the difference in potential between COrt- Assume that the incom'ng generator is far RESPONDING term'nals of the two generators out of synchronism lagging. All three lamps is zero. Watch the voltmeters on the two units will, appear to glow steadily, because the fre- until they read the same. To bring the incomIng quency of the voltage across them is .the dif- generator into phase with the voltage on the ference in the frequencies of the two generators, bus, you will either use a lamp method or a and thus is too high for individual alterations synchroscope of synchronizing lamps. In paral- to be observed. As the lagging generator is leling generators, you will either use a lampaccelerated, however, the lamp(differential) method or a synchroscope. frequency decreases until their light flickers visibly.Their flickering will have a rotating sequence, if connections are correct, and will Lamp Synchronizing Methods indicate which generator is faster. The most satisfactory method ofs: 'Aro At a point approaching synchronism, lamp nizing generators, using lamps,is th,wo- L1 will be dark because it is connected between bright one-dark methcd of figure 9-33. Note like phases. That is, the two phase C voltages that the lamps are connected directly betweenwIll be so nearly synchronized that their dif- the incoming generator's output and the buses. ferential voltage across L1 will be insufficient to make it glow visibly. However, this differen- In this way, the twoa-c sources may be tial may still be of sufficient magnitude to damage synchronized before theincoming generator's the generators should they be connected at this main power contactor isclosed. At the instant time. The reason fOr cross-connecting L2 and thetwo generators areto be paralleled, L2L3 is now indicated. Under perfectly synchro- n1z.ectconditions, the phase voltages across L2 L3 are both 120° apart, because of their cfuss-connection, and both glow with equal brilliance. However, if the generators are not in complete synchronism, but only very near it, one of the bright lamps would be increasing in SYNCHRONIZING voltage as the other was decreasing. This action L AM PS would cause a visible difference in the brilliance L3 of L2 and L3. Thus, by adjusting the incoming generator'sfrequency so that no visible dif- ferenceof brillianceexists between L2 and L3, the exact point of synchronism can be approached very closely before paralleling the A-C incoming generator with the generator on the BUSES bus. Two other methods are used, one is called the "all-dark" method, the other, the "bright- SYNCHROSCOPE lamp" method. Intheall-dark method ofsynchronizing, lamps are connected across an open three-pole switch between the bus and the incoming generator as shown in figure 9-34. If the lamps increaseand decrease in brilliance together, _L the phase sequences of the two generators are BUS I NCOMI NG the same. If the lamps rotate in brilliance, the GENERATOR GENERATOR phase sequences are not identical. Interchang- ing any two of the three leads from the incoming generator will obtain the correct phase sequence. 13E299 Be sure the lamps have a voltage rating twice Figure 9-33. Synchronizing lamp connection for the generator terminal voltage. If lamps of this two-bright one-dark method. voltage rating are unavailable, several lamps in

301 311 CONSTRUCTION ELECTRICIAN 3 & 2

Synchronizing With Synchroscope A c The sequence of operations in paralleling two alternators by synchroscope follows. Compare the bus voltmeter reading (voltage produced by the already operating generator) with that on the incoming generator voltmeter. If the readings are not the same, adjust the voltage ( LAMPS FOR regulatorrheostatof the Incoming generator PHA SING OUT until its voltage is equal to the bus voltage. Thisisan importantstep, because unequal GENERATOR NO. 1 GENERATOR NO. 2 V.,,Lt11598will cause circulating currents to flow between the parallel genei.ators. 73.60 Compare the fl equency of the incoming gen- Figure 9-34.The all-dark synchronizingerator with that -)f the bus, and adjust to cor- method. respond by means of the incoming generator's governor motor-control switch. Turn thesynchronizing switch to the ON series, voltage dropping resistors, or stepdown position. The synchroscope will rotate in one transformers must be used. When the lamps are direction or the other.(If the switchboard is dark the voltages are in phase and the paral- alsoequipped with synchronizing lam.ps, they leling breaker may be closed. will increase and decrease in brilliancy.) Use the governor motor control switch to The "bright-lamp" method is more sensitive adjust the speed of the incoming generator uitil and is used for large, high-speed generators.it is operating at approximately the same fre- The arrangemeat of lamns is shown in figure quency as the bus voltage. This will be indicated 9-35. When lamps A and C burn with the same by the synchroscope rotating slowly in the FAST brilliancy the unit isin phase. As ore of the direction. (The synchronizing lamps will slowly two increases in v.. .,c1 the other de- increase and decrease in brilliancy.) creases, the instant of synclionism 's the in-. Make sure the voltages of bus and incoming stant when they match in briihany. The sequence generator are the same. Then, JUST BEFORE of brightness of the 1- rapt.'indicates whetherthe synchroscope pointer passes through the the incoming alternator is fast or slow. It is zero positioa, close the incoming generator's standard practice to close the generator breaker breaker and thus "cut in" the generator. when the incoming alternator's frequency is After the incoming generator has been thus slightly ahead of that of the already operating"cut in" to the bus, there are two additional alternator. adjustments that must be made. One of these ensures that each generatoris carrying its share of the kilowatt load. The other ensures that each generator is operating with the same BUS LINE TO GENERATOR A power factor. NO. I The division of kilowatt load between a-c generators operating in parallel depends on the relative setting of their engine governors.Ecpal- izing power factor means ensuring that each generatorisproducing its share of wattless current or "reactive kva." The am3unt of reactive kva two generators supply depends on the relative setting of their voltage regulators. Therefore, to adjust the generators for parallel operation you take the following steps. GENERATOR NO. 2 Turn the governor motor control switches until the wattmeters of the generators read the 73.61 same (if the generators have the same rating), Figure 9-35.T h e bright lamp synchronizingor until the load is proportionally divided (if the method. generators have different ratings). The load is

302 312 Chapter 9 CENTRAL POWER STATIONS increased on a too lightly loaded generator by CAUTION: Tne field circuit of a generator increasing engine speed, on a too heavily loaded which is to be disconnected from the bus bars generator by decreasing engine speeds. These must not be opened before the main breaker adjustments must be made simultaneously, tohas been opened. If the field circuit is opened maintain constant frequency. first,a heavy current will flow between the To balance reactive load, turn the voltage armatures. regulator rheostat of each generator until the power factor meter reading is the same for Move the governor control lever to the each, indicating that the burden o! reactive kva low idle engine speed and run the engine about isbeing properly shared. If the switchboard 5 minutes until it cools down. is not equipped with power factor meters, the a-c ammeter of each generator can be used. Stop the prime mover by moving the engine Proper adjustment exists when the ammeters operating lever to the GOV STOP *)osition show equal currents for generators of the same 9-32). rating, or proportionally equalcurrents for those of different ratings. It may be necessary to secure a generator which is operating in parallel with another. The The direction in which you turn the voltagetypical situation is Gne where a peak load (as regulatorrheostat of each generator depends when darkness falls and many lights come on) on the reading of the generator's power factoroccurs and then passes. When the load comes meter or ammeter before the adjustment is on, another generator is cut in; when it passes, made. The voltage should be decreased on the the generator is secured. generator carrying too much power facto-, in- Pefore you remove the generator power from creased on the one carrying too little. the bus, It is very important that you shift the After closing the main breaker, observe thekilowatt load being carried by the generator a-c ammeters of equal generating units to ensure which will be cut out to the generator or gen- that they read the same. Unequal readings ms,anerators which will remain on the line. This that one generator is doing more work than hilt of kilowatt load is accomplished by turning the other. You can even out the load by increasing tne governor motor control switch of the gen- the speed of the generator having the lower am- erator to be secured to LOWER, and the same meter reading. Adjust the control governor motor switches on the remaining generators to RAISE. until both a-c ammeters read the same. The wattmeters on the switchboard will indicate how theshift is progressing aad when it is SECURING GENERATORS completed. When the load has been shifted, trip the cir- When a SINGLE generator, connected alone to cuit breaker on the generator which is to be a bus, is to be taken out of operation, proceedtaken out, and then secure that one as you would as follows: a single generator. Remcwe as many individual loads as pos- A generator which has been operating under sible to reduce arcing and damage to the lin.e a heavy load should not be shut down until it switch or circuit breakers when the circuit 'ishas been run on a light load for a few minutes opened. Open the feeder breakers to furtherto reduce temperatures. reduce the generator load as much as practicable. EMERGENCY SHUTDOWN Trip the generator circuit breaker. In the event of engine overspeed, high jacket water temperature, or low lubricating oil pres- sTurn the voltage regulator switch to the sure, the engine may be shut down and discon- OFF or MANUAL position. neoted from the main load by tripping the main circuil, breaker. In addition, an indioator may Turn the handle of the exciter field rheostat light or an alarm will sound to indioate the oause counterclockwise,asfarasit will go, thus of shutdown. After an emergency shutdown and cutting in all resistance to the exciter field andbefore the engine is returned to operation, the decreasing thevoltagetothe exciterfield. cause of shutdown should be investigated and

303 313 CONSTRUCTION ELECTRICIAN 3 & 2 corrected. NOTE: It is important to check the adequate amount of power. The 24-hour period safety controls at regular intervals to deter- is divided into a number of watches: the number 1-n!nethat theyarein good working order. depends, of course, upon the personnel available for this type of duty. OPERATING RUL.,.:S At most stations, 6-hour watches are the common practice. An 8-hour watch schedule The orders postedin the station for the does not ordinarily work a hardship, but watches guidance of the watchstanders should includeof more than 8 hours should be avoided except a general list of operating rules and electrical an emergency. safety precautions. MAKE SURE YOU CARR Y P.esides operating the generating equipment, THE m ours Hare are a few simp'e, but impor-watchstanders must keep the daily operating tant, operating rules. log, do housekeeping chores, and the generating equipment. Watch theswitchboard instruments. They show how the system is operating, reveal Keeping a Station Log loads, improperdivisionof kilowatt load or A station log is a written record which serves of reactive current between generators operating a number of purposes. For one thing, it indicates in parallel, and other abnormal operating con- when various equipment units require periodical ditions. maintenance work or replacement. A series of entries can often pinpoint signs of breakdown Keep thefrequencyand voltageattheir when the breakdown occurs so gradually that it correct values. A variation from either will never becomes an obvious problem at any parti- affect, to some extent at least, the operation cular instant. of the base's electrical equipment, especially With a great many items of complex equipment teletypewriters and electric clo3ks. working togetherto produce heat, light, and USE GOOD JUDGMENT WHEN RECLOSING power for an entire base, it is vital that each CIROUIT BREAKERS AFTER THTEY HAVE TRIP- item of this equipment be kept operating satis- PED AUTOMATICALLY. Generally the cause factorily. A well-kept log is an important means shouldbeinvestigated if the circuit breaker trips immediately afterthefirstreclosure.for alerting a trained man to the first signs of However, reclosing the breaker a second time trouble. may be warranted if power has to be reScored The form sed for log entries varies with immediately, Don't forget, repeated closing and the views of the supervisory personnel in dif- automv.tictrippingmay damagethe circuitferent plants, and there is no standard form to breaker and thus increase the repair or re-be !_ilowed by all stations. Regardless of form, placement work. any log must describe the hourly performance, Don't start a plant unless all its switchesnot only of thegenerators, but also of the and breakers are open and all external resis-numerous indicating and controlling devices. tance is in the exciter field circuit. Figure 9-36 shows one type of log that may Don't operate generators at continuous over- be kept on the generator units of a power plant. load. Record the magnitude and duration of the This is only a suggested form, of course, and overload in the log; record any unusual con-there may be at your station many other items ditions or temperatures observed. Roadings taken to keep a record on. over a period ct time may show a trend, such as decreasing oh pressures or increasing engine Housekeeping temperatures, that points to a trouble or fault. Don't continue to operate a vlbratingmachine. As a watchstander keep your duty station Find and correct the cause; then record theclean and orderly. Also keep in their proper cause In the log. places tools and auxiliary equipment that arn not being used.Store clean waste and oily GENERATOR WATCH waste inseparate containers. OILY WASTE CONTAINERS MUST BE KEPT COVERED. Empty Constant, around-the-clock attention must be oily waste containers at least once a day to given to the generators at a central power station reduce fire hazards. Care given the station thatisrequired tosupply a continuous and floor will depend on its compositiOn. Generally,

304 314 Chapter 9CENTRAL POWER STATIONS

SUGGESTEDFORMOF PLANT OPERATION LOG

ITNIT NO I 71.5- UNIT NO_jf2 uNn. No_j±d.r_____ 7 fqf MAMA', 11.1.114 10..4 11,rsed

4//q1701 boo tf.SO220 se 34.240km.. 32 5.34,.226 17 Siorkd up .. 17301'16 r atiled2y8c,/X,R/765- . 2,002oo o11/ s'ff 3o 7o ax, 4147 SAurobbwri #396.5.

OPERATOR

73.57 Figure 9-36. Representative generating station operator log. it should be swept down each watch. Remove atthe engine crankcase. Tne oil level of the a r once any oil or grease that is tracked aroundoil bath filter should be checked daily. Opera- the floor. tionof theunitin extreme dust conditions necessitates more frequent maintenance on oil Operator Maintenance bath air filters. 4. Grease water pump belt tightener idler Since there are many different types of gen- pulley. erators, you should consult the manufacturer's 5. Replace brushes if less than 1/4" long. instruction manual for details concerning main- 6. Every three months, clean load contactor tenance of your equipment. SAVE THIS INSTRUC- faces(do not file); check all connections for TION MANUAL: Additional copies are rarely tightness and wipe msgnet faces clean. available. 7. Inspect pole shader every three months The lubrication and maintenance schedule and replace if cracked or broken. taken from an instruction manual follows: 8. Set battery charger tim'ng relay to 24 hour position monthly. 1. Grease fuel transfer pump every three 9. Renew element and reassemble oil filters m =the. every 51 hours of operation. 2. Grease generator yearly with M11-G-10924 10. Drain andrefill engine crankcase with grease. MIL-L-9000 lube oil every 50 hours of operation. 3. Change oil in air cleaner every 50 hours of operation. 011 in oil bath air cleaner should Observe all safety precautions. Safety warn- be changed every time the oil is changed inings,such as keeping thefUnnel in contact $05 o CONSTRUCTION ELECTRICIAN 3 & 2 with the fuel tank wlien filling with gasoline,Adjust the pointer of instrucment, so that might save a life. Here are = general daily itreads zero when the tastrument is not en- maintenance and routine practIcos. ergized. Examine all indicating lamps, to make sure Check the following: that none are burned out. Level of coolant Inspect all instrument transformers mounted Radiator and coolant hoses for leakson the switchboard. To be in good condition, an flattery electrolyte level instrument transformer must have all primary Fuel tank for leaks and secondary connections tight, and all ground- Free movement ofradiator shuttersing connectionsintact.Potential transformer All switches for proper oderation fuses must make firm contact in their clips. Check the condition of all rheostat mecha- Bring oil level to high mark on dipstick. nisms. Replace broken or burned-out resistors. If no replacements are available, make tempor- Drain water and sediment from strainers. ary repairs by bridging the burned-out sections. Check to see that there is nothing to block the Drain water from fuel tank. ventilation of rheostats and resistors. Test the operation of switchgear position- Fill fuel tank as required with appropriate changing mechanisms, such as the lowering and diesel fuel. raising mechanisms, and the pullout devices of the circuit breakers used in metal-clad switch- Connect battery charger to utility source gear. if unit is not o7arating. SAFETY DEVICES AND INDICATORS The use of daily, weekly, m inthly, and other periodic inspections and p--eventive maintenance Many generator sets are equipped with various programsrigorouslyenforcedwill minimize safety devices to protect the equipment from down-times of your equipment and help keepdamage. These include low lubo oil pressure, your equipment operational for longer periodshigh coolant temperature, overspeed, overcurrent of time. and verse current, undervoltage and overvoltage relays. When a fault occurs, the generator is usually caused to shut down by appropriate SW:TCHGEAR MAINTENANCE automatic switches. Additionally, indicator lights come on making diagnosis of the cause of the At least once a year, a check should be made fault easier. For example, when the oil pressure of the switchgear component, with careful atten-gage falls below 10 psi (pounds per square tion given to the following factors. inch) in one generator, the main contactor opens General cleaning of the component parts is toshut theengineoff, and the low lube oil essential. Tne front panels of dead-front switch- pressure indicator bulb lights UN Take advantage boards can be wiped off with a dry c1. A of the help provided by these indicators. Train metal-covered sw!tchgear can be opened ani in- yourself to identify the various indicators on the spected for surface cleanliness.Before anygenerator equipment. Ask yourself what would work is done on live parts, however, deenergize be wrong ifsuch and such an indication is the switchboard. W!pe all dust from bus bars observed and what measures would you take and insulating m:o.terial. to correct the fault. Inspect electrical connections and mechanical Ithelpsto become familiar with wiring fastenings. Do not limit this check to a sightdiagrams, such as in figure 9-37 alld to learn inspection, but touch and shake the various parts the physical locations of the components. Doing to make sure that all connections are tight, andso: will enable you to find and to troubleshoot all mechanical parts free to ,function properly.them faster in an emergency. Pay special attention to the bolted Joints of the Station personnel ralst observe all electrical bus bar, because a loose Joint can cause over- safety precautions. Everelectrical circuit, in- heating. cluding those, as low as 35 volts, is a potential Examine all meters and instruments mounted source of danger. Never work on an energized on the switchgear panels. Look for cracked orcircuit excopt in an emergency. In such a case, broken glass, or signs of damage to the cases.insulate yourself from ground by covering any

306 316 Chapter CENTRAL POWER STATIONS

OV RP UFUV OL SC

Ki CONTACTOR COIL d.c. RUN FUEL SWITCH SOLENOID

CRANK OP WT FL OS SWITCH

K COIL

START MOTOR 0 0 EMERGENCY SWITCH d.c. K 1 RUN RELAY SC- SHORT CIRCUIT 0 V OVER VOLTAGE OP- OIL PRESSURE RP -REVERSE POWER WT- WATER TEMPERATURE UF -UNDER FREQUENCY(400 CYCLE ONLY)FL- FUEL LEVEL OL OVERLOAD OS- OVERSPEED

26.251 Figure 9-37.Practical wiring diagram of a representative safety control system for portable generator sets.

Kijacent grounded metal with insulating material, components. You will find the manufacturer's luch as dry wood, rubber mats, dry canvas,book the most reliable way to check out the serveral thicknesses of heavy dry paper.entire system. Always check with the manu- Uso, provide enough lighting, cover metal tools facturer's book when troubleshooting, ordering vith insulating rubber, and wear rubber gloves. and replacing parts. Uways stationmenatappropriate circuit meakers or switches so that the switchboard ;an be deenergizedimmediatelyand have avail- POWER RECTIFIER Lblea man qualified to render first aid for Plectric shock. A power rectifier (diodes) is used to change a-c to d-c. The powerrectifierof figure 9-98 can be comnared to a hydraulic check valve in TROUBLESHOOTING that it only allows current to flow in one direction (the direction of the schematic arrow). Its Comnonent parts found in most SRCR con- characteristics are such thatit has a high rolledregulators are power rectifier, siliconresistance in one direction and a low resistance ontrolled rectifier, full wave rectifier, saturable in the other direction. Failures occur due to eactor, and choke. four reasons: Tne troubleshooting information that follows rillenable you to check out each of these 1. Excessive current - causes overheating.

307 317 CONSTRUCTION ELECTRICIAN 3 & 2

2. Excessive voltage - electrically damages the rectifiers interior parts. 3. Too much torque when replacing diode physically damages the rectifier's interior parts. 4. Lack of silicon lubricantcauses rectifier overheating due to no transfer of heat A from the rectifier to the heat sink. A power rectifier can be checked with an ohmmeter. Its resistance should be over 100 times higher in one direction than in the other (1,090 times higher on the silicon type). 710- CURRENT FLOW Silicon Controlled Rectifier 73.344 A silicon controlled rectifier (SCR) in figure Figure 9-38. Power rectifier. 9-39, controls the amlunt of 11-c that flows. It allows current to flow in one direction as a

ANODE (STUD)

GATE

CATHODE (P I GTAI L) 73.345 73.346 Figure 9-39. Silicon controlled rectifier. Figure 9-10. Cathode (pigtail).

1OR 4AC (YELLOW OR GREEN)

BLACK-STRAP FROM END 4 3 TO END RED AND CENTER TERMINAL 2 AC YELLOW OR GREEN

73.347 Figure 9-41. Full-wave rectifier.

308

3 1-8 Chapter 9 CENTRAL POWER STATIONS

---15151Rfn-- B LM H

73.348 Figure 9-42.Saturable reactor.

Table 9-4. Rectifier check out

+1 -2 Reading high -3 Reading low -4 Reading high

+2 -1 Reading high -3 Reading low -4 Reading high o-15116-61575-111

+3 -1 Reading high 73.349 Figure 9-43. Choke. -2 Reading high -4 Reading high power rectifier does but only when a small positive voltage is applied to its gate terminal by some external means. 'Men no positive voltage is applied to its gate terminal, the current +4 -1 Reading low will not flow through it. A silicon controlled rectifier can be checked -2 Reading low out with an ohmmeter. Readings across the terminals (fig. 9-40) should be as follows: terminals S-P, high ohms value; terminals S-G, -3 Reading low high ohms value; and termlnals P-G, 10 to 259 ohms. Full-wave Rec:tifier A full-wave rectifier(fig. 9-43.) is used to change a-c to d-c. Consisting of four diodes

309 319 CONSTRUCTION ELECTRICIAN 3 & 2 arranged as shown in the figure, it fully recti-change in current. The terminal B is one end fiesa-c to d-c to allow full current flow; a ofthecoil and the other end is L-low, M- single rectifier or diode allows only half of the medium, or H-high, each corresponding to a a-c to flow. different -umber of turnsin the coil which Itcan be checked with an ohmmeter byaffects the operatirz characteristics. A saturable placing the positiveand negativeohmmeter reactor can be checked vrith an ohmmeter for leads as follows using table 9-4 as a guide: continuity and grounds. Place positive test lead on No. 1 terminal and negative test lead on No. 2 terminal. The reading should be high. Then place negative lead Choke Dn No. 3 terznnal, reading should be low, etc. If one of these readings is incorrect, the full- A choke (fig.. S-43) is used to smooth ou. a wave rectifier can be discarded. pulsating (rough) d-c. Like the saturable reactor, a choke is a coil of wire wound around an iron Saturable Reactor core. Its operating characteristics enable it to resist sharp changesincurrent flow. When A saturable reactor (fig. 9-42) consists of aplaced in a circuit, the choke will smooth out coil that is w.)und around an iron core. It enablesany d-c flow. A choke can be checked with an a small change in voltage to produce a large ohmmeter for continuity and grounds.

310 CHAPTER 10 OVERHEAD POWER DISTRIBUTION

Power from the generating plant at an ad- Whether underground or overhead, the distri- vanced base may be carried to the various points bution system at an advanced base is of the of consumption by overhead transmission andradial type. A representative transmission and distribution lines, by underground cable, or bydistributionsystemis shown in figure 10-1. a combination of both. At most advanced bases, While working on a line crew you will be the high voltage developed at the central powerinvolved with the various stages of line work. station is usually, and preferably, distributed by You will begin as a groundman (helper), learning overhead feeder lines. Such lines are cheaper to the proper procedures of doing line work, hard- build, simpler to inspect, and easier to maintain ware required,speciallinetools used, and than underground cables. Obviously, use of under- types of transformer hookups. Later on you will ground cables is preferred at airports to prevent work as a lineman, mounting crossarms, stringing hazardous flight conditions. wire, and installing protective devices.

Voltages developed normally range from 120/ Your line crew leader will start off by ex- 208 volts to 7620/13200 volts. The initialgenera-plaining the project details from a set of blue- tion and distribution system at an advanced base prints. Mese details will include the route, class is provided by a 110/220 volt, 3-phase, 4-wire ofpoles, and type and size of transformers grounded neutral. Replacement may thenbe required for the project. provided by a 2400/4160 volt, 3-phase, 4-wire grounded neutral supplied by banks of two or The basic concepts of pole line design are moregenerators.Finally,asrequirements considered in the layout of each powerline job. increase, power sourceJ capable of providing the Factors that are considered in designing the job larger voltages are installed. are: the route, power load requirement, location and size of transformer banks, and class and types of poles suited for the project. GENERATING DISTRIBUTION CENTER The line work generally accomplished by a STATION battalion can be found in a standard set of SUBSTATION drawings,FacilitiesPlanningGlide, P-437, voldme I (thisreplacestheP-140series, SERVICES Advance Base Drawings). This publication gives project layouts and lists materials needed to SECONDARY LINES accomplish the project as shown. HIGH-VOLTAGE TRANSMISSION This chapter provides information that will LINES be useful to the CE engaged in the installation DISTRIBUTION TRANSFORMERS and maintenance of an overhead power distribu- FEEDERS PRIMARY LINES tion system. Topics covered include pole line components, powerline erection, distribution and current transformers, street lightingfixtures and 26.77 circuits, and obstruction lighting. A section also Figure 10-1. Transmission and distribution isincluded on troubleshooting, along with a system. troubleshooter's chart for the series circuit. CONSTRUCTION ELECTRICIAN 3 82 2

1-17/32 DRILL 6 HOLES r1-5/8" 48'1 FOR INSULATOR PINS

14-1/2 30" 4" 96" 3-1/4"' H 6" 23" 19" 1-7-19" 23"

(1) $- DOUGLAS FIR 7/16" DRILL 11/16" DRILL 2-1/8 2 HOLES 96" LIGHT CROSSARM 3 HOLES 4-5/6-"R

73.351 Figure 10-2.----Crossams.

POLE LINE COMPONENTS by 5". The first two of these sizes are standard for distribution work, and the latter two sizes The basic components in a power distribution are for transmission work. Crossarm length system are: poles; crossarms that will go ondepends on the number of pins and the separation the poles; insulators and insulator pins; trans-between pins. Standard crossarms include two-, formers and protective devices. Information onfour-, six- and eight- pin sizes with standard each of these components is given in variouspin spacing of30inches between pole pins sections of this chapter. and 14 1/2inches between outside pins as shown in figure 10-2. POL ES INSULATOR PINS T 'treetypes of poles used in distribution systems are; wood, steel and concrete. You will Insulator pinsare used to mount the in- run across all three types but will be working sulator on the crossarm. They may be either wood mostly with wooden poles. or steel (see fig. 10-3). For wood pins, well- seasoned locust in standard sizes for the arms and Wooden poles are commonly classified as toinsulators is used. For galvanized steel pins, length,top circumference, and circumferenceuse the minimum lengths recommended by the measured 6 feet from the butt end. The length insulator manufacturer. They are available intwo varies in 5-foot steps and the circumference at sizes; long shank for use on wood arms and short the top varies in 2-inch steps. The circumference, shank for use cn steel arms. measured 6 feet from the butt end, determines to which class (numbered from1 to 10) a pole of a given length and top circumference Standard-pin thread sizes are 1 inch and 1 belongs. The classification from 1 to 10 deter- 3/8 inches. With insulators having porcelain mines the strength to resist loads applied 2threaded pinholes, use pins having lead thread. feet from the top. Use solid steel threads on pins only for insulators with metal thread pinholes. CROSSARMS INSULATORS Crossarms are the crosspieces on a pole which support the insulators and conductors of a line. Insulators for overhead lines are classified There are four widely used standard sizes of into three clnQq..-ls; (1) pin, (2) suspensions and wooden crossarms; namely, 3 1/4" by 4 1/2", )vis) type. Tile porcelain pin 3 1/2" by 4 1/2", 3 3/4" by 4 3/4", and 4" (3% in figure 10-4 are the most

322 Chapter 10OVERHEAD POWER DiSTRIBUTION

2" 4-1/4" 1-3/8" LEAD A HEAD

1-1/4" 9"

5" 3/4"

SCREW PIN

%am \am__ NEM

GALVANIZED STEEL PINS STANDARD LCCUST PIN

73.352 Figure 10-3.Insulator pins. commonly used. The one-piece type is used forvoltages and make it difficult to obtain suffi- low voltage. The two-piece type (and largercient mechanical strength in the pin to support size types) is used on high voltage lines. One-the insulator. piece insulators are used for voltages below 23,000volts;two-piece insulators for 23,000 to 44,000 volts; three-piece insulators for 44,000 Strain (or clevis) type insulators are used to 66,000 volts; and four-Tiece insulators foron primary systems at corners, angles, dead 66,000to88,000volts. The layers on theseends, suspended buses, and wherever pins do insulators are called petticoats or skirts. Tlieynot provide adequate support. They are built help to spill rain and provide a long, dryarc-the same as suspension type insulators butare over path. stronger mezhaaically.

Suspensioninsulators(see fig. 10-5) were do-HARDWARE veloped whenvoltageswer.; increased above 44,000 voLs.ney area big advantage since Hardware consistsof a variety of bolts, pin insulatorsbecome quite heavy at these highnuts, screws, braces and clamps, which enable

$13 3,23. CONSTRUCTION ELECTRICIAN 3 & 2

LOW VOLTAGE

73.354 TWO-PIECE TRANSMISSION Figure 10-5. Suspension type insulator.

73.353devices, because they are used for isolating only Figure 10-4. Pin type insulators. certain parts of the line. By opening a disconnect switch, linemen can cut a line off from you to mount crossarms, string guy wires, andthe main line or circuit, for repair work, without hang transformer banks. Figure 10-6is andeenergizing the complete circuit. This type of example of somi; f the common types of hard-switch is made for single-pole or gangoperation. ware with which you will be working. Although it may be motor-operated, it is more commonly operated by hand on the ground, by throwing a switch handle. Both handle arrod PROTECTIVE DEVICES mustbe grounded. A handle-to-the-ground operated gang disconnect switch must also have Circuit protective devices are divided intosome means of locking the switch in ON or OFF two main categories: primary devices and sec-position, to prevent operation by an unauthorized ondary devices. The primary devices protect theperson. Figure 10-7 shows gang-operated dis- high-voltage transmission lines, the transformerconnect switches. installations, and the substations. The secondary devices protect the electrical equipment on the secondary side of the transformersthat is, the Primary cutouts or fused disconnect switches lighting circuits, motors, and other appliancesare placed ahead of tranformers, in the primary which arethefinal consumers of power. Infeeder, to open the circuit should the trans- this chapter we ara mainly concerned withformer become overloaded to a dangerous point. primary devices. Information on secondary de-They are also used to isolate the transformer in vices is presented in the chapter on interiororder to make repairs or changes on the secon- wiring (chapter 8). dary line.Figure 10-8 shows a 100-ampere 7500-volt fuse disconnect equipped with a standard The primary protective devices consist offuse holdet and fuse link. By substituting the fuseddisconnect switches, circuit breakers,switch blade (shown at left of cutout) for the lightning arresters, and grounds. fuse holder, the cutout can be used as a straight disconnect switch. The switch blade has a 200- Disconnect switches used in transmIssionampere carrying capacity. Figure 10-9 shows lines are not, strictly speaking, true protectiveopen-type fused disconnect switches. Disconnect

314 324 Chapter 10OVERHEAD POWER DISTRIBUTION

133/161 THIMBLE CURVED SQUARE ROUND EYENUT CLEVIS WASHER WASHER WASHER 7/16" 9/16" 11/16" HOLE HOLE HOLE

STRAIGHT THIMBLE -EYE (ALSO AVAILABLE IN DOUBLE -SPAN FLAT CROSSARM BRACE TWINEYE DESIGN) CROSSARM BRACE OPEN-HEARTH STEEL

ing111011IIII,1111,114

THIMBLE CLEVIS DOUBLE ARMING BOLT, THREADED FULL LENGTH INSTALLED ON INSULATOR II 11 11 1 1111111 111' tntilltltr 1-1/2" X 2" MACHINE BOLT OPENING EYEBOLT 4 to" 5/8" 1111111LIA0,1111111111!

I-1/2"X2" OPENING SHOULDER EYEBOLT HOOK-HEAD POLE STEP

11111111itilultm 11)11»,»P»»111»10111!IIIMIT)110»ii)k X 2" I I CARRIAGE BOLT OPENING DOUBLE-ARMING EYEBOLT !tttttrnI

LAG SCREW DR111»11)1 A » ANGLE THIMBLE-EYE BOLT »»»»»)))»ERIBIN»)! STRAIGHT THIMBLE-EYE BOLT THIMBLE-EYE NUT

73.355 Figure 10-6. Pole line hardware. 315 325 CONSTRUCTION ELECTRiCIAN 3 & 2

5/6"X 3" GALV MACHINE BOLTS

41te.-L

HEAVY 6-PIN CROSSARM

I/ 2"X5"L."'", SCREWS

CONTROL-ROD GUIDE

1"EXTRAI, HEAVY

CONTROL-ROD INSULATOR

PIPE CLEVIS

SWITCH HANDLE

GROUND PADLOCK LEVEL GROUND

73.356 Figure 10-7.Gang-operated disconnect switches. switches are generally used in the primary circuit when opening the circuit is necessary 73.101 under voltage but with little or no load current. Figure 10-8.Fused cutout and disconnect Oilcircuit breakers are used in circuits blade, carrying more than 600 volts. One of these can be used to open a circuit automatically uponarresters and circuit breakers which are integral overload.Theyaregenerallydesigned andparts of the transformer (fig. 10-10). A heavy connected for one or more automatic reclosings, overload on the secondary circuit opens a breaker thus restoring service rapidly when a fault hasinside the tank, disconnecting the transformer cleared itself. Oil switches are, therefore, usedfrom the load. Overloads not large enough to where control of a high-current circuit as well damage the transformer cause an indicating light as protection from overload and short circuiton the outside of the tank to turn on. The glow- are desired. ing light indicates that the load is too large. Some transformers are protected against ex- Unless the overload is only temporary, the trans-. cessivevoltagesandoverloadby lightning forme r must be replaced by one of larger capacity, 316 326 Chapter 10OVERHEAD POWER DISTRIBUTION

OVERLOAD-BREAKER OPERATING HANDLE

OVERLOAD LIGHTNING INDICATING PROTECTION LIGHT

LIGHTNING PROTECTION

73.103 Figure 10-10.Self-protected transformer. ing device. Tills is the same action as a safety valve on a steam boiler. When an excess of pressure builds up intheboiler, the valve 73.102 relieves the excess by opening up. It then closes Figure 10-9.Open-type fused disconnect automatically as the pressure returns to normal. switche s. POWERLINE ERECTION a* some of the load must be transferred to a iifferent transformer. The erection of powerlines is a responsibility of the CE 3 and 2. This phase of our discussion will acquaint you with various duties involved in LIGHTNING ARRESTERS the erection of powerlines; for instance, preparing poles, erecting the poles, stringing and tying Various types of lightning arresters are used conductors,and so on. We willalso cover n transmission work. A few examples of light- safety apparel and equipment, care of pole- Ling arresters which you may encounter in your climbing equipment, and safety precautions to be york are shown in figure 10-11. A lightning observed in the erection of powerlines. Lrrester protects a line against the very high roltagewhich occurs when lightning strikes. PREPARING POLES When a voltage rise above normal occurs, an Lrch forms across a horn-gap in the arrester kt an advanced base you may have to use Lnd the overload passes from the horn-gap to standing trees as eoles. If this is so, select ;round through the ground wire or other ground- the straightest trees you can find and trim them.

317 CONSTRUCTION ELECTRICIAN 3 & 2

BROWN PORCELAIN BROWN PORCELAIN BROWN PORVLAIN BODY BODY BODY

GROUND CLAMP 5/16" MAX. BARE 01A. COPPER

VISIBLE GAP TYPE VAIVE TYPE PELLET TYPE EXPULSION TYPE WITH ISOLATOR

73.104 Figure 10-11. Types of lightning arresters. Trimming consists of cutting branches off is toward the ground. Men cut the roof diag- flush with the trunk. This procedure is necessary onally and thegainor gains on the upper to make the pole safe for a linemnn to climbsurface, so that the relation of roof to gains using tree gaffs. is as shown.in figure 10-12. Remember that the gain is always cut on the face of the pole, Most of the poles you will use will be already and thefaz:e is the inside of any curve the trimmed and treated with creosote (to preventpole may have. Following this rule ensures rotting) before they arrive at the site.-Creosote thatthepull of wires on the crossarm will is a toxic compound that will blister the skin. be against the curve of the pole. Remember, Therefore, use gloves when handling or climbing too,that theslopeoftheroofshouldbe creosote-treated poles and AVOID touching your paralleltothe wire lines, not across them. eyes with the gloves. Be sure to have yourThe reason for this is to ensure that water sleeves rolled down. draining off the roof will run down the back of the pole, and not into the crossarm gains. The next step is to cut the "roof" (a roof- The center of the first or top gain should like cut at the upper end, made by sawing a be located 12 in. from the top of the pole. Since single slant cut that drains toward theback the width el the gain is the height of the crossarm, of the pole) and the "gains" (a gain is a notch measuring half the height of the crossarm above in which a crossarmisset).This cutting and below the center of the gain will give you should be done with the pole in a rack of some the top and bottom of the gain. The gain should kind which will hold one end of the pole above be cut about 1/2 in. deep. It is good practico the ground.Ifthe pole is curved, it should to make the gain slightly concave, so the cross- besetinthe rack so that tha curve or sagarm will bear solidly against the outer ends.

318 328 Chapter 10OVERHEAD POWER DISTR1H I7TION

Table 10-1.Depth for setting pole in soil or rock

ROOF TOP En0 Length Setting depth r,f pole (ft) ft) In soil In rock THROUGH GAM BOLT LO HOLE 5. 0 3. 0 Z5 5. 5 3. 5 30 5. 5 4. 0 35 6. 0 4. 0 40 6, 0 4. 0 45 6. 5 4. 5 50 7. 0 4. 5 BACK 55 7. 5 5. 0 60 8. 0 5. 0

FACE 73.310

GROUND LINE

STRAIN

29.233 Figure 10-12. The parts of the pole. SURFACE OF The spacing between succeeding gains depends on GROUND thevoltageinthe lines. For voltages up to 8700 volts the minimum spacing is 24 in. For voltages from 8700 volts to 60,000 volts the He+ rnininr,rn ?pacing is 48 in, The next step is to bore the holo for the crossarn) through-bolt in the center of the gain 6-FOOT (see fig. 10-12). The standard through-bolt has LENGTH a diameter of 5/8 in. The diameter of the bolt OF POLE hole should Jx11/16 in. To center the hole, draw intersocting diagonal lines across the gain. 11 D[Gt aNG POST HOLES The depth for a pole hole depends on tho length of tho polo and tho composition of the soil. A hole in firm, rooky terrain does not need Figure 10-13.Cribbing a polo withsto7.69ne3 to im an (loop/lbfthuh.) in ooft soil. Table 10-1 and log.

319 329 CONSTRUCTiON ELECTRICIAN 3 & 2

There may be a power-driven hole-digger available, but in the absence of one of these the holes must be dug by handtools (fig. 10-14). You use a "digging bar" to loosen the soil. About SPOON the first 2 ft of depth can be removed with a short-handle shovel. Below that you loosen the earth with an earth auger or long-handle shovel, LONG-HANDLE SHOVEL and haul it up with a long-handle device called a spoon. -5 BAR A hole should have a diameter about 6 in. larger than thatofthe base of the pole, to EARTH AUGER allow room for tamping backfill. It should be a little larger at the bottom, to allow for plumbing the pole. ERECTING POLES 29.234 Figure 10-14,Digging tools. If a line truck with- winch and A-frame is gives recommended post-hole depths for polesavailable, the job of erecting poles is simple. from 20 to 60 ft long in firm soil and in rock. A sling is placed around the approximate midpoint of the pole and the winch heaves it up. The truck A pole set in sandy or swampy soil must be then proceeds to the hole, and the base of the pole supported by guys or braces, or by "cribbing."is guided in as the winch lowers away. Since the Cribbing means the placement of some firmbutt or base is heavier than thetop end, the material around the part of the pole that ispole will be raised to an almost vertical posi- below ground. One method of cribbing is to tion. sink an open-bottom barrel in the hole, set up the pole in the barrel, and then fill the space around the base of the pole with concrete or small In the absence of this equipment, the pole stones after the pole has been plumbed (brought must be "piked up"meaning that the pole is to the vertical), Another method of cribbing is placed with base adjacent to the hole and the shown in figure 10-13. upper end supported on either a "mule" or a "jenny." A jenny is a wooden support made in the form of an X, while a mule is a wooden stip- port made in the form of a Y. The upper end is CANT HOOK then "piked" into the air by men usingpike poles. (PEAVEY) A pike pole and mule are illustrated in figure 10-15.

PIKE POLE This procedure is illustrated in figure 10-16. The "butt man" holds and guides the butt of the pole with a carat hook or "peavey" (see fig. 10-15). This is a handle, the hook being designed to grasp the pole when pressure is applied to the handle. As the upper end of the pole is raised, a man keeps the jenny or mule in approximate POLE SUPPORT contaot by moving it toward the butt. The "butt (MULE) board" is a length of plank, set in the hole and long enough to protrudeabove thesurface. It prevents the butt of the pole from sliding 29.235 past the hole, and also prevents the butt from Figure 10-15. Pole tools. caving in the side of the hole. After the pole 320 330 Chapter 10OVERHEAD POWER DISTRIBUTION

RAISE PIKERS

73.70 Figure 10-16. Piking up a pole. has reached upright position,it is"facod". - man shovels. When the hole has been filled meaning that it is rotated with the cant hook to ths ground line with tamped baAfill, the re- bring the crosearm gain to proper position.maining exoavated soil is banked in a mound On a straight line it is the custom to set adjacent around the base of the pole, to allow for sub- poles with crossarrr^, facing in opposite direc- sequent settling. tions, as.own in ,,ure 10-17. This procedure, called facing "gain to gain" or "back to back," SAFETY IN POLE RAISING providesfor maximum strengthin the line. As a pole is being raised,itis safest to assume that at any 1em3at something may slip On a curve the gains must be set so that theor break. Stand as tar away from the pole as crossarm is on th3 side of the pole nearest thepossibleif you are not in the raising crew. center of the curve, as shown in figure 10-18. The pike-pole method of setting poles should After the pole has been faced,it must benot be used unless thsre are enough mea to plumbed vertical. This is done by four pikers dothe work safely. In using pikes, the men on four sides of the pole, acting on signals givenmust stand far enough apart so that they will by one man who sightsalong the line andnot interfere with each other. Never brace a another who sights from one side. In somepike pole on your stomach. If the pole shifted cases a small amount of rake or lean (approxi-your way, you would not be able to gat clear. mately 12 inches) is left to allow for a wireUnmanned pikes aloneshould not 133 relied strain or the normal give of a guy. upon to support a pole while a man is on it. All pike pole tops shoald be kept covered atall After the pole has been plumbed, the hole is time3sxcapt when actually in use, backfilled and the backfill tamped down hard. Backfilling should be done gradually, in shallow layers, with each layer thoroughly tamped down. Workmen should not be on poles while they Usually two or three man tamp while a single are being plumbed, canted or tamped.

321 331 CONSTRUCTION ELECTRICIAN 3 & 2

/3.72 Figure 10-18.Facing crossarms on a curve. A "line" guy is one installed in a straight pole line and parallel to the line, to reinforce thelineagainststresscausedby broken conductors. A "head" guy is one which runs from the top of one pole to a point below the top on another pole. An 'arm" guy is one which runs from the end of a crossarm to the next adjacent pole. It is used when a line dead ends at the end of a crossarm.

A "storm" guy (fig. 10-19) is one installed in a line to prevent the entire line from being pulled down in the avant that line conductors should break at some point in the line. A storm guy consists of two line guys (that is, guys running parallel to the line) and two side guys (guys running crosswisetothe line). Storm guys are Usually installed at intervals of 1/2 mi to 1 mi. A "sidewalk" guy is outrigged (as shown in fig. 10-19), so the guy will not obstruct pedes- train traffic on the sidewalk. A guy which runs from the top of a pole to a ground anchor is called a "down" guy.

A "stub" guy runs from the top of a pole to 73.71 the top of a shorter pole called a stub. The stub Figure 10-17.-- Facing crossarms on a itself braced by a down guy. straight line. Locating Guys A "guy"isa brace or 'cable which is "anchored" in some fashion at the lower end, GI:is are installed and secured to a point on the pole at the other, t.tt any place in the line where the stress of the conductors could.pull and serves to brace the pole in position. Normally, the crosnarms or the pole out ofproper posi- cable or wire guy is made of 7-strand galvanized tion. It is not possible to mention all the situations steal. There are various types of guys used,which call for guying, but some importantguy soma of which are as follows: locations are as follows:

322 332 Chapter 10OVERHEAD POWER DISTRIBUTION

STRAIN INSULATORS 6' Ou MINIMUM

8'-0" MINIMUM

, r - r-,---/ ANCHOR/ jll DEAD END GUY

CORNER GUY

kv.,t I

STORM GUY SIDEWALK GUY

73.73 Vigare 10-19.--Types of guys. 233

323 CONSTRUCTION ELECTRICIAN 3 & 2

DEAD ENDS.Dead ends or terminals must be The "expanding anchor" (view B of fig. guyed as shown in figure 10-19. 10-20)is installed by digging an 8-in, hole in line with the guy wire from the pole or at about a 450 angle. The anchor is put in the hole, and CORNERS.Corners (thatis, poles wherea heavy tamper is slipped over the rod. The the line changes direction radically) must beanchoris rammed withthe tamper until it guyed as shown in figure 10-19. expands toits full width. This usually takes about five or six blows with the tamper. BRANCHES.Where a branch line takes off The "log" anchor (view C of fig. 10-20) from a main line, a side guy (fig. 10-19) shouldis a simple do-it-yourself type which is very be installed to support the stress of th e. brancheffective in soft or sandy soil. The log usually line. consists of a 6-ft long section of a pole. The trench is dug at right angles to the line of the ANGLES.A corner is, of course, an angle,guy, to a depth of at least 6 ft, and long enough but it is an angle which comes close to 900.to receive the log. A narrow trench, to accom- When a line makes ANY angle, however slight, modate the guy, is dug as shown. A threaded aside guy should be installed. For a largerod is run through a hole in the log and secured angle, two or more guys should be installed.with nut and washer. The rod :s long enough to permit the eye in the upper end to reach a point 6 in. above the ground line. CROSSINGS. Electric lines crossingrailway tracks must be equipped with head guys installed A "screw" type anchor is one which can be on poles on both sides of the crossing. riese "screwed" into the ground as shown in view D guys rual from the top of the pole adjacent to of figure 10-20. A shallow hole is dug to start the tracks to about midway of the next pole.the screw blade, and the rod is then rotated by two men using a bar-toggle run through the eye. Strain Insulators CLIMBING POLES All guys on powerlines should have one, preferably two, strain imlulators installed in the guy to break contact between ths upper part of To climb a woodon pole or tree you wIll use the guy and the part low enough to be contacted the equipment shown in the lower part of figure by persons on the ground. The lower insulator 10-21. The "stirrup"fitsunder the arch of should be at least 8 ft above the ground andyour foot, and the leg iron runs up the inner the upper one should be placed at least 6 ft from sideofthecalfof your leg. This puts the the pole to prevent electrical contact (fig.10-19). "gaff" in a position on ths inner side of your foot where you can drive it into the pole or tree GUY ANCHORS as you climb. Two leather straps run through the loop straps and hold the climber tightly against your calf and ankle. The "leather" pad keeps For securing the lower or ground ends of guys the upper end of the climber from digging into there are various types of "anchors" used, some your leg. of which are illustrated in figure 10-20.Ths "Never Creep" anchor (this is a trade name) The term "leather" refers not only to treated isinstalledby digging a hole about 8 in. in animal hides but also to neoprene impregnated diameter, at about a 450 angle and sloping down nylon products such as body belts, safety straps, toward the pole. After the hole is dug, a rod is and leg straps. These non-leather items are driven in the ground in line with the guy wirecleaned with soap and water and are available from the top of the pole. This rod intersects to the battalions. ths hole at a right angle about 6ft from the The "safety strap" and "body belt" shown in surface. The plate part of the anchor is thenthe upper part of figure 10-21 are what might placed over the rod and locked on by the slot be called your extra pair of hands when you work plate. A Never Creep anchor is shown in view aloft. The body belt, strapped around your waist, A of figure 10-20. contains various pockets for small tools. The 324 334 Chapter 10OVERHEAD POWER DISTRIBUTION

A NEVER CREEP ANCHOR

LOG ANCHOR SCREW TYPE ANCHOR

73.74 Figure 10-20.-- Types ofguy anchors in gonsral use. safety strap is a "leather" belt with a tongue-way, or a good part of the wa.,, down a pole as type buckle (keeper snap)at each end. Whilea result of defective equipmen'; or some error you are climbing you will have the safety strapin climbing techn:que made on Cie way up. The hanging by both ands from the left ring (called aburning you get doesn't need , le explained in D-ring because of its shape) on the body belt.detail, and be.s' leg burniig y may get a good When you are at working position, you willunsnapmany splintern. Acwev,r, nbers, body belt, one end of tho safety strap, pass it around theand safety strap sh . you up where you pole, and hook it to the right "D" ring on thebelongif you use tlera properly and take proper body belt. One adjustable buckle permits variationcare of them. to suit the lineman and the circumference of the The body bolt andsafetystrap require pole. You can now lean back against the safetycontinuous inspection. Look for: strap and maintain a steady, comfortable, and SAF E position. 1. Loose or broken rivets. 2. Cracks, cuts, nicks, or tears in leather. Care of Climbing Equipment 3. Broken orotherwise defective buckles. To a lineman the term "burning" apole means 4. Deffectsinsafety-belt snap hooks and the highly unpleasant experience of sliding all the body-belt D-rings. 325 335 CONSTRUCTION ELECTRICIAN 3 & 2

SAFETY BELT

POLE CLIMBING SPUR OR GMF TREE CLIMBING SPUR OR GAO

SAFETY STRAP FOOT LEO IRONS LEO

73.357 Figure 10-21. Pole-climbing equipment. 3. vv;-,rn leather. sure the leather is clean before applying oil. 6. Enlarged tongue holes for belt buckles.Use about2 teaspoonfulsof neat's-foot oll, working ths ell in gradually. Place the belt in If you discover any of tly.:se defects, turn in a shady place and allow to dry for 24 hours. Then I the oquipment and replace it. rub down with a soft cloth. You must periodically perform mairt.2nonce Always, before you climb a pole or tree, work ontheleather parts of your clirol$Iyig inspect the climbers for the following defects: equipment. Cleaning comes fir3t. Use a Ournp sponge and a mild soap. Work up a thick, el awirj 1. Broken or loose straps. lather. Then wash the soap off and the hAt 2. Stirrup worn to a thickness of 1/8 in. or with a dry clotli. less. 3. Length of pole gaff or less than 1 1/4 Next, to make the genuine le- &rid in. as measured along the inner surface, pliable, lather well with saddle :3utl.p.V, unt the 4. Length of tree gaff not less than E 1/2 latherintoallparts; then place the belt in in. as measured along the outer surface the shade to dry. After the lather has nearly and not less than 3 1/2 in. along the dried, rub down the leather with a soft cloth. inner surface. Body belts and safety straps made of genuine 5. Difference in gaff lengths of more than leather require oiling about every 6 menths. 1/8 in.

326 336 Chapter 10OVERHEAD POWER DISTRIBUTION ONIMII=11=a10

If you find any of these defects, turn in your climbers for a new pair.

LONA REFERENCE LINE

OPENING Climber's Gage To minimize certain dangers which can occur from neglect of the climbers, make sure you check your gaffs frequently using a climber's gage (fig. 10-22). This gaga is used to check the dimensions of gaffs. These must be within certain tolerances or the climber will "cut out" or lose contact with a pole or tree.

SNORT REFERENCE LINE Measurements of the length, width, and thickness of the gaffs are made as follows. 26.259 LENGIA. Place the lined face of the gage Figure 10-22.Climber's gage. against the inner surface of the gaff with the short edge of the gage held tightly against the crotch (fig. 10-23A). The crotch is the point where the gaff joins the leg iron. If the point of the gaff extends to or beyond the short reference line, the length of the gaff is satthfactory. WIDTH. Insert the gaff as far as possible through the small slot marked W, with the inner surface of the gaff resting against the lined face of the gaga (fig. 10-23B). U the point of the gaff does not extend beyond the long reference line, the width of this section of the gaff is satisfactory. Insert the gaff as far as possible through the large slot mnrked W, with the inner suiface of the gaff towaA the lined face of the gage (fig. 10-23C). If the point of the gaff does not extend beyondthe far edge of the gage, the width of this section of the gaff is satisfactory. THICKNESS. Insert the gaff as far aspossible through the small opening marked TH, with the innersurface of the gaff resting against the lined face of the gage (fig. 10-23D). If the point of the gaff does not extend beyond the reference line, the thickness of this section of the gaff is satisfactory. Insert the gaff as far as possible through thelarge opening marked TH, with theinnersurfaceofthe gaffrosting against the lined face of the gage (fig. 10-23r)0 If the point of the gaff does not extend beyond the far edge of the grge, the thickness of this secton of this gaff is satisfactory. Sharpen any dull gaffs by taking long strokes with a file' from the heel to the point of the gaff, removing only enough material to make a good point. NEVER USE A GRINDSTONE OR EMERY 26.260 WHEEL TO SHARPEN GAFFS, sinoe the metal Figure 10-23.Use of climber's gage. may become overheated and lose its strength 327 337 CONSTRUCTION ELECTRICIAN 3 & 2

(temper). Never sharpen the gaff toa needle- point (fig. 10-24) since it will sink toodeep into the pole and make climbing difficult.Al- ways leave a shoulder about 1/8 in. back from the point. Remember that climbers are foruse on poles ONLY. Do not wear them while working on the ground, and do not use the gaffs for such I/8" irregular procedures as the opening ofcans and the like. -T- Going Up RIGHT Before starting to climb a pole, there are a number of preliminary steps that should be 26.261 taken. First,of course, make the preclimb Figura 10-24. Sharpening the gaffs. inspection of equipment previously described AND PUT ON YOUR HARD HAT. Then inspect the pole to determine the best sideon which to start. This is usually the back, or high side. Get against the pole and grasp each side of it with your handsnot that you will hand-support your weight in climbing, but simply because you will use your hands to help in balancing yourself on the climbers (fig. 10-25). To learn pole climbing you must practice actual pole climbing. Some pointers that will

^ help you become efficient in pole climbing in a_ minimum time axe as follows; Raise your right leg about 8 in. off the ground BOOY APPROXIMATELY and sink thegaff on that leg into the pole. PARALLEL TOPOLE Don't jab the gaif in the wood. Allow your weight to sink it in. Now, swingyourself up off the ground and lock your right leg in stiff-leg position, ;4; so that all your weight is supported on that leg. KRILL HI NT

,414"41 As the next step, raise your left foot about APPROx 8 "10' in. and sink the gaff on that foot into the wood. Then swing up onto the left leg stiff- pgi legged, and take the next step simaarly with the right foot. Continue this stepping up and looking stiff-legged until you reach working position. Keep the upper paxt of your body away from the pole;If you "hug" the pole, you will tend to H 10IN (NOT! I NOTL throw the gaffs out of the wood (fig. 10-26). (WITH OF 'OLP 'RILL VARY IN ACCORDANCt WITH THr SIZE OFmr LAEMAN At Working Position At working position your feat should be Placed so that most of your weight is on the right foot, stiff-legged. The left foot should be slightly above the right, so that the left leg is slightly bent. When you have atained this position,you must 73.311 proceed immediately, with greatcare, to attach ?igure 10-25. Starting to climb a pole, the safety strap. 328 338 Chapter 10OVERHEAD POWER DISTRIBUTION

KNEE BEND

APPROX 30 SAFETY STRAP

GAFFS ENGAGED AT SAME LEGS LEVEL

, STRAIGHT * 8-10 IN (NOTE)

NOTE LENGTHorSTEP WILL vrtar IN ACCORDANCE WITH THE SIZE OF THE L INEMAN 73.313 Figure 10-27. Working position.

73.312 Coming Down Figure 10-26.Continuing tile climb. Bdore you start down the pole you must Crook your right arm around the pole. Userelease the safety belt. Crook your left arm your left hand to unsnap one end of the safety arouna the pole, and unhook the safety strap from strap from the left "D" ring on the body belt.the right D-ring with the right hand. Pass the Holding the end of the safety strap In yourend of the safety strap to the left hand, crook left hand, pass it around the back of the pole. your right arm rcound the pole, and snap the end Transfer the end of the safety strap from the left of the safety strap to the left D-ring. hand to the right hand, at the same time crooking you are now ready to descend. Break out the your left arm around the pole to hold yourselfleftgaffby swinging the left knee out from in position. Then swing the end of the safety the side of the pole. Step down with the left foot strap quicl ly around with your right hand and to a point about 12 in. below the right; stiff- snap it onto the right D-ring on the body belt.leg the left leg, and bring your weight on it to sinkthegaff. Then break out the right gaff WARNING Visually check to ensure that the by swinging the right knee away from the pole snap engages the D-ring. Don't depend on the (fig. 10-28) and proceed as formerly with the left sound of the keeper snapping to indicate thatleg. Continue this stepping-down process until tho snap-hook has engaged the D-ring. you have reached the ground. Safety In Pole Climbing you can now release your left arm gradually, so as to lean back against the safety strap (fig. Ne-otr climb an erected pole until it has been 10-27). plumbed, backfilled, and tamped. Before going 329 339 CONSTRUCTION ELECTRICIAN 3 & 2

Never use an improvised safety strap, or one that has been lengthened by the addition of rope or wire. Never attach the strap to pins or to crossarm braces. Never put the safetystrap around the pole above the highest crossarm if the length of pole above the crossarm is short. The strap should never be loss than 1 foot below the top of the pole. Never wear climbers except for climbing. Be careful not to gaff yourself or anybody else. Some additional precautions to keep constantly in mind are as follows: 1. NEVER carry tools or other objects in your hand when climbing. 2. NEVER trust pins, crossarm braces, or guy wires as supports. 3. If you are working with anotherman on the same pole, and he goes up first, wait until he is strapped in working position beforeyou start up. 4. Do not depend on the snapping sound when you snap the safety strap to a D-rini Look down to ensure that the snap is engaged to the ring. A 5. If the top crossarm is near the top-/of the pole, do not pass the strap around the short 73.314 lergth of polo protruding above the orossarm. Figure 10-28.Descending. Protective Clothing and Equipment aloft, make sure the pole can stand your weight, and carefully mOce the previously described A lineman shouldalw.*: -tr gloves or inspection of body belt, safety strap, and climbers, gauntlets when tending -. atringing conductors. Never work ..... gauntlets of the Tie bodybelt contairt.'; pockets for small gloves turned down. tools. It is important to keep the tools in these Do not wear hobnailed shoes or shoes with pockets. Never use the center loop in the bodymetal plates. When trimming trees for pole lines, belt for carrying a tool, however. In case ofa wear rubbers or rubber-soled shoesfor climbing. fall, the tool may injure your tail bone. Always test safety strap and body belt before using them. Never wear a strap with stitching across it,or one mended with tape. Make all If you try to climb with tools in your hands, the safety checks of climbing equipment every time your own balance on the pole will be unsafe, andyou prepare to go aloft. you could drop tools on someone below. Pole-Top Rescue The safety strap is used to secure you to the pole, leaving your hands free to work. Asyou go When a man working aloft is shocked into up it is always fastened to a single D-ring onunconsciousness, there are several ways of thebody belt. For a right-handed man it isperforming "pole-top resuscitation," depending carried on the left D-r1ng. on the prevailing circumstances. 330 340 Chapter 10OVERHEAD POWER DISTRIBUTION

4.227 Figure 10-29.Oesterreich method of pole- top resuscitation.

If the victim has not received severe face or nose injuries, the mouth-to-mouth method should be given in preference to other pole-tog methods, becauseitiseasiertoapply, can be started more quickly, is more effective, and can 73,358 be given for a longer perio:i of time mithout Figure 10-30.Knot detaiis of rescus htch tiring the operator. Th3 same :Niles apply for 71sing a body belt and rope. this method on a pole as for on the ground. abdomen with an upward squeezing motion. At If the mouth-to-mouth method cannot be used, the finish of this motion, cup your hands with the the next-best alternative is the Oesterreichpole-fingers depressing the abdomen just below the top method. This is administered as follows.breastbone. Repeat this process of squeeze, First free the victim from electrical contact, pressure, and release about 12 times a mlnute. making careful use of rubber insulating equip- Ifthevictim begins to breath, take care to ment. Then, if possible, maneuver him into ver- keep him under control while the violent motion tical position and remove his climbers. which usually accompanies recovering conscious- ness is occurring. Next take a position on the pole just below If you are the only other person !besides the the victim's feet, and with your safety belt around victim) at the scene, inch yourself and the victim thepole,climb behind the victim with your safety strap between his legs. When the strap down the pole as you apply the resuscitation. is as high between the legs as you can got it,After you complete each stroke, lean forward to hold the victim In straddle position on the strapslacken the safety belt (while etiii holding the as shown in figure 10-29A. victim onit)and move downward, even if you Next clear the victim's mouth of any ob- can only make an inch or two. structions and/or foreign matter and tilt the head If others are available on the ground, have a back to clear the air passage. Then encircle theline passed up and secure it to the victim (see waist of the victim with your arms, and place fig.10-30). T len secure a line to yourself. both hands on his abdomen, with thumbs belowBoth you and the victim should be lowered at the ribs and fingers touching, as shown in figure the same time so you can continue to give arti- 10-29B. With your arms and hands, compress the ficial respiration.

331 341 CONSTRUCTION ELECTRICIAN 3 82

This gives the man doing the sighting an advantage. When a crossarm is mounted before the pole is set up, the crossarm through-bolt is sat up tight, but the crossarm braces are left hanging loose. After the pole is set, the crossarm is leveled and the braces then attached. Finally, the through- bolt is set up hard. HALF-HITCH TOP If the crossarrn Is mounted after the pole is set, it is ptdled up to a lineman in working position by a helper on the ground, using a handline attached as shown in figure 10-31. With the handline attached in this fashionthe lineman can, after he inserts the through-bolt, cast off the upper half-lutch, and the helper on the groundean then heave the crossa3rn level. Braces are usually fastened to a crossarm with 3/8-in, by 4-in, carriage bolts. Each brace comes down diagonally and is attached to the pole at the lower end with a 1/2-in, lag screw. CLOVE-HITCH On a straight line without excessive strains, BOTTOM crossarms are used singly-mounted face-to-face or back-to-back, as previously mentioned. At line terminals, corners, angles, or othsr points of excessivestrain, crossarms are doubled. Where a powerline crosses a railroad or a telephone line, crossarms should bs doubled. When double arms are used, they arefastened together at the ends with double-arm bolts. One of these is threaded all the way, and has two 73.75 square washers and two nuts on eachboltbstween Figure 10-31.Crossarm, showing the proper the arms. The lineman can adjust the spacing way to fasten handline. between a pair of crossarms by settingthese nuts the desired distance apart on the threaded bolts. After a victim has revived, keep him as quiet as possible until he is breathing regularly. HE.ve him lying down, of course. Keep him well covered SECONDARY RACKS and under constant close observation. Do not allow him to sit up, walk, or move until he is under Secondary conductors may be strung on cross- regular medical care. arms, but are usually put on secondary "racks." These racks are made in sizes to accommodate 2, 3, or 4 conductors, A secondary rack is mounted MOUNTING CROSSARMS AND RACKS on the side of a pole (for a straight run) or on the inside of a pole (for a dead end). A raok is Crossarms are made in a variety of sizes,fastened to the pole with lag bolts on a straight the size used depending on the voltage on the line line,with a through-bolt at the top and lag and the number of conductors. For average use, screw at the bottom, or with through-bolts with a "six-pin" arm with four pirs, occupied by nuts for a dead end or where a branch line takes conductors, is common. The size of this arm off from the main line. A dead end secondary gives a good clearance space between condcutors. rack is illustrated in figure 10-32. Crossarms are sometimes mounted on a pole Insulators are held to a rack by a rod passing before the pole is raised and set in the ground. through the insulators and brackets on the rack as

332 342 Chapter 10 OVERHEAD POWER DISTRIBUTiO`

BRACKET

POOL INSULATOR

ROD

26.85 Figura 10-32.Dead end secondary rack. shown in figure 10-32. On a straight line or inside angle the conductor is run on the inside of the insulator. On an outside angle it is run on the cutside. The conductor is always placed here with strain against the insulator. Figure 10-33 shows rack arrangements at corners and angles. Another type of secondary construction consists of a patented bracket for holding a signal conductor. This bracket can be opened in such a way as to perm:t the conductor to be palled over the insulator, which revolves like a pulley during the process. After the conductor has been pulled up to proper sag, the conductor is tied in and the bracket snapped up into vertical position.

STRINGING riT; CONDUCTORS 73.77 There arevarious waysof stringing theFigure 10-33. Rack arrangements at corners conductors. One method incluies placing the and angles.

333 3 4 3 CONSTRUCTION ELECTRICIAN 3 & 2

crossarms for a horizontaldistance of from 1000 to 1500 ft. This line is draped on each crossarm by a lineman climbing the pole. Aftertherope has beerl strung over the crossarms, o".e end is secun, ''o the wires to be pulled, and a couple of turiltaken with the othe-r and around th:, winch drum on the line tiuck. The drum is then rotated to haul in the rope, aril ;he wires with it. As each wire passes a c_ossarm, a lineman must climb the pole to et the wire ir. proper position and guard against twisting. To kecp a paying-out reel fromevolving too fasL, a brake or drage is set against the reel. rhis can be s'Inply a board, held against the outer edge of the reel by a helper. As a wire or wires are being pulled, enough men must ba stationed along the waj to establish a chain of signal communicr4ion fr)rn the head of the line back to the line truck. A neutral wire should always be plAced on a center croosarm pin or on a pole-top pin. With a secondary rack, put the neutral wire on the top spool, so the neutral can protect the hot wires againstanything that might fall from above.Pattingtheneutral on a center pole 73.78 pin also gives the lineman a clear space around Figure 10-34.Cable reel on reel jack. the pole to climb throughthat is, it ensures that the hot wires are a considerable distance reels on a truck or trailer and driving along apart. thelineof right-ot'-way, unreeling the wire. T is method has the advantage of not allowing the When the conductors have been hoisted in place wire to drag on the ground, but in soma locations on the crossarms and dead ended on one end, you may not be able to drive a truck along theyou are ready tostart "pulling in"that is, right-of-way because of rough terrain. heaving on the conductors until each has been raised to p:oper sag. This is done with a tackle No matter how you string the wire, you willequipped with cable grips like those shown in have to mount the reels on some support thatfigure 10-33. A cable grip is a clamp-type device allows them to revolve freely. This is usuallywhich grips the wire tightly when a strain is done by raising a reel on cable jacks as shown in applied to the grip. figure 10-34. A metal rod strong enough to support the reel is put through the hole in the center, and When pulling two or more wires at once, it the rod and reel are jacked up on each side,is best to use the equalizer shown in figure with the leg of the "T" base away from the10-35. This device distributes thc. strain equally reel as shown. You may have to fasten down theon all the wires. bases ofthejacksto keep the strain from upsetting the reel. When jacking ap, it is only When wires have been pulled to approx- necessary to raise the reel just clear of the deck. imatelythedesired sag,a lineman goes to thecenterspanto measure the sag. Meas- When stringing wire in rough terrain, theurement atthe center of each span ensures best method is to anchor a reel to the ground atuniformity. Three common ways of measuring the endof the line by means of guys'run to sag are by dynamometer, by timing vibration, uriven stakes. A rope line is then run over the and by the use of targets.

334 344 Chapter 10OVERHEAD POWER DISTRIE UTION

CABLE GRIP WIRE ROPE EQUA-IZER SNATCH BLOCK

CONOI,C SOH

.-- EYEBOLT

CoNotIc TOP

PULLING LINES CONDUC'OR

o.,E ROPE SNATCH BLOCK

E YE BOLT

73.79 Figure 10-35. Pulling wires with equalizer. A lever-earn dynamometer is an instrumentthen sights from one slat to the other, and the which is installed in the pulling line and which conductor is hauled up or lowered until its lowest measures the strain of the pull. It is used inpoint is on the line of sight between the slats conjunction with a chart which gives the desired (fig. 10-37). pull tension for a given condictor size, span length, and temperature. A traction dynamometer, also After the wiresare "sagged in," you allow installedinthepulling line, provides direct arest period of from 1/2-hour to4 hours readings on the face of the dial. (varying according to the length of the pull), to let the wires adjust themselves to the tension The tirn;ag-vibration pro3ess isdone by in the pull. They will gradually "creep" until striking the wire sharply near one of the poletension in all the spans is equalized. After they supports, and timing by stopwatch the interval have crept to the final position you are ready to which elapses during which the impulse from the "tie in." blow travels to the next pole and returns. This system is not accurate if a wind is swinging the TYING IN CONDUCTORS line,or if the line is being worked on in an adjacent span. Tie wire fastens the conductor and insulator together. Conductors can be tied in various ways, The target-sight;ng method is a simple andbut the ties shown in figure 10-38 are the ones accurate means for measuring sag. The desired most commonly used. Hold the tie wire tight sag is first ascertained from table 10-2. against the insulatoz as you make your wraps around the insulator and the conductor wire. Figure 10-36 illustrates the effect of tempera- In tying in wires observe the following pro- ture on the sag in a 200-ft span of 00 wire.cedures: You target-measure sag by nailing slat targets, such as a couple of pieces of wood lath, on each Always use new, fully annealed wire for ties. pole a distance below the conductor insulator Hard drawn wire is brittle and cannot be pulled equal to the desired amount of sag. A lineman up against conductor and insulator. 335 3 45 CONSTRUCTION ELECTRICIAN 3 & 2

Table 10-2.- Sag Variation With Temperature

No. Temperature (awg) (degrees F) Sag in inches for span lengths of

100 ft 125 ft 150 ft 175 ft 200 ft 250 ft

6 30 5.5 8.5 13 18.5 60 8 12 18 24 90 12 17 23.5 30 4 30 5.5 8.5 13 18.5 25 35 60 8 12 18 24 32 42 90 12 17 23.5 30 39 53 2 30 5.5 8.5 13 16.5 20 29 60 8 12 18 22 26 36 90 12 17 23.5 28 33 44

1 30 5.5 8.5 13 15.5 28.5 24.5 60 8 12 18 21 24 31 90 12 17 ")3.5 28 31 39 0 30 5.5 8.5 13 15.5 18 23.5 60 8 12 18 20.5 23 29 90 12 17 23.5 27.5 29.5 36 00 30 5.5 8.5 13 15 17 21 60 8 12 18 20 22 27 90 12 17 23.5 26 28 34 0000 30 5.5 8.5 13 14.5 16 19 60 8 12 18 19 21 24 90 12 17 23.5 25 27 30

73.244

73.80 Figure 10-36.- Effect of temperature on sag in 200-ft span of 00 wire.

336 346 Chapter 10OVERHEAD POWER DISTRIBUTION

Corona isdefined as "the luminous discharge due to ionization of the air in the vicinity of a conductor when the voltage gradient WOOD STRIPS exceeds a certain critical value." Crossmodulation(oftentheresultof a corroded connection which causes non-linear rectification of currents) may occur when splices are made by twisting or serving the conductors rather than the more positive mr_=chanical splice. Additionally,whenconductorsof dissimilar metals are joined, corrosioa will occur unless specialconnectors designed forthe specific combination of metals are used. Remedies for conductor, insulator, and hard- .....4.9.01011er. ware interference are relatively simple (figs. 10-39, 10-40, and 10-41). Remember, the condi- tionsfor hardware interferenceareset up whenever two pieces of hardware are not securely 73.315 bonded to each other or are permanently separated Figure 10-37.Adjusting sag. by too short an air gap. Additionalspecific precautionsto take to Use the proper size wire. For No. 8 bare useminimize conductor and hardware interference No. 8 bare. For No. 6 or No. 4 bare, use No. include the thllowing: 6 bare. Use No. 4 bare for No. 2 conductor. Use No. 2 bare wire fo: No, 1/0 thiough 4/0 Maintain atleast2-inchclearance bare conductor. throughoralongwood,anda 1 1/2-inch clearance through air from metal insulator pins Use a piece of tie wire that is long enough to toany other metal parts such as crossarm make the complete tie, with enough left over tobraces, through-bolts, square washers, molding allow grasping. After the tie is completed, cut staples,conduit,brackets forarresters and off the excess and form a loop or eye at the cutouts, dead end attachments, ground wires, etc. end of any projecting end of the wire. Permanev bond crossarm braces to- Make positive contact between tie wire andgether on circuiLs greater than 5 kilovolts. Use conductor to avoid chafing and to limit possi- wood crossarrn braces. bilities of causing interference with radio communications. Where local electrical safety codes perm it, bond metal insulator pins together on circuits INTERFERENCE ELIMINATION above 5 kilovolts. Use double-coilspring washers on all Powerlines may be a source of interferencebolts of attachments that support primary con- withradiocommunications. Conductors,inductors, including primary neutral or common sulators, and hardware contribute their share by neutral supported on primary crossarms. means ofspark discharges, localized corona Use ground wire clips in place of staples discharge, and cross rnodilation. when attaching ground wires directly toa pole or crossarm, Lf metal clips are to be used on Spark discharges occur when localized ex- weatherproof or other types of covered ground cessive voltage stress exists. A conductor maywire, remove sufficient covering from the wire become partially insulated by corrosion products so '-itthe metal clip will make good contact Dr an insulator partially conductive due to cca7,ks. wit lie wire. Lf plastic clips are used, this A third source of stress occurs when a conductorproL_dure is not necessary. Ls placed with but a small air gap between it Ensure that ground wires, boad wircs and and another metallic part of a pole. all staples/clamps ara at least 11/2 inches 337 347 CONSTRUCTION ELECTRICIAN 3 & 2

SIDE TIE-SINGLE ARM

NOTE ENDS OF TIE WIRE SHOULD BE BENT BACK FIRMLY AGAINST CONDUCTOR TD PREvENT RADIO INTERFERENCE .

Top TIE SINGLE ARM STEP t HOLD B. WHILE Ai GOES STEP 2 STEP 3 STEP 4 TO A2 B4

B5 et A2 HOLD 91 WHILE SERv!NG A 2 iNTO POSITION A3 PASS B4 OvER LINE WIRE AND SERVE FINISH AT B5 Ht ND B1 DOWN SLIGHTLY

INSULATOR TIES FOR STRAIGHT TOP TIE DOUBLE ARM

SIDE GROOVE TIES FOR LINES is 6-132 INCL.

START TIE BY PLACING MIDDLE OF TIE WIRE AT I11=1/M/FLAW/.= CENTER OF TOP GROOVE Mgr en) brig 6.1111 MAKE ONE FULL RIGHT HAND TWIST BEFORE WRAPPING

TOP GROOVE TIE NOTE: TIES MUST NOT BE REUSED. ALL TIES FOR WEATHER RESISTANT CONDUCTORS FOR LINES 2 /0 AND LARGER TO BE MADE FROM WEATHER RESISTANT COPPER WIRE.

73.316 Figure 10-38.Tying in conductors. from any ungrounded metal parts such as trans- DISTRIBUTION TRANSFORMERS form3r brackets, crossarm braces, and through- bolts. For long-distancepowertransmissiona Clamp bond or ground wires only against voltage higher than that normally generated is other metal parts and with a washer or locknut.required. A transformer is used to step up the voltage to that required for transmission. Then, During coastruction, a lag screw with or at the service distribution end, the voltage must without a double-coil washer under the head should be reduced to that required for lights and equip- be screwed, not driven, into place for the lastment. Again a transformer is used, this time to 1 inch of its length. step down the voltage.

338 3 Chapter 10OVERHEAD POWER DISTRIBUTION

A. KEEP CONDUCTOR CLEAR OF BITS OF F. STRIP INSULATION FROM CONDUCTOR WIRE, KITE STRINGS, ETC. AND MAKE CLOSE CONTACT WITH ThE INSULATOR. B. KEEP ENDS OF TIE WIRES AWAY FROM INSULATOR , G. USE ONLY APPROVED PRESSURE CONNECTORS, AUTOMATIC SPLICE, OR C. USE ONLY BARE, SOFT TIE WIRE. SLEEVES FOR SPLICE.

D. AVOID SHARP POINTS AND PROTRUWNG H. USE SPECIAL BIMETAL CONNECTORS TO ENDS ON TIE WIRE. CONNECT DISSIMILAR METAL CONDUCTORS.

E. MAKE SURE TIE WIRE IS TIGHT. I. USE ARMOR TAPE AND GRADE A NO-OXIDE UNDER HOT LINE CLAMP ON CONDUCTOR.

73.317 Figure 10-39.Corrections for common sources of conductor interference. WHERE NECESSARY, USE CONDUCTING SEE THAT CONDUCTOR IS PAINT TO INSURE GOOD CONTACT IN BARE, CLEAN, AND IN TIE WIRE AND CONDUCTOR GROOVES. INTIMATE CONTACT AVOID USING TIE WIRE TOO LARGE FOR GROOVE.

SPECIFY RADIO-FREE INSULATORS. CHECK FOR HAIRLINE CRACKS. DO NOT ALLOW INSULATOR TO BECOME TOO DIRTY OR COATED WITII SALT, SMOKE, ETC.

AVOID AIR POCKETS BETWEEN PIN AND INSULATOR. USE ONLY METAL PINS.

NOTES: 1. USE FOG-TYPE NSULATORS IN AREAS WHERE FOG IS COMMON. 2. USE CLAMP-TOP POST TYPE INSULATORS AT VOLTAGES OF 24 KILOVOLTS AND HIGHER. Figure 10-40.Insulator interference corrections. 73.318 339 9 4 9 CONSTRUCTION ELECTRICiAN 3 812

CONDUCTOR TO INSULATOR 1 DRIVE GRIP SCREW 2 LOCKNUT, DRIVE GRIP WASHER HEAD PUT 2 INSULATOR TO PIN BOLT, OR TAPPED WASHER

CLEARANCE CLEARANCE, HANGER TO PIN1 SCREW TO BOLT OR PIN ...-ALWAYS USE CLEARANCE, NO.OX.ID UNDER BOLT TO PIN1 CONNECTIONS CLEARANCE, BRACE TO BRACKET FOR OvER 5 KILOVOLTS BOND WIRE )1 WASHER- wHERE PERMITTED HEAD BOLT 2 CLEARANCE, 1 CLEARANCE,. GROUND WIRE TO GUY LOCKNUT 41 SPRING WASHER 2 BRACKET TO PLATE

AVOID TWO GUYS ON SAME PLATE1

AVOID SLACK GUY CLEARANCE, WIRE OR EXTRA GUY1 - STAPLE TO BOLT OR BRACKET1'3

1 GAP DISCHARGES OCCUR IF Cl2EARANCE IS INSUFFICIENT 2LOOSE ON CORRODED HARDWARE CAUSES DISCHARGES. USE BONDED HARDWARE OR SPRING WASHER. 3USE GROUND CLIPS FOR FASTENING GROUND WIRE TO POLE. USE GALVANIZED STEEL DR COPPERWELD STAPLES OVER WOOD MOLDING.

73.319 Figure 10-41. Possible sources of hardware interference and means of prevention. Transformer theory is explained in Basictank and are insulated from the tank by porce- Electricity. To the discussion given there, thelain bushings. The secondary leads are connected following may be added. to studs on a terminal block. Copper straps on the secondary terminal block permit connecting PRIMARY AND SECONDARY the two secondary coils in series or in parallel. a CONSTRUCTION From the terminal block, three secondary leads pass through porcelain bushings to the outside The change in voltage in a transformer depends of the tank. Al oil-level line inside the tank on the number of turns of wire in the coils. marks the level to which the tank is filled with The high-voltage winding is composed of many transformer oil. turnsofrelativelysmall wire,insulated to withstand thevoltage impressed ouit.The secondary winding is composed of a few turns of COOLING METHODS heavy copoer wire, large enough to carry high current at a low voltage. Figure 10-42 shows a There are several methods of cooling trans- single-phase transformer, with secondary wind-formers, such asself air cooling, air-blast ings connected in series and parallel. cooling, liquid-immersed self-cooling, and liquid- immersed water cooling. Self air-cooled types of transformer are simply cooled by surrounding air' In a distribution transformer a secondary coil at itu.ospheric pressure, the heat being removed is wound on ea..% leg of the laminated iron core, by natural convection (Lormal dissipation of heat and the primary coil is wound over the secondary by cooling). This typelbcalled the dry type coils. The primary leads pass through a steeltransformer. 340 Chapter 10OVERHEAD POWER DISTRIBUTION ...1='14MMO

INSULATING LIQUIDS

PRIMARY Insulating liquids have high insulati,ig quality MAINS and serve two purposes: First, they insulate thecoil; and second, they help dissipate the heat generated by the resistance of the windings --1 and eddy currents in the iron core. If this heat ITRANSFORMER ware not removed, the transformer would operate at excessively high temperature, which in turn would damage or destroy the insulation on the coils. SECONDARY MAINS Two common types of insulating liquids are ( A ) mineral oil and Askarel.

Mineral oil is a nontoxic insulating liquid. PRIMARY It is used in different types of high-voltage elec- MAINS trical equipment,suchascircuit breakers, switches, and transformers. Mineral oil must be kept in an airtight container, or else sludge will form,. This sludge will settle in the bottom hfnTRANSF0RMER of the tank and slow the natural transfer of heat. -120 V-- Also the longer mineral oil is left exposed to SECONDARYN aft, the greater is the loss of insulation proper- MAINS ties. ( B )

73.83 Askarelis a synthetic,nonflammable Figure 10-42. Single-phase transformer,with insulating liquid. It has several trade names such secondary windings connected inseries and as Pyranol, Inerteen, Chlorextrol and Asbestol. parallel. This liquid imist be handled with care because ofitstoxic chemical properties. Askarel is The air-blast cooled transformer has the core used in special transformers for applications and windings enclosedina metal enclosure where flammable liquids must be avoided. through which air is circulated by a blower. This type is used for large power transformers Askarel may have an irritating effect upon the with ratings from 12,000 to 15,000 kva, skin, eyes, nose, and lips. It may irritate skin abrasions or tender parts between fingers. The liquid-immersed self-cooled transformer is the type previously describedthat is, with coils To protect yourself when handling Askarel, and core completely immersed in transformerapply castor oil or approved protective cream oil. In the larger sizes, the tanks are providedto the face and hands. Also wear splashproof with external tubes or external radiators throughgoggles. In case the liquid comes in contact which the oil circulates by natural convection with the skin, wash thoroughly with warm water caused bythedifferences in temperature in and soap. the liquid. Ensure thatthe work spaceisproperly ventilated before working on transformers con- The liquid-immersedwater-cooledtrans- taining Askarel. former is sometimes used where a plentiful supplyof cooling water is available. In this AvoidbreathingAskarelvapors. A full type, a coil of copper or brass pipe is installed stomach will reduce any tendency toward nausea near thetopofthetank in the cooling oil. in the event Askarel vapors are inhaled. Make Water is cirollated through this coil and carries sure you eat before handling Askarel. If a job away the heat from the oil as it rises in the tank. is lengthy, you should eat every 2 or 3 hours.

341 3 5 1 CONSTRUCTION ELECTRICIAN 3 &

73.86 26.82 Figure 10-43. Single transformer hung with Figure 10-44. Three-phase bank of crossarm brackets. transformers hung on crossarm.

TRANSFORMER MOUNTING added cost of building the platform.This method isstill used when installing large trans- Transformers are mounted on poles in various formers and in special job applications. Figure ways, such as suspended on a bracket bolted 10-46 shows the platform method of mounting to the pole; suspended from a crossarm witha bank of three single-phase, 25 kva trans- brackets; or set on a platform mounted on anformers, Y-connected toobtain single-phase H-frame. and three-phase power. Single-phase transformers are usually hung with a through-bo.;t type bracket or a crossarm TRANSFORMER LOAD typebracket. Fir:e 10-43 shows a single Most transformers are rated according to transformer hung wan orossarm brackets. Fig. the kva load the transformer can carry with- 10-44 shows a bank of three transformers of out developing a temperature rise ofmore than 25-kva capacity hung the same way. 55°C (about 131°F), given the following conditions; Formerly, dl banks of three transformers 1. The transformer is operating at the rated w hung witn crossarm brackets or mounted voltage, or not in excess of 105 percent of the on a platform between two poles. Because of rated voltage. improved materials, however, transformer capa- 2. The transiormer is operating at the rated cities have been enlarged without increasing frequency. their size and weight. This means that banks 3. The temperature of the surrounding air of three large transformers can now be hung at no time exceeds 40°C (104°F), and the average on apolewitha through-bolt bracket typeduring any 24-hour period does not oxceed suspension, as shown in figure 10-45. 30°C (86°F). The old method of mounting transformers The 55°C allowable temperature rise is a on a platform required an extra pole and the common standard; however, the nameplate of a 342

3 5 2 Chapter 1)- OVERHEAD POWER DISTRIBUTION

75-hp motor would require a 75 kva transformer. Transformers for small motors should have a somewhat larger kva capacity than the motor It kva capacity if the motors are to be run at full , ,,,.;

, +-4 load or slight overload most of the time. Power Ef017''a4, input to the primary coil of a transformer is ea, .4.71;1014111 practicallyequalto outputmeaning that the 1.74, ,ar. power factor is close to 1.00. However, there may be small losses, in which case P will again equal, not the product of E time I, but the product of E ;Ames I times a power factor of less than 1.00.

- . GROUNDING TRANSFORMERS , 4,4 Grounding of a distribution system helps to prevent accidents to personnel and damage to property in the event of insulation breakdown, accidental shorting of high- and low-voltage lines, or a lightning strike. If a high-voltage line is accidentally shorted with a low-voltage line, the current will flow through the secondary coil of the transformer to the secondary ground, which will in turn cause the primary protective device to open the circuit.

4 biZealga..k In this case the primary protective device which 7474 .:''.77:1421. tr, 'a AriMina functions is the substation circuit breaker. An 444Wa, aefigonsmia,t ,a1P1-e., accidental shorting of the primary and secondary s4 -4,, ..4 -,,, WSW ta.3.7,:a ,.:,. ..1.-,-., f ofaX -Imew windingsin ,..,4,VVBAJI1,22tr.14azalti the transformer will causethe 7, .,...." --A.... ".., % '21111g. } 41, ft414triliTtIttrglaMit.'- primary fuse, ahead of the transformer, to open. A+W,12,14/try. I t. JE 14WelgollatiVA 41E bail WV: V. 441 AZW.; AIM r If, howeier, there are no ground connections, the primary voltage will be Imp;7essedon the secondary conductors, which are usually insulated for 600volts,and considerabledamage to 73.88 equipment will occur. Great danger will eidst Figure 10-45. Three 37.5-kva transformers for anyonetouch!.ng any electrical evipment mounted with through-bolt type brackets. at the time. particular transformer may indicate a different Ground resistance must not exceed 25 ohms standard. toground. This resistance can be measured with various portable ground testing instruments, The proper loading of a transformer also su.:th as a megger. One procedure for measuring depends on the balancing of the load on the dis- ground resistance with a megger is shown in tribution conductors. This balancing should be figure 10-47. checked periodically with a clamp-on ammeter, to nsure that the circuit is correctly balanced. Where ground resistance is too high, it may you may at times have to shift some of thebe lowered by one of the following methods: load from one phase to another to keep the load balanced in the transformer. 1. Driving additional rods, spacing them 6 feet apart, and then connecting them in parallel. When currents being supplied to a motor by a transformer, the kva rating of the trans- 2. Larger rods are effective where low re- former should be at least as high as the hpsistance soils are too far below the surface to be 'rating of the motormeaning that a (for example) reached by ordinary length rods. 343 353 CONSTRUCTION ELECTRICIAN 3tftz 2 Mi 111111

`-;

-;;k. S.S.

tr " :4 1 liiii.mmez

-- eta.,, , , 1,..11`, 'NOM' 'NI a ,74 t j WW1 7.,4.41,e; 'Wee' VIIICININy"..1' - ; , A . , - S' ..!q3 'tAt, . ,

qt.'

- , _0: k :r . ,- ;

-.;

_ , It

...e; :..c. '1...... -.

, 41111" exak, 11,4 Artlice" `t.1:Af.tr4r,:t .1=4 Wit ,t ri.tt 144, - 11801ia '1111

amEta Trtr

,L. '54

, *,4 .1- lakrr .51 szgoidA.4.,k2tuik OMNI INal

65.62 Figure 1 0 -46.Three single-phase 25-kva transformers moun- on H-frame platform.

344 3.5 4 Chapter 10OVERHEAD POWER DISTRIBUTION

INTERCONNECTED GROUND 110 VOLTS

MEGGER OR SIMILAR RESISTANCES MEASURING -INSTRUMENT (READS DESIRED GROUND RESISTANCE DIRECTLY)

4T LEAST 25' DRiVE TWO ADDITIONAL GROUND REFERENCE GROUNDS TO BE "32 2 TO 3 FEET LONG MEASURED FOR TESTING

73,359 Figure 10-47.-1\Ieasuring ground resistance where ground wire isinterconnected with groundod distribution neutral conductor. 3. The treating soil method is advantageous the wires. It must be covered to a point 8 feet vhere long rods are impractical because of rock above the base of a pole and insulated where it uid other obstructions. Copperclad ground rods passes all strain guys. )r1/4-inch copper plating may be used for ;rounds to be treated because the heavycopper ixterior resists the corrosive conditions caused TRANSFORMER POLARiTY )3r treating chemicals. Common rock salt, copper iulphate, or magnesium sulphate are used for All transformers carry standard polarity reating the ground. These are placed on top ofmarkings. The letter "H" is used to indicate he soil and not in direct contact with the rodthe high-voltage terminals, and the letter "X" see fig. 10-48). to indicate the secondary terminals. The extreme right-hand lead as you face the high-voltage side 4. A comMnation of ths above methods may beof the transformer is marked "Hl," the next ecessary and advantageous at times. is marked "H2," and so on. The secondary ter- m!.nals,"Xl," "X2," and so on, may be in The installation of a single driven groundnumerical order or reverse order. 'od is shown in figure 10-49. The ground wire T-ansformar polarity is important only when s placed on the side of the pole subject to leasttransformersare connectedpaxalledfor amage from traffic. This wire must be properly single-phaseoperationor are used to supply nsulated from the pole line hardware wherethree-phase service. Figure 10-50 shows ,the lossible. The wire must also be covered withlead markings of single-phase transformers with nolding along the underside of the crossarmadditive and subtractive polarity. Figure 10-51 there it passes other wires on a pole and forshow how to test for polarity if the nameplate , distance of at least 6feet below and 4 feet above is miss.:.ng.

345 5'5 CONSTRUCTION ELECTRICIAN 3 & 2

CAUTION: When mz.king such tests1 voltaze NOTE: TOP OF ROD TO BE must not be applied across the secondary BELOW SURFACE side of the transformer because the primary AND COVERED WITH SOIL voltage would then be equal to the applied secondary voltage multiplied by the transformer turns ratio. This voltage waild be dang3rously 1.41, to personnel and dalv.ge tha voltmeter.

TRANSFORM ER CONNECTIONS Transfozmers are commonly connected for U-I three-phase service by either "delta" connection co or Y-connection Isalso called star con-action). APPROX 18 INCHES-4' APPROX Delta connection(fig.10-52) is made by I FOOT IJ) connecting adjacent terminals of the the trans- -J formers. The right lead of one winding is con- SOIL TREATING MATERIAL 0 nectedtotheleftlead of the next winding. PLACED IN CIRCULAR TRENCH Coil voltage equals phase-to-phase voltage of AND COVERED WITH EARTH COPPERWELD theline. Coil current equals line current in GROUND ROD each phase wire divided by 1.73. Y-connection (fig. 10-53) is made by connect- 73.360 ing the three right (or th3 three left) leads to Figure 10-48. Treating grounds. a common neuti.d. The three left (or right) leads are connected to phase wires of the lines.

WHERE GROUND WIRE IS UNDER CROSSARM IT SHOULD BE INSTALLED EITHER TOWARD THE a ACK OR THE FACE OF THE ARM. THIS PREVENTS CONTACT BY LINEMAN WHEN TOOLS ARE PLACED IN PIN HOLES

APPROX 1 FT SPACING INSTALLATION STAPLE UNDER CR OSSA RM

STAPLES MOLDING TO EXTEND APPROX 3" BELOW SURFACE 2 FT SPAONG

SURFACE

nRMLY TIGHTEN SAFETY SCREW, USE SPECIAL SOCKET WRENCH

A-- GROUND ROD CLAMP NOT LESS THAN 12" FROM POLE

SCRAPE WIRE GROUND ROD UNDIP CLAMP 10-

73.361 Figure 10-49. Ground-rod installation for single driven ground.

346 3 5 6 Chapter 10 OVERHEAD POWER DISTRIBUTION

TRANSFORMER HI AND Xi H H ONSIDE SAME 1 HIGH -VOLTAGE SIDE (RI) (in) 11,1 ego (I,W)

X COIL COIL LOW-VOLTAGE SIDE VOLTAGE CURRENT

PHASE- SUBTRACTIVE POLARITY TO-PHASE LINE CURRENT VOLTAGE

PHASE WIRES

HI AND Xi FOR DELTA CONNECTION DIAGONALLY OPPOSED COIL VOLTAGE PHASE-TO -PHASE VOLTAGE LINE CURRENT COIL CURRENT 1.73 X2 73.92 ADDITIVE POLARITY Figure 10-52. Delta connection.

73.84 Figure 10-50. Lead markings of single-phase transformer.

TRANSFORMER

HIGH-VOLTAGE 2 XI \LEADS ENERGIZE HIGH -VOLTAGE LEADS WITH A LOW COIL VOLTAGE )120 TO 240 VOLTS) CURRENT PHASE 3 TO NEUTRAL MEASURE VOLTAGE BETWEEN VOLTAGE LINE UNCONNECTED HIGH AND CONNECT ONE CURRENT HIGH-VOLTAGE LOW-VOLTAGE LEADS. IF LEAD TO VOLIAGE INDICATED HERE IS ADJACENT LOW GREATER THAN THE VOLTAGE VOLTAGE LEAD IMPRESSED ON THE HIGH VOLTAGE TERMINALS, POLAR- ITY ISADDITIVE", ; IF LESS, PHASE WIRES NEUTRAL SUBTRACTIVE'. FOR T- CONNECTION

LOW - VOLTAGE COIL VOLTAGE PHASE-TO-NEUTRAL VOLTAGE LEADS COIL CURRENTLINE CURRENT

73.86 73.93 Figure 10-51. Test for transformerpolarity. Figure 10-63.Y-oonnection.

347

3 5 7 CONSTRUCTION ELECTRIC:AN 3 & 2

Coil current equals line current in each phase wire. Thus,,fthree2400-volt transformers are Y-connected to a circuit which measures 2400-volts from phase-to-neutral or 4160 volts from phase to ph-se, coil voltage is 2400 volts. Three single-pnase transformers connected to a three-phase circuit are called a transformer "bank." Connections are made with combinations of delta connections and Y-connections, some of which are as follows: A bank of transformers is "delta-delta-connected" when the primary windings and the secondary windingsare both connected in delta (fig. 10-54). In an "open-delta" connection(fig. 10-55) one of the three transformers in a delta-delta bankisdisconnected because of failure.This converts the delta-delta connection to "open- delta" connection for emergency operation. The 73.95 open-delta connection delivers three-phase power Figure 10-55.Open-delta cornection. using only two single-phase transformers. The removal of one of the three transformers reduces use of a primary voltage of 4160 volts with an the capacity of the bank, not to 66 2/3 percent output of 240 volts. Actually the primary voltage ofthe original capacity as on3 might expectof each transformer is 2400 volts, as shown in (100 percent minus 33 1/3 percent), but to 58 figure 10-56. percent of the original capacity. A bank of transformers is "delta-Y-con- )cted" when the three primary windings are A bank of transformersis "Y-delta con- delta-connected and the three secondary wind- nected" when the three primarywindings are ings Y-connected (fig. 10-57). By Y-connecting Y-connected and the three secondarywindings thesecondary, you can take care of three- delta-connected (fig. 10-56). Thispermits thephase power andsing,!)-phaselighting from the same transformer bank. The single-phase

PRIMARY

HIS H2 His H2

73.94 73.96 Figure 10-54.Do lta-delta connection. Figure 10-56.Y-de1ta connection.

348 Chapter 10OVERHEAD POWEA DISTRIBUTION

3-PHASE DELTA PRIMARY

3-F'HASE,4-WIRE 120/208-Y-VOLT r, FOR LIGHT ° AND POWER NEUTRAL

26.87 Figure 10-57.Delta-Y connection. load is evenly distributed by using the neutral wireandalternatelines. You can supply a 110-voltsingle-p:iase lig'ating system from a delta-delta connected bank of transformers by grounding the midtap of one of the transformers; however, this is a disadvantage in that it puts thc ntirelightingloud Da D.1.3 transc.orrL3r. A bank of transformers is -Y-Y-connected" -J (fig. 10-58) when both primary and secondary windingsare Y-conneeted.13ecause the arrangement is one which causes inductive dis- LAJ turbance, it is seldom used.

CU BRENT RANSFORM ERS X2 When a large alternating current iEto be measured, the ammeter is not connected into thelinebut,instead,isconnectedinto the 220V circuit through n current transformer (see fig.. 10-59). Information on current transfornors is 127 V given in Basic Electricity, NA VPEUS 10086-B. If necessary, review material on current trans------127v formersinchapter15ofBasicElectricity before going ontothe next chapter of this mitnual. Standard practicetodayistodesignall current transformers so that G amperes will 73.98 be flowing in tilt; Fificondary when fulllond current Figure 10-58.--Y connection.

349 359 CONSTRUCTION ELECTRICIAN 3 & 2

PH() LEC TRIC- CON TROL RECEPTACLE

CURRENT TRANSFORMER

73.265 Figura 10-60.Common type of exterio: lighting fixture.

AC LINE

73.362 Figure 10-59.Current transformer. is flowing in the primary. For example, a transformer de3ignud 'o: 1,000 am:eres in its primary would supply only 5 amperes to an ammeter in its secondary as its full load of 1,000 amperes. SuchL tran3fornv:r would have a ratio of 1,000 73.266 to 3 or 200 to 1. Figure 10-61.Upsweep-bracket fixture. Current transformers are also used to supply current to overload trip coils of oil tiwitch08, to jurront cols :f wattrir)ters, and to protective relays of all kinds. STREET LIGHTING CIRCUITS

CAUTION: Never open the becondary of a A "series"outdoorlightingcircuit(fig. eurrunt transformer without shorting It be!:c)re 10-62) is supplied .V a regulating transformer remwing a meter.Extremely high voltagewhich givas a uniform current, usually of 6.6 willdevelopifthesecondary 1E3 opened. amperes, to the stroot lights in the circuit. In- sulating transformers or autotransformers are STREET LIGHTING 1.1XTURES available for stepping up the co:ront to 16 or 20 amperes. The higher amperage permits more rugged lamp filial-y.1as, which give longur life for A btroct-11 gal ng fixture In Audes u braek,st lamps of uqw.il candlepower and highelamp or post for mounting. Thu mounting bracket for ufficiuncy. an overimad light usually consists of a metal pipu or framework wIth a polo-mounting fitting Thu series circuit is easily controlled, hut any atone'jmiandluminaire at the other (fig. break interrupts the entire circuit. A film-disk 10-(;0). i1n "upswoop braekut" typo of fixture is cutout, along with a special lump holder and ffiiown In figuro 10-61. soakut (fig.10-63), will prevent lamp failures from interrupting the circuit. CAIITiON: provont fragmontod p,irion from With thu lamp oporating, thu current passes : i ii i y0,11' oyu. wbon replaeing 11 dOjetiVO from me finger through th3 latriL: and out the ItclOp your oy(jlo)volabove that of tho ether Pinot'. When a lamp fails, the soriesci,it hoop. Is opened and the quarter-like film disk (betwirm

361) :160 Chapter 10OVERHEAD POWER D:STRIBUTIO:;

CAUTION: Do not reuse punctured filmri sk cutouts or substitute tape or paper for a PRIMARY film 'Ask cutout. W:lan ni.Trcury vapor lamps are usad in street PRIMARY lighting, a ballast or transformer is required OIL SWITCH toproducethehigher voltages necessary to ec,71, operate these lamps. This system is generally L.. usadinnew construetion because of itsrow maintenance cost and longer life.

CONSTANT- CURRENT 'Mercury vapor lamps have a quartz arc tube, SERIES LAMPS REGULATOR wh(ch contains a small quantity of mzsrcury and S a starting gasargon. The lamps have a negativa 41_0W-VOLTAGE CONTROL FOR PRIMARY SWITCH characteristic, and therefore require a ballast (TIME SWITCH, PHOTO ELECTRIC RELAY, OR for proper operation. With ao ballast the current MANUAL SWITCH) to the lamp would increase until the lamp was destroyed.The ballastactuallyhasthrae functions:1)tolimit current tothe lamp; 2) to provide sufficient open eircuit voltage to start 73.2;32 tha lamp; and 3) to match available line voltagee Figure 10-62.-- S'Jries strelighting circuit. to lamp operating voltage.

FILM SHORTED A simple marcury ballast is shown in figure DISK FINGERS 10-64. This ballast has an inductive choke coil in series with the lamp, Since th!.s circuit is LAMP highly inductive, a low power factor of approx- HOLDER imately 50% is obtained. The power factor may FINGERS be corrected with a capacitor as shown

A "znultip!u" street light;ing circuit consists SERIES of a number of street lights &littering a low SOCKET voltage on a secondary main. However, running secondary conductors any grant distance to supply a lump )r group of lamps is impractical because oftheexcessivevoltage drop. Figure 10-65 is an example of' a multiple lighting system having a pilot control circuit.

INSERT LAMP a }LAMP HOLDLR HERE INDUCTIVE COIL 73.322 iguro 10-63. --- series lamp, !sockot,and film I I POWER LINE disk. FACTOR VOLTAGE CAPACITOR thu lump hulder fingers) in punctured. This allows ourrontto pussfrom cnu fingur through thu punuturad film dink, und than to thoothar fingor _ _ _ thuti compluting thu circuit. Thu nackat iu ua Inuit., that whon thu lump oold Jr its romovod tho fingura aro kuoding tho Harkin 71.3.13 circuit comnlotud. Figuro moroury ballast.

351 '2ONSTRUCTION ELECTRICIAN 3 & 2

120-240 VOLT MULTIPLE MULTIPLE 120-240 VOLT r 1/ RELAY r RELAY I I

CONTROL STATION 120-240 VOLT OPERATED BY AUTOMATIC TIME SWITCH LIGHT SENSITIVE RELAY OR MANUALLY OPERATED SWITCH

111][FirEn.'".,MULT IP LE LIGHTING

73,334 Figure 10-65. Pilot circuit energized at night, extended to control rm.ltiple relays or oil switches. Fh3 pilot circuit will turn all lights on at the same time through the use of local relays. The power needed to supply the lighting collies from looal sources. CONSTANT- CURRENT to. INSTALLING LIGf7T NG IRCUITS REGULATOR CLOSED LOOP

1. series circuit may be installed with the roturn wire on the same pole or it may follow a different route. Those are %nowi as closed (fig.10-66). A CONSTANT- loup and open loopcircuits CURRENT series circuit may b3 installed on the samo cross- REGULATOR arm with the primary-distribution conductors (fig. OPEN LOOP 10-67). If two primary crossarms are necessary, tho stroetlight wires should be carried on the lower arm in the end-pin ponition. If two soparate El singlo-conductor street circuits are on the same CONSTANT- of load, th3y should not b3 placod in adjacent pin CURRENT COMBINATION por3Ition8 because it would cause confusion in REGULATOR troubleshooting. The constant-curront rogulator may be of the indoor or outdoo: typo. Most installations have 73.263 utdoor regulators. me main types of installation Figure 10-66. Closed and opon loops in usod for these regulators are platform- or single BOritm circuits. pole-mounted. Note that any rogulator larger than 20 kva should no on a ptatformA 9Inglo polo becauso of thu many devices involved, and be- mounting and wiring diagram Is shown in figure etf183any um in a "!lbcircuit interrupts 0-Gb. thentire ciritt. The mos'. comloon and moot 'ruubleso;ne fault is failure of all lamps in the iireuit. Troubleshooting with the circuit energized T 11.01,1131.1SHOOTING Fives quickest rosultn, but p3rsonnel must bo qualified toi such work nndU90al standard A tioriati circuit producos many inoro opera- fiaLty oquipmeni and praeticos. 'Yheil the circuit ting problemsthanaBurin rnultipio Jrn u iriallr ..a. cheek for fallon wires.

362 3 Chapter 10- OVERHFAD POWER DISTRIBUTION

SERIES STREET- SERIES STREET-LIGHT CONDUCTOR PRIMARY LIGHT CONDUCTOR . PRIMARY

STREET SIDE STREET SIDE

6-PIN CROSSARM " 6-PIN CROSSARM-I4- 2PIN SPACING SERIES STREET CIRCUIT ON SERIES STREET CIRCUIT ON ARM WITH DELTA PRIMARY ARM WITH WYE PRIMARY

73.264 Figure 10-67. Series circuit on same crossarm with primary distribution system, grounds, andr, ha like, before any setionalizing Jumpers are removed and placed nearer the proceduresareattempted. When thecircuit regulator andthewhole procedure repeated. covers a large area, sectionalize before checking. Table 10-3 lists the various types of trouble 2. Open Loop. The open-loop series eL:cuit likely to occur and gives their possible ealses.is worked similarly to the closed loop except SEC'TION aiLIZING that, instead of shorting, the conductors may betemporarilygrounri.,d (using primary or By locating trouble with the regulate, arnr-secondary ground wire if present) at two points. gized you can trace the fault to a sn Tnis shorts out Vie portion of the circuit beof the circuit. Every electrical forerin ..reen the grounded p:,!.iits. Tha lamps in the have a diagram for use in sectionalizing. Sec- shorted portionwillnot burnifit has the ticnalizing procedums for closed- and open-loon open, but the lamps in the remaining portion series energized circuits are as follows: will light up. 1. Closed Loop. Short ciccuit (jurn:er) both .ealductors hea2 the rn1(10 portion of the circuit. USN G A MEGGER Faults may be lo...,ated wi.L the street circuit a. Iflamps towardthere; 'ator light dehd by using a 1,00C-volt megger. The primary up, open mAst exist in renn:Ining portiu.. cutouts must be first opened and tagged. The :flogger isile?i in place of the jumpt.r, with a (i) Dividethis open portionishall high (infinity) reading indicating an open in Ulf, and jtslyer it again, leaving the first on. portion of the oircuit being meggered. A juniper may be installed at each point mcgored and (2) Lit the first jumper so a 1-inch,tfter ea:h -neggering until the open has beea gapowisi.s. excessive .!entinues,it looated, All jump.ers must be removed altar the circuit .1rdie seeend jum23r fault hits been lochte( and repaired. should et, ir:veel closer '.o the first and another atiompt mute toliftthe first jumper. No dy- Aric arc, however, indicates the fault tobC5 OBSTRUCTION LIGHTING 12'73,j"; the second Jumper. obstruction lighLe are used to indicate the xistence of obl;ahiJtions. Thei lights aro rethn b.If no lamps are lighted after the first cola.,withanIntensity of not len than 10 short is made, the open is toward tha regulator. c infllepower. Tne number and arrangement of

363 6 3 CONSTRUCTION ELECTRICIAN 3 & 2

PRIMARY CIRCWT

SERIES CIRCUITS NEUTRAL \ OPEN-CIRCUIT \ PROTECTIVE RELAY LIGHTING ARRESTER LIGHTNING ON SERIES CIRCUIT FUSED CUTOUT \.ARRESTER

MULTIPLE 24" CONTROL MIN. SWITCH

LIGHTNING ARRESTER REGULATOR

FUSED 20" LIGHTNING ARRESTER CUTOUT M N.

111 At: -1111.1SPREISION°U.6j. liavon v 115V TOGGLE i!Mta BYPASS 2#14 ANN SWITCH 115 VOLT 0 OIL 3*14 SINGLE-POLE SWITCH TIME SWITCH

REGULATOR 3#14 FUSED SAFTY SWITCH CONDUCTOR IN CONDUIT

TYPICAL WIRING DIAGRAM

30 AMP WP FUSED SAFTY SWITCH 15 AMP FUSE MOUNT THESE DEVICES TIME SWITCH OR AT A CONVENIENT HEIGHT PHOTRONIC RELAY FROM THE GROUND

10 AMP 125 V WP CONTINUE TOGGLE SWITCH AND GROUND

73.365 Figure 10-68.Schematic diagram of pIe-mounted installation.

364

354 Chapter 10OVERHEAD POWER DISTRIB UTION

Thble 10-3. Troubleshooter'sGuide,Series Circuit

TROUBLE POSSIBLE CAUSE

LAMPS FAIL TO (I) PRIMARY FEEDING CONDUCTORS OPEN. BURN, EVEN (2) PRIMARY FUSES BLOWN. DIMLY. (3) PRIMARY FUSE CUTOUTS DROPPED OUT. (4) PRIMARY Oft SWITCH OPEN. (5) SERI ES OR MULTIPLE CONTROL CIRCUIT OPEN. (6) PRIMARY PROTECTI VE RELAY OPEN. (7) STREET CIRCUIT OPEN. (8) PRIMARY LEADS TO REGULATOR OPEN. (9) DEFECTIVE REGULATOR. .

LAMPS BURN (I) REGULATOR OVERLOADED. DIMLY. (2) SECONDARY CONNECTION POOR. (3) POOR CABLE INSULATION CAUSING A LEAKAGE TO GROUND. (4) REGULATOR MOVING MECHANISM OUT OF ORDER.

EXCESSIVE (I ) HIGH AMPERAGE (CABLE HOLDING BURNOUTS. SECONDARY MAY BE BROKEN). (2) LIGHTNING. (3) POOR LAMPS.

LAMPS BURN (I) FILM CUTOUT PARTIALLY FAILED. NORMALLY, (2) VOLTAGE LEAKING TO GROUND. EXCEPT FOR ONE OR TWO (3) BREAKDOWN IN INSULATING TRANS- WHICH BURN FORMER. DIMLY. (4) INCORRECT LAMP SIZE. (5) LAMPS ABOUT TO BURN OUT.

FILM CUTOUT (I) IMPROPER CUTOUT USED. FAILS BUT (2) ABNORMAL LINE SURGES. LAMP NOT (3) LAMP LOOSE IN SOCKET. BURNED OUT. As NOT MORE THAN 150 FT. WATER IN (I ) BRACKET THREADS IMPROPERLY RED- NOTE: FIXTURE. LEADED. WHERE w EXCEEDS ISOFT. INTERMEDIATE LIGHTS WILL. (2) JOINTS IMPROPERLY GASKETED. BE REQUIRED FOR EACH ADDITIONAL !SOFT. OR FRACTION ABNORMAL (I) FIXTURE OVERLAMPED. THEREOF. BREAKAGE OF (2) HOLDER ACCOMMODATES GLASSWARE GLASSWARE. IMPROPERLY. (3) WRONG GLASSWARE FOR FIXTURE. 73.323 (4) ABNORMAL EXTERNAL VIBRA TION. Figure 10-69.--Lighting of towers, poles and (5) EXTERNAI. DAMAGE BEYOND CONTROL. similar obstructions. SOCKETS AND (I) CONNECTIONS LOOSE. RECEPTACLES (2) CUTOUT NOT BREAKING DOWN COM. BURNED AND lightsat each level to3)3 lighted should bs PITTED. PLETELY. such that the obstruction is Indicated from every (3) VOLTAGE LEAKING ACROSS SOCKET. angle of azimuth, Figures 10-69 through 10-71 (4) SOCKET FITTING RECEPTACLE illustrate these methods oi lighting. IMPROPERLY. (5) LAMP NOT MAKING CONTACT IN SOCKET. ABNORMAL ATMOSPHERE CON TAINS GASES OR VAPORS VERTICAL ARRANGEMENT DETERIORA ATTACKING METALS. TION OF ME 1AL PARTS. At least two lamps, either operating 81mu1- 73.366 taneoublyOrcircuited80that upon failure of 355

3 6 5 CONSTRUCTION ELECTRICtAN 3 & 2

NOT LESS THAN 5 FT NOT MORE THAN 10 FT. T

A MORE THAN ISOFT, BUT NOT Atte. NOT MORE THAN .I6OFT. MORE THAN 300FT.

INTERMEDIATE LIGHTS REOUIRED AT INTERVALS NOT TO EXCEED ISOFT.

A MORE SOO FT BUT NOT MORE THAN

73.324 A VARIABLE Figure 10-70. L,ghting of smokestacks and B. IISOFT. OR MOrtE similar ob3tructions, ons, ancthsr becorns operative, will be located 73.325 at the top of ths obstruction. An exception is Figure 10-71.Lighting of water towers and made inthe caso V a cif.ey or similar similar obstructions. structure, on which the top lights are to be placed between 5 and 10 feat bslow the top. on the point or edge of the obstruction highest Where the top of the obstruction is more than in relation to the obstruction marking sarface, 150feet above thelevel of the surrounding at intervals of not more than 150 feet. If two ground, an intermediate light or liglIts will be or more edges of an obstruction located near provided for each additional 160 feet, or fraction an airfield are at the EIILME1height, the edge thereof. These intermediatelightswill bs nearest the airfield will be lighted. spaced as eqinny as pl:aciicable between the top light, or lights, and the ground level. LIGHTING OF OVERHEAD WIRES When obstruction lighting of overhead wires HORIZONTAL A RRAN GEM ENT is needed, the lights will be placed not more than 150 feat apart at a level not below that of the Obstructions conststing of. built-up and tree highest wire at each po:nt lighted. When the covered areas are examples of extensive obstruc- overhead wires are located more than 150,000 tions. Where an extensive obstruction or a group feet from the ilenter of the landing area, the of closely spaced obstructions is mr.rked withdistance between lights may be increased to obstruction lights, tha top lights will be displayed no more than 600 feet.

366

166 CHAPTER 11 UNDERGROUND POWER DISTRIBUTION

Underground power distri button and communi- and devices attachedto the walls support the cation systems are used by theU. S. Armed cables inside the manhole. Forces for the following reasons: Manholes are installed not more than 500 ft apart because themechanical strain placed on thc 1. Underground lines are secure against da- sheath and conductors of a cable may become mageinflictedby high winds and storms on toogreat during the pulling-in process. The overhead lines in some areas. best shape for the vault of a manhole is usually 2. Overhead lines often interfere with clear elliptical or ma to prevent the necessity for approach to aircraft landing fields. sharp bends in the cables passing through the 3. Undergroundlines leave clear areas and manhole. Care should be exercised not to exceed open spaces for the operation of cranes and the manufacturer's recommended bending radius other mobile equipment. for individual cables when installing or pulling 4. Underground lines are rn..cli more securethem n manholes and handholes. against enemy attack than overhead lines. A manhole should haveatleast6ft of headroom, so that men working on cable wIll This chapter presents information on installa- not have to assume stooped positions. Average tion and maintenaiice procedures applicable to inside horizontal dimensions are 5 ft by 7 ft, underground power distribution systems. The though a manhole may be smaller if it contains structure and function of manholes and handholes, only a few duct openings. Duct openings a andthestepsinvolvedinpulling cable are manhole wall are shown in figure 11-1. described. Of particular interest to you is the If possthle, a drain to a sewer line should section containing detailed cable splicing instruc- beinstalledinthebottom of a manhole. If tions. Safety precautions that you must observe thisisnot possible, there should be at least are outlined, and a general overview of airfield a drain hole in the floor to allow water to drain lighting systems is given. out. A cavity below the floor, off to the side, and filled with broken rock as shown in figure 11-2, will facilitate the draining process. CONSTR i.!CTION A handhole is used principally as a pull or There are three principal categories of under- junction space.It serves the same purpose as ground lines: duct lines, cables buried directly, apull box in interior wiring. A handhole is and conduits located in tunnels. The system most usually about 4 ft square and from 24 to 36 in. frequently installed by construction battalions is deep, with a metal cover the full size of the hole. the underground duct system, with its attenthnt manholes,la. Adholes,ductlines, and cables. DUCTS AND TRENCHES

MANIHGLE.0 ANID HANDHOLES Several types of underground ducts are in general use, such as fiber, wood, vitrified tile, Manholes and handholes (a handhole is essen- iron pipe, asbestos composition, and concrete. tially a small manhole) are installed at intervals The type generally u.ed by the Navy is a fiber along an underground line to facilitate the intype with the trade rame "Orangeburg." This stallation, removal, splicing, and rearrangement is a conduit which is ,tade of wood pulp treated of the underground conductors. The conduits enter and thoroughly Battu-fed with a bituminous com- the vault of a manhole along the side walls, pound. The compou .ontains about 6 percent

357 CONSTRUCTION ELECTRICIAN 3 & 2

An underground installation will usually consist of several duct lines. Joints between sec- tionsshould be staggered, so that the joints in several lines will not all occur at the same place. To ensure staggering, starting sections ofdifferentlengths are used at the starting manhole. For duct set in concrete, there must be at least 3in. of concrete around each line ofduct.This spacing is ensured by the use of spacers like the one shown in figure 11-5. The upper linesof duct must be at least 2 ft below the ground surface. The location of the trench will vary according to ground conditions, but it should run as nearly as possible in a straight line from one manhole to the next. To ensure drainage, the line should slope downward about 1 ft but never less than 3 inches every 100 horizontal ft. If one manhole cannot be locatedat a lower level thanthe other, the line must slope downward from about the midpoint both ways toward the manholes.

MANHOLE COVEN

73.105 Figure 11-1.Duct openings in a manhole wall. creosote to prevent rotting in the ground, Sec- tionsarejoinedtoeach other with a self- aligning coupling, and can be laid in a trench very rapidly. The duct has a smooth, oily surface which allows cables to be drawn through easily. It comes in 8-ft lengths, and can be easily cut toany der,ired length with an ordinary wood crosscut saw. A standard 8-ft length of fiber cut is made with a turned-down spoce at each end to accommodate the coupling.l'hen you cut a length, you have to make this turn down fl t the cutoff end. The tool usedf r rthis purpose is called a "field tooling lathe," Figure 11-3 shows the lathe dismantled. Figure 11-4 shows the lathe on a piece of dixt after making the cut. The latheisset to cut the vxact amount from the piece of ducttoensure a tightfit between thecoupling and the duct. In some locations you may not have this tool avalla5le, and will have to use a coarse file or rasr). Be careful 73.106 not to cut too deeply. Figure 11-2. Drain pit for manhole. 358 368 Chapter 11 UNDERGROUND POWER=1.= D:STRIBUTION

rimg"114- Aergeopmes\NImmami

11.e- M 1 N r 11- Jiraigrui.

73.108 Figure 11-3.Field tooling lathe dismantled.

73.109 Figure 11-4.-- Field tooling lathe set for turning down fiber duct. Dig the trench to the desired depth and tam7 the bottom hardto ensure a solid beci for the 3-in. hottom layer uf ccncrete. Spacers can be ernbe d in the bottom layer of concrete for a depthofabout 1 ia.before the concrete 73.107 sets to ensure a solid base. Figure 11-5.Spacing fiber du.A in concrete.

359 369 CONSTRUCTION ELECTRICIAN 3 & 2

UNDERGROUND CABLE Only a very little moisture under the lead sheath is enough to cause a breakdown of the Underground cables have various types ofinsulation between the conductors or between insulation and sheaths. Because higher voltagesthe conductors and the ground. For this reason, generatemire heat,the amount ofvoltage when pulling in cable, you must be very careful carried determines the comoosition of the in-with short bends or any other conditions that sulation. mIght cause cracks or damage inthe lead Cables rated at 5 kv and below usually have sheathing. rubber of varnished cambric insulation and a lead orrubbersheath. Thoseratedat 600 Figure 11-6 shows a way of preparing cable voltsto425 kv have oil-impregnated paper for pulling in a duct line. This procedure ensures insulation and a lead sheath. that the cable will not pick up any moisture Cables rated at 5 kv and above have metallicwhile being pulled through the duct. tape shields between the insulation and sheath for mechanical protection. Exceptions to this are single conductor (1/c) cable with a lead sheath Step 1: Cut back the lead sheath with four and three conductor(3/c)belted type cable. V-shaped cuts. Much of the new cable being installed is cross- linked-polyethylene (XLP) or ethylene-propylene- Step 2: Bend the lead sheath back over the rubber(EPR). These are calledsolidtype cable and remove all insulation and metal tape. insulations. The size and number of conductors Step 3: For a three-condactir cable, separate in the cable will depend on the job requirements. the strands of all three conductors and bend back over the sheath. PULLING CABLE For a single-conductor cable, bend the two When you install a new run of duct you pull outer layers of strands back over the sheath, in "pulling wire," usually a 10-gage iron wire. and cut the remaining strands 1 1/8 in. from Withthiswire youpullina wire rope, tothe reference mark. which youattachthe lead-covered cable for pulling in. Step 4: Place the head of the bolt as shown. Then bend the outer strands over the assembly Sometimes, if the duct has been in the ground tofitevenly onthe shank of the bolt. Bind along time,theoriginal iron pulling wire thestrands with six turns of No. 14 copper may be rusted so that it is not strong enough wire and sweat thoroughly. topullthe wireropethrough.For a 400- to500-ftrun you would also have difficulty Note: If the strands of the outside layer do not pushinga fishtape through the duct. The job fit evenly around the shank of the bolt, remove can he simplified by using an air compressor from the outer layer three strands equally toblow achalk-line cord through the duct. spaced from each othei before making the To do this, take a small cloth, and tie the chalk sweat. line end to the four corners, so the cloth will function like a small parachute. WW1 airhose Step 5: Beat the ends of the sheath forward in the end of the duct and the core _Lee to runover the solder sweat. From a point 1/2 in. out, you will be able to blow the cioth through beond the reference mark, make a waterproof to the next opening, even on a long run of duct.wipe over thesweat. The outside diameter of the wipe must not exceed the outside dia- Cleaning ducts is accomplished by rodding. meter of the cable. Quick-coupling duct rods (about 4 ft long and 1 in. diameter) are connnted together with a Tin the head and the unthreadcd portion wire brush or other duct rod leader at the the bolt thoroughly before installing in the end head to facilitate cleaning. The rods may heof the cable. The threads of the bolt mIst be pushed through manually or by means of power clean ofsolder and weh greased to ensure equipment. A 12-gauge galvanized steelire at-easy running of the nut. Do not use bolts on tached to the leader is left in the duct for the which the threads are in unsatisfactory condition. cable pulling crew. Use great care to make the wipe waterproof.

360

"10 Chapter 11 UNDERGROUND POWER DISTRIBUTION

REFERENCE MARK

3h" -00

FIRST STEP

REFERENCE MARK

I..- 3 41" 3 4S"

""°°1111111 1111 SECOND STEP REFERENCE MARK

THIRL) STEP

REFERENCE MARK

REFERENCE NARK

I I

Annnnnonnn i-iwouuuuuuuu ".40110.111 II iii

FIFTH STEP A = 4IVFORS" BOLT A :5" ,0 RSIS" BOLT

73.110 Figure 11-6. Installing pulling bolt on lead-covered cable.

361 371 CONSTRUCTION ELECTRICIAN 3 & 2

RIGGING the cable requires heavy pulling. For jobs of this nature, you willfind the other views in Figure 11-7 illustrates a nunther of wa7s to figure 11-7 helpful. rig manholes for cable pulling. View A shows When pulling lead-covered cables into a long thecable pulleyattachedto a tiirther blockduct, use a feeding tube or bell for applying which,inturn,is supported by a wedge. Ina lubricant at the duct mouth. Make sure you view B, the pulley is shown attached to the man- use the lubricant specified by the manufacturer hole wall by means of an embedded eye.If of the cable. you use this method, make sure that the lower sheaveisinline and level with the duct in REEL PLACEMENT which thecable is to be pulled. To prevent Lijuryto the cable by sharp edges, line the Make a plank runway to support the reel for duct mouth with a shield. movement overareaswheredirt,cinders or crushed stone might damage the cable. All Either of the above methods will probably cablereels are marked with an arrow Indi- be satisfactory for most of the jobs you willcating the directionin which they must be handle. Sometimes, however, more complex rig- rolled. Comply with this arrow when placing the gingiscalled for, especially in cases whenreel at a manhole so that it turns in the proper direction as cable is pulled from the reel. Place the reel as near as practicable to the manhole and raise it on reel jacks just enough to clear I-RUCK the ground. Figure 11-8 shows a reel in proper WINCK position overthemanhole sothat the bend P LLEYS inthe cable is not reversed as the cable is A. unreeled. Notice the scuff boot at the edge of themanholeto prevent damage to the ce)le sheath. A section of an old tire casing can EYE WEDGE BLOCK serve as a protective boot for this job. SIMPLE RIGGING WITH TIMBER USE OF EYE EMBEDDED BLOCKS AND WEDGES IN MANHOLE WALL The boards nailed to the two edges of the .... reel are called lagging. When the reel is in MINEi place, remove this lagging. You must be careful notto damage thecable when you pry the lagging loose. Be sure to remove any projecting nails from the edge of the reel before starting to remove cable. Next you must release the end UPRIGHT SHEAVE STAND DOUBLE SHEAVE STAND of the cable from the reel, and you will then E . F. be ready for the main part of the job. Assume that the winch line has been drawn into the duct as the test lire was pulled out. TIMBER RIGGING FOR SI mGLE SHEAVE STAND A basket grip is now r.,.1 1,ed to the end of the HEAVY PULLING underground cable on the reel. The end of the basketissecured tothe cable with a tight H. wrap of tape or wire. A swivel connection is necessary between the basket and the pulling cable to relieve twisting of the rope. If the cable reel is within sight of the winch, DOUBLE SHEAVE STAND USE OF OVERHEAD it will take four men, in addition to the winch WITH ANCHOR TO MANHOLE CAPSTAN FOR operator, to do the job safely. One man attends ROOF FOR HEAVY PULLING PULLING CABLE the reel to see that the cable pays off the reel properly. A.I.,ther man in the manhole guides 73.370 the cable into the duct. Both men inspect the Figure 11-7. Manhole rigging for pulling cableasitunreels and immediately signal cable. "stop pulling"if a defect appears so that a 362 372 Chapter 11 UNDERGROUND PuWER DISTRIIIUTION

from the cable. The cableis then cutto the clesi red length and the cutoff end in the manhole issealed unless splicing is done immediately. Thu end of the cable remaining on the reel tst also be sealed. In addition, check the seal on the end of the cable which has traveled through thedir_.t,!Indreseal ifit has broken from the strain.

SPLICING UNDERGROUND CARLE A primary consideration in splicing underground cable is to keep moisture out of the splice. The first thing to doin the manhole, then, is to make it as dry as possible. If there is water onthefloor,pumpitout, because standing \VA% water can c.-Isc: condensation to accumulate on your tools z.nd -,,n the cable. The splicing procedures outlined in the following sections apply to most types of cable. Variations in technique are dictated by differences in cable constmction. Factors influencing changes are: the kind of insulation, presence or absence \\\VA\VVMV\A\AVV\\ of a conducting shield, and whether the cable is single or multiple conductor. 73.371 PREPARING A LEAD SPLICE Figure 11-8. Reel in proper position. The principalsteps in cable r _icing are (1) preparing the cable for splicing by removing closerinspectioncanberri^defor possiblethe lead sheathing and insulation from the con- damage to the sheath. A third man, stationedductor and cloaning the conductor, (2) sweating in the other manhole at the pulling end, signalstheconnector on the conductor and polishing "stop pulling" when the cable appears. Thetheconnector, (3)reinsulrting the joint,in- fourth man aboveground at the pulling-end man-stalling the sleeve, and wiping the ends or the hole,relayssignalstothe winch operator.sleeve to the cable sheath, and (I) filling thc This procedure enables the winch operator tosleeve with insulating compound. Each of these concen+rate on his job of seeing that the winchstepsis essential, and a poor job on a one line is wound into the reel properly. of them willresult in a faulty splice. Figure 11-9 shows most of the tools used in splicing The speedforpulling cableintoa ductunderground lead cable. varies withthelengthofthe duct and cable size. A single cable can be pulled in success- Assumra that the cable shown in figure 11-10 fully at 75 feet per minute in a clear, straightissize 4/0,andthatitis a straight joint, duct. If you are handling more than one cable,rubber-insulated,lead-covered cable rated at reducethespeed toal)out 20 to 25 feet per *5000 volts. The table in figure 11-10 shows mInute so you can prevent the conductors fromthatfor splicing a size 4/0 cable you use a -.:rossing as they enter the duct. sleeve 2 1/2 in.in diameter and 11 in. long. When the "stop pulling" bignal is given, make Scrape or rasp about 3 in. all around each sure there is sufficient slack in both manl endof the sleeve and coat with a comoound for splicing or terminating the cable. The E, tckcalled"stearing." Nowusethetriangular can beadjustedwiththe cable basket scraper,frequently referredtoas a shave Exercise care to prevent injury to the _ blehook (fig. 11-9, number 18), to smooth the Inside insulation. Remove binding tape and baske ipofthesteeve,so as to have a sLight inside 353 373 coNsTnucrioN ELECTRICIAN 3 & 2

SEIM,

4 3

5 _tre.ss

8 11 9 10 2

*7 -

sW;41 , s

1 . Splash pan 10. Ringing tool 2. Dressing tool 11. PArrot-nose pliers 3. Soldering copper 12. Crimp..ig tool 4. Stearine block 13. File card 5. Hack saw 14. Rasp Q. Cotton tape 15. Wooden rule 7. Cable sheath 16. Hook knife splitting knife 8. Diagonal pliers 17. Riveting hammer 9. 8" screw driver 18. Triangular scraper

73.111 gu re 11-9, Tools and material for splicing lead cable. 364

3 7 4 Chapte r 11 UNDERGROUND POWER DIST RI It I ITION

LEAD SLEEVE

I IMMI I IN I II I II IIIIIIIIIII d'v SCRAPE FIRST STEP

REMOVE RUBBER-FILLED TAPE h-B-4-13-d

NATURAL BELL SECOND STEP

BONDING CEMENT

SOLDER-TYPE CONNECTOR THIRD STEP 5 11 ""' MINIMUM THICKNES5-OZOP1E RESISTANT In 16 RUBbER TAPE, HALF-LAP 41 t

FRICTION TAPE, 2 LAYERS, HALF-LAP FOURTH STEP

FILLING ASSEMBLY PLASTIC Fa.LING COMPO:1ND

LEADSLEEVE-.fr WIPE FIFTH STEP

TABLE

SIZE OF DIMENSIONS (INCHES) CODE LARGER CON- K) CONDUCTORLEAD SLEEVENECTOR A B AWG OR MCM I D LENGTHLENGTH

1 6 1 15 9 1 /4 3 '5 1

2 3 1 /i 9 2 3 /4 1 %

3 2 1 /4 9 2 3 /4 1 %

4 2/0 2 /4 11 2 4 /4 1 % 5 4/0 2 Y2 11 2 /4 4 1'2 1 /4

6 350 2 Si 11 2 /4 4 /4 1Y2 7 500 2 /i 12 3 4 % 1 %

8 750 3 13 3% 5 2

9 1500 3 /i 18 5 5% 2 % 10 2000 3 /4 18 6 6 % 3 %

73.113 Figure 11-10. Steps in lead cable splicing.

365

3 7 5 ('o\--111,vv()N ECA RICIA hevelat eachinith Then slipthe Siet2ve ovt21' (Met'Ildof the cabletind pushithack out of yo.lr wty as shown in the fi rst ttp of figui c 11-10. keferring again to the table in figure 11-10, you 11 see that the "A" dimension for a 4/0 cahle is 4 1/2 in. Meatiure 4 1/2 in. from each end.mci mark this distance by a shallow ring (:;, ) :L (le,p or thn)ugh ring) around the sheath. Nowt tke the triangular scralk.ir and clean about 3in.back from the "A" ring on each cable enth.Coat the area (which is where the sleeve will ;oin the sheath when the splice is finished; with siearine. Split the sheath on each cooductor end 4 1/2 hack, using the eahle sheath splitting knife );.11-9, nom'ter 7) and a hall-peen ham-n-2r Figure 11-12.-- Removing sheath from :able. tig.1`. -11).Hold the knife at an angle so :'tcut the insulation on the conductors, t14; w you hit the kuife givt.it a slight hackfrom theendoftheconductor to the . !: lends to turn up one side of tne split, sheath.Put the protective heat shields on Lb... etylure that you do net cut or scrape conductors by sliding them over the insulation thc. (fig.11-13). Then remove the belt insulation back to the ootton. ottfittvc:split up tothe cut ring on the ta, pullihg the sheat'i away frcm the Splicing Conductors cocci: s nittii it breaks at the ring (fig.1-12). If...ou do not cut too deep a ring, a natural bell Before you make thesplice,youshould willforntat t.t-te remaining end of tne sheath, refer toabill of material like the one shown as shown in the secord step, figure 11-10. The in figure 11-14. Tne table shown in figure 11-10 til'eve-..tsany rough edge from cutting theindicates that for a size 4/0 cable you use code instilr:jton, artd also allows connound to flow under 5. In figure 11-14, then, it is the column under the sheath and give better protection. First take code5(fourth column from theright) that a rollof cotton tape and make thrre wrapscontains material quantities for the splice in aroutA the exposed insalation irom 1 1/2 in. 4.4/0 cable. You are now ready to remove the rubber insulation on the ends of the conductors where the connector will be sweated on. For a 4/C cable,this means 11/2 in. from each end (distance "B" in fig.11-10). Cut 1 1/2 in. of rubber from each of the ends, remove the cut off insulation and pencil the insulation on ea .h conductor end by tapering. Clean the exposed copper conductor very thoroughly with a small strip of emery cloth. Now slip the connector onto the cable ends. This connector isa split copper sleeve, well tinned inside and outside. Figure 11-15 shows the connector and the materials used to splice it to the conductors. You may have to form the 73.114 cableendstogetthe connector over them, Figure11-11.-Splitting sheath with cable sheathbut do not spread the connector. When you have splitting knife. it centered on the ends, there should be a Space

366

`3 7 6 Chapter 11 UNDERGII,DYND11 POWEE

-4 ..s : `.' Pku 1 LCTIVE .71, 11' HEAT SNILLD v, J .11dik .

It SPLI1 4%

CONNECTOR .04 ;-

C'7TATPCCN WRAPPINGS

73.118 Figure 11-13.-1nsta1%ng connector on conductor.

,.,(;i ICfl J.1'

4,5,6 , 10

i. r tzt.,r ,4/u, 5., 754, 150u

Az.):1,ivoni jth L. 12

5 -r...... ,in.!, :. .41. 5 5

,r. t..,r,.:,Lr, r i,,,Jac.:ng ,ni :I' 3 .)

:',..r-1,,..-!1,.. n:i; 15 15 15 0 15

1 1 Stnri.r,, . /....;tic:, I 1 1

...,..t.,!r!:,t'rir 12 12 18 24

i.-. r Plq.:t.i.: ..x.L.eng-th) ,FiCri 3(1 1/X)) 3(2 1/2x11) -.3;2 1/2x12)i(?(1') ?("4 1/2x18

pound 4 6 6 9 12 Lice, :-.7i.7tr1 roll i i 1 1 2 lip,..!,,.u.,no.,.r.,I..-,nnt :01bn. ,Ii,' C.:, rc11 2 3 4 6 12 1 1 11ink dga pound 1 1 1

65.10 Figure 11-14.B111 of materiC3 for lead cable splicing. 367 CONSTRUCTION ELECTRICIAN 3 & 2

of :IWO. 1/4 in. between the end of ihe connector : 77-rr.77"r!rtr7:77, 7-17o and the conductor insulation, as shown in the third step, figuren-10. Fill this space with wrappings ofcotton tape, as shown in figure 11-13, to protect the rubbt.r insulation against the heat vilieurigailledinamem of the solder. 0 gib Be sure the connector is tight on the con- 0 ductor ends, because there should not be any more solder inside it than is required to bond connector toconductor. Never use solder tofill space inside the connector.If a space exists, fill it 14-1100. with strands of copper wire.If the connector isstillloose, use the crimping tool in figure 0 11-9 (number 12), to crimp the connector tight. Now with two ladles (one to pour hot solder, the other to catch the drip, as shown in fig. 1.Lead sleeve 5.Tape, ozone resistant11-16) start pouring hot solder over the connee- 2.Bonding tape rubber tor. Keep pouring until the connector is well 3.Friction tape 6.Splice tag heated and the solder completely penetrates the 4.Cotton tape 7 .Flux conductor and flows freely off the connector. 8. Split connector Then make one last pour of m Ishy solder over the splice and lay the ladles down. Use a folded 73.117 softclothand make a wipe from bottom to Figure11-15. Material for splicing cor-inctor. top on theback and then the front, leaving

73.119 Figure 11-16. Soldering connector.

368 3 7 8 Chapter 11 UNDERGROUND POWER DISTRIBUTION

time 1/4 in. farther away from the lead sheath, until you have put on enough layers'to bring thediameter of connector plus tapeto that set on thecalipers. Now put two layers of half-lap friction tape over the joint. The splice has now reached the stage shown in the fourth step, figure 11-10.

41.r Wiping the Joint

The splicehasbeen completc,d,andthe nextstepisto wipe the sleeve to the cable and seal thejoint. Most of the tools used for this are shown in figure 11-18. Center the sleeve over the sp'Lice, and start forming theends by rotating the sleeve and 73.120 tappinglightlywitha wooden dressing tool Figure 11-17.Polishing connector, (fig.11-19). If the bell starts getting too long, tapitlightly on the end. If itis too short, hit a small ridge of solder over the split in thea few taps further back on the: sleeve. Figure connector. 11-20 shows a well-formed bell. After a little practice you will be able to control the shape Clean the1/4-in,spaceat each end ofquite easily. the connector, and then polish the Connector using an emery cloth (fig. 11-17). The surface must Now you are ready to put the"pasters" have a very smooth finish, because any points on the sleeve andsheath. These are strips or rough spots will cause a corona, which willof gummed paper, 2 inches wide, that protect in turn cause heating. the lead sleeve and sheath from the initial heat of the wiping lead and give a smooth line to the The connector is now sweated on, cleaned andfinished wipe. On each end of the sleeve, about polished. The lext step isto wash away any1/4in. back from the beginning of the bell, traces of metal filings. To do this, use tapingputapaster aroundthesleeve. Now about oilheatedtoapproximately 230° F, using a 1 in. from the bell of the sleeve put a paster portable furnace and melting pot such as thoseon the cable sheath. Figure 11-21 shows pasters illustrated in figure 11-18 (numbers 4 and 5).in place. The pasters outline the working space Pour the hot oil over the connector, and overfor the wiped joint. Take a small am3unt of any bare metal which might have any metalhot lead and bond the sleeve to the sheath at filings or abrasive material on it. one end. This bonding wi'll prevent the sleeve from moving while you are wiping the jo'at Now take a pair of calipers and measure thethe other end. diameter of the connector. The fourth step in figure 11-10 shows thatthereshouldbe a Wiping is done in four stages:tinning, heating, MINIMUM of 5/16 in. rubber insulation on therough-forming, and finish wiping. The tinning connector. You therefore increase the connectorprocess is more or less the beginning of the diameter set on the calipers by twice 5/16.,heating process. Heat the wiping lead to ap- or 10/16 in., or 5/8 in. proximately 760° F. If you do not have a thermometer, use a piece of folded brown paster You have 3 in. of rubber remaining betweenpaper to check for temperature as follows: Dip the sheath and the connectoi. rhis you coat withthe paper in the lead and remove immediately. rubber bonding cement. Now start with ozone- Ifit is scorched to the point where it appears resista,ii. rubber tape at one end of the connectorabout to ignite, the lead is hot enough to use. and fillthe 1/4-in. space; 'then tape half-lapA 60/40 percent mixture or bar solder (60 per- across the connector and fill the opposite 1/4-in.cent lead and 40 percent tin) is the best mixture space. Continue back and forth, stopping eachfor wiping. 369 379 CONSTRUCTION ELECTRICIAN 3 & 2 MN! amor 11

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1. Wind shield 5. Melting pot 2. L-P tank and 6. Ladles regulator 7. Pads 3. Hose and torch 8. Pot hoc': 4. F,irnace 9. Furnace hood 73.121 Figure 11-18. Tools for wiping sleeve. Pour the hot metal from a ladle onto the You are now ready to heat the joint. Re- pasters first, and the n allow it to splash overmember, to get a good wipe, the lead in the the joint until the joint is warm. By rapidly sleeve and the sheath Laust be almost as hot maving tl'e ladle back and forth, the whole areaas the wiping lead that is, almost at the melting can be tinned without burning the sleeve (fig. point. Determining the correct temperature takes 11-22). Hold a catch cloth about 1/2 in. belowpractice; no book can tell you jus, when the joint the joint to keep the cool lead in the cloth from is at the right heat to start the form'ng process. stickingtothe joint. Do not bring the cloth up the sides of the joint at first, as you will You wipe the joint with a finishing cloth. have a lot of cold solder that would tear the Have it handy, so you can pick it up as soon as cloth. Keep pouring in this manner until the metal you are ready to lay, down the ladle. When you flows freely over the joint and you have a good think you have the lOint at the right heat, and tin all over the joint. have a ladle about 3/4 full of mlshy lead, pour 370

3 8 0 Chapter 11 UNDERGROUND POWER DISTRIBLMON

'...... ,,i. 4t.4-' \?_,: ;..`,1tf* : ''',0

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73.122C Figure 11-21. Sleeve with pasters in place.

73.122A Figure 11-19. Forming the bell with dressing tool.

73.122B 73.123 Figure 11-20. A well-formed bell. Figure 11-22, Heating the joint.

0 8 1 CONSTRUCTION ELECTRICIAN 3 8,z2

fingers along the edges of the cloth so that the clothis cupped somewhat to the shape of the joint), start at the bottom on the back side and wipe uptothetop. Now reverse the cloth, but holdit in the same way, :tn,-.3 wipe from bottom to top on the front side.:'ne Olird motion isto wipe gently lengthwise along the cable from sheath to sleeve, to remove the excess metal broughttothetop. After a few trial wipes you will find this is not as hard as it sounds.Figure 11-24 shows a finished wipe. Let the joint cool before removingthe pasters, because any movement can crack the joint while the lead isstillsoft. After it cools, inspect for smoothness and uniformity. One common error of a beginner is to wipe too heavily on the bottom, to the extent that the joint comes out concave instead of convex below. Do not attempt to smooth a wipe with a torch or hot iron. If it is not right, the only thing to do is melt the wipe off with hot lead and start all over again. If the wipe looks all right, remove the pasters and put an air gage on for a pressure test as

4hki- .14 ,sA t "NAk 41"-.P4-742Ns ' 73.124 ,^ ;1*.",1".4..Ft.*'';1

Figure 11-23. Shaping the rough form. CtrZ - the lead over the joint, lay the ladle in the drip pan, pick up a finish cloth in one hand and a L catch cloth in the other, and start forming the joint. With the catch cloth under the joint, slide the finish cloth between the catch cloth and the lead. In.this way you can start working the excess lead from the bottom to che top of the joint. Now with one cloth on each side(fig. 11-23) you can get a very good rough form. Use the finish cloth to push the lead from the pasters back onto the rough wipe. With a little practice you will t;-!. able thave a rouei form in a very few movements, but remember you have to work fast and with as little handling ofthelead as posr-Able. DO NOT PAT THE LEAD IN PLACE. Now you are ready to finish the wipe. This should be done in thrPz. movements. First, with the finish cloth in both hands (held at the top 73.125 with thumbs and forefingers, and with the middle Figure 11-24.The finished wipe. 372

2 8 2 Chapter 11 UNDERGROUND POWER DISTRIBUTION

When the compound has cooled, bend the flap down and close up the vent hole as much as possible.Then put pasters around thehole

4, 1/4 in. from the cut, and solder with the soldering 'fls r " ; iron. ' 1 1.1/44' Cable Splices for Higher Voltages For voltages from 5 kv to 15 kv the splicing procedure is about the same as that previously 04* described, except that there is the additional step of boiling out the joint after the splice is completely taped. For insulating splices in this 5 kv to 15 kv range, varnished-cloth tape is '4hs. used. The oil used for boiling out is taping oil, heatedtoapproximately230°F. Boiling out consists of pouring the hot oil over the joint, to drive out any moisture caused by damp air or by moisture on the hands. The varnishedclothtape used for these higher-voltage splices is soaked in taping oil, and a layer of oil is put on the joint after each layer of tape. The pressure applied with eacn

me" 14.4 layer of tape forces out, with the excess oil, e .

73.122D Figure 11-25. Making pressure test on cable splice. shown in figure 11-25. Using a hand air pump, build up pressure to read about 6 psi on the gage. If the joint holds the pressure for about 15 minutes, you can assume it is tight and remove the gage.

Filling With Compound

You are now ready to fill the joint with compound. If the sleeve does not have filling plugs like those shown in step 5, figure 11-10, cut a fillingslotin the end opposite the pressure gage. Cut this slot in the shape of a crescent, and bend back the flap (see fig.11-24.). The quarter-inch punctured hole made by the pressure gage can, after the gage is extracted, serve asa vent hole while the compound is being poured in. Heat the compound in a kettle to a temperature between 275° F and 300° F, DC NOT HEAT THE COMPOUND IN THE CAN OR CON- TAINER IN WHICH IT WAS RECEIVED. Pour itin as shown in figure 11-27, until it over- 73.122E flows the vent hole and the slot. Figure 11-26. Slot for pouring connound. 373 383 CONSTRUCTION ELECTRICIAN 3 8z 2

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73.126 Figure 11-27. Pouring compound.

74,

73.127 Figure 11-28. Three-conductor 15-kv joint partly taped. any air bubbles which might be under the tape. For this process you make up the joint and Figure 11-28 shows a three-conductor 15-kvtapeit for the sleeve as previously described, joint partly taped. but withoutsliding the sleeve first onto the cable. You form the bell on each end of the sleeve Split-Sleeve Connection as prev'wsly described. Next, however, you split the sleeve lengthwise with a saw, and spread it In the cable splice previously described theopen wide enough to go around the joint, being sleeve was sad over the end of a conductor andcarefulnot to twistit out of shape (see fig. pushed back out of the way. Sometimes the space11-29). for pushing back doesn't exist, in which case a sleeve must be split, opened out, and applied Clean a space 1in. wide on each side of directlytotheplaceitwill finally occupy.the split for the entire length of the sleeve. Use 374

3 8 4 Unapte r 11 E'NDERGROUND POWER DISTRI P 1"FION

materialifthespliceisfaulty.Follow the printed instructions stepby stub for service- wIPING AREA wWING AREA able cable splices. You may use the materials from oneofseveral mitnufacturers. But the process of making the splice will be similar, , regardless of which brand you usu. The first SPLIT IN SLEEVE step is to prepare the ends to be joined. :\ssume that a splice is to he made in it single-conductor cable with either neoprene or rubber insulation. Preparation Firsttneasurethe connector sleeve from CROSS SECTION SHOWING BEAD IN SPLIT SLEEVE one und tothe center indention. :\dd 1/2 in-h to the ineasuretnent as allowance for expansion 73.128 of the connector, and mark this distance from Figure 11-29. -Split sleeve. the end of the conductor. Shave off the insu- lationbetweenthe mark and the end of the conductor. Be careful not to cut or nick the \vire a piece of rope to form a slack loop around theas you remove the last of the insulation. Next, sleeve. Insert a toggle, such as a hammer handle, pencil theinsulation to make a slope of about intheloop,andwind the loop tight enough450 from the end. If you are going to finish to close the splitsleeve up around the joint.the splice with a kit using a resin or similar Tack the two sides together with solder, to hold compound, be sure to check the length of the the sleeve closed. mold. Kit instructions direct that a cable sheath Next put a pastel. on each side of the split, betrimmed a specified distance so that the lengthwise, about 3/4in. from thesplit, andmold will cover at least an inch of the sheath one at each end.Use a hot soldering iron toon each end. Remove the cable sheath as re- melt stearine over the space between the pasters. quired. Check the conductor to see that the end With the soldering iron, melt a small amount iscut square, to make a good electrical con- of 50-50 bar solder along the split. Then usenection. A conductor which wascut witha the iron to spread the solder over the area,hacksaw should not be any problem. However, to give the exposed surface a good tin. conductors which were cut with a tool such as Again using the soldering iron, run a heavy acable cutter will have been distorted. The bead of solder the length of the seam. With a metal will have been compressed out of shape hot iron held at a slight Pngle, and one con-so that there isa bulge. This bulge must be tinuous movement, run a bead down one side eliminated by trimming itoff with a file beof the seam, tapering from the edge of the paster fore the conductor will slide into the connector to about 1/4in.thick at the center. Move to sleeve. The mold from the splicing kit must the other E i de and repeat the process. Whenhave theends trimmed tofit the cable. To finished, you should have a smooth bead along determine the trim point, insert the cable into the seam, from a feather-edge on the outside themold andcutoff the mold at the point to 1/4 in.thick at the center. Then proceedwhere the cable stopc. Slip the mold over one to make the end wipes, air-pressure test, and of the cables befc-the conductors are spliced. compoundfillingof the splice as previouslyOnly a split mold can be installed after con- described. dectors are joined. SPLICING WITH MOLDS Connecting the Conductors knytime that you make a splice, you will Use a comprezsion sleeve of the proper size havea print(a sheet of instructions) whichand material for the conducton being joined. comes with the material. It usually is labeled Slide the connector over one c("uctor so that "RecommendedProcedures."Somelinemen theend buttsagainst the ce: 4ndentation. make the mistake of believing that a print is Using a compression tool with the correct size unnecessary; they throw it away and haphaz- die, make the first press next to the center. The ardly make the splice. Then they blame the edge of the die should overlap the center line. 375 05 CONSTRI*L.TION ELEC IiLC1AN 3 & 2

To muke the ne xt. press, the edge i SIte di(2 should would for asplice.Attach the laterul tothe just ove clap the previous press. rioutinue working tapped cable with approved connectoi s. he sure to the end of the sleeve in this m .m)or. Next, that the ei_nie.,; have enough slack so that there insert the second condu,-tor in the sleeve until will be no f-rain on the tee. Last of all, position it butts against the cent dr, The press this, side the m.)lcl body and fill with compound, according the sahr: way, wori:ing from flie eente: of the tothe instructions for thekit you are using. sleevetotheend. Tape the splicexith:n- sulating tape if required foe the voltage curried TAPP:CAST SPLICE by the cable. The first step in making a tapecast splice Pouring the Co:opound istobe sure that you have scraped the cable so thatalldirt, wax, and c.ible pulling com- Center the m,:ld over the splice and seal thepounds are remuved. You m ist do this so the ends with material provided in the kit. Wrap resin will bond and make a moisture-tight seal. with tape to completethe seals and hold the Follow the m:inufacturer's instructions as you rncildin place on the cable. Mix the compound remove the cable jacket and nonmetallic filler according to directions for the pack you aretape from the ends which you plan to splice. using.In cold weather, the bag of compound You ring-cut the jacket at the designated places. should be warm,d to about 70° F before mixing Be careful not to cut into the metallic shielding; isstarted. As soon as the coxipouni is mixedunwrap it from the cable. Leave about 1in. of (about 2 miattes), pour compound into the mold the shielding exposed on each end of the cable at the poaring spout. Tilt the mold slightly to where you have rem,-,wedthe jacket. Tack the elim'nate trapped air. Ti'e compound acts verymetallic shielding in place 'with solder so that rapidly, so you must complete pouring with no itwillnotunwind from around the cable. delay. As soon as the splice is completed, the cable Any time that you must solder during the should tie tied securely in its permanent positionmaking of a splice, be careful not to overheat with tying material approved for the cable. As theinsulation. Later, as you wrap electrical an example, a cable with a lead sheath should be shieldingtapeandusethelast of one roll secured with lead tiewire. The cable can be to which you must connect another piece, hold placed in service as soon as the compound sets, the two pieces away from the cable splice. which mu take about 20 minutes. However, it Pliicea drop of solder or. the soldering iron. is customary on a new eable first to make a Then put the iron uder the overlapped pieces megger test for insulation resistance and thenof electrical shielding. Apply solder on top of to measure the conductor's resistance with a theshielding overthe drop of solder which Wheatstone bridge, After testing, the cable ms'Y you left on the iron. beplaced in service. The cable should have atag attached toitin a prominent place at You will solder a ground strap into the cable each manhole and at both terminations. The cable shielding if you plan to use one. Use a ground tag should identify the cable by letter and/or strap having the same amperage capacity as the number and should also tell the voltage at whichcable metallic shielding. Next, remove the semi- the cable operates. conducting material. Leave the designated amount (approximately 1/2 inch) exposed in-side the two A lateral cable is similar to a service drop,pieces of cable metallic shielding which you exceptthatitisunderground. The cable ispreviously left exposed. Clean all of this ma- installed by pullingitinto a duct as alreadyterial from the cable insulation. Use a knife, described. Because a lateral is connected to rasp, or nonconductive abrasive cloth. Be careful anexistingcable,you need to make a tee-that you do not cut into the cable insulation. connection splice. There are a few differences between a tee and a conventional splice. First, Being carefulnot to nick the conductors, you needakitwith a special mold body to remove the cable insulation from the end of the accommodate the tee. Next, the conductor you conductors for the right distance (approximately tap is not cut; just clean the sheath and remove 1/2 inch plus 1/2 the length of the connector). the insulation for the distance required as d.- Follow the instruction measurement as you pencil rectedbytheinstructionsin the kit. Then,the insuiation at each end. Buff the tapers so prepare the end of the lateral conductor as yon that no voids remain after the joint is insulated.

376 386 Chapter 11 UNDERGROUND POWER DISTRIBUTION raper the cable jacket at each end sm-13thly and provides a path to ground, thus preventing the Miff the taper. Finish the preparation by usingelectricity from traveling further down the con- t lint-free,cleanclothtocleanthe entireductor and causing afault whereit would be 7plice area. After preparing the cable, you areharder to correct. Shape this ground wire close eady to connect the conduAors. to the tape and solder it to the metallic shielding at each end, being careful not to overheat the Follow the m-nfacturer's di rections as you use insulation.Thisprovides continuity from the connector to join conductors. If you are joiningshielding on the other side of the splice, Use opper and aluminum .:ondIctors, you must use a a wire which has the same impel age capacity ;pecial connector, or the two dissimilar metalsas the shield. Next, appl,the resin overcast will set up an electrolysis. Use a hydraulic press sne.tth. )r crimping tool to cause the connector to make he connection. After you have the cables correctly Wrap theentiresplice with spacer tape. onnected, fill the connector indents with a semi- Extenditinto the cable jacket approxime.tely .ion!ucting tape. When you use a hydraulic press 3 inches. Start wrapping in the areas which have )r crimping tool,it leaves indents or voids insmaller diameters and build up to the Mckness ,he connector. given in the me.nufacturer's directions, approx- Penciling cable may also leave imately 1/4 to 3/8 inch, Place an injection fitting tvoid. Any void or high point tends to make lectricalstress points. These points act asin position according to the instruction sheet. Tapethisintoplace with electrical tape by mthstoground.If youfillthese voids andtaping from the center of the fitting over the ndentswithsemiconducting tape, there isa spacer tape and onto the cable jacket. Form a ;mooth flow of energy with no buildups. You wrap lignidtight seal. Wrap the entire splice with the he tape over the exposed conductor and con- electrical tape. Cover this with two half-iapped lector area, and overlap the cable insulation. layers of restricting tape. ...Isea half-lap so that the tapewilllay uni- brmly throughout the splice. Because you have trapped air in the splice, you will need to vent the splice so that as the Next, wrap high-voltage splicing tape overresin goes in,it can force the air out. Be care- he semiconducting tape and over the exposedful that you do not puncture the cable jacket as nsulation according to the manufacturer's di- you vent the splice. 7ections. Taper the outside gradually, making he greatest diameter over the penciled insulation. Follow the manufacturer's directions closely Uways try to half-lap when taping; this produces as you mix theresin. When you have mixed uniform buildup. Also hold the tape so that theresin, clear one corner of the container t does not slant but goes straight arow'd theor clear the center top by pushing the resin :able. When it slants, voids or holes are some- down into the lower part of the container. Tape- imes leftin the tape on the underside of the patch the piercing nozzle firmly onto the enr-.N'T ;plice. Also, when you stretch the tape, you do corner or top of the container. Then load the totin any way change the tape's physical or resin pressure gun.Put the tip of the nczzle !lectricalqualities.Thus,if you stretch thethrough the hole in the gun cap and lock the ape in the connector area and at the splice cap in place. Then pull the nozzle through the mds, you reduce voids. cap and lock it to the cap by twisting slightly. Connect the nozzle to the injection fitting on the After using the splicing tape, wrap one layer spliceby rotating the gun itself so that you half-lapped) of semiconducting tape over it and will not damege the resin container, When you ollowthisby wrapping the splice with one haveit connected, you start working the gun ayer (half-lapped) of electrical shielding tape. handles. This pierces the container and resin )werlap this onto the cable metallic shielding begins to flow into the splice. Inject the resin it each end and solder the ends of the shielding. slowly. Let the resin run out of the vent until Chen cover the entire area of shielding braid there is no longer any air escaping. Then wipe vith one layer (half-lapped) of plastic electrical the resin off the tape and close the vent by taping ape. If you stretch the tape as you work, itit. The resin sets quickly. If the splice takes lattens and holds the shielding braid. more than one container of resin, someone should be mixing the resin in one container while you Next, attach a bonding or ground wire.If injecttheresin whichisin the gun. When he splice becomes defective, the ground wireyou empty the container, be sure to release the

377

1 8 7 CONSTRIVTION 1,.1,L;;TitiCIAN 3 & 2 pressure on the gon so thut the valve in the in- SAFETY jection fitting..ianse.1',and prevent the :'esin fticiin backing out of the litting. Rein.we the gua Strictailbei'encetisafe practic;-5 is man- bI otating the entire gun. datory. There are three major areas of con- Wien you have rem Dyed the gun, take the sideratio,1inunderground power distribution: cap offit,rem-ve the emoty resin contain:.r, (1) testinA for live cable, (2) safety in and around andreload the gun with ano'_her eoltainer oi manholes, and (3) handling of hot liquids. resin. Continue injecting resin until the splice isfull;thatis,until the very shows that the TESTI,`:(.; FOR 1 TVCARLE spliceisfilledby spilling resin. Removc any resin that has spilled before it li.irdrr:Soap and water will remove the resin from ,iour hands. Refore working on a cable that has been in Do not move thecableswith the splice until service, make sure that it is dead. The shorting the resin has hardened. Wien it has hardened, tool ._howu in figure 11-30 is used for this purpose. you can remilve the restricting tape. To usetheshortingtool,also known as a "lifesaver," fasten it onto the cable at the point RESIN SPEICI: where it is to be cut for splicing. Lead the hose toa nydraulic pum: outside the marihole. Be In making a resin splice, you prepare the sure no one is in the manhole when you make the cable in the same manner as for the tapecast test. splice except that you do not taper the cable jacket at each end. You connect the conductors As you work thehydraulic pump outside inthesame miinner by joining them with a the manhole, the shorting tool drives a plunger connector and crimng according to the man-into the cable, shorting out all the conductors. ufacturer's directions, and by filling the indents IfLhecableislive,there will be a terrific with semiconducting tape. Then you apply oae flash, which will give you an idea of what would layer of semiconducting tape, nalf-lapped, over have happened to youif you had cut the cable the cable semiconduction material and onto each with a hacksaw without prior testing. end of the cable metallic shielding. The rest of the procedure is different because the makeup of thisspliceis primarily resin as its name You wl'ap the recommended amount of spacer tape o,,er the semiconducting tape and the cable insulaticn almost tothe cable semiconducting material. Start with the indents and level-wind the spacer tape across the joint. Do not stretch the spacer tape. Wrap shielding tape (quarter- lapped) over the spacer tape and overlap the cable nietillic shielding at each end. Solder the ends of the shielding tape to the cable metallic shielding, being caretul not to overheat the insulation. Attach the correct size bonding wire (usuallyNo.6 AWG is adequate) and solder itto the cable metallic shielding at each end. Shape the wire closely against the splice. Again level-wind spacer tape over the entire joint to thedesignatedthickness, taperingitat each end. The rest of th .. procedure is the same as that for the tapecast Using the same method that you used for the e., tapecast splice, you install the injection fitting, ventthe splice and coveritwith restricting tape, mix the resin, load the resin pressure gun, and inject theresin. The resin type of splice 73.112 requires m cii more resin than the tapecast type. Figure 11-30. Lead cable shorting tool.

378 Cnapter 11 lNDERGROI'ND POWER DISTRIBUTION

MANHOLES Alwaysin-eplaincottongloveswith knitted waistlets. in working in or aroued tidies, alway!-: ensure your own safety andthat of other In wo,king with sealing and insulating com- poands, be carefu' ooserve the manufacturer's firstcht ekingtheventilation.Proper aufeAinstructions as to teni:aratures. lieat slowly at preeautions require that a gas teid ne Ic:,- roalified personnel hefore A manhole is entered.first;youcanin,:reasetheamount of heat If gas is detected, the manhole must he venti-later.Avoid makeshift containers for heating; lated with a pow_ r blow2r, and it ne,v neces-always use a regulation explosion-proof kettle. sary toreventilate periodically to maintain a oe of a safet, can for fueling furnaces safe working atmosphere. If men working Wowreducesfirehazards. Oneof these cans is are not visible to men on the surface, someoneequipped wtth a pressure-release valve, so that above ground should check frequently to ensureext rein,'heatwillnotcauseittorupture. that all is well with the men below. When manholes are locatedinthe vicinity When soldering loints, or tinning conductors, of gasoline storage tanks, the check on venti-make sure that the furnace is far enough away lation must he extra thoroagh, becaes«)f thefrom tht manhole that no hot metal can spill additional danger of rcasoline leakage md faM(:3.into the manhole. Itgoes without saying that an Open flame Using a wet or a cold ladle wil1 cause hot should never be taken into or near a manholecompound or molten metal to spatter. in. which explosive gases may he present. Never use an acetylene torch underground, or even aear the end of a pipe or conduit leading AIRFIELD LIGHTING underground. A m'xture of 3 percent at.'.etylene with 97 percent air is explosive in a eonfined Airfield lighting refers to system:! Df illu- space. Maximum explosive effect is reached wi thminated visual signals provided to assist pilots amixture of 7.7 percent gas and 92.3 percentin the safe, efficient landing operation of air- al ta craftatnight and during periods cf restricted V11en you work in - manhole or other excava-visibility.Airfield lighting is standardized and tion, you sho- .ilways make sure thatitis includes runway, approach, taxiway, and obstruc- 2dh.5011: sort of harrier or guard.tion and hazard lighting, plus beacons, lighted Any openingthat -aust ee left open overnightwinddirectionindicators,and special signal should oe harricaded and provided w,tn warninglights.Notallthese items areincluded in advanced base airfields. All lighting, howerer, Use the safety Ilarness if you are going toexcept certain obstruction lighting is normally work in inanhole wlwrt gas may he present.controlled from the control tower. The lighting This harnessia eqfipped with about 25 ft ofsystem includes allcontrol devices, switching manilaline,fastened to ring atthe hack.gear, regulators, transformers, and all acces- Itis so 'designed as to make it possible for ansories necessary to produce a working facility. unconscious mcn to he hauled up in nearly erect position. STANDARDIZATION HOT LIQUIDS The configuration,colors, and spacing of runway, approach, and taxiway lighting systems To avoid spillage, do not move hot liquid ifare uniform, regardless of anticipated length of itslevelis within 2 inches of the top of theservice,mission, or method ofinstallation. container. Adjust to the correct level. Wien youThe basic color code is as follows: carry it, your shoe soles must he clean and dry, and you should walk with a sliding or shuffling Blue taxiway lighting movement. Clear (white)the sides of a usable landing Always wear high shoes when handling hot area liquids, such as melted lead. Always wear goggles Greenthe ends of a usable landing area when pouring melted lead, hot oil, or wiping (th re shold lights) solder.Never use leather-palm gloves when Redha ard, obstructioa, and non-landable wiping lead. A leather palm glove will transfer area the heat from the lead. A cotton glove won't. Yellow-- caution 379 389 CONS [I(t 'ION IMECTRICiAN 3 & 2

APPR)ACH IAGTPING An approach lighting system presents a configuration of lights which provide extended visual guidance toward the centerline of a runway (fig. 11-31).Atairportswith primary instrument approaches, the system extends 3030 ft outward from tne threshold of the usWe landing area. For other than primary instrument approaches, the approach lighting system extends outward only 1500ft.Directional guidance is provided 1.)y barrettes, a crossbar, and sequential flashing lights (fig. 11-32). Barrettes The barrettes, or centerline bars, are composed of five spaced incandescent lights. These may be mounted flush with the runways or as shown in figure 11-33, depending upon their required elevation. Crossbar White crossbar lights (fig. 11-32) provide an unmistakable definite distance indication to the pilot. The bar is placed 1000 ft outward from the green threshold lights, and is approximately 100 ft in length. Sequential Lighting Im:nediate identification of the system and possible earlier view are provided by the use of sequenced flashing blue-white lights of high peak intensity. No two units flash simultaneously. Each unit is precisely timed by means of cams on a rotating shaft to flash one after another, beginning with the outermost unit and continuing to the innermost unit. Each cycle takes one- half second and repeats continuously. The re- sultingeffectisone of a light moving at a rapid pace toward the runway. There is no appreciable pause between the innermost flash and the beginning of the next sequence. Mounting is shown in figure 11-33. Runway Lighting Thisisthe principal element of airfield lighting.Itprovides thestandard pattern of lights outlining the runway to clearly indicate side and end limits (fig. 11-32). Side limits are marked by two parallel rows of white lights, 73.326one row on each side of, and equidistant from, Figure 11-31. Approach lights in foreground. the runway centerline. The spacing of the lights 380 3 9 0 Chapter 11 UNDERGROUND. POWER DISTRIBUTION LEIMIM

PLINerAY I ['GI LIGHTS LIGHTS ,0V SEQUENCE) FLASHING 0 Q_

0 0 0 0 0 0 0 0 0 0 0 0 0 0 00 0 0 .00O 0;05r0-0 L0 0 0 0 0 0 0 0 0 0

CENTI:R L INE BARRETT E *HITE RUNWAY CE ITER GREEN RUNWAY CROSSBAR GREEN THRESHOLD LIGHTS L GMT L LINE LIGHTS END LIGHTS -Y- S. WING BAR L'GH1S OE APPROACH L4GH1ING SY S T LA4

73.327 Figure 11-32. Lights visible to an airplane moving from left to right.

within the rows is uniform, and the rows extend the entire length of the runway. End limits are outlined by runway threshold lights, which are green and visible from all sides and vertical angles. Runway threshold lights are spaced along the threshold line, which is 0 to 10 feet from the end of the runway, and perpendicular to the extended centerline of the runway. A runway edge LLEVATIor.., fixture and handhole installation schenntic is cmcNITEIRLINE L-)NP shown in figure 11-34. Tor,c, 2 .00 mt., 9+00 Figure 11-35 shows theplan for runway centerline lighting together with a representative ELEVATED FLAWING LiGH1, woL-LESSII wiring diagram, FIXTURE TYRE MS-2 wt.-L-24764 On occasion, certain airports require narrow gage runway lighting. A representative wiring erDAT OR FILAGIBLE CORPLING,OR / 2A410 STEEL CONOLoT diagram and installationinasphalt concrete - GRADE is shown for this type of lighting in figure 11-36. Expedient Lighting ELEVATION uc.mr MTG. NGT. : it 0.-5- You mist beresourceful when equipment is not available from the regular supply sources. FIXTURES TYPE ute:2 Lanterns, simidge pots, vehicle headlights, or AwLL26/64 reflectors may be used to distinguish runway STErt ANGLE 51./PRORT TO WINIAIN LEVEL LIGHT OAR edges. Use of a searchlight pointed directly into METAL WIMAIG TROUGH the air sometimes is used as a substitute for TOR 1RANsi-ORNIERs R). beacon lights.

wopK,NG pLATEORM HANDRAIL MAINTENANCE OF MARKING, LIGHTING, ELEVATED FLASH.NG , LISHT MLL 2s311 AND RELATED ELECTRICAL FACILITIES FRONT ELEVATION Visual inspection of the airfield lighting system LIGHT AATG. HOT. tify.6.AND ABOVE should be made periodically, taking into account the recommendations of component manufac- 73.329turers, weather, location of the airport, numbers Figure 11-33. Centerlin ba- and sequential and nature of operations, and system complexity. flashing mpunting. In addition, regular readings should be made 381

9 1 CONSTRUCTION ELEC'FRICIAN 3 ez 2

5EMI FLUSH Lk-al-171NQ FIXTURE, CLASS b15, MIL-L-2(020a 2 E A1RFCRT MAR 4-1:i--- 1_1(-41T, N 24526 4 STA5I LIVID SHOULOER7.1 5TAE.ILIii".rj-510-Cr.R E feND NIPPLE -L. 0 1 T)LISHII.44 Z"PLIJC.. CONCRETE ENVELOPE3, '91-Pajyrik:7143 ".9 -ro 25- o

4" CND. A - r,-;1, -. A71- 4" CND. 4C.I1D. : 74:k 6" GRAVEL 60T Tom COW:PETE ENVLLOVE.. TIZ.P0,1'5F-072...tsAER SECTION 4A-,1

Figure 11-34. Runway edge light fixture and handhole installation in runway s,1 vilder. 73.331 RUNWAY CENTERLINE LIGNTS FAA SPECL-842, TYPE II,STYLE A

SMALL D14METE2 WIRES vc.No10 FM SPEC L11 7 , 1 1 I ISOLATING TRANSPORME95

200W 45.6A I Ill n E3 Es 1 ____,I >1"1-)--zi--)>-P-r1-»-r"I \->-rrn-»-,. 1_ TYPICAL EDGE LtT HANDHOLE-, e DaELIEHT 14ANDHOLE SHOWING EXTeA CIRCUIT REQUIRED AT ENDs OF RUNWAY WIRING DIAGRAM

EDGE OF RUNIWAH_

E.T4 0 OF RUNWAY RUNWAY CENTERLINE 'RUNWAY GENT ERLIt4E LIGI-375 SPACED 25'.0"CENTERS FOREm-mAr_LEtsta-rv-+OF RUtiWAY '0" 'et"' e--e- -e- CENIEFIUNE OF L/6HTS. UGHTS MAY BE LocATED ON ±01-...-WHEN REQUIRED TO MOVE Ern-1ER SIDE OF RUNWAY CENTERLINE. AN INDIVIDUAL UGHT: 1216"10

EDGE OF RUNWAy

MXI WAY PLAN Figure 11-35. Runway centerline lighting. 73.332 382 392 Chapter II UND71:11GROUND POWER DISTRIBUTION

_150E_ATN4G TRANSFORMER ./ 200 WATT, 20/L. AMP TuRE TvPE oB25, MIL-L-262oz, wITH 200 0,ATT LAEAP r 1 I

1 .13 r r---

'ti .S2H4T5256A-54EL..

L _ I j -4 \-HANID.OLES AT LDGE OF RUN WAI;')

D I AGR4M

LG COEECPF Ti /216.. ILAN C IL OP Cl E,ELNE EAbILIZEL EME f,INDER C^IIPc.E PurEvNAY I. 3' .5 C" , WE APIN COURSE SuRFACE

P.:". E'C C BASE r BAsE COURSE ^ t_ ; PCC i

suBGP ADE \ c,CALE : SECTIU TO NANONOLL AT RUNWAN' EOZ,E INSTALLATION IN A.C. RUNW'Y PAV't- MEN T

73.333 Figure 11-36. Narrow gage runway lighting installation. on system resistance, and other circuit tests Burned-out bulbs and lamps should be made as recommended by manufacturers. Standby units should be run at regular Broken lenses or filters intervals to assure readiness, if required. Complete visualinspection of the lighting Dirty lenses system should be made routinely at least once a week. If severe storms occur in intervening Vegetation obscuring lights periods, resulting in excessive rainfall or lightning strikes, additional inspections should be Fixtures knocked over or displac. conducted immediately thereafter. Operations of snowplows can be damaging to light fixtures, Damaged or insecure cones and inspections of light units should be made following such plowing operations. Circuit re- Evidence of lightning strikes sistance measurements should be taken at least once each month. Decreasing circuit resistance As you proceed with your inspection and maintenance routines, you should look for Faulty ground connections 383 393 CONSTRUCTION.... ELECTRICIAN 3 8z2 Malfunctioning regulators When you check the circuit resistance with a megger, BE SURE TO SWITCH THE POWER Water in below grade fixtures orCOM- TO THE REGULATOR OFF. Then you may dis- ponents connect the series cable leads at the regulator and take your resistance measurements. If you Readiness of standby power source have taken periodic megger readings, you will Torn or damaged wind indicator be provided with a forecast of potentia7 problems whichwillpermit correction beforesystem Faded or obscure markings failure occurs.

3 9 1

384 CHAPTER 12 COMMUNICATIONS SYSTEM

In this chapter, we will discuss fundamentals 2. A means of signalingthat is, activating f telephone corn munication, interoffice the signal device in the subset so that the called ornmuniz:ation, and public address systems so party knows someone is calling him. lat you will have a clear understanding of these 3. A source of electrical energy, required ystorns and how to install ai:d maintain them to impel the signals over long stretches of wire. fficiently. Careful study of this material should 4. The wiring circuit connecting the phones nable you to do the following: and carrying the electrical energy. describe a basic telephone communication In telephone lineman's technical terminology, ystem; a telephone is called a subset, and the place where a subset is located is called a substation. operate a variety of advanced The wiring system connecting the subsets is ase telephone equipment; called the outside plant.

discusselectricaltheory and planning HOW THE TELEPHONE WORKS atures of telephone line construction; Figure 12-1 is a wiring diagram of a basic identify components of telephone switchtelephone circuit. You can see that this is a oards and state the purpose of each; series circuit from the fact that the current travels from the negative terminal of one battely install, repair and maintain a telephone backtothepositiveterminalofthe other. ystem; A battery is the source of electrical energy which provides a constant voltage. install and maintain a public address and nteroffice communication system. To get an idea of how the transmitter and receiver work, examine figure 12-2. Features of Lie transmitter are as followk: BASIC T EL EPHON E SYSTEM COMPONENTS I. It contains a cha.a,Der pecked with small granules or grains uf 2. The carbon granules are under pressure A telephonesystemconsistsofmany from a movable carbon disk at one end of the elephones connected together by a maze of wires. chamber. ou can understand the system better, however, f you reduce it in your imagination to a single ircuit connecting two telephones. This circuit onsists of the following components: 1. A transmitterand receiver at each of he two locations. (You use the transmitter to ransmitthatis, to sendoutyour voice nessage. You use the receiver to receive the -oice message sent out by the transmitter at 73.170A he other end of the line.) Figure 12-1.Basic telephone circuit. 385 395 CONSTRUCTiON ELECTRICIAN 3 2 ..., vibrates with the liaphragm, and thus alternaely TRANSMITTER RECEIVER applies and release:_, pressure on the granules. This in turn varies the current to the coils of the receiver magnet. The varying currentvaries thestrengthofthemagnet, and this varies the magnetic attraction on the receiver diaphragm. oe- AS thereceiver diaphragm vibrates,itiiets )) upairdisturbances or sound waveswhich are identical with the ones which are sent into the transmitter. "Chishas been a very general explanation of how the telephone works. The following sections 73.168A deal with advanced base telephone equipment in Figure 12-2.How transmitter and more detail. receiver work.

3. The movable carbon disk is itself directly TRANSMITTER attached to a flexible metallic diaphragm. 4. When the diaphragm vibrates forward, it pushesthe carbon disk aga,nst the granules, The basic function of the transmitter and the thus subjecting them to pressure. way it performs that function were previously 5. When the diaphragm vibrates backward, described, However, energy losses during trans- it releases the pressure on the granules. mission over the wires would naturally cause thi useful energy at the receiver end to be less than Featuresofthereceiver are as follows: that of the initial sound waves at the transmitter. Therefore, the circuit of the transmitter mast 1. It contains a U-shaped permanent magnet.be capable of amplifying the original energy of 2. It contains a flexible metallic diaphragm thesound waves in accordance with the line which is slightly attracted to the pole pieces ofdistance the energy must travel. the permanent magnet. 3. It contains a pair of coils wound on the Various telephone subsets with carbon trans- legs of the permanent magnet. mitters provide this necessary energy increase by the use of an induction coil, a device that Now trace the electrical flow in figure 12-2.functions like a transformer. The battery, the The electrons leave the negative terminal of the caroon, the diaphragm, and the induction coil batterj, travel through the coils of the magnet compose the basic circuit, as illustrated in view in the receiver, and then over to the transmitter.A of figure 12-3. View B shows the construction Atthetransmitter,the electrons pass down of the carbon transmitter. the metal diaphragm;intothecarbondisk, through the carbon granules, and then back to A bell-shaped chamber is packed with carbon the positive terminal of the battery. granules, which have uniform contact with two You can sr:e that, given a constant voltage,gold-plated electrodes. The diaphragm is of the amount of current which flows in the circuit flexiblealuminumalloy,supported by paper will depend on the amount of resistance in the spacers. The r:,gati ve terminal of the battery circuit. If the resistance is high, current will connects with the diaphragm, which in turn rests be low, and vice versa. against the chamber of carbon granules. The Now, the electrons meet resistance as theyother side of the carbon chanther is connected pass through the carbon granules. The an-puntwith the primary ofan induction coil. The of resistance offered by the granules depends return of the primary to the positive terminal of on the pressure on the granules. If the pressure the battery completes the circuit. You can follow is high, resistance is low. If the pressure isall of this ir figure 12-3, view A. low, resistance is high. As you speak into the transmitter, you set Sound waves entering the diaphragm cause it upsound waves which strike the transmitter to vibi ate, and the moving front electrode exerts diaphragm. The diaphragm vibr ate s at the same a vaxying pressure on the carbon. As the state rateasthesound waves. The carbondiskof compression ofthegranules varies,the

386

3 9 6 Chapter 12 COMMUNICATIONS SYSTEM

mOvINC,FRONT ELECTRODE DIAPHRAGAI TRANSmITTER

SECONDAR

INDUCTION SOUND COIL WAVES

PRIMARY

CARBON - BATTERY GRANULES ft

CONNECTICH TO PRImARY OT INDUCTICN COIL

CONTACT PAPER SPACERS -

DIAPHRAGM BACK SILK CLOSURE ANO CONTACT --- ELECTRODE MEMBER CARBON MOVING FRONT CHAMBER ELECTRODE CONTACT OILED SILK ---

----BRASS GRID ----

INSULATIONS

73.167 Figure 12-3.Carbon transmitter. (A) Circuit; (B) Construction. resistance alsovaries. AN compression strike it at right angles, and from a very short increases, resistance decreases, and the eurrentdistance. Ifthe nound originates too far from In the circuit increanes. theinstrument,it will enter the transmitter from both the front and tho back of the diaphragm, For example,ifthebatteryhas an erofand thus will equalize pressure on the granules. (electromotive force) of 6 volts, and the carbonThe effectofthesedistant Roundo ,then,is granules have a normal resistance of 300 practically zero. This type of transmitter has the average value of current flow will bo 20great value for military use,iNfelltifieit Nue- milliamperes. When the diaphragm is made tocessfully cancels out background noises. vibrato (by speaking into it), the compression on the carixm granules may deerease reeistaneo RI11 V I:it to200 ohms, and currentwill consequently increase to 30 minims:won. Two common typos of receiver, the moving- coil type tuid the magnetic-diaphragm typo, are On recently developed transmittAirs, sound shown in figure 12-4. Both types are permanent- waves intended to actuate the diaphragm should magnet devices, but the moving-coll typo operates

`,1 9 7 CO.\15THUCTION ELECI;UCIAN 3 & 2

When dry cells are used as the source of energy, the telephone installation is known as a local battery set. The cells provide the current PERA.ANE NT fortalkingcircuit,butsignalingisusually MAGNET produced by a small hand generator. moviNo COIL When a common or central source of power is used to provide energy, the system is called a common battery system. The source provides DIAPHRAGM both signaling current (by rnsans of a ringing machine attachedtothepowc.rsource)and current for the talking circuit.

A MOVNG - COIL RECE iv( R A manual installation at an advanced base may bethelocalbattery type, the common battery system, or a combination of both. Where local battery sets are used, tele.phones may be DIRE C TIO1 PERMANENT OF CURRf N T MAGNE T connected directly, but connections are usually I. MAGNE TIC made through a switchboard. 11APNR AGM Where a local battery system is established (A1,111/V7 in the first days of occupation of an advanced base, it is possible to interconnect the switchboard of this erilrgency system with the switchboard of the common battery system, as soon as thelatterhas beenestablished.A simple diagram for this typo of interconnection is s'. wn

MAGNETIC DIAPHRAGM REM /ER in figure 12-5. The difference between a local battery and a 73.168B common battery system is more than just the Figure 12-4, Moving-coil and magnetic- difference in power source. The location of the ,Itaphrligillreceivers. power source is also different. A local battery system has a battery (either ()nu dry cell or on theearn() principle as a meterthat is, as several)at each telephone station. A common the current in the moving coil varies, the magnetic battery is centrally located, and serves all the field around tho coil varies. As a result, thestations of the system. coil vibrates and causes the diaphragm to vibrate, which generates sounds of the same wave form The common battery cannot serve all the and frequency as the current in the coil. stations unless the stations aro in parallel with each other as far as direct current is concerned, The magnetic-diaphragm typo operatesand the battery is connected across the line by variation of the strength of the magnetic field.inf3tead of in series. The common battery, con- Variationsin amplitude and frequency of thesequently, maintains a fairly constant voltage, magnetic field cause corresponding variationsand gives a more uniform Fignal than the local of mmition in this diaphragm. This iithe nmst battery. This signal on the switchboard is auto- common type used in telephone systems. matic when the receiver is lifted; there is no necessity for the hand generator.

LOCAL BATTERY AND COMMON Advantages of the common battery system BATTERY CIRCUITRY are that some of tho equipment is simpler and cheaper,and Inspectioncan be madeat a The electrical energy for a telephone circuit single point to seeiftho cell or other power may come from a central Hourco of power, or sourcei functioning. However, there is the it may come fromttlocal source, nuch as adieadvantage that the common battery system dry (Jell, or a combination of dry mils. requires tulch better line eonstruction than the 388 3 9 8 Chapter 12 COM vIUNICATIONS SYSTEM

LOCAL -BAT TERY LOCAL -BATTERY STATION SWITCHBOARD

RINGER DROP SHUTTER

TRANSMITTER JACKS TRANSMITTER LOCAL AND LOCAL BATTERY AND AND PLUGS BATTERY RECEIVER RECEIVER

HAND [ HAND I GENERATOR GENERATOR

COMMON-BATTERY COMMON-BATTERY STATION SWITCHBOARD

SIGNAL RINGER LAMP 1 I

TRANSMITTER JACKS TRANSMITTER COMMON1 AND AND AND BATTERY RECEIVER PLUGS RECEIVER

POWER SWITCH RINGING MACHINE

73.169 Figure 12-5.Local battery system connected to common battery system. localbattery system needs. The switchboard receiver. This would, of course, permit oneway equipment, too, must be more elaborate. conversation only. View C shows a system which permits two- The hookup of the components of a simpleway conversation, but lacks a signaling device telephone systemaroillustrated in the fourfor alerting the receiving end to a call. drawings shown in figure 12-6. View A is a simple schematic diagram, showing the negative The circuit shown in view D, using dry cells battery terminal connected to the ammeter, the alone, has a hand-generator-operated signaling ammeter to the resistor, and the circuitCOM- device. However, line resistance, which increases ploted by connection from the resistor to the with line length, would make this circuit positive terminal of the battery. practicable for short distances only. View B shows the most elementary form of What is lacking here is an induction coil telephone circuit; a transmitter connected to athat is, a transformer device (primary coil and 389 399 CONSTRUCTION ELECTRICIAN 3 & 2

CA)

STATION A STATION B

TRANSMISSION LINF

STATION A STATION B

TRANSMISSION LINE

STATION A STATION B

TRANSMISSION HAND LINE GENERATOR

73.170 Figure 12-6. Basic telephone circuits. secondary coil)for stepping up the energy by how,ineachstation, the primary coils are magnetic induction. Putting a varying current connected to the transmitter and to the battery. ir,,ne coil induces an a-c voltage in the other,The secondary coil is connected to the receiver the value of the induced voltago depending on the and to the line wires. ratio between the number of turns in the two When you speak into the transmitter at set A, coils and the rate at which the current changes.yoLr voice causes a varying ourrent to flow in Figure 12-7 shows induction coils in a circuitthe transmitter circuit. As this current passes containing two localbatterystations. Notice through the primary coil,itproduces an expanding

390 400 Chapter 12 COMMUNICATIONS SYSTEM

TE LEPHONE SE T A TELEPHONE SETa MDUCTION COIL INDUCTION LI I L, COIL C> 5, SECONDARY SECONDARY PRIMARY TELEPHONE RINGER IGEN ERATOR LINE GENERATOR

-1 2

73.171 Figure 12-7.Induction coils in c relbutween local batterystations. ndcontracting magneticfield. Thisfield uts the turns of the secondary coil, and induces current in the secondary circuit. The receiver .t set B reconverts this current to sound waves. The secondarycoiloftheinduction coil suallyhas more turns thantheprimary. Aditional turns on the secondary coil ive the same effect as a step-up transformer, nd operate to cut down power losses. Note that in the circuit illustrated in figure 2-7 there is a common connection between the irimaryand the secondary coils (a situation hat does not exist in an ordinary transfoimer). 7his connection, however, does not affect the ransformer actionofthe induction coils. It arves the practical purpose of reducing the tecessary number of handset cord conductors. :his common connection can also be used for uch special circuits as the anti-sidetone circuit, 73.172 thich reduces the passage of voice currents Figure 12-8. Hook switch. rom transmitterto receiver IN THE SAME ET. tween the leaf springs (by putting the receiver back on the hook) also breaks the talking circuit. WOK SWITCH MAGNETO GENERATOR In desk telephonesubsets a hook switch fig. 12-8) is used. The hook or cradle holds A small hand-operated generator is used in he receiver when the telephone is not in use.telephone circuits to provide signaling service. Vhen the receiver is lifted, a hook spring forcesThe generator is a magnetobecause the magnetic wo thin leaf springs together. Small buttonsfield is provided by permanent magnets rather Inthe ends of the springs make the contact.than by exciter coils. The generator is cranked 7he opposite ends of the springs are connected by hand, and at a normal cranking speed it will o the circuit, one spring being connected to the develop an emf of from 80 to 90 ransmitter circuit, and the other to the incom- volts, at frequencies of 16 to 20 hertz.Increasing ng line. Thus both receiver and transmitter the cranking speed will, of course, increase the ,reput into action. Breaking the contact be-generated voltage and the frequency. 391 401 CONSTRUCTION ELECTRICIA1.: 3 & 2

A spring switch actuated by tEe shaft of the When there is not current in the ringer, the crank handle provides a make-and-break contact, magnetic lines of force are distributed evenly in that it connects the generator onto the line, between thecores,and thearmature is in and removes thebell from across the line. balanced position. Alternating current through the ringer upsets this balance. By applying the A recently designed hand generator is provided left-hand ruleforcoils (explainedin Basic with a dial, and you can either spin the dial Electricity) to M1 and M2 in figure 12-9, you or crank in the usual fashion. The crank is observethatthe magnetic polarity of M1 is pivoted,andfitsinto a compartment on theopposite that of M2. The magnetic polarity of dial face when not in use. The generator uniteach will reverse every half-second, while the can be removed from the equipment magnatic polarityof the permanent magnetic and disaspembled for servicing. remains constant. Therefore, the lines of force ofthe,permanent magnet are attracted to a RINGER diffelent electromagnet every half-second. This CillUiesthe armature to vibrate rapidly between M1 and M2, which in turn causes the clapper to The signaling device in a telephone set is strike the gongs. usually a ringerthat is, an electric bell operating on low frequency (20 hertz) and powared by the hand generator. Figure 12-9 shows the operatAng TELEPHONE SYSTEM DESIGN principle of a ringer. Two electromagnets, formed of coils wound An advanced basetelephone system uses on soft iron cores, are permanently joined atfield wire on small installations and field cable the upper ends by a yoke of softiron. An armature for large installations. is placed under the cores of the electromagnets, and pivoted at the cencer. A U-shaped magnet Many of the problems which occur in relation issecured at one end to the yoke that joins to the installation and maintenance of military the e1ectrom2.gnets. The opposite end of telephone systems are connected with increasing the U is bent around the armature, but does nottalking range, with the overloading of lines, and actually touch it. The armaturecarries awith interference which occurs when there is a clapper rod which can vibrate between two gongs transfer of electrical energy from one conductor mounted above the yoke. to another. To understand these problems, you must have some knowledge of the principles of electrical theory as they apply to communications systems. CLAPPER GONG The electrical characteristics of communication transm!ssion lines involve (1) power loss which increases with electrical length of line, and (2) distortion and interference caused by reaction of one line to a nearby line. These characteristics are complex and highly technical. Only the highlights can be discussed here. IRON CORE COIL WINDING ELECTRICAL LENGTH CLAPPER ROD The electrical length of a transmission line M I M 2 isnot a linear dimension, but the relation -+---ARMATURE between the length of the line (which is a linear dimension) and the wave length of the trans- MAGNET mitted signal. It is this fact that makes electrical length an important factor in operating conditions. 73.1593 A short line is one in which the length of Figure 12-9. Simplified diagram of a ringer. the line is considerably less than the wave length 392 402 Chapter 12 COMMUNICATIONS SYSTEM of the transm'tted signal. A Iong line is one in parallel witheach other a transfer of electrical in which the length of the line is equal to, orenergy may cause crosstalk. When telephone longer than, the wal, "k length of the transmitted lines run parallel to powerlines for a considerable signal. distance, the transfer of electrical energy causes noises on the telephone lines. Battery chargers The wavelength istheratio between the used to maintain storage batteries in a common velocity of the electrical wave and the frequency batterysystem may cause a humming noise. of the signal. This may be expressed in the following formula. Interference may be kept to a mininnun by maintenance of lines, transposing wiro 3, balancing Wave length = Velocity line capacitance, and using repeating coils, and Frequency noise filters. However, careful installation of lines and regular inspection of splices, joints, ATTENUATION insulators, and other line equipment also helps to keep down noise. Methods and techniques The general term for power losses along a for minimizing interference by proper installation transmission line or network is "attenuation."were discussed in the chapter on the overhead Inan open-wire pair, attenuation depends on distribution. (1) the size, spacing, and material condition of the conductors, (2) the kind, number, and con- Capacitive coupling between adjacent telephone dition of the insulators, and (3) the frequencywires can also cause crosstalk. This effect of the current. Under ordinary conditions therecan bereduced by transposing wires in the is less attenuation in an open-wire line than cable at points where one length of cable is there is in cable or field wires. spliced to an adjacent length of cable. Another method of reducing capacitive coupling is to LOADING connect the wires on one end of a short length of a twisted pair to the cable pair, leaving the The talkin,- range of a cable or field wirewires on the other end of the short length un- used for military communication is frequently connected. increased bya procedure called loading. As applied to a transmlssion line, loading means In emergencyinstallation,1-wire ground- increasing the series inductance of the line byreturn telephone circuits may be used in con- adding external.nductance. Lumped loadingjunction with a 2-wire circuit. A 1-wire circuit means the addition of loading coils with rela-is especially sensitive to inductive interference tively high inductf lc(at regular intervals alongfrom adjacent circuits. Such interference can Le line. TrC lie method most commonlybe greatly reduced by connecting the 1-line used at a ob. es, circuit to the 2-line circuit through a repeating coll. Continuoue 'sidingmeans wrapping the cable conductor with tape or wire made of Low-pass filters may be used to remove hum magnetic material. This wrapping distributes the caused by battery chargers and similar equip- inductance continuously along the line and resultsment. These filters consist of a series of choke inimproved performance. Continuous loading coils and shunt electrolytic condensers of rather is used on submarineSables, because lumpedlarge capacity. By filtering the output voltage, loading would subject them to excessive strainthey remove the higher frequencies that lie in at the points where loading coils ware inserted. the voice frequency range.

INT ERF ERENC E TRANSMISSION SYSTEM PLANNING Interference is a serious problem on telephone lines.It may result from lightning or other Transmission lines used in military telephone natural electrical disturbances in the installations may be field wires, open wires, atmosphere, orit may be caused by nearbyor field cable. powersourcessuchas powerlines, railway Field wires consist of simple pairs of in- facilities, or other communication circuits. When sulated wires twisted together. As a rule, you two or more telephone talking circuits operate will use field wire chiefly for emergency and 393 403 CONSTRUCTION ELECTRICIAN 3 & 2 temporary installations.Transmission losses If field wire is placed on poles carrying bare are so high that field wire lines must be confinedconductors, it mast be strung below the lowest to short lengths. bare conductor. Precautions must be taken to Open wires are parallel single bar conductors ensure that, in swinging or otherwise, telephone strung on pole crossarms. wire will not contact the bare conductor. At junctions between overhead and surface A telephone cable consists of one or more pv:rs lines,tie the wires securely to the bottom of of wires, with each wire individually insulated.the support and tag them. Where there are long Field cable is available in 5-pair and 10-pair stretches of overhead lines, install test stations cable,colorcoded,rubber insulated, copperat junctions with other types of construction. jacketed, and equipped with a connector on each end. OPEN WIRES Begin planning by making a prelirrO.nary survey ofthe number ofoverhead and underground For open wire installations, you will use crossings the line must make, of the streams it steel wire, hard-drawn copper wire, or copper- must cross,of the general character of the clad steel wire, diameter from 80 to 165 mils. terrainand of any possible obstacles in the Two wires constitute a line. way of future maintenance work. Theconductors arestrung on electrical insulators mounted on the crossarms of telephone In routing, consider points where the linespoles. As each basic telephone circuit requires might be damaged by construction operations, two wires, you will have to mount quite a number remembering that about everything at the base ofbare conductors on the crossarms. Keep will be under construction at this time. Wheneach conductor in place by tying it to an insulator. you have mapped the route along which the lines Standard spacing distancesare8in.for a are to be laid, choose the wire or cable according single pair of wires, 10 to 12 in. when more than to the type of line to be built. one pair are strung. The procedure for stringing telephone wire is similar to that for stringing powerline wire. FIELD WIRES You should know the main operations (reeling out thewires,raising wires to crossarrns, In laying field wire, select the shortest and tensioning, and tying in) by now. themor.,, effective route. At advanced bases, savings of time and of material can be very important factors. Surface line construction is TELEPHONE CABLE the quickest type, but is vulnerable to weather conditions and mechanical damage. If the wires Becauseofthe numerous wires that are are surface-laid, they should be laid loosely, carried in a cable of nominal cross section (as, to minimize any damage from bombing. for example, 1 1 '2 in. in diameter), there are certain disadvantages in using cable. The voltages Test the reels of wire for continuous circuit. carried arelow, which means that a single Install test stations at exposed points on the wrap of dry paper is insulation enough for each wire line forexample,where circuits wire. However, this insulation is so thin, and diverge (or may diverge with future expansion the wires are so tightly packed, that a very of the system), and at the end of a line that does small amount of moisture can produce a short. not terminate in a switchboard. In the actual laying of a line, you will find additional points at TYPES OF TELEPHONE CABLE which it will be desirable to set up test stations. Use overhead lines near headquarters and The following are commonly used types of camp areas, and at road points where it is likely telephone cable: thattraffic will be diverted from the road. 1. Exchange cable is the outside cable of Trees can be used as supports for overhear] a central office that furnishes the facilities for wires, but they may sway during high wind-. sending out and receiving calls through local To offset this, a slightly more-than-normal nag switchboards. should be provided. In some cases you may have 2. Tollcable is a quadded or nonquadded touseslingstogiveintermediatesupport. conductor (the term "qaadded" means that all 394 404 Chapter 12 COMM UMCATIONS SYSTEM or some ofthe conductors are arranged in top of the pole will prevent the suspension strand quads, or groups of two pairs) used for com-from being pulled out of the grooves on the munication between widely separated local ex- clamp. changes. After the suspension strand has been pulled to the specified sag,it must be dead ended. 3. Trunk ortiecableis used primarily You can terminate the strand at the eyebolt used for connecting exchanges which are fairly close for the guy wire. Thread the free end of the together. strand through a thimble in the eyebolt, then double 1G back and clamp it to the main part of Post oradministrative cable forms partthe strand, or use a preformed dead end grip. of a fire control communications system. Target The last step in the installation of suspension range cableis used exclusively on a tug, strand is the tightening of the suspension clamps. range, and is not connected to any other system,At first you tightened them just enough to hold Fire alarm cable is used exclusively in a fire the strand in the groove. Now they must be fully alarm system,, tightened.. It is best to start at the middle pole and work toward each end in turn.

OVERHEAD CABLE LINE Cable Rings Open wire needs no intermediate support One method of fastening the cable to the between poles. Telephone cable, however, must supporting suspension strand is to use cable rings. be supported between poles by a series of metal To string these rings on the suspension strand rings which are suspended from a galvanizedyou will probably use a cable car like the one steel wire called a suspension strand or shown in figure 12-10. A loop of wire attached messenger, or the cable is held to the messenger to the car holds the rings. A drag line, marked by a process known as spinning or spun cable. with the ring spacing as shown, is left threaded A small wire (or wires) is spun around both the through each ring as the car passes along. The cable and the messenger by a machine called a drag line then serves as a pulling-in line when cable lashing machine. you are ready to pull the cable through the rings. If you line the reel up carefully with the suspension clamp,thecableshould pullsmoothly Suspension Clamps through the rings. The first step in stringing the messenger is Lashings to provide support at each pole by installing a suspension clamp. One of these clamps consists Instead of being suspended on rings, the cable of two metal bars which can be clamped to- may be lashed to the suspension strand, First the gether by tightening a nut and bolt assembly.cable is brought up to the strand. Then the two An overhanging lip on one of the bars forms a groove that holds the suspension strand.

MESSENGER MARKINGS Stringing Suspension Strand When suspension clamps have been mounted on all the necessary poles, you can string the suspension strand. As the strand is unreeled, LOOP DRAG it is carried up each pole, and placed in the LINE suspension-clampgroove.Theclampnuts CABLE -4-CABLE RINGS should be tightened only enough to keep the CAR strand from falling out. The next step is to pull the suspension strand to the proper tension or sag. Leading the pulling linethroughasnatch block (block on which the side strap can be opened for inserting a line 73.175 Or wire when the end is not available) set at the Figure 12-10.Cable car for placing rings. 395 405 CONSTRUCTION ELECTRICIAN 3 & 2 are lashed tightly together with a spirally wound the end of the wire into a splicing chamber,or wire using a cable lashing machine (fig. 12-11).up to the ground surface, to splice it. Backfill To bring the cable up to the strand, you canexcavated earth witha grader or bulldozer. use temporary cable rings, which can be removed Again as with underground powerline ducts, as soon as the lashing is applied. An alternatehave the trenches slope toward the manholes method is to mourit the cable reel on a truck,for drainage. Make sure that ducts have been and pay the cable up to the suspension strand cleaned of dirt or concrete before pulling cable through a cable guide (shoe) to which the lashing through. Push a rodding tool through fromone machine is attached. manhole to the next. Attach a threading wire to the last section of rod in the rodding tool, UNDERGROUND T EL EPHON E and a rope to the threading wire. When the LINE rope appears in the manhole, fasten the end to the pulling source of power. Fasten the other The advantage of direct burial of telephoneend to a cable grip on the cable to be pulled cable, a method frequently used in laying field through. cable,liesinthefact that an underground system 1^, usually much easier to construct thanan OUTSIDE TERMINALS overhead system. Incarrying telephone wires from switch- Protection against corrosion and damage is board to subsets, there will benumerous places provided by placing the cable in ducts, a method where the cable will have to be spliced. Methods which also facilitates pulling in and replacing ofsplicing telephonecable are described in cable when necessary. Manholes and splicing chapter 13. chambers constructed at intervals along the line Terminal boxes are mounted at convenient serve as convenient points for inserting cablepoints along the pole linestwo or more boxes in ducts. must be used, if the number of telephones to Make the trench no wider than necessary, be installed exceeds the nury0-,erof terminals but deep enough to allow 18 inches of earthcover in a single box. over the cable. Remove any rocks that might The appropriate wires are brought out from damage the cable. Where a reel runs out, bring the cable and connectedIntotheseboxes.

ROTATING DRUM LASHING WIRE

WIRE MAGAZINE COVER

SUSPENSION STRAND

REAR/ CABLE LIFTER CABLE

TOWING LINE24444

73.337 Figure 12-11. Cable lashing machine. 396 406 Chapter 12 COM _VI UN1CATIONS SYSTEM

Outside drop wires are then installed to lead Torminal Box Panel from the termnal boxesto the substations. Inside a terminal box there is a nanel fitted Mounting Terminal Boxes with binding posts, nuts, and washers. A short Mounting terminal boxes on poles is a joblength of lead-sheathed cable is attached at the commonly given to the CECN. A can bracket back of the box. Drop wires from the individual is first attached to the pole, about 24 in. below subsets are attached to the binding posts. thb main cable, by four screws. The terminal Figure 12-13 shows how conr lotions are made box is then placed in supporting notches in the at the panel of a terminal box. As soon as the bracket, (See fig. 12-12.) wires in the cable stub are spliced to the wires in the main run of cable, you will have a completed circuit from main line to subset. In figure 12-12 you can see the cable stub coiled and ready for splicing to the main line. Tapping the main line, and calling the wire chief or switchboard operator to assure proper lins number and subset operation, is usually the last step in telephone installatiokA.

TELEPHONE SWITCHBOARDS ATTACH WITH 4 - V4 IN. Connectingalarge number oftelephone X 2 YI IN. stations directly to each other would require an DRIVE SCREWS enormous maze of wires. To reduce the amount of wiring and to simplify the wiring arrangement, a switchboard is installed in the system

INSULATED CONDUCTORS SHOULD NOT BE IN CONTACT WITH ADJACENT BINDING POSTS.

TRACER CONDUCTOR AT RIGHT. EXTEND BRAID BEYOND FIRST ROW OF EXTEND BRAID BINDING POSTS. THROUGH FANNING STRIP. B ADJUST ABLE KEEP INSULATIO EXTEND RUBBER GRADE CLAMP BACK 1/11. INCH INSULATION FROM WASHERS. BEYOND FIRST ROW OF BIND. ING POSTS.

TWISTED-PAIR WIRE PARALLEL WIRE 73.177 Figure 12-12. (A) Can bracket for pole- 73.176 mounted box; (B) Box installed in bracket. Figure 12-13.Connections at terminal box. 397 407 CONSTR!TCTiON ELECTRICIAN 3 & 2

Figure 12-14 shows how a switchboard simplifiesconnected to lines to the switchboard.For each connectio, between eight telephone stations. Each line in use (that is, connected up in this fashion), station is connected directly to the board. Con-jumpers or cross-connecting wires make a con- nectioa betwe ,....i.any pair of stations can be nection between terminals. made at the board by means of a plug-fitted cord. Particular types of switchboard are discussed The side of the frame carrying the terminals later in this chapter. to which outside wires are connected is usually known as the vertical side of the MDF. Cablen or lines from the inside equipment terminate oil DISTRIBUT:ON FRAMES what is usually called the horizontal side (in someinstallations, however, both sides are vertical). Cross connections between vertical W;-,en a large number of lines conehinto a and horizontalsides are made by jumpers. switchboard, there must be some arrange,, ,mt for rapidly connecting them to the propericks The use of distribution frames permits rapid on the board. This is accomplished by the uso switching of the switchboard load. It also makes of distribution frames. These frames not only outside wires accessible without any disturbance provide for an orderly arrangement of incomingof the switchboard wiring, and provides a con- lines, but also serve as an effective means for vanient place from which to test for line faults. identifying outside lines where they enter the central office. Main distribution frames (M))F), Distribution frames may be either the wall either in manual or in dial systems, serve these frame or the floor frame 1,,pe. Wall frames two purposes. They connect the inside equipmentare used in small central offices, and consist with outsidelines, and they interconnect theof units capable of accommodating 20 pairs, or variols units of inside equipment. Figure 12-15, lines. Screw type terminals are frequently used, view A shows the vertical side of a combinedbecause theyallow for easy disconnections. distributing frame. Figure 12-15, view B shows the Juinpers are flexible and can be made fast to horizontal side. anyset of terminals. Standard floor frames, also used at military installations, differ from ach outside line is connected to a PAIR ofwall frames in that they have one side vertical te,v,-)iTials on one side of tha tram?, as shown in and one horizontal, while a wall frame has two iigr12-16.Noticehowthecorresponding vertical sides. terininals on the opposite side of the frame are Basides being distinguished as wall or floor frames, distribution frames may be distinguished as type A or type B. The type A frame has the verticalsideof the frame connected to the switchboard. The type B frame has the vertical side connected to outside lines.

SWITCHBOARD PROT:ECU V E DEVIC ES SWITCHBOARD Bccause the distribution frame is the dividing point between the outside plant and the inside plant, it becomes the logical location for central office protective devices. The switchboard must be protected against excessivevoltage,including that caused by 73.178 lightning; and against excessive current, including Figure12-14.Hcw eight telephones can be current surges through unexpected channels. connected by switchboard. The protective devices must operate before

398 408 r NOY ., n COF ALM ,01PER 11,61ES TRIQ TO - 911 BOWS 1WITCHING TOGGLE SW ECwiPMENT, TEST HANDSET JUMPER SWITCHING CN TTUR:EATAL TELL TALE TERLTINANN5 FINISHING BAR RINGS 5,DE COF Otos EQUIP. 114iZONTAL jf. cnr Weltittl"

,a.tr

ARROIVASIvan''-: 6." t. ok. --mak ,t1i1504,

h,eltitf - Ipi,:0

FIRE TRIM MOUNTING (Non BAR PROTECT GANG COVER* NAIL SOLDERING IRON STAND

Figure 12-15,(A) Combined distributingframe, vertical side (B) Distributing frame, horizontalside,

409 . " 4 r4.%4 Th.X.P7rAlrtM CV ALM TRKS TO lkiTC,11,4 TOGGLE SW TEST HANDSET JUMPER SWITCHING 1E4111,..ATisr, FINISHING BAR RINGS EQUIP, JUMPERS CN,-fo*..,:roAL sicr 1,/,/rArIPIPPIr

llli'e l niwo, ',psi, r

I, It.' ,

,,, ,*-111,T '4"

, ti ....% 1

AV" a

1, ;',rogio. ,.,.*c'pW' ''1111".

TERM. BOARDS

FIRE TRUNKS ArieUNTiNG(NOTE BAR PROTECTIVE PROTECTOR COVERING1 EQUIPMENT SOLDERING IRON STAND

73.179(73B) (A) Combined distributing frame, vertical side (B) Distributing frame, horizontal side,

410 coNs-rit(vTioN ELC1'II:ct.1ti 3 & 2

operatedsw;tch which makesitpossible to oontrol (by moans of one switchboard circuit) the

400 4 1 1 Chapter 12COMMUNICATIONS SYSTEI

RAtORS 9,NGING Tf LEPHONE MACHINE

73.180 Figure 12-17..-Universal cord circuit. This circuit is called universal bscause itno hook switch contacts. Switchboardssignal provides a talking circuit in either directiondrops or lamps perform the functionof the between two common battery lines, or betweenringer. 0?3rator's jack, plug, and leverswitch two local battery lines, or bstweer one co:nromsubstitute for the hook switch. battery line and one local battery 1 ;. RINGNG AIACHINES The various cord circuits provide for ELEC- TRICAL paths between selected stations, but A ringing machins is a device that operates they are no: sufficient of themselves to enablefrom a standard power source to p-....ovids ringing the user of a calling telephone to tell ths switch-current fortheswitchboard and connectors. board op3rator what station he wishes to call.A varietyofdevices areavailable to moet For this,it is necessary that the oparator bedifferent requirements. In any case they convert able to listen to or talk into each telephone.the a-c or d-c voltage of the power source to This need is met by installing an oparator'sthe required frequency (usually 20 hertz) of the telephonecircuit fk. :he entire switchboard.ringing current. If the powar input is from r. battery, a d-c Operator's Telephone Circuit vibrating reed CON VERTE t changes the d-c to 20 hsrtz. The function of this circuit is to connect the An a-c vibratingreadINTERRUPTER operator's telephone set across ths line fromproduces 20-hertz ringing current output from a any calling station, eithsr before or after the110-volt 60-hertz input. This is accomplished by calledstationisconnected. The operator'salternately opening and closing the output circuit telephone circuit, therefora, provides an addi-atregularintervals. The interruption f th3 tional voice frequency path which is in parallelout circuit results in an output voltage consist- with the cord circuit. irof alternate positive and negative half-cycles , over a 1-second psriod, are the equivalent Generally, the operator's sat is cox sctedel a 2-hertz frequency variation. to the switchboard by means of a plug and jack. The machines described above have moving A lever switch alloxs the operator to cut hisparts which need frequent adjustment and are telephoneinto or out of any cord cirLmit. Itdifficult to mo'ntain. Subcycle static frequency differs from user's set in having no ringer andconvertershave been designed to minimize

401 412 CONSTRUCTION ELECTRICIAN 3 & 2 maintenance andreplacement ofparts. Tni3 WIRING device is essentially a series L-C circuit designed toresonateat20 hertz. A switching action, The drop wire is exposed to the weather, accomplished electrically by a z,aturable reactor, and both wind and rain can do damage unless the allowsthe60-hertz currentto turn off andwire has bean given prcosr protection. Both onatthe proper times todevelop ths 20-conductors should be insu dted with a rubber hertz current. compound, and the wire should then be further proL.ected with a covering of weatherproof cotton SWITCH KEY braid. The wire used inside a building is rubber insulated, but protective braid covering is not The switch key on the switchboard is simply necessary, except in very damp locations. a make-and-break spring switch. Vaen you move the key handle, it causes a cam to press against Drop wire niny be either the twisted-pair type the spring of the switch, and to open or closeortheparallel-droptype. Vie twisted pair the contacts in the cord circuit. consists of two conductors separately coveredbut W!.an the switchboard operator receives anspiraled together. In a parallel-drop wire there incoming call, he pushes the key forward into are two separately insulated wires that run thetalkingposition. When he has made theparallel to each other and are under a single connection with the circuit on which the call is to braid covering. be placed, he pulls the key back into ringing position. When the calling party has a connection The drop wire must have a definite sag with thecalled party,the operator lets the between pole and building, but the weight of the key return to neutral position. There is now a wire should not be allowed to exert a strain on closed circuit from calling to answering plug.the remainder ofthe run. Clamping the drop This circuit is broken when one of the telephones wire prevents this. is returned to its cradle. The clamp installation consists of a wedge secured to a copper wire loop, and a tapering INSTALLING ;`. TELEPaONE sleeve. The copper wire loop is attached to the support point on the pole. Then the sleeve is After you havestrung the outside lines, placed over the drop wire, with the tapered end installed the switchboard, and provided for the toward the support point, and pushed firmly up necessary connections between main lines andon the wadge. When the free end of the drop subsets, then a telephone can be installed. Thewire is attached to the building, the weight of steps for installing a telephons Mil be briefly the span induces a tight fit at the wedge. outlined here, then explained at more length in subsequent section. The type of support you use to train the drop wire along the building depends on the material Span thedrop wire from the pole to the of the 'ouilding wall. On wood or other com- building, and trainit along the building to the bustible material, supports must be insulated. entrance hole. Bring it through the hole, andAnchor bolts are used on concrete and masonry connect it to the INPUT side of the fuse, lightning walls. Toggle bolts are used n clay tile walls. arrester, or other protective device. Some commonly used types of supports on various kinds of walls are shown in figure 12-18. Connect the inside wiring to the OUTPUT side of the protector; run the inside wiring to Wire can be run on a sheet-metal wall (such thesubset location; and terminate the inside as the wall of a quonset hut) without the nece- _ty wiring at the connecting block. for drilling into the metal. Nail knobs (s..,11- lar to the T-knob shown in fig. 12-18, but with Attach the subset wires to the connecting a nail instead of a holt) can be driven into points block; secure the drop wire to the pole; tap Itwhere the sheet metal is secured to the rib- to the designated pair of wires in the main runframes. On a metal base the knobs must, of (through the terminal boxifcable is used; course, be insulated. directly to a pair of open wires if the main run consists of open wires strung on crossarms); On a frame building you can attach the drop and finally check the installation. wire with an S-knob (fig. 12-18) and a drop wire 402 413 Chapter 12 COMMUNICATIONS SYSTEM

T-KNOB ...-APPROX 6INCHES

WHERE ONE S -KNOB IS REQUIRED USE 5/16"X 2° INSULATED SCREW EYE FH STOVE BOLT rC KNOB S-KNOB OVER 9 FEET PLACE ADDITIONAL INSULATED SCREW EYE SCREW EYE 5/18"X 3"FH STOVE DROP WIRE CLAMP BOLT 711ext WASHER UNDER NUT

C-KNOB

IF OVER , 12 FEET, PLACE ADDITIONAL SCREW EYE

BRIDLE RING INSERT EXPANSION SHIELD (WOOD SCREW THEAD) OF HAMMER DRIVE ANCHOR INTO HOLE OF CABLE CLAMP KNO9--

ENTRANCE HOLE 73.181 Figure 12-18. Supports for telephone wires. 4. *ft11`.` 'T. clamp. In a line with the S-knob, and about 6 in. --.- -7 away, screw ina C-knob(fig. 12-18). Still following a horizontal line, attach an insulated screw eye (fig. 12-18) a few feet further along. The horizontal distance will depend on the location 73.182 ofthe entrance hole, because you want the Figure 12-19. Drop wire installation on wire to drop from a point vertically above the wood frame building. hole. Screw in another insulated screw eye and another C-knob as shown in figure 12-19, if theto the possibility of being struck by lightning, indicated distances exist. It therefore requires some protective device, such as a fuse or lightningarrester. This Figure 12-19 will aid you in installing a dropprotector may be enclosed in a weather-proof wire. You attach the drop wire clamp to themetal can outside,orit may be an inside drop wire and attach the clamp to the S knob.unit mounted on a porcelain block. Allow a slack loop of about 12 inches (6 inches for slack and 6 inches to the first C knob). Place Fuses are inserted n series with the line, the drop wire in the C knob. Tighten it downbut an arresteris placed between line and and run it through the necessary insulated screwground. With a fuse, current must pass through eyes to the last C knob. Allow a 4- to 6-inchthe fuse before it can reach the output terminals drip loop between thelast C knob and the to which the subsets are connected. An arrester entrance hole. A plastic or porcelain tube isensures that excessively high potential is bypassed usually inserted in the hole toprotect the enteringto ground before it canreachthe output terminals. wire. Where a protector is used, the DROP When you bring in the drop wire, remove the LOOP ends inthe protector, and the insideinsulation for about 3/8 in. from the end, and wiring goes through the tube. then bring the bare ends of the conductors around the input terminal posts on the protector. Give each wire a 3/4 clockwise turn around its CONNECTIONS TO PROTECTORS post, and then tighten the terminal nuts. Connecttheinside wiring totileoutput The wire from pole to buildingusually crosses terminalsthat is, to the outside binding posts lightand powerlines, and is always exposedon the bottom of the protector.

403 .114 CONSTRUCTION ELECTRICIAN 3 & 2

The center terminal is the ground terminaldrop wire along the crossarm. The type of for the arrester. Connect it, by a single in-bridle ring you will use has an open spiral eye sulated conductor,toacold water pipe, ifthrough which you can slip the wire after the possible. If there is no available metallic objectring has been screwed into the crossarm. in close contact with the ground, drive a ground Each conductor of the drop wire should be rod. NEVER ground to gas pipe systems or to separate, as if for splicing. You can then wrap lightning rods. Hot water, steam, or sprinkler each of the two conductors around the main run pipes provide poor grounding, and electric rail-wires, for about three turns, before extending ways should never be used to ground any equip- the conductorst..,he point of connection. The ment other than that supplied by the railway'screw chief will tell you which pair of wires to own circuit. use in the main run. Thejoint at the connection is solderless. CONNECTIONS TO SUBSET:, The connector will probably have a slotted bolt, nut, and washer assembly. Place the main wire In routing Cie inside wiring from protectors in the slot, and wind the bared conductor of the to subset locations, keep the run parallel with drop wire around the bolt, between two washers. or at right angles to the building walls. Where-Be sure to wind in the same direction in which ever wires must pass around sharp corners or thenut tightens.Turning down the nut will over metal objects, use friction tape to protect ensure a firm .:oint. them from mechanical injury. If you must run Terminal boxes were previously described. wiring along a floor or ceiling, placeit in aThe method ofconnecting a drop wire to a metal raceway for protection. You can secure terminalboxisillustratedin figure 12-20. inside wiring to walls and ceilings with insulated Important matters to bear in mind are: connect the staples, because inside wiring carries a pro-pairs of binding posts to the proper wires in the tected low voltage. main cable; remove only a smEll amount of At the telephone location, run the inside wire tothe connecting block. One of these blocks usually consists of four terminal posts mounted ona composition base and provided with a I removable cover.

HOOK ON FACE Bring theinside wire to the back of the OR BACK OF POLE. connecting block, wind it around the projecting CLAMP lugs, and connect it to the terminal posts on the face Of the block. There will be less strain on thewire thaniftheconnection were made PLACE RINGS SO THAT WIRES WILL directly, and there will also be enough wire so NOT TOUCH CABLE . that it can be reconnected if a bare end breaks off. ALL RINGS TO BE C BRIOLE RINGS FOR 16 PAIR OR SMALLER These connecting blocks provide not only a TERMINALS; A BRIDLE RINGS FOR LARGER ABOUT 6 INCHES PADRE OR point at which to connect inside wire and telephone THAN 16 PAIR TERMIN- LESS, PRESERVING HOWEVER, ALS. PROPER JOINT USE CLEAR- cord, but also a convenient test point. ANCES.DRIVE HOOK MAY BE PASS DROP WIRE THROUGH 8 INCHES PLACEO BELOW GABLE IF HOOK OF ORIVE HOOK ONLY PROPER CLEARANCES GAN WHERE DROP WIRE IS RUN BE OBTAINED ANO THERE IS CONNECTIONS TO THE ALONG THE GABLE LEAO NO INTERFERENCE WITH MAIN RUN OR WHERE DROP WIRES CABLE sTue. OBTAIN A ARE RUN TO BUILDINGS ON MINIMUM VERTICAL SEPARA- OPPOSITE MOE OF STREET TION OF 4 INCHES BETWEEN FROM CABLE RUN. AN EXISTING POLE STEP ANO Before you can make final connections with A DRIVE HOOK PLACEO move IT. the main run, there is the matter of training the drop wire back to the connecting point in the run. The method to follow in doing this will depend upon whether the drop wire is to be coanected to open wires or to a terminal box. If the drop wire is to be connected to open 73.183 wires, train it under the crossarrn to the point Figure 12-20.Connecting drop wire to a of connection. Use bridle rings to support the terminal box.

404 415 Chapter 12 COMM 'iNICATIONS SYSTEM insulation from the drop wire, so there will be no a low-voltage source either dry cells or a bell risk of a bare conductor touching an adjacent post; transformer connected to a lighting circuit. You make one conductor of the drop wire slightlywill require a pushbutton to make and break the shorter thantheother,to acoommod.,te the bell circuit, a signaling device, and a wire to post positions; and make sure the conauctors onnect these components. are wound around the posts in the same direction Mount a bell at each telephone. There should as that in which the nuts tighten. be a pushbutton for each bell, but these buttons should be located together at the central tele- At the pole, you will have to attach the tracer phone location. Connect the transformer to the conductor of the drop wire to the ring line, and lighting circuit at any convenient point. the plain conductor to the tip line. The tracer Use No. 18 wire for the bell circuit. This conductor must always beconnectedto the wire is attached to the secondary side of the RIGHT-SIDE binding post, to ensure that the transformer. One conductor is trained directly connections are made correctly. r-tis is alsoover to the bell; the other cOnnects with the standard procedure in making connections at the pushbutton. Another wire runs from bell to protectors and at tha connecting blocks; that is, pushbutton, being connected at the screw ter- always connect the gracer wire to the right- minals of each of these components. hand terminals. FIELD TELEPHONE SYSTEMS At the central office the positive side of the A field set is a telephone system designed battery is permanently grounded. This makesfor easy transportation from one location to the negative or tracer wire a hot wire, and itanother, and for rapid installation. Navy field must therefore bereadily identifiableat all set components include central office sets, dis- points for purposes of testing and repair. In tribution systems, and station equipment, capa- atwisted-pair drop wire the outer coveringble of serving small, medium, or large bases. often has a raised thread to identify tha tracer Because the SEABEES use a considerable amount wire. In parallel-drop wire the conductor withof Army equipment, brief descriptions will be the ridged insulation is the tracer wire. In the given of some of the commonly used Army field inside wiring the wire with a red thread is the sets you may need to install and operate. tracer. TC-2 SET HOOKING UP A HANDSET The TC-2 sat is a central office set with the receivers mounted in the headband. It con- A telephone set is practically a self-containedsistsofa combination of local and common unit. In a desk or table set, the base containsbatteries, switchboard, main distributing frame, ringer,inductioncoil,condensers, and hookpower unit, power panel, rectifier, and acces- switch. The transmitter and receiver are con-sories. The switchboard has 57 circuit lines tained in the handset. Installing the set simply and 3 trunklines for connections to other switch- involves connectingthe terminal lugs of the boards. telephone cord to the block. Tae power unit is a self-contained 2500- watt a-c generating set, driven by a gasoline CHECKING AN INSTALLATION engine, and producing 120-volt single-phase 60- hertz current. The panel contains a voltmeter As soon as a telephone is hooked up, checkand ammeter for use in controlling the rata of to ensure that connection to the proper line has chargeofthestoragebatteries. A rectifier been made. Then have someone ring back from capable of charging the batteries at a maximum the switchboard, to check the bell circuit. Check rate of 12 amperes is installed to change the for satisfactory strength and quality of voice alternating current to direct current. transmission. The components of this set can be easily damaged, and care must therefore be exercised BELLS AND BUZZERS in unpacking. When installing, locate the switchboard as far away as possible from any source Where thereareseveral telephones at a of excessive noise. station,all working from one or two incoming Figure 12-21 shows an interconnecting dia- lines, bells and buzzers will be a great con- gramofa TC-2 set. Cords may be small, venience. To energize a bell circuit, youwillneed flexibleinsulated cables or stranded wires. 405 416 CONSTRUCTION ELECTRICIAN 3 & 2

INTERRUPTtm MANUAL TELEPHONE CENTRAL OFFICE AN/TTC-7A The AN/TTC-7A is a transportable telephone central office (central office set) which basically can handle 200 local lines, 20 plug supervision trunks, and 20 manual or dial trunks, If the set is used to terminate incoming manual dial or trunks from another AN/TTC-7A, 20 of the line circuits must be used for termination. When not being used as terminators, the line circuits can be set up for either 200 common battery (CB) lines or 100 CB lines and any combination of 100 local battery (LB) and CB lines. The basic AN/TTC-7A installation can be modified to handle up to 960 lines, 100 plug supervision trunks and 100 manual or dial trunks bytheinstallationofadditional components. The main components of the AN/TTC-7A are shown in figure 12-22. The location of the units is limited only by the length of the interconnecting cables (these come in set lengths) and the amount of space in which the set is to be installed. FIELD SWITCHBOARD SB-22A/PT Tte SB-22A/PT f.s a lightweight field type, local-battery switchboard. Figure 12-23 narnes the main parts. The set is a self-contained unit, Figure 12-21.Interconnecting diagram and requires no special mounting equipment for of a TC-2 central office set. 26.118 operation.

TELEPHONE WAIN DISTRINUTING LLLLL TA-267/ TTC MINE SIDE

MANUAL EEEEEE ONE TRUNK RELAY SWITCHIOARDI LINE RELAY TELEPHONE 1111-2411A/TTC TELEPHONE CIRCUIT CIRCUIT TA- 223 A/ T IC TA-2 711/T IC

POWER TRISLITION PANEL 311-103E/T IC

7iiO BAH NTIISEITT:

TEUNK RELAY , ; TELEPHONE MAIN 1 ElISTRIEUTING AAAAA LINE AAAAA STAND LLLLL NONE CIRCUIT TA-207/ ITC RACE LLLL PHOHL CIRCUIT EASE TA-MA/TIC ,IEWITCHIOANO SIDE/ , 0 TTTTT on's cHnons TA-WA/TIC MT- IISI/TT

-... _- TEL(PHONE GAIN OISTRISUTINE AAAAA TA-EST/ITC (LINE SIDE)

Figure 12-22. Manual telephone central office AN/TTC-7A, main components. 26.268 406

4 1 7 Chapter 12COMMUNICATIONS SYSTEM

LINE PACKS BATTERY PACK BATTERY CASE

HANDSET-HEADSET SWITCH ( OPERATOR'S HANDSET-HEADSET OPERATOR PACK

ETCHED WRITING SURFACE HANDSET-HEADSET TELEPHONE ILLUMINATION 4C:=ZOT; PLUGS SWITCH

CAPTIVE SCREW

RINGING GENERATOR HANDCRANK DROP

JACK ALARM SWITCH immillmummummultstaa , .

OPERATOR'S PACK

HANDSET-HEADSET RINGING IDENTIFICATION STRIP LINE PACKS RECEPTACLE SWITCH

26.104 Figure 12-23. SB-22A/PT manual telephone switchboard.

The switchboard is comprised of four major Under normal conditions, you will becon- components. Three components make up the cerned with only the telephone lines. Thepro- actual switchboard (the line pack, operator pack, cedureforconnectingthewiresof the and battery pack). The other component is the switchboard to a radio circuit is very similar handset-headset. to the procedure fer making connections to the telephone circuit. The switchboard is designed to establisha working telephone system for unitsup to and Line Packs including battalion size. The SB-22A/PT oan be used for interconnection up to twelve local- The 12 line packs are located on the left battery lines and for remote cortrol radin -,- side of the front panel. A line pack is shown in munications. It may also be 1~' figure 12-24. Each line pack is fastened to the a common-battery (CB) switchu.$). switchboard by two captive screws, one at the

407 418 CONSTRUCTION ELECTRICIAN 3 & 2

The LINE SIGNAL consists of a plastic ball (indicator) with a permanent magnet embedded in it. The black plastic ball has a white strip around it. The magnet is embedded in part of this strip (fig. 12-25). When a telephone user turns the crank of the hand generator serving the telephone, a circuit is completed, setting up a magnetic field in the armature of the line signal indicator which attracts the magnet. The magnet aligns itself with the core, and the in- CAPTIVE dicator shows white. When the line signal shows SCREW white and the operator inserts the operator's cord plug into the associated line jack, the ball is mechanically restored to show black. DESIGNATION LINE STRIP The JACK is used in conjunction with the SIGNAL cord of the operator's pack, or with cords of thelinepack,tointerconnect line circuits. LINE/ CAPTIVE SCREW The IDENTIFICATION STRIP is a piece of JACK white plastic fastened beneath the line jack. PLUG-. Marks on this strip identify the telephone circuit associated with the line pack. A LIGI-VNING P.RRESTOR is provided for protectionofthe line from outside voltages. Operator's Pack The operator's pack (fig. 12-26) is located on the right of the front panel. Tne pack con- LIGHTNING sists of a reel unit, ringing equipmsnt, alarm ARRESTOR equJprnent,and a handset-headset receptacle. The REEL UNIT is identical to that of the line pack. The ringing equipment consists of a CORD

REEL UNIT

26.105 Figure 12-24.Line pack. top of the unit, and the other at the bottom. The line pack contains a reel unit, a line signal, a jack,anidentificationstrip,and a lightning arrestor. Tne REEL UNIT consists of a reel, a cord, and a plug. The cord is fastened to the spring- loaded reel by three screws at one end and is equipped with a standard switchboard plug at the other end. Tne cord may be extended 26.266 toa maximum distance of 35 inches andis Figure 12-25.Lins signal indicator (with retracted by the spring-loaded reel. indicator lens removed). 408 419 Chapter 12 COMMUNICATIONS SYSTEM

HAND GENERATOR

OPERATOR'S JACK

NIGHT ALARM AND LIGHT,_ SWITCH

HANDSET- HEADSET RECEPTACLE ;

OPERATOR'S CORD VISUAL AND isftefte,,awAUDIBLE ALARM SWITCH RINGING SWITCH

EXTERIOR

REEL UNIT

\ \

INTERIOR

26.106 Figure 12-26.Operator's pack. hand generator and a control switch. Ringingbuzzer and a lamp. When the switchboard is currentisgenerated when the handcrank issignaled by an outlying telephone, the drop on rotated. The control switch has two positions:the line pack associated with the outlying field RING ?ACK and PWR RING FWD. This switchtelephone falls; this completes a circuit through enables the operator to connect ringing currentthe alarm lamp or the buzzer. Depending on the to the calling or to the called telephone. settingofthe switch, either the lamp lights The ALARM EQUIPMENT provides a moreor the buzzer sounds. positive signal for the operator than that af- forded by the drop mechanism of the line pack. The HANDSET-HEADSET receptacle is a po- The alarm equipment consists of the signalinglari zed, bayonet-locking,10-conductor receptacle

409 420 CONSTRUCTION ELECTRICIAN 3 & 2

TRANSMITTER NIGHT ALARM FIELD BATTERY BATTERY TELEPHONE BINDING POSTS BINDING POSTS BINDING POSTS

EMERGENCY TELEPHONE BINDING POSTS

POWER RING FRONT GENERATOR COVER BINDING POSTS

POWER RING STARTING BINDING POSTS FRONT COVER SPRING LATCH

NIGHT ALARM BINDING POSTS

GROUND BATTERY IDENTIFICATION SPRING BINDING CASE STRIP RETAINING POST CLIP

26.104.2 Figure 12-27. Rear view of switchboard, SB-22A/PT. which is used with the plug on the handset- headset cord. Battery Pack The battery pack is located under the rear cover of the switchboard (fig. 12-27). Itholds HANDSET-HEADSET four BA-30 batteries which supply power to operate the set. N44120410C" Handset-Headset As illustrated in figure 12-28, the handset- headset cons.sts of the actual handset-headset, the talk-listen switch, and the 10-conductor plug for connection to the operator's pack. TALK-LISTEN SWITCH

Unpacking You should instruct your crew to be careful in unpacking the equipment. Immadiately upon unpacking, you should haveitinspected for possible damage during shipment. The original packing cases and containers 26.104.3 should be saved, so that they can be used again Figure 12-28.Handset-headset. 410

421 Chapter 12 COMMUNICATIONS SYSTEM when theequipmentis repacked for storagethe opsrator's pack has been removed) should or shipment. be removed. The field telephones can then be connected. A maximum of 29 lines can be served Connecting Procedures with this arrangement as shown in figure 12-29. The ground connection should be made before Maintenance and Repair connectirig the wire lines tothe switchboard. Select the lowest, dampest site in the vicinity; See that your crew makes frequent inspections clay or loamy soilis best. Scoop out a hole of the equipment to keep it in good working order. 6 inches deep and drivea ground rod intoDust, dirt, grease, or moisture should not be the hole until the top of the rod is about 3 inchesallowed on the exterior of the switchboard or below the undisturbed ground surface. Connect the handset-headset. A clean, dry, lint-free cloth one end ofthe wire to the ground rod. Theor a dry brush should be used for cleaning. The earth around the rod should be saturated with electrical contacts on the frame of the switch- water, and the hole filled with earth. Now con-board should be cleaned with a cloth moistened nect the other end of the wire tothe ground with drycleaning solvent, and should be wiped binding post (fig. 12-27) located on the framedry with a clean dry cloth. A burnishing tool behind the rear access door. should be used to clean the switch contacts. To connect the wire lines to the switchboard, Rust, fungus,dirt,and moisture tend to a pair of binding posts should be selected and accumulate on thebinding posts, plugs, and connectedto the desired circuit.13::sure toexternal portions of the line jacks. Have these record the circuit identification on the properremoved with a dry rag or brush. The battery identification strip. ease and clip contacts should be inspected for When the wire lines are connected, you are corrosion, moisture, fungus, and tightness. All readytoinstallthe four dry call batteries. linesshould be checked forkinks,strains, Remove the battery case and insert two bat- moisture,fungus,and looseterminals;also teries into the compartment so that the brass have the insulation checked to see that it is not contact end of each battery faces outward. Re-frayed, cut, or otherwise damaged. peat the procedure for the compartment at the Normally moving parts of the SB-22A/PT do other end of the battery case. After con-qileting not require lubrication. When necessary, lubri- this operation, replace the case into the springcate the spring latches of the front cover, and the retaining clips. thumb latches and hinge of the rear access door. After the connections are made, talk over Failure of the switchboard to operate properly the line and note the quality of transmission. If is usually caused by one or more of the following? transmission is poor or speech cannot be heard at normal speech level, check the connection 1. Rundown batteries wiring.Ifthetrouble continues, replace the 2. Defective operator's handset-headset operator's pack and check again. 3. Defective line pack 4. Defective operator's pack Stacking of Two Switchboards Rundown batteries may be indicated by any To serve more than 12 but fewer than 30 of these difficulties: lines, stack the 12-line switchboards. Remove the operator's pack from the switchboard and 1. Pull switch is pulled out, but lamp fails install five line packs in the empty space. This to light. modified switchboard should be placed on top 2. Drop of a line pack indicated that a tele- of a normally equipped switchboard. Use twophone is signaling the switchboard, but the lamp jumpers to connect the two switchboards. One or buzzer of the operator's alarm fails to work. jumper must be connected to the NA binding 3. The operator cannot talk toar..::of the posts of both switchboards, and the other jumper telephone users. must be connected to the GND binding posts of both switchboards. Bc sure that the jumpers Remove rundown batteries, and replace thern pass through the slot at the side of each switch- in the manner previously described. board. Only one set of batteries is required to A defective handset-headset prevents the op- serve both switchboards; the battery case from erator fromtalkingtoany of the telephone the one containing the 17 line packs (from which use .from receiving calls from any of the

411 422 CONSTRUCTION ELECTRICIAN 3 & 2

CLIP (UPPER)

SECOND SWITCHBOARD COVER LATCH 1641L- CLIP (LOWER) intarpi FIRST

COVER LATCH

3" -

26.267 Figure 12-29.Installation arrangement for two switchboards. outlying phones, or both. Replace defective hand- captive screws from the front panel, inserting set with one that is in working order. the plug into the jack, and pulling on the plug until the line pack is free from the front panel. A defective line pack may be indicated byThe replacement should then be inserted. After any of the following troubles: the two captive screws are tightened, the new line pack is ready for operation. 1. The userofa telephone cannot signal A defective operator's pack may be indi- the operator -_ecause the drop does not function. cated by any of the following difficulties: 2. The drop of a line pack for a particular telephone works, but the operator's alarm fails 1. Lamp fails tolight when a pull switch to function. (If this difficulty occurs with all is pulled out (also may be caused by burned-out telephones, the trouble may be rundown batteries lamp or rundown batteries). or a defective operator's pack.) 2. The operator's alarm fails to work when 3. The operator cannot talk to or receivethe drop of a line pack indicates that a telephone calls from the user of a telephone. is signaling the switchboard (may also be caused 4. The users of two telephones cannot con- by rundown batteries). verse with each other, but the operator can con- 3. The operator cannot ring any field tele- verse with each user separately. phone. 4. The operator cannot talk to any telephone The line pack is a self-contained, p-g-in users (may also be cax.sed by a defective handset- unit. It may be removed by loosening the twoheadset or rundown batteries).

412 4 23 Chapter 12 COMMUNICATIONS SYSTEM 111111.

5. The operator cannot receive calls from Functions telephones on the line (may also be caused by a defective handset-headset). The unitisself-contained,requiring two 6. The operator cannot ring back. internalbatterios or an oxLynal 3-volt a-c source (which isconnectedto theexternal The operator's pack is also a self-contained battery terminals) for operation. plug-in unit. A replacement is ready for op- The set is designed :o allow the handset to eration after installation of the unit and tight- hang inthe housing panel (handset retaining ening of the four captive screws. bracket) when not in use. When the handset 1.1 at all possible, you should always have isintheretaining bracket,the line switch handy a circuit wiring diagram and exploded disconnects the internt_ battery. A receptacle viewsof the various parts of the SB22A/PT connector is provided for linoof an external switchboard, in order to make emergency re- handset/headset (fig.1 2-28). The EXT-INT pairs. switch determ!.nes which handset is used. The phone can be used in three modes as FIELD TELEPHONE TA-31 2/13T selected bythe CIRCUIT SELECTOR switch: CB ,taiking and signaling, LB talking, and CB The TA-312/PT field telephone (fig. 1 2-30) signalizig. A buzzer is included for signaling is a versatile phone for use in manually oper-from another set. The buzzer volume is con- ated two-wire CB or LB iield systems. It cantrolled by the BUZZER VOLUME control. To be used eithsr outdoors (regardless of weather signal another set, the hand generator crank conditions) or inside as a desk or wall phone. must be manually turned. Besides being used as a phone it can control The binding posts are used for hooking to remote control radio equiPment. another set or a switchboard.

EXTERNAL BATTERY COMPARTMENT CIRCUIT HANDSET BATTERY TERMINALS COVER AND LATCH SELECTOR RETAINING SWITCH BRACKET CARRYING CASE HANDSET RETAINING STRAP CUSHION

UNE SWITCH .....;,...... ,," PANEL AND HOUSING ASSEMBLY

HANDSET v BUZZER RETAINING VOLUME rifl ,.; ...... _..,,,,,, BRACKET ..,, CONTROL KNOC v . ,/,g7 "//// ,-4*//,

LINE 1-2 BINDING POSTS TELEPHONE SET RECEPTACLE CASE CY-1277A/PT CONNECTOR U-79/U

SWITCH ASSEMBLY ELECTRICAL SA-I29/PT CORD ASSEMBLY DE-ICING CX-215I/U SCREEN HANDSET H-60/PT

73.185 Figure 12-30. TA-312/PT set. 413 424 Co.cs-ri(ccrION ELECTII:ClA:: 3R. 2

Maintenance

Maintenance 18 diviaed into two types: operation and shop. EE-8 EE-8 Operator's maintenance is performed daily and consists of cleanin- . exterior surfaces A POINT-TO-POINT witha lint-freo cloth. .:ter.ad with an approved cleaning solvent, chucking the handset switch assembly for vif mechanical action (binding,scraping, nass),and a normal operator's check (Ulla.,eceive, buzzingand buzzer). EE-8 SB EE-8 maintenance is performed weekly, and , is more extensive. Included are in- B L8 SWITCHBOARD t, theexternalfinish,cords, housing, carrying case, binding posts, and battery compartment for breaks, cracks, cuts, frays, fungus, dirt, moisture, corrosion, or general deterioration. The handset is also chocked for loose EE-8 SB EE-t3 receiver or tranomitter elements. The panel should not be removed nor the handset disassumWed unless the maintenance checks indicate a malfunction ef internal parts. CB TEL EPHON E EE-8

Telephone EE-8is designed for LIde in C CB SWITCHBOARD point-to-point circuits and LI3:dr CB ciwitch- board systems. Depending uponthetypeet 26.288 wirelinos used, the range for point-to-point Figure 12-31.Telephone EE-8 system circuitsisanywherefro.n 4.5 to360 miled and in switchboard systems, the range varies hookup. from 0.9 to 72 miles. ratio of range switchboard systems to point-to- point circuits is approximstely 1:5 with trunked Operation switchboards, or 1:2 using only one switchboard.) Figaro 12-31 diagrams the hookup for dif- CB switchboard systems (fig. 12-31, view ferent U1308. Figure 12-31, view A id a point-C) use the common battery for signaling, though to-pointcircuit.Notethatthe telephones atlocal batteries are still used for transmission. both ends of the circuit aro connected withoutIn this case, the hand generator is not used intervening switchboards. Local batteries areas the telephone lever switch is used to signal used and thohand generator (a part of thethe switchboard operator. telephone) is used for signaling. Figure 12-31, view B (LB switchboard system)Maintenance has the telephones sot up through an LB twitch- board to enable circuits to be sot up between In general, the same maintenance require- any telephone in tho system. In this case, asments prescribed earlier for the field switch- inpoint-to-point circuits, local batteries areboard apply here inspect, tighten, clean and used and the hand generator id still used foradjust. Since these sots are used outdoors, there signaling. The advantage overpoint-to-pointaroa few extra requirements. For instance, systems is that several switchboards may besuch things as dust, rapid weather changes, and trunked together for a greater number of stations.excessive dampness all require more meticulous The disadvantage is loss of talking range. (Themaintenance to keep the equipment dependable. 414

4 23 Chapter 12 COMMUNICATIONS SYSTEM 111111.111

In addition, batteries will begin to deterio- many wires are used between units of switch- rate in as short a time as 48 hours with the hand- ing equipment inside the central office, only two setswitch leftinthe operate position. Even wires extend between the central office and the batteries in a stored telephone, with the switch telephone served by it. The two wires may be in the OFF position, will begin to deteriorate enclosed in a cable to form a cable pair. They in tiin, due to the physical breakdown of the may be a twisted insulated-wire pair, or they battery ca.i.ied by the prassure of the contact may betwo bare wires on insulators. The springs. Consequently, the handset switch must term "46- to 52-volt, common-battery" refers be turued off when not in use, and the batteries to the source of electrical energy provided at must be removed when the telephone is to be the central office to operate the automatic equip- stored for any length of time. ment, and to supply transmission (talking) and signaling (ringing) current to the outside telephone lines. T'le voltage range indicated means AUTONL1TJC TELEPHONE SYSTEM that the equipment will operate efficiently over a range of from 46 to 52 volts, direct current. ,111 telephone systems in use at the present time fall into two categories: NONDIAL (M:\ N- The switchinz equipment in a step-by step UAL) SYSTEMS and DIAL SYSTEMS. Dial tele- dial central office operates directly from dial phonesystemsarealso calledMACHINE- pulses transmitted from the pulse-sending de- SWITCHING :q :11JTOMATJC SYSTEMS. vice, or dial, of the calling telephone. The dial pulses are interruptions of current caused by Any telephone system consists of a group thealternateopening and closingofpulse of telephones with lines tec.'minating at a central springs in the dial mechanism. Figure 12-32 point (switchboardor central office)in such shows the circuit of a typical dial telephone a way that any two telephones inthe system withthecontactsin talking position. Figure may be connected with one another. A nondial 12-33 shows front and rear views of a typical or manual system is me in which connections dial. must be made by hand by an operator. In a dial system connection is made automatically In a step-by-step dial telephone system each by means of electromechanicallyoperated set, or series, of dial pulses (sometimes called switching mechanisms remotely controlled by train of pulses or pulse train) corresponding a dial, or calling device, at the telephone ini- to eachdigitdialed bythe telephone users tiating the call. extends a connection one step at a time through the switching equipment to the called telephone. There are two types of automatic dial tele- The wipers, or contacting arms, of numerical phone systems;thestep-by-step type, which (dial controlled) stepping switches establish the utilizes electromechanical switches to find and proper connections at the central office. These connect the number being called; and the relay wipers are moved one step at a time by electro- system, which utilizes only the closing of elec- magnets operated by pulses from the dial of the tricalcontactsto connectthe linesin the calling telephone. This is how the step-by-stop system. dial telephone derives its name. A step-by-steptype may be expanded to Figure 12-34 shows a step-by-step switch- handle a larger number of lines by simply add- room, The can-like containers house switching ing additional equipment. An 'all-relay system equipment consistingoftwo-motion Strowger is limited to the number of lines for which the switches (fig. 12-35). unit is designed. Most of the dial installations used by the Armed Forces are of the step-by- step type. Some small installations use the all- STROWGER SWITCHES relay system, but these are usually systems with not more than 100 lines. The Strowger switch is an electromechanical product that extends the connection from the The commonly used step-by-step dial cen- calling to the called telephone. It consists of tral office is usually a 2-wire, 46- to 52-volt a bank of electrical contacts arranged in 10 common-battery, fully automatic type telephone levels with 10 sets of contacts to a level. The system. Two-wire means that no matter how wipers, which make contact with the selected

416 426 CONSTRUCTION ELECTRI9AN 3 & 2

RINGER

4ME 5 2 INDUCTIONCOIL PULSE SPGS DIAL r0 1001). 4 MAI

0.7MFL SHUNT SPGS T,C R, HANDSET -E[ (L2) +(LI) 73.186 Figure 12-32.Circuit of representative dial telephone, talking position.

set of coatacts, are connected to the switch shaft. The switch mechanism elevates the shaft (and wipers) any nuniber of steps from 1 to 10. When theshaftisreleased,itrotates backwards under the influence of a spring and then returns to normal under the pull of gravity. The Stowger switch, because of the up and around movement, is referred to as a two-motion or step-by-step switch. Itis the basic switch of the step-by- stepsystem, and with a few mechanical and electrical variations, is used as a linefinder, XY connector, and selector. 9 maTo 0 The LINEFINDER finds the line of the tele- A phone station seeking to make a call and extends the lineto the selector for all systems in excess of 100 lines. The linefinder mechanism GOVERNOR WORM PULSE CAM is controlled by the finder control relays. The impulses to step the mechanism up and around PULSE are furnishedbyinterruptersprings on the CONTACTS vertical and rotary magnets. The finder switch FUNCTIONAL is referred to as a NONNUMERICAL type of CONTACTS Strowger switch, because its operation is automatic and not under the control of dial impulses. The linefinder switch depends on its associated GOVERNOR line-and-cutoffrelays,group control relays, CUP and distributor relays. The LINE-AND-CUTOFF RELAY 's a relay individual to the line with which it is asso3iated (in contrast to the switch circuits which serve many lines and the control circuics which serve many switches). For example, when a call is initiated by a telephone, the line-and-cutoff relay Figure 12-33.Front and rear views of functions to:(1) apply ground (positive side of telephone dial. 7.85 the battery) to start the linefinder control relays

416 427 Chapter 12 COMM JN[CATIONS SYSTEM

73.187 Figure 12-34. Step-by-stepdial telephone switchroom. to actuate a linefindar swi.tch to hunt for the to the set of contacts associated with the called calling line; (2) mark a contact in the bank of a telephone station. A connector switch is referred linefinder by placing battery (negative voltage) to as a NUMERICAL type of Strowger switch on the contact so that when the linefinder wiper because it operates under the control of dial encounters battery the linefinder will know Itimpulses. has located the line it is trying to find. The simplest arrangement for establishing aconnection between two telephones consists The SELECTOR extends the line of the call-of two elements, a linefinder and a connector, ingtelephonetothe connector. The vertical and is called a link. Th's combination performs steppingof the selector is controlled by the satisfactorily in an exchange servicing less than first digit dialed at the calling telephone, and100 telephone lines. When additional lines are the rotary stepping is controlled by interrupter required, first, second, third, and so on, selec- springs on the rotary magnet. tore are added. A group of links is called a The CONNECTOR extends the line of the bank. calling telephone to the line of the called tele- Figure 12-36 shows atypical wiper and phone. The impulses transmttted from the dial terminal bank for a two-motion stepping switch of the calling telephone actuate the connectorthat operates vertically on the first operation mechanism `.ostep the wipers up and around and horizontally on the second operation.

417 428 CONSTRUCTION ELECTRICIAN 3 8.z 2

VERTICAL BANK LINE WIPERS

WIPER CORDS

73.189 Figure 12-36.Wipers and terminal bank. in the system whenthe handset of that particular telephone is lifted from the cradle. Because each of the 100 lines of the system is also connected in par 'lel with each of the connectorsinthe bank, e connector linked 27.336 withthelinefinder can raise and rotate its Figure 12-35. Strowger switch. wipers, under control of dial pulses from the calling telephone, to complete a connection to 100-LINE SYSTEM any one of the 99 other telephones in the 100- line basic linefinder-connector system. Notice Figure12-37 shows a schematic diagram that the leads from the connector banks back of two linefinder-connector links for a basic to the 100 lines of the linefinder bank are called 100-line linefinder-connector system. One such linenormals. Line normals are also called link is required for each simultaneous conversa- normals, normal wires, or normal cables. tion. For example, if the normal operation of the system shows an average of 20 siniultane- To trace a typical call through the 100-line ous conversations, then 20 links are needed inbasic linefinder-connector system, assurne that thebank inorder to, handle all calls. Eacha telephone user at telephone No. 44 wishes to link is like a cord circuit of a manual telephonecall telephone No. 75. When the handset of tele- system. Noticethatthe100 lines (indicatedphone No. 44 is lifted from the cradle, an idle by the lines numbered 44 and 75) are connectedlinefinder(inthis example linefinder No. 1) paralleltoalllinefinders as well as to all automatically elevates and rotates Its wipers connectors In the bank. until they come to rest at contact set No. 44. The linefinder automatically extends the call- Since eaciloff the 100 lines is connected ining line through to the connector which is linked parallel to all of the linefinders in the bank,to the linefinder. The connector returns a dial any idle linefinder in the system can automati- tone to the calling telephone, to signal the User cally hunt for and find the line of any telephone that the digits of the called telephone number

418 429 Chapter 12COMMUN1CATIONS SYSTEM

TP 75 LINE NORMALS

S S S

S S

S S S

S 0

0 4 S 0

S S

S e S SI. S LINEFINDER 1 CONNECTOR 1

n 0 S *

e 0 a 0

SOS & CS S 0 0 0 0 *

or, e

e 9 LINEFINDER 2 CONNECTOR 2

MULTIPLED TO OTHER LINEFINDER- CONNECTOR LINKS AS REQUIRED

NOTES 1. ONLY TWO OF THE 100 TELEPHONE LINES ARE SHOWN ALTHOUGH EVERY ONE OF THE 100 LINES HAS A MULTIPLE APPEARANCE AT THE BANKS OF EACH LINEFINDER AHD CONNECTOR IN A LINK. 2. ONLY TWO LINEFINDER- CONNECTOR LINKS ARE SHOWN. EACH OF THE 100 LINES IS MULTIPLED SIMILARLY TO OTHER LINEFINDER -CONNECTOR LINKS AS REQUIRED. 7.80 Figure 12-37. Linefinder-conneetor links. 419 430, CONSTRUCTION ELECTRICIAN 3 & 2 i01.

(No. 75 inthis example) may be dialed. When searches forthecalling line and extendsit the digits 7 and 5 of the called telephoneare to the selector. The selector extends the call- dialed, the connector operates inresponse toing line to a succeeding connector in the switch theresulting pulses from the dial of the call-train. The connector, or lastswitch in the ing telephone and raises its wipers to the 7thswitch train, extends the calling line through contactlevel, and then rotates its wipers to tothe called line, and the callis completed the 5th contact, so that the wiperscome to rest in the usual manner. on bank contact No. 75. The connection is then completed from call- Unlike the linefinder but like the connector, ing telephone No. 44 throughlinefinder-connector theselector faces forward toward the called link No. 1, and over the line normals of lineline. In a basic 1000-line system, the telephone No. 75 to telephone No. 75. T le connector then lines are associated into 10 groups of 190lines tests called telephone No. 75. If the called tele-each. It is the function of the selector to select phone is idle (not in use) the connectortrans- the group of 100 lines (hundreds group) in which mits ringing-tone current over tha called line the called line is located. The connector selects to operate the ringer of the called telephone.both the subgroup of 10 lines (tens group) in If, however, the called telephone is inuse, the which the called line is located, and the partic- connector transmits busy-tone current to the ular line itself (unit line) in that group. calling telephone to advise the caller that the called telephone is busy. The busy-tone signal This straightforward 1000-line systemre- advises the calling telephone user to replace the quires telephone numbers containing three dig- handset on the cradle, and to try to make the itseach,theselector operating in response call again a few moments later. to the pulses of the first number dialed and the connector responding to the following two 1000-LIN E SYST EM numbers. A 1000-line central office thus has 10connector groups, one for each hundreds Systems with a capacity of more than 100 group. Only two of the ten connector groups lines require the use of an additional two-motion are shown in figure 12-38: the group of con- stepping switch called a selector. Trie mechan- nectors that serves the 100 lines in the 300 icalstructureofabClectorresembles thatgroup, and the group of connectors that serves of a linefinder and a connector. The banks, the the 100 lines in the 700 group. The term "300 method of intik contact numbering, the wipers, group" refers to lines with telephone numbers andthe two-motion stepping mechanism ofa from 300 to 399; the term "700 group" refers selector are practically the same as those of to lines with numbers from 700 to 799. the linefinder and connector. To illustrate the operation of the 1000-line Theselectoris introducedinthe switchsystem: assume that a telephone user at the train between the linefinder and the connectorcalling telephone in figure 12-38 wants to call (fig.12-38). Te linefinder and the selectortelept, le number 344. When heremoves the form the link. One such link Is required for handse irom the cradle, an idle linefinder hunts each conversationtobe held. The linefinderfor and finds the calling line, and extends the

GALLING LINL .(/111 100 TP5 IN CONN 5 F.LEGTOR 700 100 TP$ IN T FINOLP LcAc 300 GROUP GROUP 700 GROUP 1111111111 11.111 410 0011111 MON 111111=11 1111.1. 1=1IM LEVEL 7 ammell

0111111MP ONIONINI MOMONINII MININIMMO .11111 MEM= LEVEL 3 MOM= DININUMM 1.- =Way MIMEO 7.82 Figure 12-38.Block diagram of 1000-line system, showing selector.

420 431 Chapter 12 COMMUNICATIONS SYSTEM calling line to the selector linked to that spe-under control of the first digit dialed (the thou- cificlinefinder. The selector, when grasped, sands digit), and automatically rotates the wipers returnsadialtoneto the calling telephone over the dialed level until they seize a trunk user, who then dials first the digit 3 (the hun- toan idle selector. The second selector el- dreds digit). Three pulses from the dial of theevates its wipers to the dialed level under con- callingtelephone cause the selector to raise trolof the second digit dialed (the hundreds itswiperstocontactlevel3.T.ie selector digit), and then automatically rotates the wipers then automatically rotates its wipers over theuntil they seize a trunk to an idle connector. contacts onlevel 3, searching for a contactT le connector completes the call in the usual set (trunk)to which an idle connector in the manner. All this is illustrated in figure 12-59. 300 group is connected. Tne sets of wires from the selector to the connectors are called trunks. TROUBLESHOOTING The automaticselectionofan idle trunk is called trunk hunting. Tables 12-1 and 12-2 show common troubles, Upon findinganidletrunk on the dialed symptoms, and corrections in typical step-by- level (3 level in this case), the call is extended step dial central-office equipment. by the selector through to the connector. When thedigits 4 and 4 are dialed, the connector completes the call in the usual manner. CROSSBAR SWITCHING SYSTEM 10,000-LINE SYSTEM The crossbar switching system has two main divisions of equipment, each with different func- The procedure for a central office with a tions. The two divisions of equipment are: the capacity of more than 1000 lines follows the control equipment and the switching network. same pattern as that for the 1000-line system, The CON nun EQUIPMENT establishes the except that an additional selector is added in talking path by causing the proper switch to the line between the linefinders and the con- operate. The SWITCHING NETWORK consists nectors. The firstselectorreturns the dial mostly of crossbar switches through which the tone, steps its wipers up tothe dialed level talking paths are set up.

_ (4) E3) 4600 (D(D GROUP OF 1ST .T,E1 EC Tow; 20 SELECTORS CONNECTORS TELEPHONES

000 GROUP ITO LINES 900 GROUP 4659 TO 800 GROUP 4600 INCL 700 GROUP ---- 0000 0000GROUP 9000 9000GROUP 00 100) 11000GROUP 09 7000 7000GROUP Oa OOI GROUP 5000 S000 GROUP 40 JO 59 MOO 000 11.58 1L.O. 57 CALLED h00 TELEPHONE /00 4658 --11h.C.00 13 SOO j 12 400 11 :SOO NOTE 200 1 CONNECTOR 100 ThE 1S1 I'. 4 AN AWATIONAI. 1 1600 GROUP/

FIJOCTION .F I OF TI1L 20 SELEC TOR 'OLE SIP' J. 1 1' .1 r TOP, IN AODITiON 14000 GROUP/ 500 GROUP ITO LINES T-/-jglf., r '4,-, .,09 ihouP IF 20 97.1. T. 11,14S, 400 GROUP 4611 TO T1.1 'JL1-:21/ SELECTOR INTIIAT 3000 GROUP ------300 GROUP 4657 INCL GROUP ------2000 GROU' 000 GROUP 1000 GROUP 100 GROUP

73.190 igu e 1 2- 39 Simplified 4-digit dial system.

421 432 CONSTRUCTION ELECTRICIAN 3 & 2

Table 12-1. Troubles Indicated by Supervisory Signals

Symptoms Probable troubles Corrections Fuse alarm operates on powerShort circuit or overload in power Test circuit for trouble. Repair distributing fuse panel. circuits. equipment and replace power fuse and alarm fuse. Defective alarm fuse. If power fuse was not blown, replace alarm fuse. Motor-generator control Open charging fuse or fuses. Clear trouble in circuit, if any. panel fuse alarm Replace fuse and associated operates. alarm fuse. Defective alarm fuse or fuses. Replace alarm fuse. Open reverse-current relay ,Test relay circuit and replace fuse. fuse. Main battery fuse alarm Open main fuse. Clear trouble in circuit, if any. operates. Replace main fuse and associated alarm fuse. Defective alarm fuse. !Replace fuse. Voltage alarm operates be- Main battery discharge or ,Check battery cells.Adjust cause of low voltage. failure. motor-generator controls to charge battery. Motor-generator voltage too ;Adjust generator voltage con- low. trols. Motor-generator paealleling 'Check control circuits and motor panel fails to start No. 2 generator. machine. End-cell control switch fails Clean and repair end-cell con- to switch end-cells into trol switch. main battery circuit. Open LV relay coil or resis- .Replace relay coil or relay. tor, or ^,ontact springs Adjust contact springs. out of aa,ustment. Voltage alarm operates be- End-cell control switch fails 'Clean and repair end-cell con- cause of high voltage. to switch end-cells out of trol switch. main battery circuit. Generator voltage too high. Adjust generator control. Check Motor-generator control panel control circuit and relays. fails to cut No. 2 machine out of circuit when power load diminishes. Ringing current supervisory No. 2 ringing machine fails to Clean contacts on transfer re- alarm operates steadily. start automatically when lays. Test transfer relays. No. 1 machine shuts down. Test automatic starting switch. Clean ringing machine commutator. Replace commutator brushes. Gonerator hold-up relay Replace relay coil or relay. (GEN HU) fails to operate. Supervisory fuse alarm Open fuse or fuses in ringing, Remove open fuse. Cheek cir- operates. tone, or signal circuits. cuit and clear troubls. Re- place fuse. 73.248.1

422 433 l-24.1.2.11111ftf WNW Chapter 12 COMMUNICATIONS SYSTEM

Table 12-1. Troubles Indicated by Supervisory Signalscontinued

Symptoms Probable troubles Corrections Group fuse alarm operates. Open fuse or fuses on shelf fuseRemove open fuse. Check cir- panel. cult and clear trouble. Re- place fuse. Release alarm operates. Linefinder, connector, or se- Restore switch manually. Busy lector failed to restore to out the defcctive switch. Re- normal position when repair, test, and place in serv- leased. ice. CDF (central distribution Operated heat coil or coils. Test and clear line. Replace frame) lamps operate. heat coils. Permanent signal (PERM) Called party fails to disconnect.Locate affected switch. Chal- on connector shelf. lenge on the line. Test line and use howler. Open line by removing heat coils. Make out trouble report. Calling party fails tc discon- Same as P.ve. nect. Short circi it or ground appearsTest as above. Open line by reon line after connector has moving heatulls. Fill out seized it. trouble report. Step signal (ST SIG) lamp glows on Linefinder fails to step from nor-Locate faulty switch. Operate linefinder shelf and mal position and hunt for cal- busying switch to remove alarm buzzer operates. ling line. faulty switch fro 'n circuit. Repair switch, ti..st, and replace in service. Defective relay A-3 in group re-Clean and adjust cor'...t.A.s. lays. Supervisory signal lamp Calling party fails to dial or hangChallenge seized line. Test line (SUPY) glows on se- up after selector switch has and use howler. Fill out lector shelf, been seized. trouble report. Dispatch repairman to telephone set in question. 73.248.2 Table 12-2. Troubles Indicated by Service Complaints

Symptoms Probable troubles Corrections Noisy, intermittent, or poor Wiper tips worn too thin. Replace wipers. transmission.

Insufficient tension on wiper tips1 Adjust wiper spring tension. Broken conductors in wiper Replace cords. cords. Dirty switch bank contacts. Clean switch bank contacts. Dirty relay contacts or insuf- Clean relay contacts. Ad- ficient contact spring just contact spring tension, tension if required. 73.249.1 423 434 CONSTRUCT.ON ELECTRICIAN 3 8,c 2

Table 12-2. Troubles Indicated by Service Complaintscontinued 73.249.2

Symptoms Probable troubles Corrections Cannot make outgoing calls. All trunks busy. Instruct user to place call later. Linefinder or connector per- Clear troubles and restore manents, or off-normals. blocked switches. Defective telephone line Repair defective line equipment. equipment. Defective line relay coil. Replace relay coil. Line relay contacts not making.Clean relay contacts. Adjust contact spring tension, if required. Open resistor in linefinder Replace resistor. start circuit. Fault in group relay circuit. Check group relays. Calling party does not receiveRotary cam springs on first Clean and adjust cam spring dial tone. selector not making contact. contacts. Selector relay contacts not com-Inspect for dirty or pitted con- pleting dial tone circuit. tacts. Clean and adjust. All linefinders in group busy. Advise telephone user to restore handset and to place call again. Calling party does not receive'Connector relay contacts not Inspect for dirty or pitted con- busy tone. completing busy tone cir- tacts. Clean and adjust. cuit. Open capacitor in busy tone Replace capacitor. circuit. Calling party receives busy All trunks are busy. Check trunks for possible tone before completion of trouble. Advise telephone dialing. user to place call at less busy time. Calling party does not receiveConnector relay contacts not Inspect for dirty or pitted con- ring-back tone. completing ring-back tone tacts. Clean and adjust. circuit. Open capacitor in ring-back Replace capacitor. tone circuit. Bell does not ring. Open-circuited or short-cir- Test the line from the CDF. cuited line crossed with battery. Open-circuited ringer. Send repairman to the telephone set. Ringing current not being sup- Check operation of the ringing plied to the line. group relays. Check each connector ringing relay in group. Clean and adjust relay contacts, if required. Called party does not answer. Same as above. Same as above. Calling party cannot hear Connector relay contacts not Make routine test of connectors. called party. completing transmission Inspect, clean, and adjust circuit. relay contacts. Reverse-battery relay does Inspect, clean, and adjust con- not supply battery to tacts. called party. Open capacitor or capacitors Replace the capacitors.

424 433 Chapter 12 COMMUNICATIONS SYSTEM

Table 12-2. Troubles Indicated by Service Complaintscontinued

Symptoms Probable troubles Corrections in connector transmission circuit. Called party cannot hear Relay contacts faulty in pre- Test selectors, line finders, and calling party. ceding switches. line relays. Relay contacts on connector pre-Make routine test of connectors. ceding switches not complet- Inspect for dirty or pitted relay ing transmission circuit. contacts. Cleanandadjust. Reverse-battery relay does not Check, clean, and adjust con- supply battery to calling tacts. party. Open capacitor or capacitors in Replace the capacitors. transmission circuit. Relay contacts faulty in pre- Test selectors, linefinders, and ceding switches. line relays.

73.249.3 When you dial, you tell the control equip- are provided to transmit signals to the different ment the number you want. The control equip-types of central office, such as stap-by-stap, ment then finds the proper path through thecrossbar, and mannal offi.?.es. switching network and closes the necessary switches to complete that path. SWITCHING NETWORK

MAJOR COMPONENTS Two important units of the switching network are the line link frame and the trunk link frame. Major components of a crossbar office, or- The LINE LINK FRAME is a unit consisting ganized according to function, are: a m-rker,principally of crossbar switches, to which tele- an originating register, number group frame,phones are connected. A line link frame is the and a sender. first link in the call you make; it is also the The MARKER is the brain of a crossbar. last link,since any telephone you call is con- It insrks points in the switching network through -- line link frame. which calls must go and selects and establishes paths between these points. This operation is TRUNK LINK FRAME .is a unit to which per'formed at the rata of about one-half secondtrunks in the certral office are connected. A per connection. trunkibsimply a telephoneline or circuit An ORIGINATJNG REGISTER gives you a dial leading from one place to another. Such a line, toneand remembers the number you dialwhich begins and ends inthe same central using relays and switches. Incoming registers office,is called an intra-office trunk. Lines perform the same function for calls from otheron circuits which lead to or from other central central offices. offices are called outgoing or incoming trunks. The NUMBER GROUP FRAME is amechanical telephone directory which knows the number of CROSSBAR SWITCH every telephone in the central office. It knows to which terminals on which line link frame The crossbar switch, which is the key unit each telephone Is connected and is prepared to of a crossbar switching network, differs from give out this information anytime itis asked thastep-by-stepswitch as radicallyas the forbythemarker. The SENDER transmitstwo systems differ from each other. A cross- numbers, in special codes, that other officesbar switch is a rectazigular device with hor- are set up to receive. Different types of sendersizontal and vertical bare crossing eaoh other 425 436 CONSTRUCTION ELECTRICIAN 3 & 2

VERTICAL VERTICAL ARMATURE ARMATURE OPERATED HOLD OFF NORMAL PILE-UP HOLD OFF (OPERATED CONDITION) NORMAL OPERATING SPRING P1LE-UP (4. CROSSPOINT (CROSSPOINT 1:1) VERTICAL CONTACT IN OPERATED / STRIP TERMINAL CONDITION

Nga TRAPPED SELECT SELECT FINGER II FINGER (NORMAL POSITION) 2 OPERATING 2 kV111 COMB AA ii 3 INN

MOVABLE CONTACT 7

HOLDING BAR 9 9

10 10

I 11 1111011; BIM 12 12 VERTICAL ----CONTACT STRIP INSULATION A STRIP (FIXED

73.341 Figure 12-40. Vertical unit after select operation; vertical unit after hold operation. in a latticework fashion. These bars are mounted possible to produce multiple connections. When ona frame so that they can move (pivot orconnections are made, electrical paths are es- tilt) with the movements controlled bY electro- tablished as indicated in (figure 12-43.) Only magnets. (See figs. 12-40 and 12-41.) three completed paths are shown, but as many could be made simultaneously as there are The principal components of the switcheshorizontal paths-10 in this case. Tie avail- arerelay type sets of contacts mounted one ability of so many connections is an important above the other behind the vertical bars. Theseasset to the central-office switching networks. setsofcontactsarecalled crosspoints. To close a set of crosspoints and thereby com- TAACING A CALL pleteaconnection through theswitch, first ahorizontalbar moves and then a vortical The block diagrams in figures 12-44 through bar (fig. 12-42). The switch design makes it 12-48 show how the different units in a crossbar

426

437 Chapter 12 COM VIUNICATIONS SYSTEM Ifi=IMM4M

HOLD (7\ VERTICAL OMA GNET \L./ ARMATURE

("7" SELECT FINGER (AFTER SELECT OPERATION)

(";" Sr_LEC1 BAR cyPERArINO Cro \.f.../ ARMATURE SPRING (CROSSPOINT NO. I) là-

SELLC7 MAGNET

HOLDING 73.344 O BAR Figure 12-43. Electricalpathsestablished when connectionsaremade in acrossbar switch. officeareinter-connected(throughcross- bar switches)foran intra-office call. When you pick up your handset you are connected to your crossbarswitchina line link Jrame. (Seefig.12-44.) A markeris signaled and C:\ SELECT FINGER (NORMAL POSITION) connects youto an originating register. The marker now disconnects itself to handle other calls. You hear the dial tone and dial the number 73.342 you want which is recorded by the relays of Figure 12-41. Sectional view ofcross- the originating register. bar switch. The originating register now connects to an idle marker and transmits the number you want to the marker. (See fig. 12-45.) The first three digits of the number (known as the office code) tell the marker the name of the office called. Assume that the called number is in another central office. The marker, therefore, disconnects your line from the originating register, connects the proper sender to the proper outgoing trunk, and connects your line to the trunk throughtheline link and trunk link frames. The sender transmIts the number you want to the other central office. In this second central office (figure 12-46), an incoming register records the number from the distant sender after whichitconnects to a marker. The marker receivesthe number from the register. The marker must now locate the called number in itsoffice. To do thisit checks the number group frames (fig. 12-47). This electrical telephone directory tells the marker the location of the number, the right line link frame, the 73.343 crossbar switch, and so on. The number group Figure 12-42. Perspective viewof part frame and incoming register are dismissed by of a crossbar switch. the marker, which now connects the incoming

427 488 CONSTRUCTION YLECTRIC1AN 3 & 2

SWITCHING NETWORK

O.-. INTEA-OFFIC: LINE TRUNK TRUNKS LINK LINK OUTGOING TRUNKS FRAMES FRAMES

INCOMING TRUNKS

CONNECTING SWITCH

INCOMING ORIGINATING REGISTER REGISTER KER NUMBER OUTGOING1 GROUP SENDER

73.345 Figure 12-44. Switching network.

SWITCHING NETWORK

LINE\. TRUNK LINK LINK FRAME FRAME

siORIGINATING I REGISTER MARKER

OUTGOING TRUNK

73.346 Figure 12-45.Block diagram showing how different unitsin a crossbar office are interconnected for an intra-office call. 428 433 Chapter 12 COM IJNICATIONS SYSTEM

SWITCHING NETWORK SWITCHING NETWORK TRUNK LINK TRUNK LINE FRAME LINK LINK INCOMING TRUNK INCOMING TR., FRAME FRAME

CONNECTING SWITCH..

CONNECTING SWITCH- INCOMING REGISTER INCOMING MARKER REGISTER NUMBER MARKER GROUP

73.348 73.347 Figure 12-47.Marker connects the incoming Figure 12-46. Path of c,11 in second trunk to the called number through a trunk link central olfiQe. fra.me and line link frame. trunk tothe called number throughatrunk tcome with th3set and using wiring di- link frame and lina link frame. Since the con- agrams. nection is now complete, the marker disconnects An intercom system consists of one or more itself and goes on about other business. Themaster stations, a junction box, one or more incoming trunk rings the called line. T le call remote speaker units, and the wire rAecasary is complete when thecalled party liftsthe to make the connections. One type of inter- receiver (fig. 12-48). com set is shown in figure 12-49. The master station has a capacity of 6 remote-mir .ophone INTEROFFICE COMMUNICATIONS units; however, if one or more of the remote SYSTEMS units are connected to the call-in circuit, the capacity of the system is only 5 remote stations. An interoffice communicating system is used to transmit orders and information among of- The basic parts of the master station shown fi .esthat areonlyashort distance apart. consist of a 3-tube chassis, a speaker-micro- Frequently such offices are in the same build- phone, and a selector switch panel (fig. 12-50). ing. Intercoms are not used at all advanced The parts are installed in a wooden cabinet. bases; if they are used, the job of installing A combination volumecontrol andON-OFF and maintaining them usually falls to the CE. switch is mounted directly below the selector The installation of an intercom system can be switch panel. The pilot light is illuminated at accomplished easilyay following instructions all times when the switch is on. A 3-position

OFFICE A OFFICE 15

LINE TRUNK LINE LINK LINK LINK LINK FRAMES FRAMES FRAMES FRAMES

73.349 Figure 12-48.Completed connectionthrough switching newtorks of two crossbar central offices. 429 440 CONSTRUCTION ELECTRICIAN 3 & 2

MASTER SELECTOR REMOTE STATION PILOT LAMP SWITCH SPEAKER PANEL

..:341vtd11,

SPEAKER TALK-LISTEN VOLUME CONTROL CASE MICROPHONE SWITCH AND ON-OFF GRILL LEVER SWITCH KNOB

Figure 12-49.Intercorn set. 26.286

MASTER STATION REMOTE SPEAKER PUSH SPEAKER SWITCH MICROPHONE BUZZER ,

CABINET SPEAKER MICROPHONE TERMINAL SELECTOR BOARD SWITCH JUNCTION BOX PANEL INTERCONNECTING CABLE

Figure 12-50.Intercorn set, rear view. 26.287

430 441 Chapter 12 COMMUNICATIONS SYSTEM switch at the center of the cabinet front controls talk-listen or idle position. The speaker- m'crophone is mounted inside the cabinet be- hindthe grill on the front panel. A junction Th box, used for interconnection to remote stations, isattachedto the chassis by flexible cable. An a-c power cord is attached to the chassis. The remote unitconsistsofaspeaker- microphone mountedina wooden cabinet, a push switch for signaling the master station when intercommunicationsisdesired,and a terminal board for interconnection to the master station. The switch panel consists of the selector switches(6forthe model shown),a space above each switch for identifying the station, and an annunciator for each switch. (All intercoms are not equipped with annunciators.) The switches have three positions: OFF, ON, and a third position to operate annunciators on a CALL-IN remote annunciator's master station unit. LINE The annunciatorsare solenoidplungers mounted above eachstationselector switch. When the button atop a remote speaker-micro- phoneisdepressed, or when a switch on a remote master unit is pressed down, a buzzer at the master station sounds, and the annunci- atorabove the switch for the calling station springs outward. The annunciator remains out untilthe operator pushes itin;it should be pushed back to its normal position at the same time that the selector key is raised to answer the call. The talk-listen lever is a 3-position switch. The three positionsare IDLE, LISTEN, and TALK. Under normal operating conditions, the lever should be leftin the idle position. The idlepositionshould be usedtodetermine whether a station to be called is in communi- 26.131 cation with another station. Leaving the lever Figure 12-51.Six-station intercom in theidle position, flip the selector switch system layout. of the station that is to be called. If no other station is conversing with this station, pressnot necessary for remote stations to communi- thelevertothe talking position and speakcate among themselves, only one master station into the master station. If the system has onlywill be installed; this is the usual case. (Figure one master unit, you may press the lever into12-51 shows a circuit with all remote speakers the talk position without going through the idle connected to call-in line.) position, since remote speaker microphone units Install the master station within reach of a cannot communicate with one another. 110-125 volt, 50-60 hertz a-c power outlet. The master station and the speaker microphone units INSTALLATION PROCEDURES should be placed on the desks or in the working spaces of the personnel who will use them. If Anycombinationof master stationsand some of the units are installed outdoors, take speaker microphone units up to the capacity ofthe necessary precautions to protect them from the master station can be used. Where itis adverse weather conditions. 431 442 CONSTRUCTION ELECTRICIAN 3 & 2

The size of the wires to be used in making Componentsinintercomsets arereadily connections between units is governed by theaccessible and may be easily replaced if found length of wire. For the voice lines, No. 22 to to be faulty. When a defective component such No. 19 twisted pair wire is used. The maximum asa burned-out resistoror transformer is wire resistance permissible will be stated inlocated, remember that the cause of the con- the operating instructions. For the model shown dition may be in some other part of the circuit. the maximum resistance is 50 ohms per pair. Ifthe cause is not located and corrected, the The amount of wire determines the wire size tonew part will be burned out in the same way be used. No. 22 wi-fe gives a resistance of 32as the one that was replaced. ohms per 1000 feet, and No. 14 wire gives a When trouble develops in an intercom sys- resistance of 4 ohms per 1000 feet. The largertem which has been properly installed and has Fizes of wire (lower number) should be usedbeen operating properly, the fault will usually when long lengths are necessary to connect the be in one of the units of the system rather than units. in the interdstation wiring. If the fault is in the interstation wiring it can easily be traced be- The wire resistance of the annunciator linescause the units will usually operate properly on must be kept below 15 ohms per pair. Normally, some branches of the system. Once a fault has No. 14 or No. 16 wire is used. been traced tosome particularunitit can sometimes be located by sight or smell (burned- AllconneJtionstoa masterstation unitout resistors and shorted transformer) but most are made on the junction box. Be sure that thefaults must be traced by checking voltages and interstation wires do not cross hot pipes. The resistances. wires should never be placed where they are in In troubleshooting ALWAYS REMEMBER: danger of being covered by water. 1. Noise or hum may be mechanical noises After the wiring is installed, check the re-picked up by the microphone and amplified at sistance with an ohmmeter. Make certain that the master station; or it may be caused by office the maximum perrn!.ssibleresistanceisnot equipment, or other external causes. exceeded and that there are no opens, grounds, 2. The majority of master station trouble orshorts. (Note: Follow installation instruc- can be traced to faulty tubes. Replace the tube tions that come with each new set.) witha set of tubes known to be good before becoming involved in major troubleshooting pro- TROUBLESHOOTING cedures.

Many of the troubleshooting instructi,,D that Before parts are unsoldered the position of apply to switchboards apply equally to intercomthe leads should be noted. If the part has several systems. In general, troubleshooting techniquesconnections toit, each lead should be tagged. consist of five steps: Care should be taken that other leads are not damaged by being pulled or pushed out of the 1. Look way. 2. Feel Remember the following facts when you are 3. Tighten soldering connections: 4. Clean 5. Adjust 1. Acarelessly soldered connection may create a new fault. The first step consists of looking for such items as unlit tubes, frayed or broken wires, 2. A poorly soldered joint is a very diffi- broken component connections, and dirt. cult fault to locate. The feel operation is necessary to check and 3. Don't allow drops of solder to fall into determ'.neif electrical comnonents are over- theset as they may cause a short circuit. heated. Be certain that th ower is disconnected before performing peration. These poin's should be remembered particularly when leads ara being soldered on inter- The tightening, cleaning, and adjusting oper- coms. This information however,appliesto ations are self-explanatory. soldering of all communications equipment.

432 443 Chapter 12 COMMUNICATIONS SYSTEM

PUBLIC ADDRESS SYSTEMS periodicaltests,checks, and inspections, designed to head off trouble before it develops Daring the early stages of an invasion, port-to the extent that it causes damage. abletypesof public-address systems are in extensive use for making amplified-voice an- I3..TTERY MAINTENANC E nouncements in the landing area. Small types of PA systems are d-c battery powared and Inspect containers regularly for dirt, dust, completely self-contained. Forstrongsound or cracks. Clean them with a dry cloth, never coverage required to overcome a high level ofwith a damp or wet cloth. noiseinthearea, a large a-c portable PA system, powered by a gasoline engine-driven Examine the terminals and the straps between generator, is used. the cells for luoseness or corrosion. If ter- At an established base a PA system may be minals need tightening, do not use excessive used for the auditorium, for outdoor movies, force because it may damage the connections. and for camp-wide announcements. Tie system Remove corrosion with sandpaper or crocus generally used is a portable set consisting of cloth. a 100-watt cabinet-type amplifier, a dynamic Check the electrolyte for level and for spe- (movable coil) microphone with heavy-duty floor cific gravity. The level should be at the upper stand, two 25-ft lengths of shielded microphone red line on the jar. To check specific gravity cable, and one 25-ft length of heavy-duty power you use a pilot cell. Use a new cell after every cable. The systemrequires a 100/125 volt, 50 readings. 50/60 hertz power source. For telephone storage batteries the voltage should beatleast 46 but not more than 52 The horns used as loudspeakers can be con- volts if the batteries are charged during use. trolled individually or in any combination. The Violent gassing and temperature rise in the speaker can address a single station, several electrolyteindicate that the charging current stations, or all stations. A changeover switch is too high. is provided to adow signal input from either a Guard against fire hazards at or in the vi- microphone or a phonograph. cinity of batteries. Loose connections can be As with any electrical circuit, the wiringvery dangerous because of the possibility of diagram provides the key for the proper wiringsparking. AT ALL TIMES keep open flame, connections. Normally, No. 14 size wire should lit tobacco, or any other type of fire, however be used forwiring connections. Horn loud- small, away from batteries. speakers may be mounted on buildings, poles, speaker stands, or even in trees. In selecting CIRCUIT 1' ESTING a permanent location for a loudspeaker, you should test for uniform loudness,minimum All circuits should be tested at regular in- echo, and the possibility of an acoustical dead tervals. When you know a fault exists, the wiring spot. diagram is an invaluable aid in helping you to When installinga PA system, make sure pinpoint the location. If you cannot find a broken you follow the manufacturer's instructions care-wire,faulty connection, or other fault avail- fully. abletocasual inspection, you will have to locatethe trouble by continuity, voltage, and resistance measurements. Start at a point where COMMiNICATIONS MAINTENANC E thecircuitis known to be good (up to that AND REPAIR point), and isolate parts beyond, step-by-step, until you have located the fault. The best possible equipment develops occa- sional faults in service. Also, the addition of WIRING MAINTENANCE new circuits, the placing of cross connections, the installation of local switchboards, and simi- Most of the maintenance on wiring will be larchanges and rearrangements may be re-corrective rather than preventivethat is,it quired. It follows that maintenance means more will consist of the location and correction of than just cleaning and lubricating. Bzsides whatfaults which have become evident. However, has been suggested, maintenance includes pre-you will inspect terminal boxes for broken lugs ventive maintenancethat is, a set routine ofand defectivefaceplates;and you will check

433 444 CONSTRUCTION ELECTRICIAN 3 & 2 drop wires for adequate support, connections, and insulation.Most of your maintenance on wiring, however, will consist of locating and correcting opens, grounds, a:id shorts. If the signal lamp on a switchboard lights I In:10 ...) continuously, a ground is indicated. Check the TROUBLE ring line (or tracer wire) first. Place the re- L___J ceiver of your test telephone in series with the / tracer line at the nearest terminal box. If you FIRST SECOND hear a sharp click, move to apoint nearer the TEST POINT TEST POINT A defectivetelephone. When you hear no click, the ground is between the point where you then are and the last point where you heard a click. If the ground is in the plain conductor or r tip line, there will be a noise on the circuit, OUBLE I I caused by ground returns of other currents. 1 I Disconnect the tip line from its terminal at the pole, and then attach your test receiver leads .k it. to the ring line and to the part of the tip line that leads to the defective telephone. A click FIRST SECOND indicates that the ground is between you and the TEST POINT TEST POINT subset. Keep moving toward the subset until you fail to get a click, This indicates that the 73.191 ground is between the point where you are now Figure 12-52. Testing for ground. (A) Ring located and the last point where you received line; (B) Tip line, a click. the open is probably in the drop wire. Perhaps The diagrams in figure 12-52 illustrate thean inspection will indicate the break, and you method of testing a ring line and a tip line forcan splice the wire. Otherwise you m have ground. to replace the entire drop wire. To locate an open circuit in one of the pairs of wires, start at the terminal box which is To determine if the ground tine at the pro- closest to the central office, and which has ter-tector has an open, use your st telephone minals tapped to the pair of wires to be tested.leads where the pair of wires aids into the Connect the leads of your test telephone acrossprotector, byattaching one lead to the ring the proper terminals.One leadshouldbeline,and tapping the tip line with the other clamped on, the other just tamped against thelead.If you receive a click, tap the ground terminal. Jyou fail to receive a sharp click,line (instead of the tip line) with the second one line overhead cable is dead, and willlead. A click indicates that the circuit is good require spitz-1 ..2;atthf; open. You may hear ato ground. Absence of the click indicates an very faint click, but this will be caused probablyopen. by a difference in ground potentials and not by battery voltage. To locateashort, go to the first check If you hear a sharp, definite click, you canpoint and place your test receiver in series be assured that battery voltage is present up towith thetip line. A click indicates that you that pointmeaning that there is no open in theare between the short and the central office, line up to that point. The next point of testingso keep working along the drop line until you will have to be the terminal box to which thefail to receive a click. At that point, you are drop wire is connected. A sha.p click at thisbeyond the short, so you know it lies between point indicates that the open is in the drop wirethe last two points that you tested. or the inside wiring. SUBSET MAINTENANCE The dividing point between drop wire and inside wire is the protector, so make that the The first step in checking a subset is to next testing point. If no click is received whenidentifythe cause of the trouble. It may be you place the test leads across the protector,onlya loose connection, or the presence of

434 445 Chapter 12 COMMUNICATIONS SYSTEM some foreign material or iron filings around headset, chestset, and exterior of the distribu- the ringer magnet. tion frame should be inspected. Chigoed paint, mildew, and corrosion must be removed, and You should know the number and locationthe storage batteries must be checked for elec- of the subset, the cable pair number, the lo- trolyte level. Do not forget to inspect the wiring cation and number of the cable terminals, andon the rear of the panel. the location and number of the cross-connecting box, if any. Examination of any previous trouble Weekly inspection should be given to cords, reportsis helpful, because previous troubles keys,shutters, fuses, protector blocks, heat may suggest the nature of present troubles.coils, repeating coils, and ground rods. Subset troubles may usually be broadly di- Inspect the cords for dirt, dust, or fungus. vided intothose that lie between the centralCheck the cord weights a.nd pulleys for ,mooth office and the subset and those that lie in theoperation. Wipe the cords with a clean, dry subset itself. For those between central office cloth. and subseta good point of beginning is the main distributing frame. This is the dividing Use long-nosed pliersto adjust the drop point between outside plant and inside plant,shutter latches. Then test to see if the shutters and also the point of location of the centralfall freely when a call is received, but remain office protective devices. in place when the switchboard is jarred. Check the protector (where chop wire con- Ascertain that fuses are of the proper ca- nects with inside wire); look for moisture; checkpacity, and tighten the fuse mounting screws. for broken, defective, or loose fuses; replace badly pitted carbon blocks; check the ground Remove dust, dirt, or other foreign matter wire. from the protector blocks, and replace porcelain or carbon blocks that are chipped or broken. At the subset, examine the transmitter for Use care in cleaning, because if you dislodge cracks or breaks in the mouthpiece; for missing a block you can cause trouble on an incoming rim screws or loose contact springs; and for line. dirt or moisture. Look inside the receiver for dirt, corrosion, moisture, or cracks. Examine Inspect heat coils for cleanliness, and re- the mounting of the ringer, and look for dentsplace any that show chipped or broken coils. or cracks in the coils. Observe the contact andDo not remove the covers of repeating coils, lever action of the hook switches, and look forbut examine the mountings for loose, damaged, rusty, bent, or pitted springs. Check to see thator missing screws. Clean the coils with a dry, stay cords and hooks are secure. clean cloth. The main thing is to put the line back into Look for rust or corrosion on ground rods. service as soon as possible, so for considerable Check to make sure that the wing bolt at the repair, replace the subset and send the defec- terminal connection is tight. tive one back to the shop. Plugs, relays, capacitors, terminals, bind- SWITCHBOARD MAINTENANCE ing posts, and cables should be given monthly inspection. Clean theswitchboard plugs with Inspection, tightening, cleaning, and adjusting cord plug polish, using a clean, dry cloth. Re- are the basic operations in switchboard main- move all residue of the polish after cleaning tenance. Periodic inspections are of the utmost inorder to maintain good electrical contact. importance, because a minor defect may not interfere at once with the performance of the Inspect relays and capacitors for dirt and equipment, but may lead in time to a majorforeign matter, and clean with a dry cloth. breakdown. Keep all food and beve-rtges away Inspect terminals and binding posts on the from the switchboard. switchboard forcleanliness and tightness of connections. Check incoming line connections D:ery day the switchboard exterior shouldfor good electrical contact. Tighten any loose be wiped off with a soft, dry cloth. The batteries,terminals with a suitable screwdriver or wrench.

435 446 CONSTRUCTION ELECTRICIAN 3 & 2 rea4,.1-mrin ,/ 1 ft e

Clean the terminals and tnnding insts w!th a In soldering '.nthat. soft bristle brush. both metals are Jiean, 1:1- i the completed soldering Pio E.: firm..-nddtr.able. Examine connecting cah' .3 for damaged or FaultysolderinginP. PA system can cause worn insulation. Check the fittings on the endedefects which are very difficult to identify and of the cables for 'ightness and good electi'icallocate. Too much solder can cause shorts in connection. Tightc,: the connections on the cables microphone connectors that may not be visible as required. to the eye. The identificationand location of serious INT ERC OM SYSTEM M -UNTENANC E troubles in the system may require the use of In general, the four basic steps in switch- signaltracing equipment,such an ,tn audio- board maintenanceinspect, tighten, clean, andsignal generator, an output meter, or an os- adjustapply to intercom system maintenancecilloscope. In testing the electric circuit, the as well, with inspection being always of primary most important point to remember is that the im2ortance. trouble should be pinpointed as to location. A careful study of the circuit diagram i s essential. The components in an intercom set are all readily accessible, and for the most part they TOOLS AND EQUIPMENT can easily be replaced when they are found to be faulty. However, you must have enough knowl- Tools and equipment required for mainte- edge of the working principles of the systemnance and repair are included as part of a field telephoneset component. For subsets taken to be sure that the defective part is the causeout and sent to the shop for repair, the mainte- of, and not a result of, trouble in the system.. aance tool is the same test telephone which you For example, suppose you find a burned-use in locating shorts, opens, or grounds. out transformer or resistor. You replace it, and Ingeneral, you should have the following the replacement burns out. Actually, the burned- tools, equipment, and materials available when out part was not the cause of the trouble, but ayou begin any cleaning, adjustment, or repair result of it. process: Test telephone PUBLIC ADDRESS SYSTEM Clean, dry cloths and soft bristle brushes MAINTENANC E A drycleaning solvent Cord polish Trouble in a PA system Is often caused by Crocus cloth or No. 00C c--idpaper nothing mere obscure or complex than a loose Screwdriver set cable connection or a break in the cable shield. Long-nosed pliers Check for simple faults of this type before you Wrench sets, both oçan and socket begin a lengthy system of tests. Battery hydrometer

4 7

436 CHAPTER 13

TELEPHONE CABLE EPLICING

Telephone c:tole spL,-!ing is an important func- There are four types of cable installations: tionoftheCE's job. This chapter provides aerial, direct-burial, underground and submarine. information that will aid you in splicing telephoneAerial installation is aboveground, and most of cable safel,,, economca1iyind efficiently. your experience will be with thistype. When cable is buried directly in the ground without The knowledg you acquire in this chapterconduit, you have a direct-burial installation. In regarding cabL term;nology, 'ypes of cable, and an underground installation, the cable is installed the procedures for splicing a variety of cables underground in conduits. Sometimes cable must be will enable you to rendr vital services in the installed in submarine areas; that is, under water cornim!nication link. or in swampy areas. Most lines, whether for telephone or for power The following paragraphs tell about the differ- distritmtion, :equire some splicing. The length of ent kinds of cable, how they are used, and how cable on a reel seldom equals exactly the length they are installed. to be Installed. Even after a system has been installed, there will always be a certain amount LEAD-COVERED CABLE of splicing necessary, to take care of repairs on defective cable sections, or to add extra sections Lead-covered cable is insulated with paper. to the main cable. The insulation may be sprayed on as a pulp, or the paper may be wrapped spirally around the Whenever splicing is required, reme..mber that coacluctors. Double-wrapping of wires provides you are playing a vital role in keeping comrnuni- a highly dielectric (non-conducting) insulation, cation lines operating properly. both because of the additional thickness of the paper and because of the additional air space. This higher insulation protects against insula- TELEPHONE CABLE CLASSIFICATION tion breakdown which might occur if a telephone line came into contact with a powerline. Lead- There are four types of telephone cables: sheathed cable is used for installations under- lead-covered, tape-armored, building and switch- ground in conduits. coa:d(silkandcotton),and plastic-covered (pothylene)cable.For many years, lead- TAPE-ARMORED CABLE covered cable was used more than the other types. Howevr,r, plastic-covered cable is now beingused Tape-armored cable is a lead-covered cable more than the lead-sheathed type ;or two reasons: fitted with a protective covering of paper, jute, plastic cable is cheaper to produce than lead,'and steel tape. This covering protects the cable and it also has the advantage of being lighter against damage by rodents and against mechanical in weight than the lead-sheathed type. You can damage. It is used for direct burial (placed under- expect to be working much of the time with plastic- ground without conduit) and also for submarine covered cable, andin some cases you will be installation; that is, in swampy land or water. replacingexistinglead-coveredcablewith plastic-covered cable. Two considerations will Tape-armoredcableisquadded, colored- determine the selection of the type of cable tocoded, and composite. In quadded cable, some or be used: the jobitwill perform and the kindall of the conductors are arranged in quads, or ofenvironmentinto whichit will be placed.groups of two pairs. A cable containing 26 or

437 448 CONSTRUCTION ELECTRICIAN 3ez2

more pairs of conductors is color-coded according to groups, to simplify matching for splicing. Composite means that the cable contains conductors of two or more sizes.

BUILDING AND SWITCHBOARD CABLE A. STRAIGHT Building cable is made up of copper conductors covered with weatherproofed neoprene jacket insulation. It is used to make connection from telephone poles to buildings. Switchboard cable is made up of copper, or tinned copper, conductors with a silk and cotton insulation; butitis also available with black B. BRIDGE enamel insulation. Pairs of conductors are usually bound together with a spiral layer of paper, a layer of lead tape, another layer of paper, and a fireproofed braid. The insulation is colored according to a standard color scheme, so that each pair of wires and each unpaired single wire can be identified. Switchboard cable is used to C. BUTT o anec t the switchboard apparatus to the main dif=tribution frame. It may also be used for local wiring in the switchboard. On newer installations, 73.192 the switchboard cables, or jumper wires, will Figure 13-1.Types of telephone cable splices. probably be No. 22 copper conductors with a plastic insulating jacket. This wire ordinarily conies on 1000-foot spools and is used primarily Straight splicing is the simplest method of for making connections on the main distribution splicing, consisting as it does of joining two frame. wires that approach the splice pointfrom opposite directions. Most of the splicing that you do will PLASTIC-COVERED CABLE be by the straight sp1icing method. Bridge splicing usuallyconsistsofsplicing a branch into a Polyethylene or plastic-covered cable has main cable. Butt splicing is usually done to attain solid copper conductors, each with polyethylene flexibility; a butt spnce is often later changed to insulation. It is used in aerial installation; that a straight or bridge splice. is, suspended on poles, and for direct burial underground without conduit. SPLICING LEAD-SHEAT:0 CABLE While most of the splices that you make in lead-sheathed cable will be straight splices, you SPLICING TELEPHONE CABLE willalsoon occasion make bridge and butt splices in this cable. The procedure below applies The three most commonly used types of toall three types of splices. The steps of the telephone cable splices are the straight splice, the procedure are as follows: bridge (sometimes called branch) splice, and the butt splice. These three types are illustrated 1. Mounting the sleeve. infigure 13-1. In view A of figure 13-1 the cables come from opposite directions, the splice 2. Removing the sheath from each cable end. in each individual wire being covered by a small cotton sleeve. In view C, the wires enter the 3. Drying out the insulation by boiling out or sleeves from the same direction. In view B, by using a desiccant. however, two cables coming from one direction have been spliced to a single cable coming from 4. Identifying and selecting the correct in- the opposite direction. dividual wires from each cable. 438 449 Cha.pte: 13TELEPHONE CAHLE SPLICING Mal .a. 5. Splicing the wi res in a staggered pattern. ISECTION I 6. Placing and wiping the sleeve. I TO BE I CLEANED I SECTION OF SHEATH TO BE REMOVED The following sections explain each of these steps in detail. - -.IRINGED POINT WV. A %. to.a*Ve. ..1.6 Mounting `Aeeve I 4 IN 18 IN The size of the lead sleeve will depend on the size of the cable, the diameters and number of wires, and the type of splice. The splice on 73,193 a pair of individual wires is covered with a small Figure 13-2. Preparing cable for splicing. diameter cotton or plastic sleeve. The size of thecotton orplasticsleeve depends on the diamettof the spliced wires it covErs. Thewill not tin properly when the joint is wiped whole splicethatis,thebundleofspliced later, and the joint will be defective. individualwiresiscoveredwithalarger diameter lead sleeve. Immediately upon cleaning thisarea,and before your hands have touched it, coat it with It is advisable to slide the lead sleeve onto stearine, and wrap it with a double layer of one of the cables as soon as the ends have beenboiled-out muslin. This is to protect the area arranged and prior to the preparing and removal while you are removing the adjacent length of of the lead sheath. Slip the sleeve up the cable sheath for the splice opening. far enough to haveit out of your way as you You split the sheath with a splitting Icaife perform the individual wil.e splicing operations. (also called a chipping knife) as described for When all the wire splices have been completed, power-cable splicing in chapter ii. You must you can draw the sleeve down over the bundle. avoid cutting through the paper wrapping of the cable core, so be careful in driving the knife Before you slide the lead sleeve on, inspect under the edge of the split to loosen the sheath. it for cleanliness and for sharp edges. If necessary, smooth uptheendswith a lead file. Grasp the cable at the section where you wrapped itin the protecting layer of muslin, Rem)ving the Sheath and gradually work offthesplit portion of the sheath. It should break off at the ringed Measure the length of the sheath to be re- point.Figure 13-3 shows the main steps in moved, and ring the cable at the point where the removing the sheath. cut is to be made. The diagram in figure 13-2 shows a distance of 18 inches, but this is only When the sheath has been broken off, inspect by way of illustration. In every case the lengththe broken-off edges on the cable ends to ensure of the splice opening will depend on (1) the size that they are smooth. Any sharp edges or burrs of the cable (in terms of the number of pairs could cause damage to the conductor insulation of wires), (2) the diameters of the conductors, during splicing. The best way to guard against and (3) the type of splice being made. thisistobutt the sheath edges with boiled sleeving mislin, or cotton tape, as shown in In ringing :able be sure, as with power figure 13-4. cable, that the( ut or score does not penetrate completely through the sheath. A too-deep cut may Boiling Out Insulation damage theconductors, whereasa properly shallow cut bells the sheath, as desired, when the "Boiling out" is a term used to refer to a section to be removed is pulled off. procedure for removing any moisture which may be present in insulation. Besides removing Clean the sheath back from the ringed point moisture and preventing the same from reentering (distance AB .tnfig. 13-2). On new cable usethe break, boiling out makes it easier for you to a file as a cleaner. On old cable a shave hook remove the paper insulation frcm individual wires is better. If dull or dark streaks are left they en you are ready to splice them.

439

4 5 0 CONSTRUCTION ELECTRICIAN 3 & 2

1ST OPERATION CUT RING IN SHEATH AROUND SCRAPE SHE ATH WITH SHAVE CABLE, WITH CHIPPING KNIFE HOOK, AND COAT WITH STEARINE

417/ A7

K,/,/7# 'rz// /7;"101. DRIVE CHIPPING KNIFE UNDER SHEATH WITH A HAMMER. DO NOT ALLOW THE KNIFE TO CuT THE PAPER WRAPPING OF THE CORE.

2ND OPERATION OPEN UP SHEATH

REMOVE SHEATH

VW:4W APPAIP'4!Pb

USING 0 CHIPPING 0 OPENING SHEATH 0 SHEATH REMOVED KNIFE

73.194 Figure 13-3. Steps in removing sheath.

Boiling out consists of pouring hot paraffin the time you have spliced 200 pairs of wires the over the sheath, starting about 6 inches back insulation will have begin to absorb moisture from from the exposed wires, and gradually working your hands and from the atmosphere. Another the stream of paraffin onto the paper insulation boiling out willremove this moisture and reseal and out to the ends of the wires. The tempera- the insulation. ture of the paraffin should not exceed 375° F temperature higher than 390° F willdamage If the splice is left incomplete overnight, or the paper insulation. If you do not have a ther- if you are working in .a very damp atmosphere, mometercapableofregistering suchhigh you may have to go through the boiling-out temperature, you can apply a practical test t process several times. Discoloration of the in- the paraffin when it is heating. Watch the dry sulation or a bluish-green discoloration ofthe ring that forms and gradually creeps up on the conductors are sure signs that excessive moisture outside of the pot. This ring will begin to form is present. If discoloration is present, boil out when the paraffin is at 2bout 360° F. When the again. ring is about 2 inches wide, the paraffin is at the correct working temperature. Drying By Desiccant The paraffin, as it cools and hardens, forms a seal which excludes the entrance of moisture. The paraffin boiling-out method of drying has When you are splicing large cable,itis ad- several disadvantages. These includefirehazard, visable to repeat boiling out as soon as you have objectionable fumes, possibleburnsto personnel, spliced 200 pairs of wires. The reason is that byand splashes of hot wax on floors or walls. The

440 451 Chapter 13TELEPHONE CABLE SPLICING

REMOVE SHEATH CAREFULLY TO AVOID SHARP EDG ES.

BEFORE REMOVING CORE WRAPPING PAPER, APPLY 2 TURNS ON APPLY 2 OR 3 SERVINGS OF BOILED SLEEV- STRAIGHT CABLE ING, MUSLIN OR COTTON TAPE

SERVE BETWEEN CABLES SO AS TO GIVE DESIRED SPACING.

-111...... '",...... COMPLETE BY TYING ENDS, AND THEN RE- MOVE CORE WRAPPING PAP ER.

73.195 Figure 13-4. Butting the sheath. method of drying by the use of a desiccant (drying cable and central office, geometric pattern, and agent) is therefore often used instead. The usual tracer pairs. desiccants envloyedareanhydrouscalcium sulfateandsilicagel. A desiccant absorbs POSITION OF CABLEAND CENTRAL moisture whereas hot paraffin drivesitout. OFFICE. The first consideration in the establishment of the count is the relative position A desiccant is used after the splicing andof the central office and the cable en o be sleeving are completed. The splice bundle is en- spliced. If the exposed eiid faces away from ihe closed in a muslin envelope long enough to over- central office, the count is made in a counter- lap at both ends of the splice. Open one end of clockwIse direction. If the exposed end faces this envelope and let the desiccant trickle intoward the central office, the count is made all over the conductors. Spread the wires apartin a clockwise direction (fig. 13-5). with your fingersto allow good penetration. GEOMETRIC PATTERN.Cable may cottain Conluctor Identification various quantities and combinations of geometric patterns(fig. 13-6). The count begins at the Ccnductor identification is predicated uponthe center of the core and proceeds to the sheath establishment of a pair count. This operation is in a clockwise or counterclockwise direction. lmilt.pensable to the proper testing and splicing tialephone cable. Threeconsiderations are As an aidin establishing or determining involveu in the count: the relative position ofidentification of pairs, the cable cores are color

441 452 CONSTRUCTION ELECTRICIAN 3 & 2

size cables, except those smaller than 25 pairs, COUNT COuNTER- COUNT can be divided by this number. The pairs within CLOCK*ISE CLOCKWISE the 25-pair groups are identifier by a simple ... .. OFF code that use3 10 colors, 5 for tip and 5 for ring, with no elplication. The 25-pair groups (table 13-1) are bound with bicolor binders which follow the 5 + 5 color code used for pairs. 0 303 TRACFR PAIRS.Thecoreofnon-poly- PAIR C %EILE ethylene insulated cable contains certain distinc- 73.201.1 tively colored conductors known as tracers. A Figure13-5. Cable conductorgroups, 303 pair tiacer pair is used by the splicer to establish cable. a talking pair to his helper at the distant end

25 PAIRS 50 PAIRS 75 PAIRS 100 PAIRS I BINDER GROUP 2 BINDER GROL'oS 3 BINDER GROUPS 4 BINDER GROUPS

150 PAIRS 6 BINDER GROUPS

ABBREVIATIONS: 200 PAIR!' B L - BLUE w - WHITE 8 BINOER GROUPS O - ORANGE R - RED OK - BLACK 03 - GREEN B R- BROWN Y - YELLOW 9 - SLATE V -VIOLET 73.201.2 Figure 13-6. Core makeup of one type of cable. coded by layers or groups bound separately byof a length of cable being spliced at a terminal colored, spirally wrapped, soft textile binders or or at the main distribution frame in a central markers. offi Terminated tracers are connected to the A group of 25 pairs is considered as the mosthighest number terminal for that cable or group. su I table 3ize for a uni fo rm group, and all standard A 101-pair terminal would have the tracer 4 2 4 53 Chapter 13TELEPHONE CABLE SPLICING 01111111iMi

Table 13-1. BinderMarkingfor 25 Pair Groups

Group Color of Group No. Bindings Pair Count

1 White-Blue 1 - 25 2 White-Orange 26 - 50 3 White-Green 51 75 4 White-Brown 76 - 100 5 White-Slate 101 - 125 6 Red -Blue 126 - 150 7 Red -Orange 151 - 175 8 Red -Green 176 - 200 9 Red -Brown 201 - 225 10 Red -Slate 226 - 250 11 Black-Blue 251 - 275 12 Black-Orange 276 - 300 13 Black-Green 301 - 325 14 Black-Brown 326 - 350 15 Black-Slate 351 - 375 16 Yellow-Blue 376 - 400

73.250 terminated on pair 101. When splicing non-color- coded cable, the conductor having red, green, or blue is the ring conductor and the white is the tip conductor. 73.196 Splicing the Wires Figure 13-7. Joining a pair of wires. The pairs of wires are aiiugedwIthinu cable in color groups, with low cr)Int ,tt the center of the beyond the turn. As shown in figure 13-8, you core and the higher count (pltside. 'he arrange- grasp the wires just below the turn and pull ment assists in quick identification. However, you the insulation off the ends.Itis best to pull should always work from a splicing diagram, or awa an the turn and slightly toward the side at least from definite identification instructions. on h you plan to slip the cotton sleeve. This will prevent the ends of the wires from Lash the cable ends into convenient adjacent curling. position, and fold the wires back as shown in figure 13-7, view A. Next, grasp a pair of wires Next you fit cotton sleeves onto both wires at from the right-hand cable end, the corresponding the same time, slipping them over the wires. pair from the left-hand end, and give them a Use a rotating motion to slide the sleeves up half-turnas shown infigure13-7, view13. to a position where they will not interfere with Then, holding both pairs of wires in ono hand, the splicing procedure. out them about 4 to 4 1/2 inches from the turn, as shown in figure 13-7, view C. Now bend one wire of eaoh pair back out of the way and draw the othor wires of each pair Before the splice can be made, the insulation together as shown in figure 13-9. Draw the wires mustbestrippedfrom the lengths of wiresclose together, so that the splicing twist oan be

. 443 454 CONSTRUCTION ELECTRICIAN 3 & 2

73.197 Figure 13-8. -Stripping insulation from wires.

73.199 Figure 13-10.Twisting the wires.

73.198 Figu re13-9. Drawingwi restogetherfor made close to the ands of the insulation. Then make the crank-handle twistshown in figure 13-10. First roll the left-hand wire over the right- hand one. Then bend them at right angles, and 3.200 twist them together with a cranking motion of Figure 13-11.--Slipping thesleeveover the your wrist,untilyouget a twist almt 1/2 inch long. dry muslin, as shown in figure 13-12. Slide the Iiend or twist the pigtail, and cut off the lead sleeve into place, exercising care to protect excess wire. Then slip the 3leeve down over the the cotton sleeves on the individual wire eplices Joint, as shown in figure 13-11. as well as the muslin wrap. This will prevent the wires from coming into contact with one It1H,Of cou rse,vitally lindortant that you another or with the lead sleeve. know what wires go together. However,itiN always possible that you may have to do lin Unless you made your individual splices neatly emergency Job where you don't have the necessary and compactly, and unless you staggered them so informationin advanee. In a cane of this kind, they don't bunch up all at the HMO point, you a knowledge of the arrangement of groups in awill have difficulty getting the fileeve over the cable will be of great value. splice bundle. Placing and Wiping the Skeve The proceoure for wiping the lad Mee After you have spliced all the pairs of con-the same as that described for a sleeve on a ductor fi, wrap the splice bundle with two layers of power cable in chapter 11.

444 4 r Chapter 13 TFLEPHONE CABLE SPLICING

and go the other way would defeat the purpose of boiling out by forcing any moisture sheath further back. The same standard splice openings, of cotton sleeve banks, and splicing procecures apply to textile-insulated change cables as apply topaper-insulatedexchangecables.When splicing silk and cotton insulated cable to paper- wrapped insulated cable, use a desiccant for drying out the joint. Mark the point for removal of textile insulation by the same procedure described for paper- 73.202 insulated cables. Cut off the conductors 4 1/2 Figure 13-12. Wrapping the splice. inches from 'he end and use long-nosed pliers to crush the silk/cotton insulation at the marked point. Don't apply too much pressure, because SPLICING SILK ANT) COTTON this will flatten the conductor and may cuase it INSULATED CABLE tobreakaftersplicing.After the insulation has been crushed,it can be removed by de- Paper ribbon or paper pulp Insulation hascreasing the pressure on the pliers and skin- certain disadvantages which make it unsuitable for ning the insulation off by pulling toward the end use on cables to be connected to distributionIn a straight line. However, if you prefer you frames, terminal strips, and other interior ter- can pullitoff with the fingers. Never use the minal points.The reasonisthat the paper backofthe splicing scissors to remove in- insulationisnotstrong enough to withstand sulation; this might break the relatively brittle the amount of handling required to make con- tinned-copper conductors in a textile-insulated nections. In working the core into a form which cable. is fanned out and laced, the paper insulation, whichisnot baked on, will unroll.Besides, Some textile-insulated cables have enameled paper insulation deteriorates on exposure to conductors, and this enamel munt be thoroughly air, and its dielectric strength falln off con- removed before the wires can be spliced. One siderably on exposure to mointure. mothod is by light scraping between the jaws of long-nosed pliersbut you munt be extremely ItIS the custom, therefore, to splice in- careful not to nick or flatten the wires. coming paper-insulated cable onto nhort lengths of lead-covered textile-irmulated (silk or cotton A good tool for scraping eflamril 1R the wire insulated) cablen called cable heads. The heads Scraper, which consists of a steel spring 3/4 are uned to make the direct connections with inch wide, bent in the form ,of a L1 and with ends central office distribution framem and term,nal turned and sharpened. AR you gain skill with this stripn. tool, you will find it effective for removing nilk, cotton, of plastic insuh,tion. Prepare Bilk and cotton Innulated cable for splicing by boiling out with beeswax, or with a Twimt the conductors by using the flame twint specialpetroleummax. Do not use imraffin, (iescribedforsplicing paper-insulated cable. becauseit discolorn the textile insulation, and After the spliceiffcompleted, tx)11 out with hot makesitverydifficultfortheoperator toparaffin or dry with desiccant an you would a sopurato conductors for fanning, form!ng, and pape r- insulated spit ce. splicing. On .the other hand, do not u beeswax on paper-wrappedinmulatlon,becauseitwill SPLICING poLywrif YLENE- make the lower brittle and may (ammo breakage. INSULA'rED CABLE Start pouring the wax n few inchem hack on Polyethylene-iasulateo (PIO (polyeth- the sheath, and gradually advance toward the ylene In commrmly cal:r ;Motto)1fI IWIll110)10 exponed cond11 ctorf1.10 fltiffl at the conductorn 11(fritil or am direct burial eable, both typem being CONSTRUCTION EL LC l'HICIAN 3 & 2 made in even-numbered pairs. The cores of both SPLICNG POLYETHYLENE types are identical, in that they are fully coded CABLE FOR AERIAL INSTALLATION meaning that each pair in the cable is distin- guishable by color from every other pair. This The procedure for splIng polyethylene cable is accomplished by the use of a color scherni- for use inaerial installationis described in which provides different colors of insulation forfollowing paragraphs. A point to note is that the each pair in a 25-pai r group, together with colored main difference between a splice in polyethylene or imprintedbindingstodistinguish 25-pair cable and one in other types of cable is in the groups from each other. fly referring to tables methodofenclosingthesplice. A splice in which give pair color codes, binder markings and polyethylene cable is enclosed in a polyethylene possiblelayups, you can match the wires in or neoprene enclosure unit consisting of a base one of these cables with little difficulty. See assemblyanda rubber or polyethylene cover table 13-2. which snaps in place over it, whereas a splice in other types is enclosed in a metal or plastic PiC has solid copper conductors, each with sleeve. polyethylene insulation of the required color. The insulated conductors are twisted into pairs. The Removing the Sheath required number of pairs are stranded into a cable core and enclosed in a metallic shield The length of the opening in the cable sheath and polyethylene jacket or sheath. varies according to the type of closure and the size of the cable. Steps in removing the sheath In cables having 25 pairs or less, the twisted are as follows: pairs are assembled to form a substantially cy- 1. After determining the length of the opening lindrical core. In cables having more than 25 from the manufactu re r's instructions, place three pairs, the twisted pairs are arranged in groups, wraps of vinyl tape around the sheath at each each group I)eing bound by moisture-resistant thread or tape. Each group contains not moreend of the proposed opening to mark the ends, than 25 pairs.For layup purposes, the basic as shown In figure 13-13. 25-pair groups may be divided into two or more 2. Ring the sheath carefully 3 inches from the subgroups called units. splice opening marker tapes, as also shown in Each unitfna particular 25-pair group is figure 13-13. enclor;ed in bindings of the colors indicated for itsparticular25-pair group.Forexample: 3. Remove the sheath between the two rings. suppose you have a 100-pal r cable and are looking for pair number 88. You look for the group 4. Remove the shield in the same area, as with binding colorE4 white rind rwown; then look shown In figure 13-14. for the pair in that particular group with black and green Insulation (seefig.13-6 and table 5. Cut tabsInthe jacket and shield in the 13-3). 3-inch space betwcen opening and marker tapes rtsshown in figure 13-16. Cut 3 tabs for cable The aerlal-type cable has an aluminum shield up to 0.6Inchin diameter, ,1 for cable from applied longitudinally over the core covering. he 0.6to IX Inches in diameter, and 6 for cable Rerun In thisfi h (AdIf;10i ntfd during the manu- from 1.6 to 2.2 inches In diametor. facturing proceris by moans of a cold wel,,4, and 6. Enlarge slot to 1/8 inch as also shown In electric weld, or soldering with a wmaeld flux. f gu re 13-15. A polyethylenejacket IS thenplaced Over the shield. 7. Place two turns of vinyl tape,adhesive side thlIn OrlIf turn with ,idhesive side In, as shown The direct-burial type r.ahle has two poly- in figure 13-16. Push these wraps or tape under ethylene hrekAs with a coppor nhivir! hf.thvt.cm th(, tom 4 shown, to form n base for the claws 1ser and outer jacket. The Inner Jacket is placed ofthe !MHO II fifierrilflytoIx)Installedlater. ove rthe completed rt.!landIs from 50to '70 arils thick according to the raire'rer of pal rrs H. Phwe two turns of vinyl tap3 to hold the in the cable. The outer lacket, placed over the (!ore wrapper in place at the ends of the tabs, and shield, is from 10 to HO mils thick. rtnnlwe the cure wrupper

446 4 5 Chapter 13TELEPHONE CABLE SPLICING

Table 13-2. Possible Layups of Polyethylene Insulated Cables With Standard Telephone Color Code ------_-_-_-_-_-___ Size Center - First Layer Second Layer Pairs PairsPairs Binder PairPairs Binder Pair Binder Pair in in in in Colors Count Colors Count Colors Count Cable Unit Unit Unit

50 8 White -Blue 1-8 9 White-Blue 9-17 8 White-Blue 18-25 8 White-Orange 26-33 9 White-Orange 34-42 8 White-Orange 43-50

75 12 White-Blue 1-12 13 White-Blue 13-25 12 White-Orange 26-37 13 White-Oranje 38-50 12 White-Green 51-62 13 White-Green 63-75

100 25 White-Blue 1-25 12 White-Orange 26-37 13 White-Orange 38-50 12 White-Green 51-62 13 White-Green 63-75 12 White-Brown 76-87 13 White-Brown 88-100

150 25 White-Blue 1-25 25 White -Orange 26-50 25 White-Green 51-75 25 White-Brown 76-100 25 White-Slate 101-125 25 Red-Blue 126-150

200 8 White-Blue 1-8 9 White-Blue 9-17 25 White-Green 51-75 8 White-Blue 18-25 25 White-Brown 76-1L 8 White-Orange 26-33 25 White-Slate 101-1r 9 White-Orange 34-42 25 Red-Blue 126-15 1r 1 f) 8 White-Orange 43-50 25 Red-Orange 25 Red-Green

300 25 White-Blue 1-25 25 White-Brown 76-100 25 White-Orange 26-50 25 White-Slate 101-125 25 White-Green 51-75 25 Red-Blue 126-150 25 Red-Orange 151-175 fled -Green 176-200 25 Red-Brown 201-225 25 Red-Slate 226-250 25 Black-Blue 251-275 25 Black-Orange276-300

400 25 White-Blue 1-25 25 White-Orange 26-50 2. fled -Or e 151-175 25 Whit-Green 5! -75 25 Red-Green 176-200

25 White-lirt) ; 25 Red-Brown 201-22!) 25 V. hite-Slate 111-125 25 Red -Slate 223-250 25 Red-Blue 1 26-1 50 25 Black Blue 151-275 25 Black- Orange27S-300 25 Black-Green 301-325 Black-Brown326.350 Black-Slate 351-375 25 Yellow-Blue 376-400

73.251 4 458 CONSTRUCTION ELECTRICIAN 3 & 2 .1 Table 13-3.-- Color Code For Piastic-Insulated group and pigtail the ands of the tie Arire,.. Conductor Cables binder threads or tape can then be remov:A; the binder groups. Mount the base assembly for the ready-access Color of involation Pair closure. The tape which was placed to,lark the No Group hinder TIII Ring splice opening may then be removed. Place the groups in a conveniez: Blue White White Blue so you can proceed with splicing the c.ductors. 2 Blue White Whi.e Orange 3 Blue White White Green 4 Blue White White Brown Splicing the Conductors 5 Blue White White Skts: 6 Blue White Red Blue Figure 13-17 shows one method oi splicingthe 7 Blue White Red Orange conductors, a method which includ,the use of 8 Blue White Red Green a plastic-filled sleeve. This methcl it.euires that 9 Blue White Red Brown the wires first be twisted with three 1.,:se turns. 10 Blue White Red Slate Strip off the insulation and make f le firm half- 11 Blue White Black Blue turns,cutoff the excess wirle.,71ng about 12 fillIC White 13Ittek Orange White Blark Green 1 inch of twisted bare wires, and solder with 13 Nue resin core solder. Then 1.1;led sleeve I 4 Blue White Bla ck Brown 15 Bine White Black Slate over the joint and bend the tql ' into position. 16 Blue White Yellow Blue 17 Blue White Ytd low Orange Figure 13-18 shows the use of a sea'iuz. 18 Blue White Yellow ',rum typesplicingconnector. The-,n(Ah. ,J.s 19 Blue White Yellow Brown twisted enough to hold the pair v. i 20 Blue White Yellow SW, gether, and the connector isslipped mor Ina 21 Blue White iolet Blue ends of the wires approximately 3 inche_, 22 Blue White Violet Orange thebeginningofthetwist. A hand.-oporated 23 Blue "11'' . Violet ( /reen crimolng toolis used to crimp the cry.ector. 24 Bloc r:i if k V 1141, i. h rown DO NOT remove the insulation f'orr Ihe ends of 25 Blue ',Vtit t ;wit. t Slate Orange White White Blue the wires when using this rnetL)c,d, bf-,,-use the 26 insulationon the wires keer,s co!,ductors 50 Orange White Violet Slate centered in the connector. 51 Green 1.''hit e White Blue 52 Green White S'Ilite Orange When a pair of conductop.rl ad end in a splice, turn back 3/4 inch of on., onductor and place 74 Green White V i olet Brown a7 lled plastic sleeve ovec the end of the pair 75 Cret W1,ite V i,11.t. Shite ofconductors,asindicatedin figure 13-18. 76 Brow.. Whitt Wnite Blue 77 Brow 4 White Whitt Orange .,yup of Sni ced Conder!tors 09 Brown Mite Violet 100 Brown White Violet Slate The number of sp.ice '..lundles required for a convenient layup will u_pend on the length of the splice open!ng and thesizeofthecable. The splices ne..s,t be placr.r.:in uniform bundlc3 mci distriliutedto give a 1. ,form shape to the 73.. 38 fulllength of the splice al...L. After the bundle Is complet.ed, it ould be Lound with layers of vinyl tape. Figure 13-19 shows a well-shaped Identifying Hinder Gro.ips splice bundle. llpon removing the core wrapp,?r, ha' c Amity Closing the Splice fi orru short piocoa of paired cord.ictor Pwith colors matching the color code e' the binder groups. After the sp:Ices are complete and the bundles Place a matching color p1ir aroma! eaeh binder are taped, thu elosurel spread open, slipped

448 4 5 :) Chapter 13TELEP1ONE CABLE SPLICING

LENGTH OF OPENING MUST MATCH CABLE CLAMPING ASSEMBLY IN TYPE OF ENCLOSURE USED. FOLLOW MANUFACTURER'S RECOMMENDATIONS. 1. PLACE TAPE TO MARK SPLICE OPENING

2. RING JACKET CAREFULLY '7 WITH KNIFE DOTT ED LINES R.') r E CABLE OVERLAP 40t1 Ih I. PRESENT WHEN SETI4S ARE JOINTED. 73.204 Figure 13-13.-- Splicing opening In polyethylene cable.

toterminal closures on other poles. Figure R EMOV E SHIELD 13-21 shows the parts of a closure. When fewer than four cables are brought out, the openings Sigatirmimmeamommiffinimamiliss14.04 . in the nipples not being used are plugged with plugs made for the purpose. Figure 13-22 shows a closure made for ter- 73,205 minal blo3ks. When only one cable enters, the Figure 13-14. Rem...ving the shield. vacant nipple is plugged.

CUT TABS IN JACKET AND SHIELD. THREE FOR CABLES UP TO .6" DIAMETER, FOUR FOR CABLES UP TO 1.6" DIAMETER AND SIX FOR CABLES FROM 1.6" THRU 2.2" IN DIAMETER. ENLARGE SLOT TO 1/8" TO ACCOMMODATE INNER CLAMP.

BEND TABS OUTWARD USING CARE TO AVOID DAMAGE TO SHIELD AND CORE WRAPPER. 73.206 Figure 13-15. Cutting tabs in Jacket and shield. over the bundle and snapped in place over the SPLICING PLASTIC-SHEATHED entire assembly. This closure is made of poly- CABLE TO LEAD-SHEATHED CABLE ethylene or neoprene, and when it is placed over the splice assembly in the proper manner and The method described here for joiningplastic- fastened with the clips which come with the kit, sheathed,plastic-insulatedcabletolead- the splice will be completely weatherproof,but sheathed, paper-insulated cable may be used on still easily accessible should the need arise to aerial, direct-burial, or duct installations. The reopen the closure. method isillustrated in figures 13-23, 13-24, and 13-25. Fig,,re 13-20 shows two splice closures in First mark the cable sheath with the location place. The cables leaving the lower nipples run ofthesplice and placeadditional marks a 449 4 6 CONSTRUCTION ELECTRICIAN 3 & 2 VIM

PLACE TWO TURNS OF VINYL TAPE, ADHESIVE SIDE OUT, THEN ONE TURN WITH ADHESIVE SIDE IN, AND SLIDE UNDER TABS. NOTE: WHEN CABLE IS LESS THAN .60" DIAMETER PLACE FIVE TURNS OF TAP E TO BUILD UP FOR PROPER CLAMPING.

SLIDE CLAMP UNDER TABS. POSITION CLAMP TO FIT INNER BRACKETS OF BASE ASSEMBLY. Mil-rairitOrfirAirAgrAdirer

PLACE TWO TURNS OF TAPE TO HOLD CORE WRAPP ER IN PLACE AT END OF,-- TABS, THEN REMOVE REMAINDER OF CORE WRAPPER.

73.207 Figure 13-16. Placing clamps under tabs. standard distance on either side(4 inches on cloth. This scuffing will ensure a satisfactory lead, 7 inches on plastic). With aerial-type cable, surface for the proper adhesion of the end seal the cable on either side of the splice should lie casting and for the subsequent taping operations. along the suspension strand without tension when Turn back the shield and remove the core wrapper the strand is at normal tension. The length of the to the end of the sheath opening. splice opening and the size of the lead sleeve required are shown in figure 13-23. Select a lead sleeve of proper size. Clean the outside of the sleeve for a distance of 7 On the lead sheath end, carefully remove the inches from the end toward the plastic-sheathed desired amount of sheath so that the core wrapper cable, and for a distance of 2 inches from the end or the insulation around the conductors will not toward the lead-sheathed cable. Place the sleeve be damaged. Scrape the surface of the lead 4 over the lead-sheathed cable and push it back inches from the point where the sheath was cut, out of the way until needed, as shown in figure making sure to remove all dull spots and streaks 13-23. to present a clean surface for wiping the lead joint.Coatthis cleaned space with stearine. Casting the Plastic End Seal Then remove the core wrapper from the exposed cable. Preparea cone-shaped oasting form (one may be made from a cone-shaped paper cup On the plastic cable end, remove the sheathor something similar). Be sure that the largest carefully for the desired distance so that thediameter of the form is not ,larger than the in- metal shield, the core wrapper, and the insulation side diameter of the lead sleeve being used. aroundtheconductorswillnot be damaged. Fashion a hole in the bottom of the form to make Scuff the &math of the cable for a distancea snug fit over the plastic-cable sheath. Slide of 7inches from the c.pening, using No. 2 1/2the form over the sheath to a temporary posi- grade sarripaber. Do not use emery paper ortion about 4 inches back from the end of the 460 461 Chapter 13 TELEPHONE CABLE SPLICING

STRAIGHT JOINT BRIDGE JOINT

INSULATED CONDUCTORS APP X 7 8" COMPLETED 3 LOOSE HALF TURNS STRAIGHT JOINT. SLiP 71LLED BARE SL EEVE OVER CONDUCTORS JOINT AND S FIRM HALF APPX BEND INTO TURNS 1" POSITION CUT OFF EXCESS WIRE. SOLDER WITH RESIN CORE SOLDER

BUTT JOINT DETAIL

TIP RING RING COMPLETED JOINTS

TIP RING TWIST ENOUGH TO TIP HOLD PAIR TOGETHER

PAIR OF CONDUCTORS IN A DEAD END

FILLED PLASTIC SLEEVES (LENGTH4-1/2")

GAUGE OF TYPE OF INSIDE COLOR CONDUCTORS JOINTS DIAMETER TURN BACK ONE CONDUCTOR OF .095 YELLOW 24X24 STRAIGHT PAIR AND CAP WITH FILLED PLASTIC .085 74 X22 SLEEVE. POSITION SLEEVE FOR .105 GREEN 24X19 POSSIBLE FUTURE SPLICING.

22%22 .105 22X19 .105 19%19 .125 CLEAR

24 X24 X24 BRIDGE .085 YELLOW 74%24%22 .105 GREEN 24X24X19 .105 PRECAUTION: TO AVOID CRACKING AND LOSS OF FILLER, THE PROPER 22X22X74 .105 SIZE SLEEVES SHOULD BE USED AND 22X22X22 .105 NOT FORCED OVER JOINTS. 22%72%19 CL FAR 19%19X24 .125 . 19X19X22 .125 19%19X19 .145 RED

73.208 Figure 3-17.Splic1ng details for various types of joints.

451 462 CONST1XCTION ELECTRICIAN 3 84 2

SIDE VIEW 3 CHANNELS. DO NOT REMOVE EACH CHANNEL INSULATION WILL ACCOMMODATE ME TAL ONE CONDUCTOR OF CONNECTING EITHER 26, 24, 22 ELEMENT OK 19 GAUGE 3 SPLICER NOTE* END VIEW ALWAYS INSERT CONDUCTOR/ TO END OF CHANNELS.

TWIST TO HOLD TOGETHER

TWIST TO HOLD TOGETHER RING

STRAIGHT JOINT BRIDGED JOINT BUTT JOINT

BRIDGED TAP CONNECTOR

MAKE CONNECTION WITHOUT CUTTING CIRCUIT CONDUCTOR

HAND OPERATED PAIR DEAD ENDING IN A SPLICE CRIMPING TOOL USE A FILLED PLASTIC SLEEVE AS SHOWN

73.209 Figure 13-18. Sealing ..:3)1,4 splicingconnector. 452 463 Cnapter 13TELEPHONE CABLE SPLICING

UNIFORM LAYUP OF SLEEVED JOINTS, AND SPLICE BUNDLE ARRANGEMENT

TAPE OR SECURE BY USE OF PIECE OF CONDUCTOR BEND DOWN

rP) SHORT BASE ENCLOSURE WILL ACCOMMODATE TWO SPLICE BUNDLES.

SPLICING PROCEEDS IN ACCORDANCE WITH THE DETAILED PLANS. THE SLEEVED JOINTS ARE POSITIONED IN BUNDLES WHICH MAY BE STAGGERED AS MOST CONVENIENT FOR AN 'EVEN LAYUP AND ARRANGEMENT. EACH SPLICE BUNDLE IS SECURED WITH TWO TURNS OF VINYL TAPE. GENERAL FEATURES OF LAYUP AND ARRANGEMENT ARE ILLUSTRATED.

TAPE OR SECURE BY USE OF PIECE OF CONDUCTOR

LONG BASE ENCLOSURE WILL ACCOMMODATE THREE SPICE BUNDLES.

73.210 Figure 13-19. Layup pattern for splice.

sheath. Turn up the end of the cable and secureoperation. After the form isfilled, allow the itina vertical position for the casting oper- m:xture to harden for approximately 10 minutes, ation. Spread the conductors to allow space foror untilitis firm and cool to the touch. Then the casting liquid to completely seal all voids. peel off the form and clean off any particles that Move the casting formipuntilit extends may iiaveadhered to the casting. The cable about 1/2 inchabove the end of the plasticthen may be bent back into position for the sheath. If the lower end of the form is not tight splicing operation. around the sheath, it may be necessary to use a few wraps of tape to hold it in position and seal Splicing and Soldering any openings. Figure 13-23 shows a form in C onductors Separate conductors into bunches by color Prepareithecasting mixture according togroups or complements, and secure them in a instructionsincluded with the container. You convenient position for splicing, leaving a suit- viiinotice that the casting resin will develop ablelengthforstaggered spacing of splices heatImmediately after being mixed, but thisto attain a uniform layup. Excess wire should tinat will not cause any harm. When the mixture then be cut off. Acnductors are selected lb) isready to pour, pouritinto the form until splicing,plasticsleevesof proper diameter it reaches a point very close to the top. Daring shouldbe placed over one of the conductors the pouring process, move the wires and shield and pushed back. Where conductors end in a slightlytoaidpenetration andtobring the splice, cut them off and place a sleeve (selected shield and %Ares into alignment for the splicing according to fig. 13-24 specifications) over the

153

4 6 CONSTRUCTION ELECTRICIAN 3 & 2

1 3/4 inchesin"length,starting with three loose half-turns (about 1 inch), thenfinishing withfivetigrqhalf-turns(about 3/8 to 1/2 inch). Afterthe excess wire has been cut off, solder the joint using resin core solder. Bend the soldered pigtail into place, and slide the previously placed sleeve over thejoint,as shown in figure 13-24. After all conductors have been spliced and placed in the proper layupt wrap the body of the splice with a plastic envelope cut from a sheet of polyethylene or the equivalent. Fill the envelope with desiccant in amounts for various sizes of cable as shown in figure 13-24. BE SURE NOT TO EXCEED THE RECOMMENDED AMOUNTS. Cover the whole splice with a single layer of half-lapped-vinyl tape, but do not overlap the cable sheath or metallic shield. To ensure continuity of the shield, rewrap the shielding material around the splice, extending in onto the lead sheath. If the shield material is not long enough Figure 13-20. Splice closures in place. to make a full wrap around the lead sheath, add an extra piece of shielding and solder it to the existing strip. This soldering operation should be performed away from ihe cable core to protect the tape from the heat of the solder- ingiron. Solder the end of the shieldto the lead sheath at the point of overlap. On aerial- type plastic cable, tin the alum'num shield with Alcoa 64 aluminum flux and solder it with 50-50 or resin core solder. ite Ar .1 C1.0101 eAst 3.00, Plac'ag tl-,e Sleeve

113Ce 11 strip of tape on the plastic sheath extending leagthwise about 2 1/2 inches from the base of the cast end seal, as shown in figuve 13-25. Secure a strip of wire cloth 2 inches ,nttfir,(3 wide, starting the edge of the wire cloth on the strip of tape and wrapping tightly around the cable, overlapping the starting point about 1 73.212X inch. Figure 13-21. Parts of a splice closure. Secure the edges of the wire cloth in place withtape.Hold a hot soldering iron firmly ends andpositionit for subsequent use. Allagainst the wire cilth at numerous points around sleeves are 3 inches long. thesheath until dark patches appear through Remove therequired lengthof insulationthe wire mesh. This operation will, by softening from the conductors as they c.re selected forthe plaJtic, anchor the wire cloth In the plastic splicing. Twistthe individual, skinned con- sheath. Be careful not to hold the Iron too long ductors together. Make a joint 1 3/8 inches toin one place, or the insulation may be burned.

454

4 6 ro Chapter 13 TELEPHONE CABLE SPLICING

-__

73.213 Figure 13-22. Terminal-block closure.

Place the lead sleeve in position over the On the plastic-sheatn side, shape the end of splice, overlapping the lead-cable sheath aboutthe lead sleeve to the copper-wire cloth in a 1 1/2 inches, and overlapping the wire coth on graemally tapering slope. This will tend to make the plastic sheath about 1 inch. Beat in the end thetapingoperation easier.Solder the lead of the sleeve G.the lead-sheath side and wipesleeve to the wire cloth, using resin-core f3o1der in the usual manner. and a soldering copper. 455

466 CONSTRUCTION ELECTRICP: 3' NIEMEN/NW' I.,-

MARK LOCATION OF STRAIGHT SPLIC': SPLICE OPENING AND SPLICING PLASTIC INSULATEDPLAs1 DISTANCE ON EACH SIDE T-HF1 CABLES TO PAPER INSULATEDLEAD 5H _Al, LO CAL btf4" * SHEATH OPENIW. i"

LEAD SHEATH REMOVE )

REMOVE LEAD SHEATH CAREFULLY SCUFF SHEATH WITH SO THAT CORE WRAPPER OR NO 2 h GRADE SAND INSULATION AROUND CONDUCTORS PAPER. DO NOT USE WILL NOT BE DAMAGED. SCRAPE EMERY PAPER OR SHEATH TO PRESENT A CLEAN SURFACE REMOVE SHEATH CAREFULLY SO THAT METAL SHIELD CLOTH. FOR JOINING. SECURE CORE WRAPPER CORE WRAPPER OR INSULATION AROUND CONDUCTORS WITH TAPE AT ENO OF LEAD SHEATH WILL NOT BE DAMAGED. TURN BACK SHIELO ANO AND REMOVE EXCESS WRAPPER. REMOVE CORE WRAPPER. 7.:>/1-/JZs:W751T LEAD SLEEVE = CLEANre

wis ECI SLcEVi: OF PROPER SIZE. REMOVE PLASTIC INSULATED 'DENT I' 'CATION RIDGES. CLEAN ENDS AND CONDUCTORS SLIr/E OVER CABLE TO CONVENIENT POSITON SELECTION OF LEAD SLEEVE

SIZE OF CABLE SHEATH SIZE OF IN 22 GAUGE Oi:ENING SLEEVE 11 TO 51 PR 11 Sir 1 Si" X 15" 76 TG 101 PR 13 Si" 1 Si" X 17" 152 PR 13 Si" 2" X 17" MIXTURE CASTING CASTING END SEAL CONE SHAPED CASTING FORM MAY BE A RUBBER OR PLASTIC NURSING BOTTLE CAP, OR IT MAY BE IMr)ROVISED BY USING TAPE OR OTHER SUITABLE MATERIAL.

A FASHION HOLE IN CON.: SHAPED FORMAND SLIDE IT OVER CABLE TO TEMPURARY POSITION. B TURN UP END OF CABLE AND SECURE IN VERTICAL POSITION FOR CASTING OPERATION. C MOVE FORM UP TO CASTING POSITION. PLACE TAPE IF NECESSARY TO HOLD IT IN POSITION OR CLOSE ANY OPENINGS. PREPARE CASTING MIXTURE AS PER INSTRUCTIONS ASSOCIATED WITH CONTAINER. WHEN MIXTURE IS READY

1 2' TO BE POURED ACCORDING TO THOSE INSTRUCTIONS, POUR IT INTO THE FURM UNTIL IT REACHES A LEVEL VERY CLOSE TO TOP. (THE WORKMEN WILL NOTE THAT CASTING RESINS DEVELOP HEAT IMMEDIATELY AFTER BEING MIXED) DURING THE POURING PROCESS THE SHIELD AND CONDUCTORS SHOULD BE MOVED BACK AND FORTH SLIGHTLY TO AID PENETRATION OF LIQUID. CUT WHEN FORM IS FULL ALLOY THE MIXTURE TO HARDEN TAPE ABOUT 10 MINUTES OR UNTIL IT IS FIRM AND COOL TO THE TOUCH. THEN PEEL OFF THE FORM, AND CLEAN CASTING. E BEND CASTING BACK INTO POSITION FOR SPLICING. DETAIL SHOWING PENETRATION OF CASTING MIXTURE

73.220 Figure 13-23. Preparing to splice plastic-sheathed cable to lead-sheathed cable.

456 467 Chapter 13 CAIIL!: SPLICING

STRMGHT SPLICE SPLICING PLASTIC INSULATED- PLAS1 IC SHEATHED CABLES TO PAPER INSULATED- LEAD SHEATHED CABLES PAPER INSULATED SEPARATE CONDUCTORS PLASTIC INSULATED rnNoucroas INTO BUNCHES BY COLOR CONDUCTORS GROUPSOR COMPLEMENTS AND SECURE IN A CONVEN IENT POSITION FOR LEAD SLEEVE SPLICING. SEE DETAIL FOR JOINT

PLASTIC END SEAL SCUFFED SURFACED i/ CLEANED ( METAL SHIELD SURFACE PLASTIC SLEEVE BRING PAIRS TOGETHER AS NEEDED, AS CONDUCTORS LEAVING SUITABLE LENGTH OF ARE SELECTED SELECTION SLACK FOR STAGGERED SPACING OF FOR SPLICING, GAUGE OF JOINTS THEN CUT OFF EXCESS WIRE COLOR INSIDE OUTSIDE PLASTIC SL EEVES CONDUCTOR DIA. DIA. STAGGER JOINTS FOR UNIFORM LAY SHALLBE PLACED. 24 GREEN .106" .138" 22 BLACK .125" .165" 19 RED .148 188" k)REMOVE REQUIRED LENGTH OF INSULATION AS CONDUCTORS ARE SELECTED FOR SPLICING -4-- SLEEVE SHIELD PLASTIC SLEEVE PLASTIC INSULATED CONDUCTOR WRAP SPLICED CONDUCTORS WITH AN ENVELOPE PAPER INSULATED/ MADE OF POLYETHYLENE. DESICCANT SHALL BE CONDUCTOR 3 LODSE HALF PLACED IN ENVELOPE AS FOLLOWS: DETAIL TURNS 5 TIGHT HALF SIZES OF CABLES WEIGHT IN GRAMS FOR MAKING TURNS 51 PAIR AND SMALLER 20 \ JOINT CUT OFF EXCESS 76 AND 101 PAIRS 40 WIRE.AND SOLDER BEND PIG- i152 ANO 202 PAIRS 70 TAIL INTO POS. TION AND ILARGER THAN 202 PAIRS 30 PER 100 PAIRS SLIDE SLEEVE OVER JOINT. USE RESIN CORE SOLDER

PLACE DESICCANT. COVER ENTIRE SPLICE WITH A SINGLE LAYER SECURE ENVELOPE IN OF TAPE HALF LAPPEO. DO NOT OVER LAP PLACE WITH TAPE. \ THE CABLF SHEATH OR METALIC SHIELD. T.Q INSURE CONTINUITY OF SHIELD, REWRAP METAL SHIELO TAPE AND SOLDER IT TO THE LEAO SHEATH. IF SHIELO IS ROT LONG ENOUGH SOLDER ON AN AODITIONAL PIECE OF SHIELD.

SOLDERING OPERATIONS SHALL BE PERFORMED AWAY FROM THE CABLE CORE TO PROTECT THE TAPES FROM THE HEAT OF THE SOLOERING IRON. ALLUMINUM SHIELD SHALL BE TINNED, USING ALCOA 64 ALUMINUM FLUX, 5r 50 OR ROSIN COkE SOLDER SHALL BE USEO IN THE SOLOER.NL OPERATION. 73.221 Figu. a 13-24. Maldngthe splice of plastic-sheathed cable to lead-sheathed cable.

457 4 6 8 CONSTIt l'ION ,E(.:THIcIAN 3 & 2

STRAIGHT SPLICE SPLICINC PLASTIC INSULATE° -PLASTIC SHEATHED CABLES TO PAPER INSULATED- LEAD SHEATHED CABLES

PLACE TAPE As STARTING BASE SECURE EDGES Cr WIRE CLOTH TIGHT LT FOR WIRE CLOTH 1 2 IN POSITION WITH APE

COPPER INI WRAP WIRE CLOTH CLOTH 2" HOLD HOT sOLDERING IRON ON TIGHTLs AROUND w1DE WIRE CLOTH AT iNTERs. ALS CABLE. OVERLAPPING UNTIL PATCHES APPE AR THRU ST ARTING POINT MESH THIS OP ER AT ION WILL ABOUT I INCH ANCHOR MESH INTO PLASTIC SHE ATH

L.IAT IN END OF St EF.VE AND WIPE JOINT AS AN ALTERNATE TO ',HIRING JOINT A BLOW TORCH IAA/ BEAT IN END OF BE USED FOR T;05 PURPOSE CARE MUST BE USED TO AVOID 01mAGE TO SHEATH AND INSULATION SLEEVE IN LONG ,L IDE LE AD SLEEVE /SLOPE TO FAVOR INT1)POSITION 7------r-T-1- TAPING OPERATION

l /METAL SHIELD,/ 7

__--2----- SOLDER SLEEVE TO WIRE CLOTH USING RESIN CORE FILL IN VOID WITH T APE 10 PROVIDE SOLDER A SMOOTH SURFACE FOR FURTHER TAPING 7 4 5 S** /4I2 I r -4-r. 2 12"

wLy 2 HALF LAPPED LASERS DF .E TO CCveR S INCH AREA APPLY COLLAR O TNREF TURNS OF APPL Y II2 TURNS OF 2 INCH ADHESIVE ADHESIVE BACKED ALUMINUM TAPE. BACKED AL UMNUM TAPE OVER LAPPED. IRON SMOOTHLY INTO PLACE !RCN SMOOTIC.- .N PLACE 6

APPLY 2 HALE LAPPED LAS IRS OF pi ASTIC TAPE.

SECOND LAYER, STAR'T ON LEAD SLEEVE FIRST LAYER. START ON LEAS SLEEVE AND EXTEND ON TO PLASTIC SHEATH. AND EXTEND ON TO pLAsIL SHEATH THIS COMPLETES THE SPLICE. 9

/ FIRST LAYER

73,222 Figure 13-2; Completing the splice of plastic-sheathed cable to lead-sheathed cable. 458

4 6 :) ('hapter 13TLP11 )NE CABLE SPL7CiNG

Fillinthe void between the plastic sheati. and the lead sleeve with vinyl tape, to provide a sm)oth sur:Iwe for further taping. Figure 13-25 showsthetaping procedure. Apply two halt- lapped layers of extending 2 1/2 incher: on each side of the point where the lead sleeve is joined to the wire cloth(atotal of 5 '.es) Apply a collar of three turns ot 3-inch backed alum'num tape and iron smoothly in place with a cahle dresser. Tids operation will allow 1/2 inch of previously placed vinyl tape to show at each end of the collar. Apply One and a half tul'Ils of 2-ineh:alhesive- backed aluminum tape at each end of the collar, overlapping the p riously plamd aluminum about 1/2 I rich. I ro inlothly witha cable dresser. T vo-inch tapmay be cut from :Iroll of 4-inch tape. Apply two half-lapped layers of vinyl tape over the aluminum tape. Start the first layer on the lead sleeve 1 inch from the alum'num tape,andcontinuetoa point on the plastic sheath1 inch beyond the aluminum tape. Start the second layer of tap:, on the lead sleeve 1 inch from the end of the previods layer, and wrap to a point 1 inch beyond the end of the fi rst layer. This completes the splicing oporation.

SPLICING POLY ETHYL EN E CABL E FOR DIRECT-BURIAL INSTALLATION Direct-burial cableis buried ina trench, usually at least 30 inches below the surf. ce. When a splice mist remain aboveground, splice or terminal housings are used. Wnen no external housings are permitted, a casting compoun-i and special splicing technique are used to allow the splice to remain lnderground. When the cable changes from direct-burial cableto aerial cable, the houcing is usually pole-m.lunted. However, when a terminal blr>ck to connect lines to a telephone is needed,or when a splice is to be made in the cable, a pedestal- 73.214 mounted housing is used. Figure 13-26. Open-terminal housing. Figure 13-26 shows a pedestal-moiinted, open- terminal housing with three pairs of conductorsFigure 13-27 shows the housing with cover in connected to the terminal block. In this type ofplace. housing the conductors passing through the hous- An example of a splice housing is shown in ing (not connected to the terminal block) are not figure13-28.Figure 13-29 shows the splice cut,but are continuous through the housing.housing with cover in place. Continuity of the 459 470 CONTRAVFION LECTRICIAN 3 & 2

73.216 Figure 13-20. Splice housing.

other damage to small aerial cable is part oi 73.215 your job. Such damar::: Cf.rt be repaired wiLli an Figure 13-27. Terminal housing with coveracetylene torch if it 6nes oci extend through the in place, sheath.

Water-!-P:.z.i.ked paper insv.:ation usually causes shield in direct-burial cable is accomplished bypairs to '...,::oorne shorted. It foIlews that shorted means of a bonding harness as shown in figurepairs a; e irequently ht: indication that somewhere 13-30. the sht.t darnag& enough to allow mo-isture When no external housings are permitted, to penetrat,6 to the insulation. casting compound is used to minimize the problem of moisture. This technique is outlined in figure Steps in making a sheath-damaige ;weir are ab 13-31. follows: 1. Opening the sheath. REPAIR OF LEAD-COVERED CABLE 2. Drying out and repair, Making minor repairs because of ring cuts, sheath bredcs, lightning burns, bullet holes, or 3. Closing the sheath. 460

4 7 1. Chapte 13 TE ThE CA ILE SPLICING .0111...

2. l'sea wire brush to brighten t:lelead sneath in the section to be split. 3. Rub stearine along the cable where the lengthwise splitisto be ...de.As the cut is made, continue to lubricate with stearine. 4. Splitthecablewithacable :gripper, a cutting tool with smallid large blades which can be set to cut a given aapt.h. Adjust the small blade of the stripper so that it will penetrate 1/32 to 1/16 inch. Make t.:Ltstarting cuts with the small end of the blade, routing out the small lead shavings as you ci.t. After a aefinite line of cut has been established, turn the stripper over and use the large end of the blade co bevel thecut.Donotcut WI the way through the sheath with the large end. Ju:,t before the blade is about to hreak through the sheath, reverse the tool and complete the cut whh the small end. 5. After you have cut through tilesheath, open it with a pair of caule plicrs. Grasp the handles of the cable pliers firmly and open the incision on one side. With the sharp jaw 'n the cut, work the pliers sideways, exerting a small downward pressure at the sa.ne time. Bend the sheath cautiously, so as not to deform It. Wher one side of the sheath is tent T-ack, repeat the process on the other side. When the sheath has been opened, push out the cable by inserting wooden wedges oetween sheathand cable as shown in figu 13 3. DRYING OUT AND REPAIR If wires must be spliced, the cut must be long enough so that splices can Lprope-'y 73.217 staggered. Apl.ly paper tape to any points _A 13 -29. Splicehousing with cover in which the wire Is sound but the Insulal.41n hat5 place. become blackened because of electrolyti, action. To apply the tape, pull the pair out and cut a piece of tape long enough to extend at least 1/2 4.. Solderingtheseam, usinga soldering inch t=yond the corrodec. portion. Press it rlwn Lorper or an acetylene torch. with your fingers, and trim off the excess. I_I at weather take great care that perspiration fr m OPENINL. THE SHEATH your hands does not dampen the insulation. After the iault has been lo:ated and the lad- Iftheconductor insulationis darnor wet, der or splicing platform has been placed for a procedure similar to that described in ;."..gur gaining access to the repair point on the cable, 13-24 may be used, but the envelope and desiccant proceed to open the sheath as follows: must be removed to close the sheath as described in the following steps. 1.--.t.raightenthecableifnecessary, and reduce cabletension,alsoifnecessary, by After all damaged wires are repaired, push placing grade clamps. cotton tape under the edges of the sheath with a

461 472 cot: murc noN ELECTRICIAN 3 8,2 2

PIGTAILED CO.-.DUCTORS FOR MA.HTMNING COLOR-CODE OF CABLE CO1P41"

CUT SHIELD AS SHOWN 10 FACILIT ATE INSTALLATION TAPE INTO OF COMrk -JSION CLIP POSITION AS SHOWN

5 8"

SHIELD BONDING HARNESS -4-- DIRECTIONAL COLOR MARKERS

STEPS I. REMOVE OUTER JACKET, TRIM CABL E SHIELD AHD INNER JACKET AS ILLUSTRATED. 2. FOLD BACK OVERLAPPED EDGE OF `,HIELD AND COMPRESS CLIP OF SHIELD BONDING HARNESS TO SHIELD AS SHOWN USING SPECIAL COMPRESSING TOOL. 3. APPLY VINYL TAPE OVER SHIELD AND BONDING HARNESS AS ILLUSTRATED. TAPE SHOULD BE APPLIED AS NEEDED TO PREVENT CONTACT BETWEEN SHIELD AND METAL OF TERMINAL HOUSING. 4. SECURE END OF SHIELD BONDING HARNESz 'N SPLIT-BOLT GROUNDING CONNECTOR.

73.218 Figure 13-30. Installation of Wilding harness. bLttingtool. Wrap the core with i-inch tapethe sheath will close readily around the press- which has been belled out in paraffin, and then boardstrip;afterremoving the wedges and push the core back into the sheath. Test thepushing the cable back into the sheath, place cable pairs to ensure that all trouble is cleared. the strip under the opening. It is not necessary toclosethe cut completely, but ifitis left CLC.3ING THE SHEATH partly open, the strip of pressboard should cover the cable so that it will not be damaged during Before closing the cut in the sheath, cut athe process of sealing up the split in the shsath. piece of pressboard about 5/16 inch wide and as long as the length of the opening. Lubricate Inclosing thesheath you should bend it with stearine generously, so that the edges of intoshape gradually. First press it together 462

473 Chapter 13TELEPHONE CABLE SPLTC1NG

NOTE: EXCAVATE A TRENCH AS SHOWN, PROvIDE A mINImUm OF THREE FEET OVERLAP IN THE I3JRIED wIRE AND PROCEED TO mAK E THE OIRECT BURIAL WIRE SPLICE AS SHOWN IN THE FOLLOWING STEPS8

1. REmOvE APPROXIMATELY 4" OF JACKET FROm ENOS AS SHOwN. CLEAN FLOODING COMPOUND FROM SHIELO WIRES AND CONOUCTOR INSULATION. 2.SLIT INSULATION APPROXIMATELY 3" AND SEPARATE CONDUCTORS. 3. REmOvE APPROXIMATELY 1/4" OF INSULATION FROm CONDUCTORS, INSERT INTO INSULATED WIRE CONNECTORS, _IMP AND BEND INTO POSITION AS SHOWN.

TWO PLAIN COPPER CONOUCTORS TWO TINNED COPPER CONDUCTORS

wIRE CONNECTOR

1. TWIST LOOSE ENDS OF SHIELO WIRFs TOGETHER. S. BRING SHIELO wIRES TOGETHER, MAKE PIGTAIL, INSERT ENDS INTO SOLDERLESS WIRE CONNECTOR AND TWIST INTO POSITION. 6. BRING SHIELDS AND CONDUCTOR SPLICES INTO ACIGNMENT AND APPLY TAPE AS REQUIRED TO OBTAIN COmpACT BUNDLE FOR POSITIONING IN mOLD.

udimfle°!

7. POSITION mOLD AROUND SPLICE BUNDLE AND APPLY TAPE AT EACH END TO PREVENT COMPOUND mIXTURE FROM LEAKING. B. SET MOLD IN LEVEL POSITION, PREPARE CASTING CIIMPOUND AS RECOMMENDED BY MANUFACTURER AND POUR. 9. 00 NOT DISTURB SPLICE OR REFILL TRENCH UNTIL CASTING COMPOUND HAS COmPLETELY CURED.

73.219 Figure 13-31.Splicing polyethylene cable for direct-burial installation.

463 474 CONSTR,JGDON ELECTRICIAN 3 & 2

feedingbarsolder(heldinthe other hand) to the vertical beveled edge of the copper ahead of the Iron. The copper must be kept moving at aspeed just slow enough tofill the opening WOOD WEDGES with the solder and fuse it to the sheath. Part of the copper edge resting on the sheath must also rest on the paper paster along one Li A side of the opening to make a smooth continuous seam. There will be a slight buildup as the molten solder streams out from behind the coppv;r. It 73.203 may be necessary to pass the copper along the Figure 13-32. Wedging section of cable out ofother poster to dress up the seam, Atter com- opened sheath. pletingthesoldering operations, remove the posters. with your hands, then shape it into its original Using an Acetylene Torch shapebyapplying pressuve withtongs kept lubricated with stearine. Do not roll the tongs Small sheath defects, such as ring cuts Ind overthesheath,becausethiswill create cracks,can berepaired by acetylene torch. depressions aroundthecircumference. Take Acetylene, however, is a highly flora-noble gas care, also, not to apply pressure directly over whichisexplosivein confined spaces. Con- the cut until the cableis well shaped, or you sequently,never use the acetylene torch for may flatten the cable. making repairs in a manhole or othar enclosed space. Before you use an acetylene torch, be SO: DE RING TU !: SE -1M sure youfullyunderstanditsoperation and particularly, the safety precautions that go with it. 3ifter the sheath has been closed over the cable sothatthe edgesofthe To make sheath repairs with an acetylene cut are from 1/8 torch,youagainusestearine core solder. to 1/4 inch apart, use the scoring tool and a wire Thoroughly clean the area around the defect with brushtocleanthesheath thoroughly. Applya brushing motion. Apply the torch flame to posters along the edges and ends of the cut, to the cleanedarea,being careful not to con- fix the width and length of the closing seam.centrate long on one spot. Apply solder over Set the pasters about 1/16 to 1/8 inch awaythe area of the defect, using sufficient heat to from the edges of the cut. Use a half-roundtin thoroughly. Build up enough solder to fill bastardfileateach end of the cut to formthe crack or depression. Use a small finishing-. a depression into which solder can be flowed tocloth to pack the solder into the defect, and to seal any fine cracks caused by bending back thesmooth off the patch so that is is onl.y slightly sheath. After the pasters are set, apply stearine more than flush with the surface of the sheath. to the portion to be soldered. A repair should extend from 1/4 to 1/2 inch Using a Soldering Copper beyond the defect. Never keep the torch lighted except when Fuse stearine coresolderto the cut bymaking repairs.If spots to be repaired are holdingthe end of the solder bar in contactclose together, you may move from one to the with the sheath. Hold the handle of the soldering other without extinguishing the torch,if you copper in one hand at a 450 angle to the cable. don't have to change position radically. How- Rest one beveled edge of the copper on the paper ever,if you have to change position or pass a paster at one end of the sheath opening. Move hole, turn off the torch, and relight again in the the iron onto the sheath along the opening while new position.

464 CHAPTER 14 ADMINISTRATION

As a C E3 or 2, you still have a great deal in charge of all operations, and be responsible tolearn abbut your trade, including the defor the care and maintenance of the equipment. velopment of skills required in performing tasks concerning electrical generating and distribution Your dutiesasa crew leader will vary systems and service. And from time to time you from one activity to another. At most activities, will be called upon tofill the role of super-however, a crew leader's duties may involve visor. Your dutiesand responsibilities as aplanning work assignments, supervising work supervisor will be limited, but they will gradually teams, initiating requisitions, and keeping time increase as you advance from one pay grade tocards. Information that will aid you in carrying the next. This chapter discusses one of the major out these duties is given below. responsibilities of a supervisoradministration. It is not intended to tell you all you need to know PLANNING WORK ASSIGNMENTS about the subject, but to give you some idea of For purposesof this discussion, planning what you, as a CE3 or CE2, can expect in the is the process of determining requirements and way of administrative duties. As part of this devising and developing methods and schemes chapter,information alsois included on the of action for construction of a project. Proper purpose of the Personnel Readthess Capability planning saves time and money for the Navy and Program (r makes the job easier for all concerned. The following pointers will aid you in planning day- to-day work assignments for work teams. ASSIGNMENT AS CREW LEADER When you are assigned a job, whether ii. writing or orally, one of the first things to do As you gain experience in construction work, if2 to make sure you understand clearly just you will probably be called upon to serve as -1,al is to be done. Study plans and specifications crew leader of CE teams (or crews) consisting wh Ireapplicable.If you have any questions, of 3 to5 men. These teams perform various find out the answers from those in a position to types of work. For example, a three-man team supply the information you need. Among other (two linemen and one groundman) maybe assigned things, make sure you understand the priority the job of mountthg crossarms and racks on oftheproject, time of completion, and any poles. The groundman readies all bolts, washers, special instructions to be followed. nuts, braces, and crossarms to be used. The groundrnan attaches the handline to the cross- In planning for a small or large project, you arm in the prescribed manner for the lineman must consider the capability of the men available to pull into a working position. After the line- for assignment. Determine who is to do what and man inserts a through-bolt,he casts off the hcw longit should take to complete the job. upper half-hitch, and the groundman then heaves Realizinc that idlencss may breed discontent, the crossarm level. The lineman fastens thearrange to have another job ready for starting braces to the crossarm in a secure manner. as soon as the first one is finished. When doublecrossarmsareused, they are Establish goals for each work day and en- fastened together at the ends with double-armcourage your men to work together as a team boltsallowing forthe lineman to adjust the inaccomplishing these goals. You want your spacing between them. As the supervisor in charge goalsto be such that your men will be kept of a job like the one described, you would bebusy, but make sure they are realistic. Daring 465

476 CONSTRUCTION ELECTRICIAN 3 & 2 an emergency, most men will make a tremendous the correct procedure and check to see that he effort to meet the deadline. But men are not followsit.In checking the work of your men, machines, and when there isno emergency, try to doitin such a way that your men will they cannot be expecteu to continuously achieve feelthatthe purposeof yourinspection is an excessively high rate of proauction. In your tc teach, guide and direct, rather than to criticize planning, you must also allow for things v.hich id find fault. arenot considered *as direct labor, such as safety training, disaster control training, leave, The supervisor should make sure that his and liberty. men observe all applicable safety precautions. He shmild also watch for hazardous conditions, To help ensure that the job is done properly improper use of tools and equipment, and unsafe and ontime,youwill want to consider thework practices which could cause accidents and methoc: to use in accomplishing the job. If there possiblyresultin injury to personnel.iVI.Jiy is more than one way of doing a particular job, young men are heedless of danger, or think make sure the method you select is the besta particularregulation is unnecessary. Very way. After selecting a method, analyze it to see often such persons get hurt. ifit could be simplified with a resultant savings in time and effort. When time permits, rotate the men on various Plan material requirements so that you will jots. Rotation gives them Iraried experience and not have a log of materials left over. But don't will help ensure your having men who can do the have your material estimate so low that you may work if someone is hospitalized, transferred, or run out of necessary items and delay the job so goes on leave. that your men may remain idle,until more A good supervisorshould be able to get materials can be obtained. At times, circum- others to work together in getting the job ac- stances come about that make it necessary to complished. He should maintain an approachable use more materials than anticipated. attitude towards his men, making them feel free Consider the tools and equipment you willto come and seek his advice when in doubt as need forthejob and arrange to have them to any phase of the project. Emotional balance available at the place where the woi-k is to be isespeciallyimportant;a supervisor cannot done, and at the time the work is to get under- become panicky before his men, unsure of him- way. Determine who will use the tools, and make self in the face of coaflicting forces, or pliable sure the men to whom they are assigned knowwith influence. He should use tact and courtesy how to use them properly ,and safely. Plan to in dealing with his men and not show partiality have the materials so that they will be in an to certain members of the work team. He should accessible place but not pose a safety nazard. keep his men informed on matters that affect them personally or concern their work. He SUPERVISING WORK TEAMS should also seek to maintain a high level of morale, keeping in mind that low morale can have a After a job has been properly planned, it isdefinite effect upon the quantity and quality of necessarytosupervise thejob carefully to work turned out by his men. ensure that it is completed properly and on time. The above is only a brief treatment on the Some pointers that will aid you in supervisingsubject of supervision. As you advance in rate work teams are given below. -rou will be spending more and more of your Prior to starting a job, make sure your mentime in supervising others, so let us urge that know whatistobedone. Give instructions you make acontinuing effort to learn more clearly, and urge your men to ask questions on about the subject. Study books on supervision any points that are not clear to them. Be sure as well as leadership. Also, read articles on the men know all pertinent safety precautionstopics of concern to supervisorssuch as safety, and wear safety apparel whcre required. training, job planning, etc.that appear frcin time While the job Is underway, check from time to time in trade journals and other publications. to time to ensure that the work Is progressing There is a big need in the Navy for petty officers satisfactorily. Determine if the proper methods, who are skilled supervisors. So, consider the role materials, tools and equipment are being used. as supervisor a big chaBenge and endeavor to If a man is doing a job wrong, stop him and become proficient in all areas of the supervisor's point out what he is doing wrong. Then explain job_

466 477 Chapter 14 ADfilINISTRATION..111.

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17.84 Figure 14-1. Single Line Item Consumption/M4nagement Document (Manual); NAVSUP Form 1260.

PREPARING REQUISITIONS contain no more than nine line Items. DD Form 1149 has many uses. It is not necessary to fill As a crew leader, you must be able to prepare in all the blocks when this form is used as a requisitions, which are orders from one activity requisition. requesting material or service from another activity. The most common method of requisition-. In requisitioning material you will need to know ing involves the use of p'. inted forms which are about the Federal Supply Classification (FSC) designed to provide all necessary information system. Information on the FSC system and other for physical transfer of the material and ac- topics relating, to supply is given in Military counting requi re m ents. Requirements for Petty Officer 3 & 2, NAVPERS 10056-C. Two forms used for requisitioning materials are the Single Line Item Consumption/Manage- ment Document (Manual), NAVSUP Form 1250 TIMEKEEPING (fig. 14-1) and the Requisition and Invoice/Shipping Document, DD Form 1149 (fig. 14-2). Your duties may involve the posting of entries on time cards for both military and civilian As a crew leader, you are not usually required personnel. Thereto' o, you should know the types to make up the entire NAVSUP Form 1250; of inform ation callea for on time cards and under- however, you must list the item's stock number stand the importance of accuracy in labor report- (when available), quantity, and reference symbol ing. Here, we axe primarily interested in the labor or name of each item needed. This form (NAVSUP reporting system used in the battalion. You will Form 1250) is turned in to the expediter who will find, however, that the system employed at shore- check it over, completing the other information, based activities is einular to that used in the sign and then forward it to the Material Liaison battalion. Officer (MLO) or Supply Department for proc- In order to record and measure the number essing. of man-hours the unit spends on various functions, a labor accounting system is mandatory. This You are not likely to use DD Form 1149 system must permit the day-by-day accumulation very often. The items most frequently ordered of labor utilization data in sufficient detail and on DD Form 1149 are bulk fuels and lubricants. In a manner that allows ready compilation of This form is limited to a single page and must information required by the Operations Officer

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43,3 Pigure 14-2.Requisitioland Invoice/Shipping Document, DD Form 1149. Cnapter 1.1 ADMI N S l'HATION in the rnanagement of the manpower resources. During theplanningandschedulingof a Italso aidsinthe preparationofthe various construction project, each phase of the project reports to higher Authority. considered as direct labor is given an identifying code, usually by the Operations Department. While the system may vary slightly from -,ine For example, "clearing and grubbing of site" unit to another, they are so similar that the one may be assigned code R-15, "trenching" R-16, describedin this manual can be considered as and "pipe laying" R-17. Due to the many types being typical for ill units. ofconstruction projects encountered and dif- ferentoperationsinvolved,codesfordirect The unit in,.ist account for all labor expended labor reporting may vary widely from one activ- incarrying out assigned tasks and functions. ityto another. The crew leaderuses direct This accounting must include the work perform'A laborcodesin reporting the hours spent by by the reporting unit and, when applicable, work each member of his crew during each wont performedbycivilian labor and the military day on assigned construction tasks, personnel of other activities. Labor expenditures mulct be accumulated under a number of reporting Codes also tire used toreport time spent categories. This degree of reporting detailis by crew mem`Jers in the following categories: required to provide the management data neces- indire:2t labor, military operations and readi- sary to determine laIxir expenditures on project ness, disaster control operations, training, and work for calculation of statistical labor costs, overhead labor. You will find the codes shown and comparison of actual construction perfor- in figure 14-3 used at most activities to indicate mance with estimating standards. It also serves time spent in these categories. to determine the effectiveness of labor utilization in perform'ng administrative and support functions, both for internal unit management and for The crew leader's reportis submitted on adailylabordistributionreport form such developnylnit of planning standards by higher com- as that shown in figure 14-4. The report is pre- mand. pared by the crew leader for each phase of the For timekeeping and labor reportingpurposes, construction project that his crew is involved total labor is considered as being either in onewith, and immediately provides a breakdown by of two categories, i.e., productive or overhead. man-hours of the activities in the various labor LABOR codes for each man in the crew for any given PRODUCTIVE includesall labor that day on any given project. It should be reviewed directly or indirectly contributes to accomplish- at the company level by the Platoon Commander, ment of the unit's mission, includingconstruction theAssistant Company Commander, and the operations,rrilitaryoperations, and training. Comiaany Commander, and should be initialed Productive labor is accounted for in two cate- by the Company Commander before it is for- gories: direct and indirect labor. warded to the Operations Department. It will be tabulatedbythe Management Division of the 1. DIREI:T LABOR inclUdesalllabor ex- Operations Department, along with all of the pended directly on assigned construction tasks, daily labor distribution reports received from each company and department in the unit.It eitherinthefield, or in the shop, and that serves as the means which the Operations whichcontributesdirectlytothe completion Officeranalyzes the 1..Jor distribution of his of the end product. Direct labor must be reported total manpower resources for any given day, separately for each assiged construction item. and as feeder information for the preparation 2. IND:RECT LABORcomnrises labor re- of the monthly operations report, ana any other quired to support construction operations, but resource report., required of the unit. which does not produce an end product itself. Bear in mind that this informatirnust oe accurate and timely, and that each el in the OVERHEAD LABORisnotconsidered to company organization should lev 7'or an beproductive labor in thatitdoes not con- analysis of its own internal construct!on manage- tribute directly or indirectly to the end product. ment and performance, rather than having it Itincludesall labor that must be performed serve merely as a feeder report to the Operations regardless of the assigned mission. Officer.

469 481 CONSTRUCTION ELECTRICIAN 3 & 2

1MM.

PRODUCTIVE I.ABOR. Produt tise Lhor in.lude) 1.1bor that directly contributes to the accomplishment of the Naval Mobile Construction Battalion, including lion operations and readiness, diraste,: recovery operations, and trairiing.

DIRF.CT IABOR. This category includes all labor expended directly on assignedconstruction :asks, either in the fic)d or in the shop, ansi ich contributes directly to, the completion of the end product.

INDIRECT LABOR. This category comprises labor required to support constructionoperations, but whls.h does not produce in itself. Indirect labor reporting codes are as follows:

X01 Construction Equipment Maintenance, X04 Project Expediting (Shop X06 Project Material Support Repair and Records Planners) X07Tool and Spare Parts Issue X02 Operation and Engineering X05 Location Moving X08 Other X03 Project Super sision

!):ILITARY OPERATIONS AND READINESS. This category comprises all manpowerexpended in actual military operations, unit embarkation, and planning and preparations necessary to insureunit mil.tary and mobility readiness. Reporting codes are as follows:

MO1 Military Operations NI04 Unit Movement M06 Contingency M08 Mobility & Defense M02 Military Security M05 Mobility PreparationM07 Military Administrative Exercise M03 Embarkation Functions M09 Other

DISASTER CONTROL OPERATIONS

DO1 Disaster Control Operations D02 Disaster Control Exercise

TRAINING. This category includes attendance at service schools, factory: and industrialtraining courses, fleet type tr:ning, and short courses, military training, and organized training conducted within thcbattalion. Rep.rting codes are as follows:

TOI Technical Training T03 Disaster Control Training 105 Safet y Training T02 Military Training T04 Leadership Training T06 Training Administtation

OVERHEAD LABOR. This category inciudes labor which must be performer') regardlessof whether a mission is assigned, and which does not contribute to the ass:gned mission. Reporting codes arc asfollows:

YO1 Administrative & Personnel Y06Camp Upkeep & Repairs Y10 Personal Affairs Y02 Medical & Dental Department Y07 Security Yll Lost Time Y03 Navy Exchange and Special Services Y08 Leave & Liberty Y12 TAD not for unit Y04 Supply & Disbursing Y09 Sickcall, Dental & Y13 Other Y05 Commissary Hospitalization

133.417(54F) Figure 14-3. Subcategories of labor.

THE PERSONNEL READINESS Force, both active and reserve. This information CAPABILITY PROGRAM can be used by all levels of managementand supervision todetermine aunit'sreadiness The Personnel Readiness Capability Program Lapability by comparing it to actual or planned (PRCP) provides a standard means of identify- requirements. ing, collecting, processing, and utilizing infor- The maiority of PRCP information consists mation on all mern'lers of the Naval Constructionof an inventory of individual skills acquired

470 A.R2 Chapter 14 AD:.DNISTRATION through formal or on-the-job training. A rec- are collecting and passing along skill information ord of these skills, combined with other dataon yourself and your men. Ihwever, the in"tial fromtheservice record, such as expiration PRCP skillinventory will be based upon an of enlistment, rotation data, and so on, provides interview with your crew/squad leader or another a ready means of predicting future capabilities and senior petty officer of your rating. requirements. Some of these may be: Special PRCP Interviewer's Standards and Guides have been prepared to assist persons 1. Construction and military capabilities. conducting interviews. Each Gui,le contains a 2. Personnel, logistics, and training require- detailedexplanationof everyskill identified ments. in the PRCP. These definitions are now standard 3. Berthing, messing, :Ind housing require- throughout the entire Naval Construction Force, ments. and any man, regardless of duty assignment, can 4. Contingency requirements. turn to these standards and know what is expected in a given skill area. Tne most im:lortant Lispects of the Personnel During aninterview,itis imperative that Readiness Capability Program, at your level, youandyour men discuss your capabilities

1 CRFA, LEADER CREW.5/re CREW SIZE ITRANSFERS TIPSDATE IAree4c w r/ 0, _...JohNsoiL., Eo a '''' ':L C I iort

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54.309 Figure 14-4. Daily labor distribution report form.

471 483 'C Ii .OTC,\ 3 2

Openly and hohestly.lterne,nh-r,ifyou eYag- down Into thre? kind:,of comm'ttees:(1)the gerate,youmay hedepriv:ng yourselves Of saletpolicy coio!nitttc;(2)the supervisor's vaivahle:indneeded raini ng. Then, too, ton committee, and (3)rut equip:rio,it shop or crew may he tne one selected to do that special Oh comm Ptee. all on yonr own.Vill you he ready? The SAFETY POI.IC V COMM ITU E is (1wil!he the responsinflity of vc-u super- presided mei Ly the exe .utive officer. Its p chnary visors to provide you with the opportunity to purpose is to develop safety do;:t.ine and policy learnnewskills. This may be done through for the battalion. This occ.linittee reports to the trainin;-; or by assigning ycur team to variou.:, corn in:kndi ng officer, who must iipprove all changcs types of work whenever possihle. You can llelp in sa:ety pol!cy. by learning what is required in the PRCP imer. The SUPER \ISORS' \IlITTLF. is presided viewer's Standards and Guides for your rating; over h.; the hattalion'..k safety chief and is made then, as you and your men satisfy those 1.equite- up of safety supervisors assigned by company ments, you can report this to your PRCP co- commanders, proje.tofficers, or officers in ordinator. lie will then have the information added Aarge (OIC's) of detail. This committee provides to.;.our inventory of capabilities. dv iceping your a convenient foruLhrough which one crew can in- PRUP record current, you can avoid the un- form anothr3r of itc work ju.;.,codures, safety pre- pleasantness of attending training in areas yak, cautions, and safely suggestions received from are already proficient in. Like practical factors,crews orindividual.This committee sends itis primarily your responsibility to see thatits recom-nardations to the policy comm'ttee. this information iskept current and accural.e. The LQUIPMENT, or CREW COM- Afterall,youwillbethe first to feel that T is assigned as required. Alfa coanany you are qualified in a new skill. has an equipment safety comm;ttee presided over All PRCP information is ultimately stored by the "A" com7any chief. The other companies in a computer data bank. People who work withuse either the crew or shop committee, both of computers have developed a ve:ky r,..alistic say- which are usually :,resided over by the company ing: "Garbage in: Garbage out." In other words, or project safety supervisor. The main objective the accuracy of reports devised for the Per- of these committees is to propoc,e '....manges to the sonnel Readiness Capability Program will only battalion's safety policy, when required, tO limt- be as accurate as the information you provide. nate unsafe working conditions or prevent unsafe acts. Tnis committee is YOUR CONIACT for recommending safety improvements. In addition to I3ATTALION SAFETY ORGANIZATION the above, the equipment committee m ist review As a petty officer, you must be familiar with all vehicle accident reports, determine the cause the safety program at your activity. This is im- of the accidents, and make recommendations for portant since you cannot function effectively as corrective action. As a crew :eader, you can a petty officer unless you are aware of how exTect toserveasa member uf either an you fitinto the schema of safety. You should equipment crew, or shop safety committee. All know who (or what group) arbitrates and estab- three of these committees forward reports and lishes the safety policies and procedures you recommendations to the supervisor's safety com- must follow. You should qlso know who provides mittee. guidelines for safety training and supervision. Every naval mobile construction battalion (NMC.B) SAFETY CONTROL AND is required by the Naval Construction Force Safety REPORTING ORGANIZATION Manual to implement a formal safety organization. The Safety Control and Reporting Organization The NMCB's safety organization is composed follows the regular chain of command. As a crew of two elements as shown in figure 14-5: one leader, you will be held accountable for industrial to provide for the establishment of safety policy accidents involving personnel under your super- (view A), the other to provide for control and vision. Tne number and types of accidents will reporting (view B). be takeninto account by your supervisor in rating your ability to supervise. It is the direct SAFETY POLICY ORGANIZATION responsibility of each crew leader to: The policy organizationof a battalion as 1. Ensure that every mnn under his super- illustrated in figure 14-5, view A, is broken visionisthoroughlyfam'liarwith the trade

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CREW LEADEKS

B 8ATT4LiON SAFETY CONTROLAND REPORI-ING ORGANIZATION

73.350 Figure 14-5. Battalion safety policy organization. peoedures, techniques, rules, and "eguIations unsafe practices encountered by those under his applicable to the man's safe conduct and wark supervision, and carry out requests to a satis- performance, and to make surc the man has a factory conclusion. general understandingofall pertinent safety 4. In case of accident, getthe injured toproper regulations. medical care as quickly as possible. 2. Ensure that all subordinates make proper 5. Investigate all accidents involving his men, use of personal protective equipment and clothing determ;ne the causes (carelessness, thoughtless- and,if necessary, personally demonstrate its ness, negligence and so on are not acceptable). proper use. submit required written reports, and promptly 3. Personally direct or request from proper apply remedial measures in the form of on-the- authority the correction of unsafe conditions and job training of all subordinates simIlarly exposed, 473 iNs FRU:: riON I.FICTWIAy 3 &7 and remvt n h;ive ni.2rin.mentlY correLted ai the one you will have the most contact with. He ...!efectv,took.,:nater...1,4,rn.:L.11nory, or en- will help you get the training necessary for you ronin,. ,ting to the accident. and your crew. A major responsibility of the ilafetychiefisto ensure that the battalion's In it I in to a cFew safety program is enforced. If you have a ques- :c1 :15t.responsible tionon safety, he should he able to find the for ,..;111"..ing out .-afe work practices as directed answer.It'simportant to remember that the by higher authority. Itis your responsibility to safety chief, the safety officer or any other per- repoyt to you:. supervisor any unsafe sonin a position of authority has the power to piitit n )t lit;ons you ot)serve. To aid voa stop a job when he has determined anunsafe con- in carrying .mutyour responsibilities, you will dition existsuntil such condition is corrected. receive .t5:FiFta:Ictfrowyoursupervisors, throughspecialtraining, :1Ndbypirlicipation Tne SAFE CY SUPERVISOR is normally a first Itm staadup safety nr-.etings.Itis also imprtant class petty officer, who is assigned this collateral to note that .11.1 HANDS a:e encour::ged to suhm't duty by his company commander, project officer, hie.Lsthiough the s;:fety policy chain of or detail 0:C. He directs, in an advisory capacity, umand. theriafety program of the con-many project or detail. His responsibilities include the following: S.11.1..1Y 1. Indoctrination of new men. von snc,ess in carrying Out your responsi- 2. The assembling, coordinating, and dissemi- bilities in the safety program, you must know who nation of information for use of crew leaders in is respwsible for wtstt in regard to safety. The their Standup Safety Meeting. three key jobs in a battalion's safety program are: 3. A-jvlsing the company corn nander/project safety .o`.ficer, safety chief, and safety supervisor. officer/detail OIC concerning the safety program, 'FileSA FF )FFIc E Itinabattalion is and reoom nending changes required to eliminate normally the Operations Officer (S3). He is re- unsafe work practices and hazardous conditions. sponsible for ensuring that the battalion's safety 4. Com2ilingaccidentstatisticsforhis program meets the requirements of the Naval company/project/team and analysis corrmaring Construction Force Safety NI mual and its refer- crew leaders. Records should be kept on a monthly ences. The Safety Officerisresponsible for: basis and all crew leaders informed as to their standing. 1. Providing continuous safety inspection of 5. Reviewing personal protective equipment all shops and jobsites. requirementsofthe men and advising crew 2. Maintainingasafety reference library. leaders on the correct type of safety equipment 3. Providing assistance inthe training of to use, where to obtain it, how to use it, and so safety supervisors and crew leaders. on. 4. Ensuring accurate accident reporting. 6. Assuring that crew leaders are provided 5. Ordering any safety equipment requiredfor withsufficientsafetyinformation for use in a shop or project w:ien such equipment is not instructing men in their crew. a normal allowance it,un. 7. Reviewing all accident reports submitted to the Safety Office, appraising the quality of the The SAFETY CHIEF is normally an F-7 or report, and assisting the company commander/ E-8 andisassigned full-time to safety. He project officer/detail OIC in making constructive assists the safety officer in all his duties and is use of the information contained therein.

Q0 474 CHAPTER 15 BASIC ELECTRONIC COMPONENTS AND CIRCUITS

Although there have been many attc'mpts to RESISTORS AND CAPACITORS expl:dn the difference between the meanings of the terins "electricity" and "electronics," they As you already know, curl ent passing through are more alike than they are different. For a. resistor generates heat. If too much heat is instance,electricity and electronics are bothgenerated, the resistor will be damaged. Wire concerned with the use of electricity to operate inthe wound resistor will become open, or equipment. The fiehi of electricityisusually some of the carbon in the composition resistor concernedwithmagnets, generators, motors, will burn away, thus changing the resistor value. lights, and heaters; the field of electronics is concerned with the use of electricity in radio, RESISTOR RATINGS television, radar, telephone, and other equipment in which electron tubes or transistors are needed. The current-carrying capacity of a resistor is rated according to the amount of heat it can Current and voltage cannot tell the difference safely release in a given amount of time. There- between an electrical circuit and an electronic fore, a resistor cannot be used in a circuit where circuit.The components that have been builtcurrem causes heat to build up faster than the into the circuit determine how the current and resistor can dissipate it. voltage willbe used to make the electrical or Since heat is a form of energy, the heat- electronicequipment work. One of the most releasingrateof a resistor is measured in recently developed electronic: components is the energy units called watts. A composition resistor transistor.Transistorsare constructed from is usually rated at 1/3, 1/2, 1 or 2 watts. The solid materials, classifiedtlizi, semiconductors, power ratings of wirewound resistors are larger. whoseresistance tothe flow of electrons is between that of insulators and conductors. RESISTOR TOLERANCES A resistor rarely measures the exact number Any circuit can be thought of in terms of the of ohms specified by its label or color codes. effects that resistors, capacitors, and inductors The amount it varies is called tolerance. Resis- (coils) have on current or voltage. The effecttor tolerance is given as a percentage value thataresistor has on current or voltageis which indicates the amount that a resistor may measured in terms of its resistance; the effect vary above or below its specified value. Standard ofa capacitoris measured in terms of its tolerancesforcompositionresistorsare5, capacitance; and the effect of a coil is measured 10 and 20 percent. Wirewound resistors may in terms of its inductance. T ie effect that eachhave tolerancesas lowas1 or 2 percent. of Laese measurable properties has on current Take a 1,000-ohm resistor with 10 percent or voltage depends on whether the current is tolerance as an example. Ten percent of 1,000 direct or alternating and, if alternating, how fast is100 ohms. Because of the tolerance factor, the current or voltage is changing (frequency).this resistor will measure somewhere between AsaConstructionElectrician,therefore, 100 ohms above and 100 ohms below the labeled youwillfindit necessary to test resistors, value of 1,000 ohms. The range is from 900 to capacitors,and inductors in an electrical or 1,100 ohms. electroniccircuit by measuring or otherwise Resistor tolerance is not an indication of determining the effects of their preperties onpoor manufacturing. Closer tolerances can be the current or voltage of the circuit. achieved, but at greater expense. A resistor with

475 487 CONSTRUCTION ELECTRICIAN 3 812 a20 percent tolerance will cost. less than one that follow the first two digits. The fourth band with a 10 percent tolerance. indicates the tolerance and is either gold for 5 percent, or silver for 10 percent. RESISTOR COLOR CODES Always use a replacement resistor with a wattage rating equal tc or higher than that of A wirewound resistor is usually marked with the originalnever lower. Otherwise, the re- itsvalue in ohms and tolerance in percentage. placement will burn out. You can use thephysical A color code is used for carbon or composition size of the resistor as a guide, if the replacement resistors. For several years, resistance values is the same type (carbon, metallized, or wire- have been coded by three colored bands painted wound) as the original. The replacement should around the body of the resistor. If the tolerancebe the same physical size or larger. is either 5 or 10 percent, a fourth color band is used; if 20 percent there is no fourth color band. CAPACITOR COLOR CODING Positions of the bands are as shown in fiffure 15-1. The value of many capacitors is printed on The first two color bands(:1)and :0 $ of figure them, but some use a color-coded system. The 15-1) Indicate the fi rst two digits in the colors and color code is the same as that foi resistors, but numbers table (table 15-1). The third band iE the methods of mirking the c-citors differ. the multiplier and indicates the number of zeros The method for fixeil mica ca;-.itors is shown in figure 15-2. A black dot in the upper left corner signifies that the capacitor has a mica dielectric. The -01sT DIGIT center dot in the upper row indicates the first -(j) 2ND DIGIT significant figure, and the upper right dot indicates the second significant figure of the capacitance -4MULTIPLIER value in picofarads (pF).The right dot in the -4) TOLERANCE (PERCENT) lower row indicates the decimal multiplier or number of zeros to be added to the right of the p!,' 4::* N two significant figures. The center dot (lower / W.N row) specifies the tolerance, which is thepossible , deviation of the actual capacitor value from that given by its dot markings. The left dot on the lower row deals with the temperature coefficient 20.373:. 174 and applications. As nn example, take a capacitor Figure 15-1. Color-coded resistor. with upper row dots colored black, red, and green (reading fromleftto right according to the directional indicator). This is a mica capacitor; the significant figures are 2 and 5. Suppose the Table 15-1. Colors and Numbers Used to Code lower row of dots (reading from right to left) Resistors are brown, red, and red. The brown dot requires TOLERANCE the addition of one zero to the value of 25, resulting COLOR DIGITDIGITMULTIPLIER (percent) in 250 pF.The red center dot indicates that the actual capacitor value may vary from 250

Black 0 0 1 pFby plus or minus 2 percent. The left red

Brown 1 1 10 dot means a bypass or silver mica capacitor. Red 2 2 100 Some mica capacitors have only three dots, indi- Orange 3 3 1,000 cating the first and second significant figures and Yellow 4 4 10,000 the multiplier. Their tolerance is 20 percent and Green 5 5 100,000 their rating is 500 volts. Try reading some of the Blue 6 6 1,000,000 capacitor values you see in electronic devices Violet 7 7 10,000,000 when they are exposed to view.Learning to read Gray 8 8 100,000,000 capacitor values is a matter of practice, much like White 9 9 1,000,000,000 reading resistor values. There are other types of Gold .1 5 capacitors whose identification codes vary. See Silver .01 10 appendix IV of Basic Electricity,NAVTRA 10086-B No color fortheexplanationofthese codes.Also see 20 appendix II of this manual for a list of prefixes 20.373:.374 which indicate multiples of basic measuringunits. 476 438 .;liapter 15 BASIC ELECTRONIC COM.)ONENTS AND CIRCUITS

BLACK DOT IDENTIFIES CAPACITANCE DIRECTIONAL MICA CAPACITOR INDICATORS COLOR -OLERANCE CHARACT ER- SIGNIFICANT DECIMAL ISTIC X SIGNI FICANT 4. 1ST FIGURE MULTIPLIER FIGURESOF CAPACITANCE 2NDIN pi BLACK 0 1 20 PERCENT A CHARACTERISTIC BROW N 1 10 B RED 2 100 2 PERCENT C CAPACITANCE TOLERANCE DECIMAL MULTIPLIER ORANGE 3 1,000 D CHARACT ERISTICS YELLOW 4 E A - ORDINARY MICA BYPASS GREEN 5 F B - SAME AS A-LOW LOSS CASE BLUE 6 G C - BYPASS OR SILVER MILA (1200 PARTS MILLION C) VIOLET 7 D - SILVER MICA (100 PARTS/MILLION C) GRAY 8 E - SILVER MICA (0 TO 4100 PARTS/ MILLION/C) WHIT E 9 GOLD 0.1 5 PERCENT F - SILVER MICA (0 TO 4 50 PARTS/MILLION/C) SILVER 0.01 10 PERCENT G - SILVER MICA (0 TO - 50 PARTS/MILLION/C)

20.376(71) Figure 15-2. Color code for fixed mica capacitors.

CIRCUIT TESTING voltage is developed across the input of indicator tube Vl. Capacitance, inductance, and resistance are In the basic Wheatstone bridge circuit using measured precisely by alternating currentd-c voltages and simple resistances, the balance bridges. These bridges are composed of capa- is obtained when the voltage drops are equal citors, inductors, and resistors in a wide variety across the ratio arms. In the a-c capacity bridge, ofcombinations.The bridges operate on the itisinsufficientto have equality of voltage principle of the Wheatstone bridge, in which an drops in the ratio arms. The phase angle between unknown resistance is balanced against known current and voltage in the two arms containing resistances. The unknown resistance is calcuhted the capacitors also must be equal in order to in terms of the known resistance after the bridge obtain a balance. When a balance is obtained, isbalanced. One typeof capacitance bridgethe current is equal on both sides of the bridge circuit appears in simplified schematic form incircuit. figure15-3. When the bridgeisbalanced by The capacitance-inductance-resistance bridge adjusting thetwo variable resistors, no a-c of figure 15-4 not only measures capacitance, resistance, and inductance values, but is also used for special tests, such as the turns ratio of transformers and capacitance quality tests. Itis a self-contained instrument, except for a source of line power. It has its own source of 1000-Hz bridge current with a sensitive bridge balance indicator, an adjustable source of direct current for electrolytic capacitor and insulation resistance testing, and a meter with suitable ranges for leakage current tests on electrolytic capacitors.

TRANSFORMER TESTING Transformers crdinarily are tested by check- 20.344 ing forshorts, measuring resistance of the Figure 15-3.-- Simplified schematic of capacity individual windings, and measuring voltage outputs checker. of each winding. The technical manual for the 477 489 CONSTRUCTION ELECTRICIAN 3 S.: 2

C'S BLACK (COMMON) RED

)BLAC?-YELLOW HIGHRED-YELLOW VOLTAGE

RED BLACK-RED i YELLOW RECTIFIEi TAPPED YELLOW-BLUE FILAMEN. INSTRUCT.ON PRIMARY BLACK YELLOW BOOK GREEN

PRIMARY EN-YELLOW FILAMENT GREEN NO.1 BLACK

POWE R CORD aND PLUG ROWN-YELLOW FILAMENT (STOWE DI NO.2 44.Q

SLATE _YELLOWHLAMENT NO.3 SLATE

20.379(71) F igu re 15-5.Color coding of small powe r transformer leads.

other filament windings, they may be green, brown, or slate. The tapped wire is yellow In STRAP combination with one of the colors just named; RINGS that is, green and yellow, brown and yellow, or CARRYING HANDLE slate and yellow. An easy way to check a suspected malfunctioning transformer isto measure its voltage 20.345 output. Use a voltmeter to measure across the Figure 15-4. Capacitanee-inductance-resistance proper terminals, and compare the reading ob- bridge, type ZM-11/U. tained withthe proper voltage given in the manufacturer's manual. If only one reading is in error, then only that winding is at fault. If equipment that contains a transformer ci3scribes allreadingsare in error, the trouble could the transformer, specifies the terminals to testpossibly be a high- or low-input voltage. Conse- for each winding, and tells what each measurement quently, always measure the input voltage as well should be. Transformers, of the size used in as the output voltage. electronic equipment, usually are color-coded as If the voltage measures high or low at any shown in figure 15-5. In an untapped primar theoutput windings,thenextstep is to both leads are black. If the primary is tappe ,-neasure the resistance of each winding. Make one lead is common and is colored blnk',.; the :re the connections to the terminals are dis- tap lead is black and yellow, and the oc'r lead onnected first. Power to the equipment must be is black and red. secured prior to disconnecting a transfon ^r On the transformer secondary,hu high- Once the leads are free, measure the resista.xe voltage winding has two red leads, ifntappecl, across each winding with an ohmmeter set to or two red leads and a yellow and red the proper scale. Check each winding carefully, iftapped. On the rectifier filament wirvilugs, including any center taps. Next, set the ohmmeter yellow leads are used across the entire winding, toahigh scale and test for shorts between and the tap lead is yellow and blue. If there are windings and between windings and ground.

478 490 Chapter 15 H -1SIC E 1.IcrftDc coM PONE NTS AND :::111CUITS

If no faults are indicated by the voltage or ELECTRON TUHE DIODS resistance readings, or by the tests for shorts, assume that the transformer is in proper oper- The major components of an electron tube ating condition. Then reconnect it in the circuit. diode are two polarixed electrodes called anode Ifa replacement isrequired, use only the and cathode. These electrodes are mounted inside one recommended by the manufacturer's manual. an evacuated envelope and fitted into an insulated Always test for shorts and check the resistance base. Cathodes are made of materials that emit ofa new transformer before installingitin electrons rapidly and easily; anode materials do the circuit. not. When heated, the cathode immediately starts IDENTIFICATION OF CHASSIS WIRING to emit electrons. Although the emission is low, you can measure the potential between the anode Standard colors used in chassis wiring for the and cathode (before an external potential differ- purpose of circuit identification of the equipment enceisapplied between them) by comparing are given beluw. For electrical and electronic the stable or reference state of the anode material symbols, refer to Graphic Symbols for Electrical to `Ile electron emission from the cathode mate- andElectronicDiagrams (American National rial. Standards Institute) Y32,2, March 1971. At the instant a difference of potential is applied externally between the anode and the cathode, an Ci rcuits Colors electric field exists between them. Under the direct influence of the electric field, electrons Grounds, grounded elements Black flow toward the anode, and continue to flow as and returns long as the field exists. The intensity of current Heaters or filaments, off B rown flowisdirectly proportional to the potential ground difference between the cathode and anode. Power supply H plus Red Since anode material does not tend to emit Screen grids Orange electrons, current flow from the anode to cathode Cathodes Yellow does not normally occur. Hence, the electrontube Control grids Green diode acts as a one-way valve or switch. Plates Blue Shoulda differenceofpotential(highin Power supply, minus Violet (Purple) value and reversed in polarity) be placed across A-c power lines Gray an eletron tube diode, the dielectric material Miscellaneous, above or White between anode and cathode may break down, below ground returns, resultinginan excessive quantity of reverse AVC, and so forth current flow. The breakdown of dielectric material in an electron tube may be closely compared to the breakdown of a capacitor's dielectric. Each DIODES is due to excessive electric field strength or extraordi:--arily high difference of potential across A diodeisan electrically operated deviceelements of the device. In each case of breakdown that has two elements or electrodes. When a there exists some physical rnt,,..ns of conducting voltage of the proper polarity is applied to thecurrent between theelementE.In soapacitors electrodes,currentflowseasilythrough the this means is the dielectric; in oIectron tubes, diode. Reversing the polarity, however, makes it is a form of dielectric. Specifically, in electron current flow difficult or prevents it altogether.tubes, it is the evacuated envelope which is not There are two general classes of diodes; an absolute void or a perfect vacuum. electron tube or solid state. The electrodes of an electron tube diode are enclosed in a glass Operation or metal envelope. A solid state diode is made of Since the evacuated envelope of an electron two dissimilar metals or two different semi- tube diode is not a perfect vacuum, some matter conductors.Depending on the polarity of the remains in the existing space. When the cathode applied voltage, current flows or does not flow isheated,it begins to emit electrons. Upon across the junction formed by the metals or the application of an electric field, these electrons semiconductors. A semiconductor diode is made are directed through the so-called vacuum to of the same materials as those in transistors the anode, through the source, and back to the usually germanium or silicon. cathode.

479 491 ClIN ,.711(IN fiIC:AN 3 & 2

In mie 5 lectr;):;rlibediodesare an:1-csourceism:e ,toheat the filament, const:.uctedw:thout me:ms torheating the an andesiied hum may lieHitroduced into the cathode.Called cold ;:rithode dicdes, they work ircuit. The hum is espEiall1; evident in low On the principleth,ita difference of potenti:d level signal circuits. plaLed :icross the anode and cathode creates an relatively constant rate of emission under electriefield.,sincecathodematerialemits mildlyfluctuatingcurrentconditions may be electrons, . :Lestarted on their path toontained with an indi ictiv heated cathode. This the anode, _Indes are filled with an inert type of cathodeisinthe form of a cylinder; sucTh reon, argon, krypton, or xenon. in its center is a twisted, electrically insulated When electrons flowinthis gas,itbecomes wi re, called the heater. The cathode is main- ionized,ot eleythcall:,charged.As current tainedat toe correct temperature by heat ra- flow through an inert gas diode increases, more diated frjm the heater. The emitting material energy is dissipated in loniz.ing the gas. Within inthis type of cathode remains at a relatively the limits established by the quantity and type constant temperature, even with an a-c heater. of gas, the diode will maintain a ,:mistant voltage Figure 15-7illustrates the schematic symbols drop across its elements, though current flow for directly and indirectly heated cathodes. through the7n varies. The cathode is normally placed in the center Since some energy is dissipated in the form of the tube structure, and is surrounded by the of heat whi le a Told cathode electron tube operates, anode, also called the plate. Figure 15-8 shows the cathode temperature does rise, 'flierefore,cutaway views of two types of diodes. One has theterm ,yithodc''isnot,'omplctely a directly heated cathode or filament, the other accurateand onlyindicates that the electron tube la(.,ks a cathode heating element. Construction Cathodes are l.eatedin one of two ways directly or indirectly. In a di retly heated cathode, the current that furnishes the heat flows directly through the emitting material. In an indirectly DIRECTLY INDIRECTLY heated cathode, the heating current flows through HEATED HEATED aheatingfilament and transfers heat to the emitting material (cathode). Fig-ure 15-6 illustrates the construction and methods of heating 179.141 the two types of cathodes. igu re 15-7. Schematic symbols for directly and The di recAy heated cathode, commcnly called indirectly heated cathodes. a filament, is fairly efficient and ean emit large amounts of energy. flowerer, due to the small mass of the filament w:re, the filament temperature fluctuates with changes in current flow. If

SUPPORT -OXIDE-COATED EMITTER SLEEVE --FILAMENT (INDIRECTL( HEATED CATHODE) (DIRECTLY- HEATED CATHODE; HEATER FILAMENT

A FILAMENT CATHODE HEATER DATHODE 13.21 179.142 Figure 15-6. Methods of heating the cathodes of Figure 15-8. Cutaway views of directly and in- electron tubes. directly heated diodes.

480

A 11 Chapter 15 BASIC ELECTRONIC COMPONENTS AND CIRCUITS an indirectly heated cathode. (The heater of the indirectly heated cathode does not count as an element of the diode.) The plate material, besides GLASS ENVELOPE not tending to emit electrons, must be able to dissipate the heat generated by electrons striking the plate. The schematic symbols for diode tubes are shown in figure 15-9. In some cases, two or ENTS more diodes are included in the same envelope to conserve space. A tube which contains two plates and one or two cathodes is called a duo- diode or twin diode. Figure 15-10 illustrates the construction and schematic symbols of duo- diode electron tubes. As a rule, electron tubes are nuL expected tolastaslong as resistors, capacitors, or other circuit components. This is due, in large part, to wearing out or breaking down of the BASE filament or heater. To make it easy to remove and replace a tube, the base of the tube (figure 15-10) is constructed in the form of a plug, which fitsinto a socket on the chassis. The PINS electrical connections between the tube elements and the circuit are completed through the plug terminals, called pins. There are various types of tube bases, con- tainingdifferent numbers and sizes of pins. Each type of tube base has a guide or key to prevent the tube from being plugged into the socket improperly. To make circuit tracing easy, the tube pins are assigned numbers. At the BOTTOM of the tube or socket, the pins are numbered in a clockwise direction, beginning 4.140(20C) witn No. 1 at the key or guide. The pin numbering Figure 15-10. Construction and schematicym- systems for several types of tubes are shown tl duo-dlodes. in figure 15-11.

Ratings 3 Each diodehascertainvoltage,current, and power ratings. By definition, a rating is 5 the limiting value which must not be exceeded N .7).---- 6 (*) () to prevent permanent damage to a device, such 4 PRONG 30 C 6 PRONG

4 PLAY,. PLATE ..;."-, 0 0 x c0 t 1 KEY' o 0 CATHODE 2 (° .) 6 OCTAL ? 0 0 Ii FILAMENT PILAIAENT 0

7 PIN 9 PIN DIRECTLY HEATED INDIRECTLY HEATED ------.MINIATURE MINIATURE

4.140 4.141 Figure 16-9. Schematic symbols used to repro- Figure 16-11. Pin numbering syntems for nay- sent diode tubes. era1 tube types.

4111 4 9 CONSTRUCTIO;s: ELEC FRICIAN 3 & 2 as the diode. The filament or heater voltage cathodeonlyduringtheperiods whenitis and current values must be correct for proper positive. operation of an electron tube. If heater current Fig-ire16-12, view A, shows a diode in a istoo low, the cathode will not emit enough half-waverectifiercircuitora circuit that electrons. Too much heater or filament current rectifies only one-half of the a-c cycle. The may reduce the life of the tube or destroy the transformer steps down the voltage to provide heater or filament. filament voltage for the diode and heater voltage. Other important diode electron tube ratingf, Alternatiug current flows through the secondary a re: winding; the output of the circuit is pulsating directcurrent. When theplate of the diode PLATE DISSIPATION the maximum average in this circuit is positive, it attracts electrons power, in the form of heat, which the plate may from the filament and current flows through the safely dissipate. tube. Electrons travel from the plate through MrAIM UM AVERAGE CURRENTthe highest the transformer and return to the filament by average platecurrent which may be handled way a the load resistor. The filament then continuously, based on the tube's permissiblebecomes the positive terminal fort!-e power plate dissipation. supply; the transformer lead becomes the negative MAXIMUM PEAK -.PLATE CURRENT the terminal. As the alternating current changes highest instantaneous plate current that a tube direction of electron flow, the plate becomes cansafelycarryinthe direction of normal negative and no current flows through the diode. current flow. Sincecurrent flows through the diode diving PEAK INVERSE VOLTAGE (PIV) the highest hall of the a-c cycle->rtly,a pulsating d-c is instantaneous plate voltage which the tube can produced. This cur. ent can be smoothed out withstand, acting in a direction opposite to that bymeans ofafill, r which enables current in which the tube is designed to pass cu rrent (plate toflow whentherectifieris not operating. negativecathode posRive). For a more constant flow of current, both DIODE !mull FT Efts halves of the a-c cycle are rectified. In this case,you have a full-wave rectifying circuit The electron tube diode is a rectifier; that thathastwo diodes or one twin diode. The device for converting alternating current high-voltagesecondary of the transformer is to direct current.Iternating current constantly tappedinthe center. One plate goes to one reverses direction as it flows through a wire. side of the secondary; the other p, 'teto the Eachtime the current reverses direction,it oppositesideofthesecondary.(Seefigure alternately carries electrons to the anode, making 15-12, view 13.) it negative, and away from the anode, making it When the plate of diode VI is positive, it positive. The anode attracts electrons from the pulls electrons from the filament and current

LI Y (LOAD) AC SUPPLY ifftramT R (LOAD) CI

IIAI FWAVE tILL WAVE

20.37:.40.1 Figure 16-12.Election tube rectifier ell(

)'1 Chapter15BASIC ELECTRONIC COMPONENTS AND CIRCUITS flows through V1 to the plate and out throughelectrons. Where an electron escapes from its the center tap of the transformer. As the alter- atom, a hole isleft inits place. The loss of nating current starts to flow in the other direc- theelectron and the appearance of the hole tion, the plate of diode V1 becomes negativeconverts the neutral atom into a positive ion. and that of diode V2 becomes positive. Electrons Thus, the hole is said to have a positive charge are now attracted to the plate of 112. Currentthat is equal and opposite to the negative charge flows through V2 to the plate and out through of the free electron. the center tap of the transformer. Electron flow When a hole appears in an atom, an electron through the center tap is always in the same from a neighboring atom may move in to fill this direction.Bothhalvesofthe a-c cycle arehole, leaving a hole in its place. Thus, a hole rectified and current flows all the time. moves from the first atom to the second atom justasafreeelectron moves, except that SOLID STATE DIODES the hole carries a positive charge instead of a negative charge. A rise in temperature or the Conductors are substances made up of atoms presenceofan electric field can force free whose outer-orbit electrons are loosely bound.electrons to move toward a positive pole. As At ordinaryroom temperature, enough heatfree electrons move toward the positive pole, energy is applied to the atoms to permit large holes move toward the negative pole. numbers oftheseelectronstobeliberated In a crystal of pure germanium, the atoms (free electrons), and to drift aimlessly aboutarrange themselves in a geometric pattern, each from one atom to another. If a voltage is applied atom beingrelatively far from its neighbor. to the end of a conductor, free electrons will Though the crystal is a three-dimensional strvc- stream to the positive side as other electrons ture, figure15-13shows two dimensions onl.f. enter from the negative end. It is in this wayThe two parallel lines linking each germanium that current flowsthroughaconductor. As atom (Ge) to iLneighbor represents a double- carriers of electricity, the electrons move from valence bond made up of one valence electron the negative to the positive side of the conductor. from each atom. Each germanium atom is linked In an insulator, on the other hand, the outer- up with four other atoms, thus accountingfor its orbit electrons are tightly bound and there are few free electrons. As a result, little current will flow when a voltage is applied to the end of the insulator.If the voltage is high enough to rupture the insulator, however, current will flow, which may beinthe form of an arc. There are solid substances, known as semiconductors, whose outer-orbit electrons are not loosely bound, as in conductors, or tightly bound, as in insulators. .Two examples are germanium and silicon.If a voltage is applied to a semiconductor, current will flow, but not as readily as in a conductor. Atomic Theory The germanium atom has a nucleus of32 protons and32orbiting electrons arranged in fourconcentricshells or orbits.The three shellsclosestto the nucleus are completely filledwith 28electrons, the outermost shell containing the remaining 4 electrons. The electrons of the outermost shell are called the valence electrons; they determine the chemical and electrical properties of the atom. Sincethe outermost electrons are loosely bound to the nucleus at ordinary room tempera- 73.372 ture, many of them escape and wander as free Figure 15-13.Germanium crystal.

483 495 CONSTRUCTION ELECTRICIAN 3 & 2 four valence electrons. When an electron escapes from one of the double valence bonds, it leaves a single-valence bond and a hole. The number of free electrons in a germanium crystalcan beincreased by adding a small amount ofan impurit: ,such as arsenic. An atom of arsenic has five valence electrons. It replaces one of the germanium atoms in the FREE crystal, combining with its four neighbors and ELECTRON leaving one of its electrons free, as shown in figure 15-14, view A. Such a germanium crystal is called a N-(negative) type. Similarly, the number of holes ina germanium crystalcanbeincreased by adding a small amount of an impurity, such as boron. A boron atom has three valence electrons. When it replaces oneofthe germanium atoms in the crystal, ARSENIC the boron atom forms double-valence bonds with ATOM GERMANIUM three of its germanium neighl-%Drs. With its fourth ATOM neighbor,itforms a single-valence bona and leaves a hole for the missing electron as shown infigure15-14,view13.Stich a germanium crystal is called a P-(positive) type. The Crystal Diode In view A of figure 15-15,a P-type germanium c rystal joins an N-type germanium crystal to form a P-N junction diode. Each N-P type of crystal contains a number of free electrons (indicated by -) and 'an equal number of holes (indicated by +). The N-type crystal, however, has many more free electrons intr oducerl bythef ve-valence impurity; the P-type crystal, on the other hand, has many more holes introduced by the three- BORON GERMANIUM valence impurity. With a battery connected as ATOM AIG!A shown in figure 15-15, view 13 (positive lead connected to the P-type crystal and negative lead to the N-type crystal) all the free electrons tend to move toward the positive lead and all the holes toward the negative lead. Thus most of the free electrons and holes tend to move toward the junction between the HOLE two crystals. Because opposite charges attract, the electrons and holes rush toward each other and recombine as a free electron drops into a hole.The effect of the applied voltageisto produce more free electrons in the N-type crystal and more holes in the P-type crystal. Hence, thereisa continuous movement of electrons and holes through the crystals, creating a rela- tivel,,gh current flow through the entire circuit 11.R indleated by the arrows. When applied as shown in figure 15-15, view A, the voltage is said to be in the forward direction. 73.373 Now suppose the battery is reversed as shownFigure 15-14. (A) Structure of N-type,:rystal; in figure 15-15, view C. Again the free electrons (B) Structure of P-type crystal.

484

4 9 6 Chapter 15BASIC ELECTRONIC COMPONENTS AND CIRCUITS

flow toward the positive lead and the holes flow toward the negative lead. But since there are relatively few electrons and holes at the junction of the crystal, the flow of current across the junction is small and so is the current flow in the circuit. When applied as shown in figure 15-15, view C, the voltage is said to be in the reverse, + or nonconducting, direction. A + If a s( me of alternating current is applied to the cryf..tL.ls connected in series with a load, the,)LageDr one-half cycle will be in the f( ,-(4dirt.C.ion(figure 15-16, view A) and cui.ent will",Ai through the circuit. During tho ry.xt Aalf-cyel?, the voltage will be in the revel d:re,-...tion (figure 15-16, view B) and no current will flow. This is how an N-P junction diode rectifies alternating current just as the electron-tube diode does.

CRYSTALS

ALTERNATING VOLTAGE SOURCE LOAD

CRYSTALS

cipALTERNATING VOLTAGE SOURCE LOAD I

73.374 Figure 15-15. (A) Distribution of free electmns and holes when N-type and P-type crystals are 73.375 joined together;(I3) Distribution of free elec- Figure 15-16, The junction diode as a rectifier; trons and holes when voltage is applied in for- (A)Voltageapplied inforward direction. warddirection; (C) Distributionof free Arrows indicate direction of current flow; (B) electrons and holes when voltage is applied in Voltage applied in reverse direction. There is reverse flirection. no current flow. 485 497 CONSTRUCTION ELECTRICIAN 3 & 2

T ANSISTORS some of them combine with the holes in the P-type crystal.If this crystal were made thin Infigure15-17, a thin P-type crystal is enough,nearly all the electrons entering the sandwiched between two N-type crystals. The emitter would be attracted to the positive collector emitter terminalisonthe left-hand N-type terminal and flow through the external collector crystal,thecollector terminal on the othercircuit to battery B. That is, a flow of current N-type crystal, and the base terminal on the in the emitter circuit produces almost the same P-type crystal. The junction between the left- flow of current in the collector circuit. However, hand N-type crystal and the P-type crystal is since the Impedance (Z) of the emitter circuit the emitter junction; the one between the right- is low and that of the collector circuit is high, hand N-type crystal and the P-type crystal is the the power (12 x Z) is greater in the collector collector junction. The entire sandwich with its circuit than in the emitter circuit. This explains terminals is a junction transistor. The junction how thejunction transistor acts as a power transistor consistsof a single unit with the amplifiera device that increases the input signal three distinct regions or layers being doped with without changingitscharacteristicsagreat controlled amounts of impurities. The schematic deal.To indicatetheobtainable increase in symbol for a transistor is also shown in figure power, or gain (Ic), the impedance of the emitter 15-17. circuit may be as low as 25 ohms, whereas Notethatthevoltage frombattery A isthe impedance of the collector circuit may be applied in the forward direction, relative to the several megohms. emitterjunction. Thus the impedance of this The basicamplifyingcircuit is shown in junction is low. On the other hand, the voltage figure 15-18. Assume that the incoming signal of battery B is applied in the reverse direction isin the form of an alternating voltage. When relativetothecollectorjunction. Therefore connected into the emitter circuit, the signal its impedance is high. As a result, electronssource alternately adds to or subtracts from flow ieadily from the emitter to the base, where thevoltage of battery A. Hence, the current flow through the low-impedance emitter circuit is respectively larger or smaller. Accordingly, a larger or smaller current flows through the high-impedance collector circuit (which contains the load in series). As explained previously, a low power input to the emitter circuit produces EMI T TER COLL ECTOR a large power output at the load in the collector circuit. The transistor is calledanN-P-N junction transistor because of the arrangement of the N- and P-type crystals. Itispossibletoform a P-N-P junction BASE transistor by sandwiching the N-type crystal EMITTER COLLECTOR between two P-type crystals. Since the relative JUNCTION JUNCTION

EMITTER - ---COLLECTOR EMITTER COLLECTOR

INeASE P N

ySIGNAL A SE 11iIII;-- (%) SDURCE FAITI

73.376 73,375 1.1);ure 15-18. N-P-N junctiontransistor used Figure 15-17. Basic junction transistor circuit. as amplifier.

436 498 Chapter 15BASIC ELECTRONIC COMPONENTS AND CIRCUITS positions of the crystals are reversed in the of identifying transistor leads or terminals, it P-N-P transistor, the polarities of the battery is quite possible to mistake one lead for another. must be reversed; also,i istead of electrons, In figure 15-20, the bases of four pairs of holes flow from the emitter to the negatively transistors are shown. Each pair, while similar charged collector terminal. Figure 15-19 shows in appearance, has different elements connected the differences in the schematic symbols for the totheleads.For thetop transistor of the N-P-N and P-N-P transistors. left-handpair,theleadsare emitter, base, Transistors can carry out many of the functions collector, reading from left toright;for the of electron tubes. Transistors have certain ad- bottom transistor of this pair, the leads are vantages :n that they consume less power, last emitter, collector, and base. If one of these tran- longer, can take rough handling, and can be sistors was connected into a circuit as a replace- built much smaller and more compactly. Also, ment for the other, the circuit would not function transistors have no filaments, so practically no properly or the transistor might be destroyed. heat is produced. The same general results apply for the other pairs of transistors. Note that in the right-hand TRANSISTOR LEAD IDENTIFICATION pair, the cases can and are used for emitter or collector connections. You must be able to identify the leads or In replacing one transistor with another, do terminals of a transistor before it is connected not rely on shape. Be sure the leads are where into a circuit. As there is no standard method they should be and that the transisinr chosen as a replacement is suitable.If there is any doubt, consult the equipment manual or a tran- EMITTER EMITTER sistor manual showing the specifications for the transistor being used. COLLECTOR COLLECTOR CIRC UITRY There are three basic ways of connecting a transistor in a circuit: common or grounded base (fig. 15-21), common or grounded emitter BASE BASE (fig 15-22), and common or grounded collector P-N-PTYPE N-P-NTYPE (fig 15-23). The connections differ in whether the base, emitter, or collector is part of (common 73.377 to) both the emitter and collector circuits. Re- Figure 15-19. -- Schomnatidi _Trams of transistor gardless of the connection, the output signal is taken from across the load.

MOUNTING HOLES

E (CASE)

MOUNTING HOLES

B' C (CASE)

179.97 Figure 15-20. Bottom view of some common transistor cases.

487 499 CONSTRUCTION ELECTRICIAN 3 & 2

LOAD LOAD OUTPUT RESISTOR OUTPUT RESISTOR SIGNAL 0INPUT SIGNAL SIGNAL B

A A +T

73.380 73.378 Figure 15-23. Common collector amplifier cir- Figure 15-21. Common base amplifier circuit. cuit.

Table 15-2. Transistor amplifiercomparison chart

AMPLIFIER COMMONCOMMON COMMON TYPE BASE EMITTER COLLECTOR LOAD INPUT OUTPUT RESISTOR SIGNAL SIGNAL INPUT/OUTPUT PHASE 00 180° 0° B RELATIONSHIP

VOLTAGE GAIN HIGH MEDIUM LOW

73.379 CURRENT GAIN LOW (a)MEDIUMWHIGH(1) Figure 15-22. Common emitter amplifier circuit. POWER GAIN LOW HIGH MEDIUM INPUT IMPEDANCE LOW MEDIUM HIGH Note that the symbols indicate the use of an N-P-N transistor in each circuit. With a OUTPUT IMPEDANCEHIGH MEDIUM LOW P-N-P transistor, reverse the polarities of the battery. Each basic circuit has its own measure- ableproperties,suchasimpedance or gain 179.94 under given operating conditions. Which circuit is to be used depends upon the design requirements of a particular amplifier. its name suggests, the triode has three elements: Table 15-2 compares characteristics of thecathode, plate, and control grid. This grid is three basic circuits. usuallya metal screen or coil of fine wire inserted between the plate and cathode,but closer tr. the cathode. As long as the grid is uncharged, ELECTRON TUBE TRIODES t.,st of the electrons flowing from the cathode to the plate are free to move through the openings Another kind of electron tube, the triode, of the grid. Placing a negative charge on the grid is widely used as an amplifier of signals. As has a repelling effect on.the stream of electrons

488

(1 0 Ch.apter 15BASIC ELE CTRONIC COMPONENTS AND CIRCUITS IIMMINIms passing through the grid, and tends to reduce the number of electrons that do.Increase the negative charge, and fewer electrons pass through the grid. When the negative charge on the grid is made large enough, electrons do not pass between the NI 1 cathode and plate (fig. 15-24, view A.) LOAD However,a positive charge placed on the grid attracts the electrons. Increase the positive charge, and more electrons are attracted to the grid. Some electronsstrike the wire of the grid, but most of them flow through to strike INPUT the plate (fig. 15-24, view B) since the grid is !OLTAGE mainly open space. The grid, then, regulates the -IIAI I-1 flow of electrons much as a venetian blind controls the amount of light that enters a room. Depending on the voltage applied to the grid, more or less plate current flows through it. 73.382 Of course, you can vary the plate current Figure 15-25. Basic triode circuits. flow by making the plate more or less positive. But since the grid is closer to the cathode (the source of electrons),a smaller variation in To demonstrate the use of a triode as an the charge of the grid has the same effect on amplifier, assume that a small varying voltage the plate current as a larger variation on the is applied to the grid circuit. Since the charge charge of the plate. Weak signals change theon the grid varies with the applied voltage, the charge and voltage on the grid, and so produceplate current flowing through the tube varies big changes in the plate current. In this way,accordingly, causing similar variations in the the triode amplifies the weak signals. current flowing through the load. If the load The triode of figure 15-25 has three distinct resistance is high, the resulting voltage drop circuits: the FILAMENT circuit consisting of the (I x R) across the load is also high and varies heater and A battery or other source of heating directly withthe input voltage. Therefore, a current; the PLATE, or output, circuitconsistingsmall varying voltage applied to the input circuit of the cathode, the electron flow from cathode to of the triode produces a large varying voltage plate within the tube, the plate, the load, and the in the output circuit. B battery (commonly known as B+); and the The triode can be compared to the transistor, GRID, or input, circuit consisting of the cathode The cathode operates like the emitter, the plate control grid, and the source of input voltage.like the collector, and the grid like the base. OSCILLATORS An amplifier, such as the triode, can also be used as an oscillatoran electronic device that producesa constant signal of a certain frequency.As an oscillator, the triode feeds backtoitself part of the signal it puts out. The feedback produces signals that oscillate, or vibrate, at a certain frequency.The resistance inductance, and capacitance of the input circuit enable the triode to amplify only the signals that CAT HODE have the desired frequency. This is commonly CATHODE known as the resonant frequency. To demonstrate the use of a triode as an oscillator, connect the input circuit of the tube as shown in figure 15-26. This places an a-c 73.381 voltage on the grid of the triode. The resulting Figure 15-24. Effect of the grid in a triode. platecurrent satisfies the needs of the load 489

5 0 i CONSTRUCTION ELECTRICIAN 3 & 2

electron tubes for special purposes. Tubes having more than these three elements are known as multielement tubes. A tetrode, for example, is FEEDBACK a four-element tune. Its extra element is another COIL LOAD R grid called the screen grid. Another electron RESISTOR tube, the pentode, has three gridsa control grid,ascreen grid, and a suppressor grid. All multielement tubes have special uses and some require special tube sockets. All of them, however, work on the same basic principle as the triode. TETRODES The tetrode is an amplifying tube. Its fourth element, the screen grid,is mounted between the control grid and the plate.(See figure 15-27.) The screen grid has a positive charge with respect to the cathode; it attracts a steady flow ofelectrons from the cathode. Because 73.383 the mesh of the screen grid is relatively large, Figure 15-26. Oscillator, triode, and feedback most of the attracted electrons pass through circuit. it and, in turn, are attracted by the plate. Thus the screen grid supplies an electrostatic force with enough left over to feed back to the oscillating that pulls electrons from the cathode tthe plate. circuitto compensate forits losses, and to As long as the plate voltage is her than remain in oscillation. The plate current feeds theeffectivescreen gild-to-cathode,oltaga, back through the so-called feedback coil that is plate current in a tetrodc depends mostly on coupled (connected) to the inductor of the oscil- screen-grid voltage and little on plate voltage. lating circuit. In this way the feedback coil serves Thus a tetrode is better as an amplifier than a as the primary winding of a transformer; the triode. Also, the screen grid reduces capacitance inductor of the oscillating circuit as the secondary by serving as an electrostatic shield between the winding. control grid and the plate. Reducinggrid-to-plate Wnen proper valuesare selected for the capacitanceresultsin high amplification and inductorandthecapacitorof an oscillating keeps the amplifier from oscillating. circuit, frequencies in millions, even billions, Figure 15-27 illustrates a basic tetrode ampli- of hertz (cycles per second) can be generated. fier circuit. Rsg is the screen-dropping resistor Example: Assume that the value of an inductor is 20 microhenrys and that of a capacitor is 80 picofarads. Determine the frequency by using the formula: VI Frequency -=2r JLxC1 CONTROL where L = 20 ph = 2 x 10-5 henrys and C - 80 pF= GRID 8 x 10-11 farads Frequency - 1 2r12 x 10-5 x 8 x 10-11 Ebb 1 1 2T/16 x 10-18 2ir x 4 x 10-8 g

108 = 4,000,000 ilz Ecc 8ir (approximately) MULTIELEMENT ELECTRON TUBES Several elements otherthanthe cathode, 73.384 plate, and control grid are insertedin some Figure 15-27.--- Basictetrode amplifiercircuit. 490 502 Chapter 15 BASIC ELECTRONIC COMPONENTS ANDIRCUITS that maintains the scroen-grid operating voltage; METHODS OF BIASING Csg is the screen-bypass capacitor that maintains the screen grid at a constant voltage. In some amplifier circuits, d-c voltage in the grid circuit is supplied from a fixed source, PENTODES such as a battery or other power supply (fig. 15-29). This type of voltage is known as fixed bias. In another type, called self-bias, voltage The pentode's fifth element, or suppressor is developed across a resistor by tube current grid, is located between the screen grid and the or input signal. Cathode bias and grid-leak bias plate. The suppressor grid is connected internally are forms of self-bias. or externally to the cathode. Figure 15-28 shows the internal connection. CATHODE BIAS Electrons flowing from the cathode to the plate cause the plate to give off electrons by This form of self-bias is illustrated in figure secondary emission, which means freeing of 15-30. When the cathode of an electron tube is electrons by bombardin.iem with other elec- biased positively with respect to the grid, the trons.Being negative N respect to the plate, electron tube operates exactlyas though an the suppressor grid keeps ue secondary emission equivalent negative bias is applied to the grid. electrons from leaving the plate and interfering Since current flow with an electron tube is from with the operation of the tube. The main electron the cathode tr the plate, a resistor can be inserted stream is hardly affected by the presence ofin the cathode line to procuce a voltage drop the suppressor grid. (cathodebias)aslong asthe plate current flows continuously. Since cathode current always Since the suppressor grid is negative withflows in the same direction, the voltage drop respectto the screen grid or plate,it does remains more positive at the cathode. Thus, not draw current. Therefore the relationshipsplate current flow within the electron tube itself of voltages and currents are usEentiftilv the same produces a positive cathode bias. as those in the tetrode. The pentode has replaced the tetrode in radio GRID-LEAK BIAS frequency(RE') amplifiers because it permits a somewhat higher amplification in moderate values Grid-leak bias is obtained by allowing grid of plate potential. In some special-purpose pen-current flow, produced by an a-c signal input, todes, the :,app re ssor grid serves as a signal grid. to charge a resistance-capacitance (RC) network in the grid-cathode circuit. Two basic circuits

VI SUPPRESSOR GRID

Rsg

cs, Ebb

73.385 73.386 Figure 15-28. Basic pentode amplifier circuit. Figure 15-29. Schematic of fixed bias.

'191

03 CONSTRUCTION ELECTRICIAN 3 & 2

A. SHUNT TYPE

73.387 Figure 15-30. Obtaining cathode bias. are usedtodevelopthis form of self-bias: shunt and series(fig.15-31). The methods of developing grid voltage in these circuits are similar,cutthephysical connections of the netwo-1- .;,,inponents are different. Thc (41.d-cathodecircuitisused in both basic (;in;uits as a diode rectifier to develop a d-cvolt3r7.; proportional to the positive peak input(thiving)signalamplitude. A grid-leak B. SERIES TYPE capacitor (Ck) operates as a coupling capacitor toapply the input signal to the grid. On the 73.388 positiveinputsignalexcursions, the grid is Figure 15-31. Grid-leak bias connections. driven positive,causing gridcurrent to flow between grid and cathode and through a grid- coupling is the same whether the amplifiers are leak resistor (Rg). The result is to produce a used singly (as input or output coupling devices) d-c voltageacross Rg which is polarized neg-or in cascade. atively at the grid. RC COUPLING RC coupling involves the use of two resistors COUPLING METHODS andacapacitor,asshown in figure 15-32. Because of their rather high frequency response, Usually more than one amplifier is needed small size, and economy of operation, RC-coupled toincreasetheamplitude ofa feeble input amplifiers are nearly always used where voltage signal to the required output valve. The amplifiers amplification is desired with little or no power are cascaded, that is, connected in series so theoutput. Since the plate resistor (RL) and grid output of one goes to the input of another. Cascaded resistor (Rg) are not frequency responsive, the amplifierstagesareconnected(coupled)by overall frequency response is limited basically resistance-capacitance (RC) networks, impedance bythecapacitivereactanceofthe coupling (LCR) networks, transformers, or direct coupling. capacitor (Cc)between the plate and grid cir-a.. Though some coupling networks respond to fre- cults, plus the effect of shunt wiring and cathode-AP quency better than others, the basic method of to-ground capacitances across the network. With

492 504 Chapter 15BASIC ELECTRONIC COMPONENTS AND CIRCUITS

73.389 Figure 15-32,RC-coupled amplifier. direct current(zero frequenc:s)Lhe coupling capacitor separates or blocks -he plate voltage 73.390 of the driving stage from tho grid bias Df theFigure 15-33. Impedance -coupledamplifier, driven stage, so that bias or plate or eiement voltages are not affected betv on stages. Note that,with respect to alternating current, theconcerned; the basic difference lies in the effect tubes are in parallel with RL. of plate impedance. By using an impedance In the conventional RC amplifier, , signal voltagein the plate circuit, there is a smaller voltage variations onthe grid produce plate currentdrop for a given voltage supply. Therefore, a variations through the plate resistor, and thelowersupplysource will providethe same resulting voltage developed across it representseffective plate voltage, smaller loss in power an amplifiedreplicaofthe input signal but(I2R), andbetter overall efficiency. Low frequency 180 degrees out of phase. The amplified signalresponse depends on obtaining a high inductive is coupled through capacitor Cc and applied toreactance in the plate circuit and requires a the grid of the next stage across the grid resistor.large number of turns for good low-frequency The same cycle of operation is repeated for eachresponse. The distributed capacitance associated stage of the cascaded amplifier. with a winding of many turns produces a large RC-coupled amplifiers generally have a lowshunting capacitive reactance with a consequent gain, or ratio of signal output to signal input;drop in high-frequency response. Since the im- therefore, they are seldom used in RF amplifiers.pedance of the plate circuit varies withfrequency, They have special applications, such as testthe response is not as uniform as that of the equipment. RC coupling. The impedance-coupling circuit is used where IMPEDANCE COUPLING alimitedresponse over a relatively narrow band of frequencies is required. As a result, impedance coupling is usually found in amplifier When an Inductor is substituted for the platestages, such as intermediate-frequency or radio- load resistor in an RC-coupled circLit, an im-f requency stages. Its use in audio frequency stages pedance-coupled circuit results (fig. :)-33). The has generally been discontinued in favor oi the impedance coupled and RC-coupled circuits oper-RC or transformer coupling, except for FiDeci%41 ate in the same manner as far as Cc and Rg aredesigns.

493 505 CONSTRUCIION FIECTRIC(AN 3 & 2

TRANSFORMER COUPLING designed to handle larger plate currents. Gen- erally speaking, a lower plate current produces Intransformercoupling(fig.15-34),the fewer d-c core saturation effects. primary of a transformer is connecteci as the Sincetheimp,lance transformationina )1ate load, and the secondary provides the output transformer varies as the square of the turns ignal, either to the next stage or an 'output ratiobetween primaryti,c1secondary, output device.Frequency response, gain, and output and input matching is possible and is a common become more difficult to predict because they practice. For interstage applications, matching depend primarilyon the transfortnr design. is not always used, because power output is not Basically, transformer couplinz -'.des addi- required;inthesecases, more attention is tional gain, through the use of i)-up turns given to the step-up ratioto provide a higher ratioof primary to secondary, but this gain voltage gain. usually does not exceed 2 or 3 to 1. Since there The limitations of frequency response gen- is no physical d-c connection between stages, erally restrict the use of transformer coupling plate and bias voltages are kept separate, and to audio circuits which do not require an exception- the a-c signal is coupled from the plate of one ally wide bandpass or frequency response, but do stage to the grid of the fo_wing stage by mutual require voltage or power outputs. inductive coupling between primary and secondary windings. DIRECT COUPLING Ina direct-coupled amplifier(fig.15-35), Transformer coupling is generally used for the plate of the driver stage is connected to the interstage applications with electron tubeF.having grid of the driven stage, and the coupling network plateresistancesof5to 10 thousand ohms is eliminated. Since the plate and bias circuits maximum, since higher plate resistances require are not isolated by a transformer or coupling excessively larger transformer primary induct- capacitor, the direct-coupling circuitry is slightly ances. For output stages, lower Idate resistancescomplicated by the arrangement necessary to areused,andthetransformeriscarefully produce an effective negative bias. Because a coupling network is not inserted between the output of one tube and the input of tne following tube, there is no phase distortion, time delay, or loss of frequency response. Since theplateand grid of the tubes are directly connected, the low-frequency response is extended to direct current (zero frequency). The high- frequency response is limited only by the tube interelectrode-to-ground capacitance, plus the

OUTPUT INPUT

es INPUT SIGNAL. ep PRIMARY SIGNAL VOLTAGE. ei INPUT VOLTAGE TO SECOND TUBE, (ARROWS INDICATE ELL F FLOW)

20.97 Figure15-34.T rans former - coupledvoltage 20.102 amplifier. Figure 15-35. Direct-coupled amplifier.

994 5 0 6 Ctla Iqer 15 HASIC ELECTit l)NIC COMPONENTS AND CIRCCITS circuit distributed wiring capacitance. Pv appro- "l'hetransistor amplifiers described earlier priate matching (or mismAching) of tubes, high were biased in forward and reverse directions values of amplification an,: power output mav through the use of two batteries. The purpose obtained. forusingtwobatteries was to simplify the Since the use of more than two stages requires explanationoftransistor operation. In actual plate voltages two or more times the normal practice, two batteries are seldom used. Single value for one tube, plate supply considerationssource biasing will point out the necessity for limit direct coupling to a few stages. Any change knowing in which direction base lead current is in the supply voltage :Lffects the bias of all the normally flowing. tut)es and is cumulative; therefore, special voltage supply regulation circuits are necessary. Noise andthermal effectsin tubes produce circuit SINGLE SOURCE HIASING instability and drift that limit the use of this typeofcouplingin audio or RE amplifiers. Single source biasing hat, the advantage of Because of its ability to amplify direct current using the existing power supply to satisfy the (zero frequency),direct-coupl'A circuitryis needsfortransistorbiasing.Thisnotonly often usedincomputercircuits, and inthe eliminates the need for a separate power sui ply, output circuits of v;deo amplifiers. It is also butalsosimplifies circuit wiring. The main usedinpulsecircuits because responseis reason for simplification is that both the collector practically instantaneous. and the base require voltages, which possess the same polarity with respect to the emitter, HASE LEAD CURRENT for biasing purposes. A transistor with its three doped elements The amount of transistor current dependsmay be simplified to three resistances in series on severalvariables,suchas type of bias,with each other. Figure 15-37, view A, shows (fixed bias, self-bias), magnitude of the inputthe schematic diagram of an N-P-N transistor. signal, basic transistor connection, type of tran- Itsthree elements can be broken down into sistor, and direction of current flow in the base their equivalent electrical representation shown lead. For example, if the base lead current is n view B. Now, by application of a negative flowinginto the base material in the P-N-Psource to the emitter material, that point is (fig. 15-36, view A), or out of the base material made the most negative irale GI-Inch, while into the base lead in an N-P-N, as in view B,the collector material la *he leasL rcgative. In more currentisflowing in the emitter. If the view C, point B is.,. ss negative than point A, reverse is true, as shown in views C and D, then or positive with respect to p,i,nt A. In effect, more current is flowing in the collector. the base is made posithtith respect to the

(A)

179.95 Figure 15-36. Base lead current flowing into, or out of, the base material in N-P-N and P-N-P transistors.

195 5 0 7 CONSTRUCIION ELECTRICIAN 3g:2

-VEE -A

-VEE

179.104 Figure 15-37.Schematic diagram of an N-P-N trarisistor broken down to equivalent electrical representation and resistance equivalent. emitter, and the requirements for forward biasB, the total resistance is increased, decreasing in an N-P-N trinsistor are met. thecurrent flow in the circuit; now point B The base material, being situated betweenis less positive than point D with respect to the collector and the emitter, will always find point A, resulting in less forward bias. itself electrically at some potential between the collectorandthe emitter. Also, the base is Figure 15-38 illustrates the P-N-P, again representedin view C of figure 15-37 as athree equivalent resistances are used and this variableresistance to show that ar. increasetime a positive source is applied to the emitter in forward bias should decrease this nistance. source terminal. It may be noted that point A When the arm moves from point B to point D, is the most positive point in the network and that the total resistance in the circuit is effectivelypoint Bis less positive than point A, while decreased, flow from point D isat the samepoint D isless positive than (negative with potential as point B with respect to point A,respect to) point B. In this P-N-P, the bias is giving more forward bias; and more currentnegative with respect totheemitter, which isallowed to flow from the collector to thesatisfies the forward bias requirement for this emitter. When the arm is moved back to point typeoftransistor. Once more, the base is

+VEE

179.105 Figure 15-38. Schematic diagram of a P-N-P transistor broken down to equivalent electrical representation and resistance equivalent. 496 508 C' i 15 BASIC ELECTRONIC COMPONENTS AND CIRCUITS

179.106 Figure 15-39. Establishing transistor polarities. shown asa variable resistance to illustrate TESTING ELECTRON TUBES that forward bias can be increased or decreased. The addition of a single resistor from the There are two types of equipment in general basetothe emitter source terminal simplyuse for testing electron tubes: emission and shunts the base-emitter junction, further de- transconductance testers. The emission tester creasing its resistance, permitting more forward indicates the ability of a tube to emit electrons bias to be applied. Should the base current flowfrom its cathode. Transconductance testers not increase and, consequently, the transistor cur- onlyindicate this ability of an electron tube rent flow, with no signal input, you should check but also the ability of its grid voltage to control the value of RB; an open base resistor would platecurrent. The TV-7/U tube tester is a allow a greater difference of potential to be felttypieal transconductance-type of tester (fig. 15- between the base and the emitter and therefore 41). With the front panel controls of this tester, more current through the transistor. The base- youadjust(or switch) the various potentials emitter resistor reduces the resistance of the necessary for testing tubes. The tube data chart base-emitter junction, reducing the amount ofthat is supplied with the tester lists the control forward bias with no signal applied. A directsettings for the most common types of tubes. short circuit from the base to the emitter would Before inserting a tube in the correct test ofcourse causeall signal to be lost and ansocket, make certain that the front panel con- excessive amount of current flow through thetrols are set to the positions listed in the data device. By considering the transistor as being threeresistances in series,you can always establish the polarity of any given material in respect to an adjacent material, regardless of the polarity of the source, as shown in figure 15-39. The N-P-N transistor may have its collector connected to a positive source as shown in figure 15-40, view A. In this case, point E in view C ispositive in respect to point D, point D is positive in respect to point C, and point C is positive with respect to point B. The base is positive with respect to the emitter, and, therefore,itisforward biased. Where a P-N-P RB transistor has a negative source on its collector, (fig. 15-40, view B), point E in view C is negative with respect to point D, point D is negative with respect to point C, and point C is negative with respect to point B. The base is thus negative withrespect to the emitter and in a P-N-P 179.107 this is forward bias. In both cases RB is shuntingFigure 15-40. N-P-N and P-N-P transistor the base to emitter junction. equivalent circuit. 497

5 0 9 CONSTRUCTION ELEC FRICIAN 3 & 2

3 I 28 30

:44111111C 29 _ TB

-1.011114 ),

1 0

3 I 9 C14111.1.11 CI 4%! I 3 7 ----.... I

6 _ a '11,A I 4 , .. 4 s -1111.111( 11: .\° t . 0.,rnwr I 5 ' NC. /) !. 0 ' TV MN \.) I 6 ) I)

A1111110.. 1 718 5 1920 0 4 21 3

2726i5 22 23 12 24 1. Fuse lamp. 11. Shunt control. 21. Line aoj. switch. 2. Line adj. control. 12. Neon lamp. 22. Function switch. 3. Pilot light. 13. Meter. 23. Suppressor selector. 4. Power switch. 14. Meter reverse switch. 24. Cathode selector. 5. Filament voltage. 15. Rectifier switch. 25. Screen selector. 6. Filament selectors. 16. 0Z4 switch. 26. Plate selector. 7. A-c line cords. 17. Gas 2 switch. 27. Grid selector. 8. Grid jack. 18. Gas 1 switch. 28.Test leads. 9. Bias control. 19. Mut. Cond. switch. 29. Pin straighteners. 10. Plate jack. 20. Diode switch. 30. Adapter. 31. Test data book.

243.379 Figure 15-41,- Electron Tube Test Set, TV-7/U

498 510 Chapter 15 BASIC ELECTRONIC COMPONENTS AND CIRCUITS chart for that tube. This precaution is necessarylogically that, if a tube under test has elements to prevent excessive voltage from being applied which are short-circuited, there is no further to the tube elements (especially the filament). needtoapply additionalteststothat tube. Short-circuit tests are usually sensitive enough LINE VOLTAGE ADJUSTMENT to indicate leakage resistance less than about AND TEST one-fourth megohm. The proper heater voltage is applied so that any tuoe elements which might The line voltage adjustment is necessary so short as a result of thi-1,eating process will be that the line voltage applied to the primary ofdetected. The short-circuit test is similar to the the transformer can be present to an operatingtest used to detect noisy (microphonic) tubes value. A 93-volt potential is used as a testcaused by loose elements. Since the only dif- reference point,regardless of the variations ference between the two tests is in the sensitivity caused by different tube loads or fluctuations of the device used as an indicator, the noise test in the a-c supply. Aiylied voltages may rangeis discussed as part of the short-circuit test. from 105 to 130 volts and still be adjustable. Figure 15-42 shows a basic circuit used for Depressing the LINE TEST button connects the detecting shorted elements within a tube. With meter of the tube tester to read the "B" supply the switch set to position 2 as shown, the plate voltage.The test equipment is calibrated atof the tube under test is connected to the leg of the factory so that the meter pointer is approx-the transformer secondary containing the neon imately centered when the voltage across the lamp. All the other elements are connected through primaryis93volts. Since various types ofswitches to the other leg of the secondary. If electron tubes draw different values of currents, the plate element of the tube is touching any a LINE ADJUSTMENT rheostat (connected in other element within the tube, the a-c circuit series with the primary) is provided. The pri-of the secondary is completed and as a result, mary voltage can thus be set to the designed both plates of the neon lamp glow. If no short operating voltage before any test is begun. A exists,only one plate of the neon lamp will small protective lamp which will burn out onglow. Each of the other elements is tested by overload is connected in series with the primary means ofthe switchingarrangement shown. of the transformer to prevent equipment damage. Resistor R2 limits the current through the neon lamp to a safe value. Resistor R1 bypasses any SHORT CIRCUIT AND small alternating currents in the circuit which NOISE TEST might be caused by stray capacitance and thus prevents the neon lamp from indicating erron- It is very important that the technician apply eously. Tapping the tube lightly is recommended the test for short-circuited elements to a tube to detect loose elements which might touch when of doubtful quality before any other tests are the tube is vibrated. made. This procedure protects the meter (or The circuit used to test for shorts is similar to any other indicator) from damage. Also itfollows the basic circuit of figure 15-42. By means of

TUBE UNDER TEST

4671111 NEON LAMP

NOISE TEST

1.75 Figure 15-42. Basic circuit used for short circuit and noise test, 499 511 CONSTRUCTION ELECTRICIAN 3 Si2 the function switch the electrodes of the tube under The basic circuit used for the gas test is test are switched in turn across a neon SHORTS shown in figure 15-43. With switch S set to posi- lamp, whichis connected in series with the tion 1, a certain value of plate current is measured secondary of the transformer. Shorted tubL ele- by the d-c milliammeter. If there is no gas ments (and any other internal tube connections) (c: a negligible amount) present in the tube, complete the a-c circuit, causing both plates of setting switch S to position 2 does not change the the neon lamp to glow. Momentary flashes of the plate-current reading. If gas is present, current neon SHORTS lamp may be caused when the flows through the grid resistor (large value), switch is rotated. These flashes are caused by causing a voltage drop to develop with the polarity the charging of the small interelectrode capaci- as shown. The net effect is to reduce the negative tances of the tube when the voltage is applied,bias voltage on the grid the tube resulting in and do not indicate short circuits. If the tube an increase of plate current. Small plate current under test has a shorted element, the neon lampincreases are normal; large increases indicate will glow continually on one or more switch excessive gas. positions. Since the filament circuit and other The value of the grid resistor used in the internal tube connections will show up as shorttypical tube tester is 1801000 ohms. Two push- circuits in this test, the tube data chart should buttonswitches, labeled GAS No. 1 and GAS - be consulted for pin connection informationbefore No. 2, are used for gas test. GAS No. 1 button interpreting the results of the test. is first depressed and the plate current reading The noise testis used to check for inter-on the meter is noted. Depressing the button marked GAS No.2inserts the 1801000-ohm mittent shorts or microphonic noise. The circuit resistor into the grid circuit. If gas is present used is the same as that employed for the short- in the tube, the grid current that flows reduces circuit test. In tests for noise, the antenna andthe normal bias on the tube and increases the ground terminals of a radio receiver are con- plate current measured by the meter. A tube nectedtothe NOISE TEST receptacles. Any witha negligible amount of gas produces an intermittent short between tube electrodes per- increase in plate current of less than one scale mits the a-c voltage from the power transformer division when GAS No. 2 button is depressed. to be applied momentarily to the neon lamp. An increase of more than one scale division The brief oscillation of this lamp contains indicates an excessive amount of gas in the tube. various radiofrequencies which are reproduced as audible signals in the receiver speaker. A less sensitive noise test can be made using a pair of headphones instead of the radio receiver. The tubeshould be tapped whileitis being TUBE UNDER tested. TEST GAS TEST In all electron tubes, except some types of rectifier tubes and thyratrons, the presence of Ig any appreciableamount of gas is extremely undesirable. When gas is present, the electrons emitted by the cathode collide with the molecules of gas. As a result of these collisions, electrons (secondarilyemitted)are dislodged from the gas molecules, and positive gas ions are formed. These ions are attracted by (and cluster around) the control grid of the tube, absorbing electrons FIXED PLATE from the grid circuit in order to revert to the BIAS VOLTAGE more stable gas molecules (not ionized). If the amount of gas in the tube is appreciable, the - collisions between the numerous gas molecules and the cathode-emitted electrons release many secondarily emitted electrons, and the resulting 1.76 flow of grid current is high. Figure 15-43. Basic circuit used for gas test.

500 5t2 Chapter 15 BASIC ELECTRONIC COMPONENTS AND CIRCUITS

CATHODE LEAKAGE TEST When a tube which uses an indirectly heated cathode develops noise, TUBE it is almost a certain UNDER indication that a leakage path is present between TEST

501 513 CONSTRUCTION ELECTEC:CiAN 3 & 2

to control the sensitivity of the meter. Setting PUSH BUTTON of the dial is required only when the function SWITCH switch isin the RANGE (A) SHUNT position. The setting for this switch is determined by the type of tube being tested and islisted in the tube data chart. F-v0C.LINE TESTING TRANSISTORS Transistors should be checked with the Tran- sistor Test Set TS-1100/U (fig. 15-46). If a test set is not available, it is possible to test tran- sistorswith a multimeter or a vacuum tube voltmeter (VTVM) 1.73 The TS-1100/U is designed to measure the Figure 15-45. Basic circuit used for emissioncurrent gain (beta) and collector leakage current test. (I cc) of a transistor. Itwill also detect short circuits. Beta is defined as the ratio of change in tube under test, and the meter indicates thecollector current to a change in base current, rectified plate current. The two sections of a collector voltage being constant. I CO is a measure full-wave rectifier are tested separately. of leakage current between the base and collector, The button for testing 0Z4 tubes provides when thebase-collector junction is reverse- a higher a-c voltage than is normally used forbiased and the emitter-base junction is open- heater (or filament) type rectifiers. The buttoncircuited. for diode tubes provides a lower voltage than With a transistor tester, beta may be measured that used for regular rectifiers, and also insertswith the transistor in or out of its circuit. You a protective series resistance. must remove the transistor from its circuit to test for shorts and to measure lc°. QUALITY TEST SEMICONDUCTOR TESTING For the quality test, the d-c grid bias for the tube under test issupplied by a rectifier When using a multimeter to test semicon- tube. The correct value of this grid bias is ductors, to avoid loading the circuit, the multi- obtained when the bias control is rotated to meter must have a sensitivity of at least 20,000 thesetting listed in the test data chart, for ohms per volt on all voltage ranges; the ohmmeter the tube being tested. An a-c vo:tage (4.7 volts circuits must not pass a current exceeding 1 rms), which is taken from a separate windingmilliampere. The VTVM should have an input on the power transformer, is applied in seriesresistance of 11 megohms or more, and must withthe grid bias.This voltage causes the have an isolation transformer between the meter gridtodeviateinpositive and negative di- and the powerline. rections from the d-c bias level, thereby effect- Three testscan b3 accomplished on the ing the grid-voltage change required for a dynamic transistor by using the multimeter. However, transconductance test. The plate voltage of thethe transistor must be removed from the circuit tube under test is supplied by a rectifier tube.for testing. The- meter which indicates the plate current Determine the type of transistor, whether change is in the return circuit of the rectifierP-N-P or N-P-N. The same resistance test can supply. The meter indicates the tube conditionbe performed on the transistor as on the diode. inarbitrary numerical units from 0 to 120. The transistor has two junctions, the emitter- The tube test data book, mounted inside the.base and the collector-base. Because each junction cover ofthe equipment,liststhe minimum can be treated as a diode, the same readings hold numerical value of meter reading for satis- true. factory performance. Tubes reading belov Before a diode is tested, its polarity must value are not considered be determined. The diode is usually marked with military equipment. The shun; a plus(+) or minus (-) sign. Connect the test 502

r 44 Cwit:r 15-- BASIC ELECTRONIC CO:,IPONENTS AND CIRCUITS

, BETA I 0 4) I \1) A \, ' 11111110.- gprp

72.37 Figure 15-46.--Transistor Test Set, TS-1100/U.

leads to the diode in a forward .bias condition, greater than 6 volts. This higher potential is that is, the positive lead to the positive side ofusually found on the higher resistance scales. the diode and the negative lead to the negative Excess current might also cause damage to the side.Current will now flow easily, and if a transistor under test. Since the internal current- reading of 1000 ohms or less is obtained, this limiting resistance generally increases as the part of the test is good. If a higher reading is resistance range is increased, the low range of ' obtained, the diode is open. theresistancescale should also be avoided. Connect thetestleads to the diode in a Basically,if we stay away from the highest reverse bias conditionthe positive lead to the resistancerange(possible excessive voltage) negative side of the diode and the negative lead and the lowest resistance range (possible ex- to the positive side. Current will not flow readily, cessive current), the ohmmeter should present and a reading in excess of 10,000 ohms should no problems in transistor testing. Generally be obtained. If a reading under 10,000 ohms is speaking, the R x 10 and R x 100 scales may be obtained, the diode is shorted. considered safe. As a general rule, the front-to-back ratio The polarity of the battery, as well as the should be at least 10 to 1. When testing power voltage value, must be known when using the transistors, the same ratio (10 to 1) holds true, ohmmeter for transistor te sting. Although, except that the reverse resistance must be inin most cases, the ground or common lead excess of only 1000 ohms. (black)is negative and the hot lead (red)is Since damage to transistors could occur when positive, this battery setup is not always the case. using voltages above approximately 6 volts, care It is possible to reverse the polarity of the must be taken to avoid using resistance scales ohmmeter leads by changing the function switch where the internal voltage of the ohmmeter is position. This means that the black or common 503 515 CONSTRUCTION ELECTRICIAN 3 & 2 lead is now the positive battery and the red lead is the negative battery. CAUTION: TUNE 0 READOUT AMPLIFIER METER Although the jacks of the meter may show a negative sign under the common and a positive sign under the other jack, these do not indicate the internal polarity of the battery connected to SW the jack. Before making any resistance measurements, make sure that all power to the circuit under test has been disconnected and that all capacitors have been discharged. RB

Do not use an ohmmeter which passes RE FE RENCE more than one milliampere through the circuit OSCILLATOR under test. A R B - BASE RE SISTANCE VARIABLE Ensure that all test equipment is isolated R COLLECTOR RESISTANCE BIAS from the powerline either by the equipment's own TRANSISTOR UNDE R TEST SUPPLY power supply transformer or by an external SW TRANSISTOR SELECT SWITCH isolation transformer. Always connecta ground lead between COMMON for the circuit under test and COMMON 124.223 on the test equipment. Figure 15-47. Measuring beta, using Transistor Test Set, TS-1100/U. Do notshort circuit any portion of a transistorcircuit.Shortcircuiting individual components or groups of components may allow the transistor in the circuit, the indicated excessive current to flow, thus damaging com- Ico would be higher than the actual Icso due to ponents. shunt current paths in the circuit. To perform the leakage current test, the Do not remove or replace any transistors manufacturer's specifications should be consulted in an energized circuit. to ascertain the allowable limits. Determine the type of transistor and set up one of the tests Ico TEST shown in figure 15-48, using a f-volt battery and microammeter. High collector leakage current (Ico) is caused If the leakage current is twice as much as the by old age and excessive temperatures. I co is specification sheet calls for, replace the tran- greatly dependent on ambient temperature, thus sistor. If no specifications are available, use the care must be taken to see that temperature is following rule of thumb: controlled when measuring Ico. One sign of a defective transistor is instability 1. Silicon transistor less than 1 microamp. of Ico. Whenever Ico increases slowly while 2. Small germanium transistorless than being measured, it is quite evident that the tran-10 microamps. sistor is defective. Excessive leakage current 3. Medium germanium transistorless than indicates transistor deterioration and usually is 100 microamps. accompanied by lower than normal beta. Common 4. Power transistorsless than1mtlli- causes of excessive I co include age, high ambient amne re. temperature, and contaminates that form on the emitter-base junction or collector-base junction. The beta test can be accomplished by inserting Figure 15-47 shows thetestcircuitfor a 10,000-ohm resistor between the collector-base measuring 'co. The transistor must be out of the Junction and connecting the meter to the emitter circuit for this test. If Ico were measured with and collector as shown in figure 15-49, 504 516 Chapter 15 BASIC ELECTRONIC COMPONENTS AND CIRCUITS

Once the resistance is obtained on the meter, use the following formula to figure the gain: B =1200 +R. The letter B represents gain, 1200 is a Constant, and R is the resistance read on the meter. Check the manufacturer's specifications for the gain of each transistor. If the specifications are not available, use the following rule of thumb: 1. Silicon transistors-5 times or more. 2. High-frequency transistors-10 times or more. 3. All other transistors-15 times or more. N P N Whenever a particular transistor is suspected to be faulty, it may be tested in the circuit if there are no low resistance shunts (such as coils, forward biased diodes, low value resistors, and so forth) across any of its leads. A low resistance shunt across any two of the transistor leads can 6V easily cause erroneous indications on the transistor test set. Erroneous indications can be eliminated by 71.99iremoving thesuspected transistor from the Figure 15-48. Transistor leakage current test.circuit. Some manufacturers have simplified the removal and replacement of transistors by using transistor sockets. Whenever a circuit board without transistor sockets is encountered, transistors will have to be carefully unsoldered in order to test them out of eircuits.

MEASUREMENTS IN TRANSISTOR CIRCUITS 10K The many types of transistor base connection arrangements require that the leads be properly identified to secure correct hookup to the tester. The TS-1100/U test socket arrangement is com- PNP patible with some transistor types, but not VOM all types. If the leads are long enough, it is generally possible to effect proper hookup by bending them. If the leads are too short, it will be necessary to use the test cable and alligator clips provided with the tester. In all cases, however, the transistor leads should be identified and then matched up with the tester connections. The advantage of the TS-1100/U lies not only in its accuracy and simplicity, but also in its use of a-c as the testing current. This eliminates interference from direct currents and voltages that may be present and permits measurement of the gain of a transistor in-circuit, thus making it unnecessary to unsolder or disconnect the the transistor for this test. This is particularly 71.100 advantageous where the transistor is mounted on Figure 15-49. Transistor gain test. a module printed wiring board. 505 517 CONSTRUCTION ELECTRICIAN 382 2

The testset has the following additionalTo determine whether the short is in the tran- features; a switch marked P-N-P-N-P-N, which sistor itself or in the associated circuit, it is selects the proper bias polarity for the type of necessary to remove the transistor from the transistor under test; a temperature alarm in- ci rcuit. dicator lamp, which will light when the ambient temperature surrounding the equipment exceeds A table in the instruction manual for the test 50° C; and a switch marked TEST, which checks set gives a numerical listing of the transistors the test set battery output. that can be tested. The technical manual for the The test set is also equipped to indicate atestset providesinformation concerning the short between any two of the three elements ofcollectorbias to be applied for a particular the transistor under test. With the transistor transistor and the maxim.im permissible collector in-circuit,itwill also indicate a short if the leakage current. When the instrument is adjusted circuitry between any two ofthe transistor according to the instruction book, the value of beta elements has a resistance of 500 ohms or less. will be indicated directly on the meter.

6 1 8

506 APPENDIX I

THE METRiC SYSTEM

The metric system was developed by French With the exception of the United States, all scientists in 1790 and was specifically designed theindustrialized nations of the world have to be an easily used system of weights and adopted the metric system. Even England and measurestobenefitscience,industry,and Canadaarechanging fromtheirtraditiona! commerce. The metric systemiscalculated systems of measure, and the metric system will entirely in powers of 10, so one need not work be almost universal by 1980. with the various mathematical bases used with Although the metric system has not been the English system, such as 12 inches to a foot, officially legislated by the Congress, the metric 3 feet to a yard, and 5280 feet to a mile. systemisbecoming more prominent in this The system is based on the "meter" which is country. Most automobile mechanics own some oneten-millionth of thedistance from the metric wrenches to work on foreign cars or Equator to the North Pole.It is possible to foreign components in American cars. Almost all develop worldwide standards from this base of photographic equipmentisbuilttometric measur...ment. The metric system of weights is standards. Chemicals and drugs are usually sold based cn the gram, which is the weight of a in metric quantities, and "caiorie counters" are specific quantity of water. using a metriF unit of thermal ener&v. Soonafterthesystemwasdeveloped Because we are allied with cournries who us.e scienti: ts over the world adopted it and were themetricsystem,muchof our military ableto dealwith the mathematics of their information is in metric terms. Military maps use e x p erimen ts moreeasily.. Thedataand meters and kilometers instead of miles, and particulars of their work could be understood by many weapons are in metric sizes, such as 7.62 other scientists anywhere in the world. During mm, 20 mm, 40 mm, 75 mm, and 155 mm. the early 19th century many European nations Interchange of military equipment has caused a adopted the new system for engineering and mixtureofmetricandEnglishmeasure commerce. It was possible for these countries to equipment since World War I when the army trade manufactured goods with one another adopted the French 75 mm field gun, and World without worrying whether it would be possible War II when the Navy procured the Swedish 40 torepairmachineryfrom another country mm Bofors and the Swiss 20 mm Oerlikon heavy withoutalsobuyingspecialwrenchesand machine guns. measuring tools. Countries could buy and sell It is inevitable that the United States will machinetoolsandother sophisticatedand officially adopt the metric system. Exactly when precisionmachinerywithouttroublesome this happens and how rapidly the changeover modifications or alterations. It was much easier will depend on economics, since the expense of to teach the metric system, since meters can be retooling our industry and commerce to new changed to kilometers or centimeters with the measurements will be very great. The cost of movement of a decimal point, which is roughly conversion will be offset by increased earnings like being ableto convert yards to miles or from selling machinery and products overseas. inches by adding zeros and a decimal instead of Another benefit is that scientists use the metric multiplying by 1760 or dividing by 36. system, but their calculations now have to be

507 519 CONSTRUCTION ELECTRICIAN 3 & 2 translated into English measure to be used by The basic quantities of the metric system are industry. With adoption of the metric system multiplied or divided by powers of 10 to give ideas can go directly from the drawing board to other workable values. We cannot easily measure the assembly line. machine partsinterms of a nick!, so the The Navy will be using the metric system millimeter, or one-thousandth oft Inc ter is used. more during the next few years. Althougji you For very fine measure the micrc:i, also cailed the willfind it easier to solve problems using this micrometer, can be used. It is cnc-ni:llionth part system, atfirst you willfinditdifficultto of a meter, or one-thousandth of a millimeter. visualize or to estimate quantities in unfamiliar For small weights the milligram, one-thous:Ath units of measure. of a gram is used. All of thcs.'multiples are Fortunately, manymetricunitscanbe expressed with standard pit.xes taken from related to equivalent units in the English system. La lin:

Themeterwhich isthebasicunitis micro =1/1,000,000 approximately one-tenth longer than a yard. milli =1/1,000 Thebasicunitof volume,theliter,is cenli =1/100 approximately one quart. The gram is the weight *deci =1/10 of a cubic centimeter, or milliliter. of pure water *deca =10 and is th: basic unit of weight. As a common *hecto =100 weightthough, the kilogram, or kilo, which kilo =1,000 equals the weigJit of a liter of water, weighs 2.2 *myria =10,000 pounds. T.:ie cubic centimeter (cc) is used where mega =1,000,000 we would use the square inch, and where we measure by the fluid ounce, the metric system * Rarely used employs the milliliter (m1). For power measure the metric system uses the kilowatt (kW), which Over the next few years the metric system is approximately 1.3 horsepower. will become more used by the Navy as well as by In termsofdistance,a, landmileis the civilian world. You will find it easy to work eight-fifths of a kilometer and a nautical mile is with once you have mastered the basic terms. It 1.852 kilometers, or nearly 2 kilometers. will be difficult to translate values from our A basic metric expression of pressure is the present system to the metric system, but this kilogam per square centimeter, which is 14.2 operation will become unnecessary once the new psi, nearly 1 atmosphere of pressure. measurements are totally adopted. When working on foreign machinery, you Tables of equivalent English measare and may notice that your half-inch, three-quarter metric equivalents are essential when you work inch, and one-inch wrenches will fit many of the simultaneously with both systems. The table bolts. These sizes correspond to 13 mm, 19 mm, which follows shows the equivalent measures of and 26 mm respectively in the metric system, the two systems. The columns on the left have and are very popularbecausethey are the equivalent values which are accurate enough interchangeable.The13/16-inchspark plug for most work, and ontherightarethe wrench, which is standard inthis country, is multiples used to convert the values with a high intended to fit a 20 mm nut. degree of accuracy.

520

508 AppendixI 1111.. SYSTFM

U.S. CUS1OMARY AND METRIC SYSTEM UNITC OF MEASUREMENTS

THESF 7REFIXES MAY BE APPLIED TO ALL SI UNITS

Multiples sod Same lllplos Profiles Symbols

1 000 000000000= 1012 tera (ter'5)

1 000000000= 109 giga (ji'ga)

1 000000= 106 mega (meg'i) M

1 000= 103 kilo (kil'O) k

100- 102 hecto (hek'tO)

10= 10 deka (dek'S) da

0.1= 10-' deci (des'i)

0.01 = 10-2 centi (sen'ti) c

0.001. 10'3 milli (mil'i) m

0.000001= 104 micro (mr'krO) u

0.000000001 - 10'9 nano (n'an'O)

0.000 000000001 =10-'2 pico (016)

0.000 000 000000001 - 10'15 femto (fem't;)

0.000 000 U00 000000001 = 10'm atto( 't'tO) a

MOST COMMONLY USW

5 2 1.

509 CONSTRUCTION ELECTRICIAN 3 & 2

ENGLISH AND METRIC SYSTEM UNITS OF MEASUREMENT

COMMON EQUIVALENTS AND CONVERSIONS

Approximate Common Equivalents Conversions Accurate to Parts Per Million (units stated in abbreviated form) Number X Factor

1 inch = 25 millimeters in X 25.4* = mm 1 foot = 0.3 meter ft X 0.3048* = m 1 yard = 0.9 meter yd X 0.9144* m 1 mile = 1.6 kilometers mi X 1.60934 = km 1 square inch = 6.5 square centimeters in2 X 6.4516* cm2 1 square foot = 0.09 square meter ft2 X 0.0929030 ma 1 square yard = 0.8 square meter ycP X 0.836127 ma 1 acre 0.4 hectare. acres X 0.404686 = ha 1 cubic inch 16 cubic centimeters in3 X 16.3871 = cm3 1 cubic foot 0.03 cubic :neter ft3 X 0.0283168 1 cubic yard = 0.8 cubic meter ycP X 0.764555 M3 1 quart (Pl.) 1 liter qt (NJ X 0.946353 / 1 gallon 0,004 cubic meter gal X 0.00378541 M3 1 ounce (avdp) 28 grams oz (avdp) X 28.3495 g 1 pound (avdp) 0.45 kilogram lb (avcip) X 0.453592 kg 1 horeepower 0.75 kilowatt hp X 0.745700 = kW 1 pound per square inch 0.07 kilogram per squarepsi X 0.0703224 kg/ctn2 centimeter 1 millimeter 0.04 inch mm X 0.0393701 in 1 meter 3,3 feet m X 3.28084 = ft 1 meter 1.1 yards m X 1.09361 yd 1 kilometer 0.6 mile km X 0.621371 mi 1 square centimeter 0.16 square inch cm2 X 0.155000 ina 1 square meter 11 square feet m2 X 10.7639 fta 1 square meter 1.2 square yards m2 X 1.19599 ycp 1 hectare 2.5 acres ha X 2.47105 acres 1 cubic centimeter 0.06 cubic inch cm3 X 0.0610237 i n3 1 cubic meter 35 cubic feet rn3 X 35.3147 in ft' 1 cubic meter 1.3 cubic yards m3 X 1.30795 ycp 1 liter 1 quart (lg.) 1 X 1.05669 qt (1q.) 1 Cubic meter 250 gallons m3 X 264.172 is gal I gram 0.035 ounces (avdp) g X 0.0352740 oz (avdp) 1 kilogram 2.2 Founds (avdp) kg X 2.20462 al lb (avdp) A kilowatt 1.3 horsepower kW X 1.34102 = hp 1 kilogram per square 14.2 pounds per square kg/cm2 X 14.223226 2, psi centimetet inch tnautical mlle = 1.852 kilometers * exact

510

5 2 2 INDEX

A Automatic telephone systemcontinued 10,000-liro fto>tem, 421 strowger it,;hes, 415 ACB breaker, 128 troubleshooting, 421 A-C generator, Elarting, 299 Automatic washers, 224 AN/PTM-5, telephone test set, 119 Accident investigation, 33-38 Accident prevention, 12 Accident reporting, 33 Administration, 465-474 Ball bearings, 189 Advancement system, Navy enlisted, 3 Base lead coupling, 495 Airf, ,d lighting, 379 Basic electronic components and circuits, approach lighting, 380 475-506 maintenance of marking, lighting, and related Basic measuring instrument precautions, 88 electrical facilitie:,:161 Basic telephone system components, 385-392 standardization, hook switch, 391 Air circuit breakers, 128 how the telephone works, 385 Air compressor safety, 80 local battery and common battery circuitry, Air compressors, 73-80 388 air compressor safety, 80 magneto generator, 391 compressed air system, 73 receiver, 387 compressor operation and maintenance, 75 ringer, 392 Air-conditioners, window, 230 transmitter, 386 Air system, conpressed, 73 Basic test equipment, 89-100 Alternating-current stator coils, 208 amtneters, 89 Ammeters, 89 clamp-on-voltammeters, 93 Armatures, 191 phase sequence indicator, 99 Appendix I, the metric system, 507 vibrotest megohmmeter, 96 Assignment as crew leader, 465-467 voltage tester, 95 planning work assignments, 465 Battalion safety organization, 472 supervising work teams, 466 key safety personnel, 474 Auger care and maintenance, 87 safety control and reporting organization, 472 Auger safety, 87 safety policy organization, 472 Augers, power earth, 80 Battalion table of allowance, 61 Automatic boiler controls, 170 Battery maintenance, 433 maintenance, 174 Blueprint reading, 45-48 pressure limit switch, 171 care of blueprints, 45 protectorelays, 174 electrical symbols, 48 safety combustion controls, 172 folding blueprints, 45 troubleshooting hints, 174 parts of a print, 46 water level controls, 170 Blueprints, diagrams and schematics, 45-60 Automatic telephone system, 415-421 Bridge, wheatstone, 106 100-line system, 418 Brushes, 185 1000-line system, 420 Brushless generators, 284

511 5 23 CONSTRUCTION ELECTRICIAN 3 & 2

Building and switchboard cable, 438 Control devicescontinued Burns, 42-44 manually operated switches, 157 Bus bar, 294 photoelectric control relays, 162 pressure and temperature switches, 168 relays, 162 Controllers, 149-157 Cable classification, telephone, 437 maintenance of controllers, 155 Cable, lead-covcred, 437 motor installation identification, 154 Cable line, overhead, 395 requirements for motor controls and mount- Cable repairman's test set, 111 ings, 15i Cables, 237 reversing controller::., 151 Capacitor color coding, 476 safaty code for motirs and motor protection, Capacitor motors, 213 1,i4 Care of instruments, 122 types, 149 Cathode leakage test, 501 Controllers, maintenance of, 155 Central power stations, 270-310 Construction, 357 Centrifugal switches, 212 ducts and trenches, 357 Circuit breakers, 128-135 manholes and handholes, 357 ACB breaker, 128 underground cable, 360 air circuit breakers, 128 Coupling methods, 492-495 oil circuit breakers, 131 direct coupling, 494 Circuit testing, 433, 477 impedance coupling, 493 Circuit, voltage control, 280 RC coupling, 492 Circuits, street lighting, 350 transformer coupling, 494 Clamp-on-voltammeters, 93 Crossarms, 312 Classifications, Navy enlisted, 2 Crossbar switching system, 421-429 Cleaning motors and generators, 215 crossbar switch, 425 Closing the sheath, 462 major components, 425 Codes, specifications, 148 switching network, 425 Coils, field, 206 tracing a call, 426 Collectorrings,184 Current transformers, 349 Communications maintenance and repair, 433 battery maintenance, 433 circuit testing, 433 intercom system maintenance, 436 public address system maintenance, 436 subset maintenance, 434 Diagrams and schematics, 48-56 switchboard maintenance, 435 electric appliance and equipment repair, 56 tools and equipment, 436 external distribution systems, 50-52 wiring maintenance, 433 interior wiring, 52 Communications system, 385-436 wire communications, 52-56 Commutators, 180 Diagrams, schematics, and blueprints, 45-60 Compressed air system, 73 Diesel and gasoline engine sets, 271 Compressor operation and maintenance, 75 Digging post holes, 319 Conductors, 236, 250 Diode rectifiers, 482 service drop, 250 Diodes, 479-486 service entrance, 250 diode rectifier, 482 Conductors, locating and installing, 254 electron tube diodes, 479 Connections to protectors, 403 solid state diodes, 483 Construction, primary and secondary, 340 Direct coupling, 494 Control and protective equipment, 123-174 Disassembly and reassembly, 178 Control devices, 157-170 Distribution frames, 398 electrically operated switches, 162 Distribution panels, 251 electronic temperature control, 170 Distribution transformers, 338-349 float switches, 166 cooling methods, 340 limit switches, 166 grounding transformers, 343

512 524 INDEX

Distribution transformerscontinued Equipment and tools, 176, 436 insulating liquids, 341 Equipment, basic test, 89 primary and secondary construction, 340 Equipment, generators, 271-279 transformer connections, 346 Equipment, special test, 100 transformer mounting, 342 Erecting poles, 320 transformer polarity, 345 Explosion-proof fittings, 248 Domestic oil burners, window air-conditioners,External distribution systems, 50-52 and large appliances, 223 automatic washers, 224 electric dryers, 225 electric hot-water heaters, 227 hermetic compressor application, 229 Filament activity test, 501 household refrigerators, 233 Field coils, 206 oil burners, 223 Field switchboard SB-22A/PT, 406 ranges, 228 Field telephone systems, 405-413 window air-conditioners, 230 field switchboard SB-22A/PT, 406 Ducts and trenches, 357 field telephone TA-312/PT, 413 manual telephone central office AN/TTC-7A, 406 Field telephone TA-312/PT, 413-415 telephone EE-8, 414 Electricapplianceand equipment repair, 56 Field wires, 394 Electric dryers, 225 righting fires, 31 Electric hot-water heaters, 227 First aid, 38-42 Electric metallic tubing (thin-wall or EMT), 242 burns, 42-44 Electrical installation, 288-295 emergency procedures, 39-42 bus bar, 294 general, 38 generator connections, 290 Fixtures, street lighting, 350 grounding, 288 Float switches, 166 reconnecting generator leads, 292 Freehand sketches, 60 Electrical safety precautions, 24-31 Fuses, types of, 125, 258 energized circuits or equipment, 29-31 high-voltage 125 lock circuit breaker handles and tag circuits, maintenance, 125 26-28 other fuses, 125 office machines, 26 safety, 127 portable equipment, 24 portable personal equipment, 25 por:able power tools, 24 replacement of fuses, 26 switchboards, 28 Gas test, 500 Electrical shock: causes and consequences, 12 Gasoline and diesel engine sets, 271 Electrical shop safety, 176 Generator and motor maintenance, 212 Electrical tester, servivar, 100 Generator equipment, 271-279 Electrically operated switches, 162 control panels, 274 Electron tube diodes, 479 diesel and gasoline engine sets, 271 Electron tube triodes, 488-490 generators, 272 oscillators, 489 switchboard controls 278 Electron tubes, multielement, 490 Generator installation, 285-288 Electron tubes, testing, 497 power and voltage requirements, 285 Electronic temperature control, 170 sheltering generators, 287 Emergency shut-down, 303 Generator set, preparing to operate, 295 Engine sets, diesel and gasoline, 271 Generator watch, 304 Engineering command drawings, naval facilities,Generators, 272 56-60 Generators and motors, repairs to, 178 Enlisted rating structure, 2 Generators, operation theory of SRCR, 279 Entrance switches, 251 Grounding, 148

613 525 CONSTRUCTION ELECTRICIAN 3 & 2

Grounding transformers, 343 Interior wiring materials, 236-249 Guy anchors, 324 boxes, 244 cables, 237 conductors, 236 electric metallic tubing (thin-wall or EMT), 242 Hacksaws, power, 67 explosion-proof fittings, 248 Hardware, 313 flexible conduit, 243 Hermetic compressor application, 229 intermediate metal conduit, 243 High-voltage fuses, 125 PVC conduit, 243 Hook switch, 391 receptacles, 245 Horizontal arrangement, 356 rigid conduit, 239 Household refrigerators, 233 switches, 246 wiring troughs 244 Intermediate metal conduit, 243 Interoffice communications systems, 429-433 installation procedures, 431 troubleshooting, 432 ICO test, 504 Identification of chassis wiring, 479 Impedance coupling, 493 Information sources, 9 commercial publications, 10 Key safety personnel, 474 government publications, 9 manufacturer's manuals, 10 training films, 11 Inspecting the generator, 295 Installation, electrical, 288 Lamps, troubleshooting, 267 Installation, generator, 285 Large appliances, domestic oil burners, window Installing a telephone, 402-405 air conditioners, 223 bells and buzzers, 405 Lead-oovered cable, repair of, 437, 460 checking an installation, 405 Lighting circuits, installing, 352 connections to protectors, 403 Lighting systems, 263 connections to subsets, 404 Lighting arresters, 317 connections to the main run, 404 Line voltage adjustment and test, 499 hooking up a handset, 405 Local battery and common battery circuitry,388 wiring, 402 Locating and installing conductors, 254 Installing and locating conductors, 254 Installing lighting circuits, 352 Installing the service, 249-257 distribution panels, 251 entrance switches, 251 Magneto generator, 391 grounding, 254 Maintenance of controllers, 155 interior wire splices, 257 Maintenance of marking, lighting, and related locating and installing conductors, 254 electrical facilities, 381 motor branch service, 255 Maintenance, motor and generator, 212 neutral wire, 253 Maintenance, switchgear, 306 service drop conductors, 250 Manual telephone central office AN/TTC-7A, 406 service entrance conductors, 250 Manually operated switches, 157 Instruments, care of, 122 Material and parts, 176 Insulating liquids, 341 Materials, interior wiring, 236 Insulator pins, 312 Measurements in transistor circuits, 505 Insulators, 312 Metallic tubing, electric (thin-wall or EMT),242 Intercom system maintenance, 436 Methods of biasing, 491 Interior wire splices, 257 cathode bias, 491 Interior wiring, 52, 235-269 '62,6 grid-leak bias, 491

514 IN D EX

Metric system, appendix 1, 507 Operation theory of SRCR generators, 279 Military standards and specifications, 235 Organization, safety policy, 472 Model 259 vibroground, 105 Oscillators, 489 Motor and generator maintenance, 212-223 Overhead cable line, 395 capacitor motors, 213 Overload devices, 135-142 centrifugal switches, 212 magnetic type, 139 cleaning motors and generators, 215 thermal type, 141 general maintenance, 217 Overhead power distribution, 311-356 generators, 215 sleeve bearings, 220 split-phase motors, 213 3-phase motors, 214 Motor branch circuits, 255 PVC conduit, 243 Motor installation identification, 154 Parts and material, 176 Motors and generators, repairs to, 178 Pentodes, 491 Multiamp tester (MS-1A), 103 Personnel, key safety, 474 Multielement electron tubes, 490 Phase-failure relay, 146 pentodes, 491 Phase sequence indicator, 99 tetrodes, 490 Photoelectric control relays, 162 Planning work assignments, 465 Plastic-covered cable, 438 Pneumatic drill, 64 Pneumatic grinder, 64 National electrical code, 235 Pneumatic pavement breaker, 65 NAVFAC specifications, 235 Polarity, transformer, 345 Naval facilities engineering command drawings, Pole line components, 312-317 56-60 crossarms, 312 Navy enlisted advancement system, 3 hardware, 313 Navy enlisted classifications, 2 insulator pins, 312 Neutral wire, 253 insulators, 312 lightning arresters, 317 poles, 312 0 protttive devices, 314 Poles, 312 Obstruction lighting, 353 Portable sower tools, 61-68 horizontal arrangement, 356 pneumalc drill, 64 lighting of overhead wires, 356 pneuma.ic grinder, 64 vertical arrangement, 355 pneumatic pavement breaker, 65 Occupational standards, 2 power hacksaws, 67 Oil burners, 223 Power-act ated tools, 68-73 Oil circuit breakers, 131 Power and voltage requirements, 285 Open circuits, 262 Pcwer earth augers, 80, 82 Open wires, 394 auger esle and maintenance, 87 Opening the sheath, 461 auger,t)ty, 87 Operating and servicing procedures, 297 ope,on of power earth augers, 82 Operating rules, 304 ng techniques, 84 Operating techniques, 84 L,..)curing a truck-mounted power earth auger, Operation of power earth augers, 82 85 Operation of power station, 299-306 Power hacksaws, 67 emergency shutdown, 303 Powerline erection, 317-338 generator watch, 304 climbing poles, 324 operating rules, 304 digging post holes, 319 placing generator on the line, 300 erecting polec, 320 securing generators, 303 guy anchors, 324 starting ax A-C generator, 299 interference elimination, 337 synchronizing generators, 300 mounting crossarms and racks, 332

515 527 CONSTRUCTION ELECTRICIAN 3 ez 2

Power line erectioncontinued Repairs and maintenance, 257 preparing poles, 317 disconnecting devices, 258 safety in pole raising, 321 fuses, 258 secondary racks, 332 lighting systems, 263 stringing the conductors, 333 load balance, 261 tying in conductors, 335 maintenance, 267 Power rectifier, 307 open circuits, 262 Power station, operation of, 299 overloads, 261 Power tools, portable, 61 short circuit or ground, 262 Precautions, basic measuring instrument troubleshooting lamps, 267 precautions, 88 wiring systems, 258 Preparing a lead splice, 363 Repairs to generators and motors, 178-212 Preparing poles, 317 alternating-current stator coils, 208 Preparing requisitions, 467 armatures, 191 Preparing to operate the generator set, 295-299 ball bearings, 189 inspecting the generator, 295 brushes, 185 servicing and operating procedures, 297 collector rings, 184 servicing the generator, 297 commutators, 180 servicing the prime mover, 296 disassembly and reassembly, 178 Pressure and temperature switches, 168 field coils, 206 Pressure limit switch, 171 Resin splice, 378 Primary and secondary construction, 340 Resistor color codes, 476 Prime mover, servicing the, 296 Resistor ratings, 475 Procedures, servicing and operating, 297 Resistor tolerances, 475 Protective devices, 123-128, 314 Resistors and capacitors, 475-477 fuse maintenance, 126 capacitor color coding, 476 high-voltage fuses, 125 resistor color codes, 476 other fuses, 126 resistor ratings, 475 safety with fuses, 127 resistor tolerances, 475 troubleshooting secondary fused circuits, 123Requirements for motor controls and mountings, Public address system maintenance, 433, 436 154 Public works department, 1 Requirements, voltage and powar, 285 duty at overseas bases, 2 Reverse current and phase-failure devices, duty within the U. S., 2 142-148 Pulling cable, 360-363 phase-failure relay, 146 reel placement, 362 reverse current relay, 142 rigging, 362 reverse-power relay, 144 Reverse power Ielay, 144 Reversing controllers, 151 Rigid conduit, 239 Ringing machines, 401 Rules, operating, 304 RC coupling, 492 Rating structure, enlibter.i, Reading bluepnnt, Reassembly snd dloc

516 528 INDEX ...1101rINIMI,

Safe working practicescontinued Sleeve bearings, 220 interlocks and safety devices, 23 Soldering the seam, 464 ladder safety, 15 Solid state diodes, 483 lifting safely, 14 Special test equipment, 100-122 new installations, 24 cable repairman's test set, 111 painting electrical equipment, 24 model 259 vibroground, 105 personal safety, 15 multiamp tester (mS-1A), 103 platforms, 19 servivar electrical tester, 100 protection of nonelectrical workers, 24 tela cable model 262, 121 safety equipment, 17 telephone test set AN/PTM-5, 119 shop machinery, 21 weston model 639 industrial analyzer type testing rubber protective equipment, 18 3, 102 tools, 19-21 wheatstone bridge, 106 use of warning signs, plates, and tags, 21-23 Special tools, 61-87 walking safely, 14 Specifications and codes, 148 wear hard hats, 15 Specifications and requirements, 235 Safety, 12-44, 378 militarystandards and specifications, 235 hot liquids, 379 NAVFAC specifications, 235 manholes, 379 national electrical code, 235 testing for live cable, 378 Splicee, interior wire, 257 Safety, air compressor, 80 Splicing lead-sheathed cable, 438. Safety, auger, 87 Splicing plastic-sheathed cable to lead-sheathed Safety code for motors and motor protection, cable, 449 154 Splicing polyethylene cable for aerial installation, Safety combustion controls, 172 446 Safety control and reporting organization, 472Splicing polyethylene cable for direct-burial Safety devices and indicators, 306 installation, 459 Safety education, 32-38 Splicing polyethylene insulated cable, 445 accident investigation, 33-38 Splicingsilk and cotton insulated sable, 445 accident reporting, 33 Splicing telephone cable, 438-460 Safety, electrical shop, 176 splicing lead-sheathed cable, 438 Safety in pole raising, 321 splicing plastic-sheathed cable to lead- Safety policy organization, 472 sheathed cable, 449 Safety precautions, electrical, 24-31 splicing polyethylene cable for aerial Schematics,blueprints,and diagrams,45-60 installation, 446 Schematics and diagrams, 48-56 splicing polyethylene cable for direct-burial Secondary racks, 332 installation, 459 Securing a truck-mounted power eaxth auger, splicing polyethyleneinsulated cable,445 85 splicing silk and cotton insulated cable, 445 Securing generators, 303 Splicing underground cable, 363-378 Semiconductor testing, 502 preparing a lead splice, 363 Service drop conductors, 250 resin splice, 378 Servicing and operating procedures, 297 splicing with molds, 375 Servicing the generator, 297 tapecast splice, 376 Servicing the prime mover, 296 Split-phase motors, 213 Servivar electrical tester, 100 Starting an A-C generator. 299 Sheltering generators, 287 Stator coils, alternating-current, 208 Shop organization, 175-178 Staticcontrols,279 electrical shop safety, 176 operation theory of SRCR generators, 279 material and parts, 176 Street lighting circuits, 350 tools and equipment, 176 Street lighting fixtures, 350 Shopwork, 175-234 Stringing the conductors, 333 Short circuit and noise test, 499 Strowger switches, 415 Short circuit or ground, 262 Subset maintenance, 434 Shutdown, emergency, 303 Supervising work teams, 466 Single source biasing, 495-497 Switchboard controle, 278 Sketches, freehand, 60 Switchboard maintenance, 435 517 529 CONSTRUCTION ELECTRICIAN 3 & 2

Switchboard protective devices, 398 Testing for live cable, 378 Switchgear maintenance, 306 Testing transistors, 502 safety devices and indicators, 306 ICO test, 504 Switches, electrically opera,ed, 162 measurementsintransistorcircuits,505 Switches, manually operated, 157 semiconductor testing, 502 Switches, types of, 166, 246 Tetrodes, 490 float switches, 166 The personnel readinesscapability program, pressure and temperature switches, 168, 171 470-472 Synchronizing generators, 300 Timekeeping, 467-470 Tools and equipment, 176, 436 Tools, portable power, 61 Tools, power-actuated, 68 Transformer connectons, 346 Transformer coupling, 494 Tape-armored cable, 437 Transformers, grounding, 343 Tapecast splice, 376 Transformer mounting, 342 Tela cable model 262, 121 Transformer polarity, 345 Telephone cable, 394-397 Transformer testing, 477-479 outside terminals, 396 Transmission system ;harming, 393 overhead cable line, 395 field wires, 394 types of telephone cable, 394 open wires, :194 underground telephone line, 396 Transmitter, 386 Telephone cable classification, 437 Transistor circuits, measurements in, 505 building and switchboard cable, 438 Transistor lead identification, 487 lead covered cable, 437 Transistors, 486-488 plastic-covered cable, 438 circuitry, 487 tape-armored cable, 437 transistor lead identification, 487 Telephone cable splicing, 437-464 Telephone cable, types of, 394 Triodes, electron tube, 488 Telephone EE-8, 414 Troubleshooting, 307, 352 Telephone line, underground, 396 power rectifier, 307 Telephone switchboards, 397-402 sectionalizing, 353 circuits, 400 using a megger, 353 distribution frames, 398 Troubleshooting lamps, 267 ringing machines, 401 Troubllespooting secondary fused circuits, 123 switchboard protective devices, 398 Tying in/conductors, 335 switch key, 402 Telophone system design, 392 attenuation, 393 electrical length, 392 interference, 393 Underground cable, 360 loading, 393 Underground power distribution, 357-384 Telephone test oet AN/PTM-5, 119 Underground telephone line, 396 Terminals, outside, 396 Using a megger, 353 Test equipment, 88-122 Test set, cable repairman's, 111 Testing, circuit, 433 V Testing electron tubes, 497-502 cathode leakage test, 501 filament activity test, 501 Vertical arrangement, 355 gas test, 500 Vibroground, model 259, 105 line voltage aajustment and test, 499 Vibrotest megohmrneter, 96 quality test, 502 Voltage and power requirements, 285 rectifier test, 501 Voltage control circuit, 280 short circuit and noise test, 499 Voltage tester, 95

518 530 'INDEX

Wheatstone bridge, 106 Window air-conditioners, 230 Warning, 280-2g5 Window air-conditioners, domestic oil burners, brushless i,enerators, 284 and large appliances, 223 voltage control circuit, 280 Wire communications, 52-56 Washers, automatic, 224 Wiring, 402 Water level controls, 170 Wiring maintenance, 433 Weston model 639 industrial analyzer type 3, Wiring systems, 258 102 Wiring troughs, 244

5 3 I

519 CONSTRUCTION ELECTRICIAN 3 8t 2 NAVEDTRA 10636-H

Prepared by the Naval Education and Training Program Development Center, Pensacola, Florida

Your NRCC contains a set of assign- higher. If you are on active duty, the ments and self-scoring answer sheets average of your grades in all assign- (packaged separately) .The Rate Training ments must be at least 3.2. If you are Manual, Construction Electrician 3 & 2, NOT on active duty, the average of your NAVEDTRA10636-H, is your textbook for grades in all assignments of each the NRCC. If an errata sheet comes with creditable unit must be at least 3.2. the NRCC, make all indicated changes or The unit breakdown of the course, if corrections. Do not change or correct any, is shown later under Naval Reserve the textbook or assignments in any other Retirement Credit. way. WHEN YOUR COURSE IS ADMINISTERED HOW TO COMPLETE THIS COURSE SUCCESSFULLY BY LOCAL COMMAND Study the textbook pages given at As soon as you have finished an the beginning of each assignment before assignment, submit the completed self- trying to answer the items. Pay attention scoring answer sheet to the officer to tables and illustrations as they designated to administer it. He will contain a lot of information. Making yourcheck the accuracy of your score and awn drawings can help you understand the discuss with you the items that you do subject matter. Also, read the learning not understand. You may wish to record objectives that precede the sets of itemsyour score on the as :gnment itself since The learning objectives and items are the self-scoring answer sheet is not based on the subject matter or study returned. material in the textbook. The objectives tell you what you should be able to do If you are completing this NRCC to by studying assigned textual material become eligible to take the fleetwide and answering the items. advancement examination, follow a schedule that will enable you to complete At this point you shn,:ld be ready all assignments in time. Your schedule to answer the items in th assi9nment. should call for the completion of at Read each item carefully. Select the least one assignment per month. BEST ANSWER for each item, consulting your textbook when necessary. Be sure fou complete the course

to select the BEST ANSWER from the sue( , the Naval Education and subject matter in the teAtbook. You may Train.....9 Program Development Center will discuss difficult points in the course not issue you a letttx of satisfactory with others. However, the answer you completion. iour command will make a note select must be your own. Usa only the in your service record, giving you credit self-scoring answer sheet designated for your work. for your assignment. Follow the scoring directions given on the answer sheet WHEN YOUR COURSE IS ADMINISTERED itself and elsewhere in this course. BY THE NAVAL EDUCAIION AND TRAINING PROGRAM DEVELOPMENT CENTER Your NRCC will be administered by your command or, in the case of small After finishing an assignment, go twommands, by the Naval Education and on to the next. Retain each completed

, Training Program Development Center. self-scoring answer sheet until you No matter who administers your course finish all the assignments in a unit (or you can complete it successfully by in the course if it is not divided into earning grades that average 3.2 or units). Using the envelopes provided,

53Z mail your self-scored answer sheets to theNAVAL RESERVE RETIREMENT CREDIT Naval Education and Training Program Development Center where the scores will The course is evaluated at 18 Naval be verified and recorded. Make sure all Reserve retirement pei:its, which will be blanks al the Lop of each answer sheet credited in units as follows: Unit 1,12 are filled in. Unless you furnish all the points upon completion of assignments 1 information required, it will be through 8; Unit 2,6 points upon completion impossible to give you credit for your of assignments 9 through 12. These points work. You may wish to record your scores are creditable to personnel eligible to on the assignments since the self-scoringreceive them under current directivesgovern- answer sheets are not returned. ing the retirement of Naval Reserve personnel. Credit cannot be given again for the course The Naval Education and Training if the student has previously received credit Program Development Center will issue a for completing another Construction Electri- letter of satisfactory completion to cian 3&2 NRCC or ECC. certify successful completion of the course (or a creditable unit of the COURSE OBJECTIVE course). To receive a course-completion letter, follow the directions given chi In completing this nonresidentcareer the course-completion form in the back course, you will demonstrate a knowledge of of this NRCC. the subject matter by correctly answering items on the following: enlisted rating You may keep the textbook and structure; principles of the advancement assignments for this course. Return them system; preparing for advancement; safe only in the event you disenroll from the practices an6 first aid measures;safety course or otherwise fail to complete the training; reporting accidental injuriesor course. Directions for returning the deaths; reading and caring for blueprints, textbook and assignments are given on thedia7rams, and schematics; maintainingand book-return form in the back of this operating test, protective, and control NRCC. equipment; repairing, testing,and maintaining motors, generators,and electric appli- PREPARING FOR YOUR ADVANCEMENT ances; fundamentals of interior wiring; in- EXAMINATION stalling and operating a centralpower station; installing, maintaining, and repairing Your examination for advancement is overhead and underground electrical distri- based on the Manual of Navy Enlisted Man- butionsystems; cable splicing; installing, power and Personnel Classification and servicing, and operating a telephonecommu- Occupational Standards (NAVPERS 18068-D). nications system; and fundamentals of elec- The sources of questions in this examine- tronic components and circuits. tion are given in the Bibliography for Ad- vancement Study (NAVEDTRA 10052) . Since your NRCC and textbook are among the sources listed in this bibliography, be sure to study both in preparing to take your advancement examination. The standards for your rating may have changed since your course and textbook were printed, so refer to the latest editions of NAVPERS 18068-D and NAVEDTRA 10052.

While working on this nonresident career course, you may refer freely to the text. You may seek advice and instruction from others on problems arising in the course, but the solutions submitted must be the result of your own work and decisions. You are prohibited from referring to or copying the solutions of others, or giving completed solutions to anyone else taking the same course.

i i Naval nonresident career courses may include a variety of items -- multiple-choice, true-false, matching, etc. The items are not grouped by type; regardless of type, they are presented in the same general sequence as the textbook material upon which they are based. This presentation is designed to preserve continuity of thought, permitting step-by-stepdevelopment of ideas. Some courses use many types of items, others only a few. The student can readily identify the type of each item (3nd the action required of him) through inspection of the samples given below.

MULTIPLE-CHOICE ITEMS Each item contains several alternatives, one of which provides the best answer to the item. Select the bcst alternative and erase the appropriate box on the answer sheet.

SAMPLE s-1. The first person to be appointed Secretary Of 15efense The erasure of a correct answer is in- under the National Security Act of 1947 was dicated in this way on the answer sheet: 1. George Marshall 2. James Forrestal 1 3 1 4 3. Chester Nimitz 1E11 4. William Halsey s-1 C

TRUE-FALSE ITEMS Determine if the statement is true or false. If any part of the statement is false the statement is to be considered false. Erase the appropriate box on the answer sheet as indicated below. The erasure of a correct answer is also SAMPLE indicated in this way on the answer s-2. Any naval officer is authorized to corresT5T1T-- sheet: officially with a bureau of the Navy Department without his commanding officer's endorsement. 3

MATCHING ITEMS T2 i1111CC Each set of items consists of two columns, each listing wor s, pirases or sen ences. The task is to select the item in column B which is the best match for the item in column A that isbeing considered. Specific instructions are given with each set of items. Select the numbers identifying the answers and erase the appropriate boxes on the answer sheet.

SAMPLE In items s-3 through s-E, match the name of the shipboard officer in column A by selecting from column B the name of the department in which the officer functions.

A. Officers B. Departments Theerasure of a correct answeris indicatedin this way on theanswer sheet: s-3. Damage Control Assistant 1 Operations Department

s-4. CIC Officer 2. Engineering Department ri KO s-5. Assistant for Disbursing 3. Supply Department Jtj 11%11 s-6. Communications Officer s-6

How To Score Your Immediate Knowledge of Results (IKOR) Answer Sheets

Total the number of in- Sample onl F correct erasures (those Number of boxes that show page numbers) erased incorrectly 0-2 3-7 I 9 fcr each item and place :e>in the blank space at Your score 4.0117) 12 the end of each item.

Now TOTAL the column(s) of incorrect erasures and find your score in the Table at the bottom of EACHanswer sheet.

NOTICE: If, on erasing, a page number appears, review text (starting on that page) and erase again until "C", "CC", or "CCC" appears. For courses administered by the Center, the maximum number of pclnts (or incorrect erasures) will be deducted from each item which does NOT have a "C", "CC", or "CCC" uncovered (i.e., 3 pts. forTOUFTEFOice items, 2 pts. for three choice items, and 1 pt. for T/F items). iii

534 Assignment 1

Meot tho i:oh::tin,11,,n Elect : Safet.y_

Textbook NAVEDTRA 10h3b-H: Pages 1-32

Id this course you will demor ning has taken place by correctly answering training items. The mere physical ing a choice on an answer sheet is not in itself important; it is the mental achiev, _ever form it may take, prior to the physical act t at is important and toward which h career course learning objectives are directed. The selection of tho correct choice for a course training item indicates that you have fulfilled, at least in part, the stated objective(s).

The accomplishment of certain objectives, for example, a physii.al act such as drafting a memo, cannot readily be determined by means of objective type course items; however, you can demonstrate by means of answers to training items that you have acquired the requisite knowledge to perform the physical act. The accomplishment of certain other learning objectives, for example, the mental acts of i'iparing, recognizing, choosing, selecting, etc., may be readily demonstrated in a course by indicating the ct answers to training items.

The comprehensive objective for this course has already been given. It states the purpose of the course in terms of what you will be able to do as you complete the course.

The detailed objectives in each assignment state what you should accomplish as you progress through the course.They may appear singly or in clusters of closely related objectives, as appropriate; they are followed by items which will enable you to indicate your accomplishment.

All objectives in this course are learning objectives and items are teaching items. They point out important things, they assist in learning, and they should enable you to do a better job for the Navy.

This self-study course is only one part of the total Navy training program; by its very nature It can take you only part of the way to a training goal. Practical experience, schools, selected reading, and the desire to accomplish are also necessary to round out a fully meaning- ful training program.

1-2. A LEC officer who heads the operating div.sion of a Public Works Department Learning Objective: Identify funda- has the title of mentals of staffing a Public Works Department. 1. shops engineer 2. leader 3. general foreman 4. group superintendent 1-1. On which of the following factors are staffing requirements of a Public Works 1-3. Which of the following blue collar titles Department determined? carries the most responsibility?

1. Size 1. Snapper 2. Location 2. Leadingman 3. Mission 3. Quart..rman 4. All of the above 4. Chief quarterman

1 535 Learning Objective: Point out purposes Learning Objective: Recognize principles of general ratingn and Navy enlisted of the advancement system. classifications (NEC's) and identify skills prescribed by NEC's.

1-10. Which of the following is NOT a general requi:rment to qualify for promotion to 1-4. A general rating is 1,ed to ide.itify CE2?

1. an indivi.dual's job gualificatio:,s 1. Completion of required training 2. a specialty used in wartime courses 3. a broad field of related'duties 2. Passing a written examination 4. an individw.l's performance in 3. Passing the required performance test comple ing his practical fac_ers 4. Length of time in grade

1-5 Navy enli:;ted classifi,:ations are desighed 1-11. Your immediate reward for satisfying all to make it easy to ,2xercise manajement the requirements for advancement is control over 1. eligibility for promotion I. CEC officers 2. actual promotion 2. Navy enlisted perso-Inel 3. more prestige 3. officers and enlisted men 4. more authority and increased respon- 4. civilian employees of a Public Works sibility Departmene '-12. refore being transferred to another duty station, you should make sure that lour NAVEDTRA 1414/1 is In items 1-6 through 1-8 select from column B the Navy enlisted classification that is 1. among your personal papers assigned to reflect the skills in column A. 2. in your service record 3. retained by your division officer A. Skills B. NECIs 4. destroyed and a new one started at your new duty station 1-6. Splicing multiconductor 1. CE-5632 cables used in telephone 1-13. Which of the courses listed in NAVEDTRA communication and in elec- 2. CE-5642 10052 for the CE rating must a CE2 tric power transmission complete before he is eligible to take and distribution systems 3. CE-5644 servicewide examination for advancement?

1-7. Repairing switchboards, 4. EA-5515 1. All courses listed telephones, and automatic 2. All courses listed for the next PBX and PAX telephone higher rate exchange equipment 3. Asterisked courses listed for the next higher rate 1-8. Repairing electrical systems 4. Unmarked courses listed for the next of shore-based power plants higher rate

1-9. Which of the following tasks would a persou

assigned the NEC EA-5515 be expected to 4 perform?

1. Placing underwater demolition charges 2. Superliising the collection of pile- driving test data 3. Supervising the day-to-day operation of the safety department 4. Preparing management da associated with one or more construction projects

2 536

; 1-19. In studying Rate Training Manuals, a Learning Objt!ctIvc: R,.cognize publi- reliable indication that you have cations for advancement study and poipt mastered the subject matter in a chapter out good study practIces. is your ability to

1. quote, word for word, passages from the chapter In items 1-14 through 1-16, select from column B 2. express in your own words the main the publication that is the source of the points of the subject information in column A. 3. memorize pertinent dates, tables of weights and measures, and other such A. Information B. Publications information 4. ask intelligent questions about the 1-14. Latest edition of a 1. Manual of subject given Rate Training Navy Enlisted Manual Manpower and 1-20. You can keep abreast of new developments Personnel that affect you, your work, and the Navy 1-15. References used as Classifica- by source material for tions and fleetwide J,Jvance- Occupational 1. obtaining and applying up-to-date ment examinations Standards information that pertains to your rating 1-16. Skills rt ,2Q1 of 2. Bibliography 2. collecting personal copies of perti- enlisteu _rsor,nul for Advance- nent oechnical manuals ment Study 3. cor ng all enlisted correspondence cou :hat pertain to your rating 3. List of Train- 4. compiLing all officer correspondence ing Manuals courses that are related to your and Corres- rating pondence Courses 1-21. Which of the following publications is published by the National Bureau of 4. NAVFAC Docu- Standards? mentation Index 1. National Electrical Code 2. National Electrical Safety Code 3. Navy Safety Precaution for Shore Activities 1-17. Which of the following hints for study- 4. Advanced Base Electrical Systems ing should help you get the most from your Rate Training Manual?

1. Devote your time exclusively to impor- Learning Objective: Recognize safe tant military topics practices in the use of tools and equip- 2. Try not to cover a complete unit in ment and identify publications that any one study period provide information on electrical safety. 3. Omit easy material; study only the most difficult and the unfamiliar 4. Make notes as you study, particularly of main ideas, then review your notes 1-22. The extent of body damage caused by electrical shock depends on 1-18 When'studying a Rate Training Manual, you should make it a practice to 1. the size of the body 2. the value of voltage touched by the 1. set up a fixed number of pages in body each study period 3. the amount of current flow through 2. relate new information to things you vital organs already know 4. whether the current was a-c or d-c 3. memorize as much as you can from a chapter and repeat it to a shipmate 4. concentrate on studying just before an examination so you will not forget important details

537 1-23. When the human body is shocked by more 1-29. Which of the following tasks requires that than 200 ma of current, the chest muscles goggles be worn? contract to Hamp the heart. 1. Soldering an electrical connection 1-24. Which is the most important factor in 2. Pouring acid into water rescuing a man in contact with an 3. Drilling holes in concrete or other electric circuit? masonry materials 4. Each of the above Preventing physical injury to the man 1-30. Hard hats provide better head protection 2. Separating the man from the electric than ordinary hats. Which of the follow- powar by the quickest possible means ing is another true statement in favor 3. Preventing the victim's body resist- of wearing hard hats instead orconven- ance from decreasing tional headgear? 4. Avoiding damage to equipment 1. Hard hats weigh less 1-25. The procedure for discharging a charged 2. Hard hats keep the head cooler on hot, capacitor is to discharge it sunny days 3. Hard hats keep the neck and ears 1. twice for at least 10 seconds each warmer in cold weather time 4. Hard hats stay on the head in high 2. once for at least 10 seconds each winds without benefit of a chinstrap time 3. once for at least 5 seconds each time 1-31. What advice should you give one of your 4. twice for at least 5 seconds each time men who objects to wearing a hard hat because it does not keep his head, neck,

1-26. In what position should your : t, knees, or ears warm? and back be when you are lifting an object? 1. Wear a stocking cap over the .rd hat 2. Wear ordinary headgear made extra 1. Feet apart 15 inches from object, thick material knees bent, and back straight 3. Wear a winter liner 2. Feet apart close to object, knees 4. Use a chinstrap to keep the hard hat straight, and back bent in place 3. Feet together and close to object, knees bent, and back straight 1-32. The wiring specifications contained in 4. Feet together 15 inches from object, NAVFAC Specifications are based on knees straight, and back straight minimum requirements for safe design of electrical installations which the 1-27. When placing an 8-ft ladder against a National Fire Protection Association wall, how far from the wall should you provides in set the base of the ladder? 1. Handbook H-30 1. 1 ft 2. National Electrical Code 2. 1 1/2 ft 3. National Electrical Safety Code 3. 2 ft 4. Safety Precautions for Shore 4. 2 1/2 ft Activities

1-28. In climbing a ladder while carrying tools, 1-33. Handbook H-43 contains engineering data you should make it a practice to carry for the installation and maintenance of the tools electrical and communications lines. The name of this publication is 1. in both hands; use no hands for climbing 1. Installation and Maintenance of Elec- 2. in the right hand; use the left hand trical Supply and Communication Lines, for climbing Safety Rules and Discussion 3. in the left hand; use the right hand 2. National Electrical Safety Code for climbing 3. Safety Precautions for Shore Activities 4. in a bag slung over the shoulder; use 4. Safety Rules for the Installation and both hands fox climbing Maintenance of Electric Supply and Communication Lines

4 1-34. When a rubber glove is being air-tested 1-38. Which of the following actions is an for holes, air trapped in the glove approved method for improvising an and forced into the thumb, fingers, and insulating barrier between a metal tool palm of the glove. Any hole through which and the hand of its user? air can escape is found by 1. Applying cambric sleeving covered by 1. submerging the glove in water and several layers of friction tape watching for bu5bles of air to rise 2. Applying several layers of friction to the surface of the water tape 2. coating the glove with a soapsuds 3. Applying several layers of approved solution and watching for soap rubber insulating tape (half-lapped) bubbles to form covered by a layer or two of friction 3. Holding the glove to your ear and tape listening for the sound of escaping air 1-39. A metal tool handle may be covered with several layers of rubber tape, and then 1-35. Which of the following is a safe practice? covered with a layer of friction tape for emergency electrical use. 1. Cleaning an electrical apparatus with a flammable fluid 1-40. What should you do if a powder-actuated 2. Wearing a hard hat when working or tool misfires, or fails to fire, after a walking in an area where hoisting or period of 15 seconds? overhead work is going on 3. Shifting positions of your feet while 1. Open the tool, remove the powder lifting a heavy object charge, then remove the guard 4. Sharpening gaffs on pole climbers when 2. Remove the guard from surface and gaff length measures less than 1 1/4 then remove the charge inches 3. Replace the charge and then attempt to refire 1-36. Which of the following materials is suitable for covering grounded metal to 1-41. If you are called while soldering the keep a worker from coming in contact with connections to a motor and have to leave the metal? your shop for a few minutes, what should you do with the hot soldering iron? 1. Damp plywood 2. Dry canvas that has holes in it 1. Display a HOT RAZARD sign and return 3. Dry insulating material that contains as soon as possible no holes or conductors 2. Leave it plugged in so others will 4. Dry phenolic material that has a see that it is hot conductor embedded in it 3. Retin it and leave it plugged in 4. Unplug it and stow it in its assigned 1-37. If it becomes necessary to work on ele storage area trical circuits or equipment in wet or damp locations, what is one very important 1-42. Which of the following procedures is step you should take? recommended for cleaning a soldering iron? 1. Making sure that there is no contact between the wet floor and your shoes 1. Hold a cleaning cloth in your hand 2. Wearing shoes that have thick rubber and wipe the hot iron across it soles 2. Place a cleaning cloth on a suitable 3. Wiping the area where you are going surface and wipe the hot iron across to stand with a dry rag it 3. Swing the hot iron with enough force to remove the solder 4. Tap the hot iron on a metal surface to knock the solder off

539 1-41. Which of the following measures is con- 1-50. Which of the following procedures apply sidered the final touch in the completion to portable, electrical personal of a high vflltage wluipment installation? equipment?

1. It is checked by the electrical 1. Inspection overy 6 months officer 2. Repair and reinspection by the 2. It is checked by the division's electrical crew, if damaged leading CPO 3. Certification by means of a Safety 3. It is tested by an experienced Officer's tag of approval before use operator 4. All of the above 4. High voltage warning signs are posted in full view of operating personnel 1-51. Assume that the personal radio belonging to one of your men has a built-in power 1-44. Warning signs are posted in work areas to transformer that presumably provides alert individuals of existing hazards isolation from the powerline, but you and to prevent damage to machinery. have found that the insulation resistance between the metal chassis of the radio 1-45. What are the ground lead requirements for and the primary of the transformer is an electrical workbench that is 8 feet only thre- megohms. 'What safety measure long? do you take?

1. One fi-f')ot ground lead 1. Check the tubes and replace the 2. Two B-foot ground leads defective ones 3. Two 4-foot ground leads 2. Ground the chassis by means of a 4. Three 3-foot ground leads grounded plug and suitable cord 3. Insert an additional resistance, 1-46. Which of the following sizes of ground approximately 100 megohms, in series lead is appropriate for a workbench that with the primary of the transformer is supplied by 12-gage line conductors? 4. Reverse the leads to the secondary of the transformer 1. 10-gage 2. 14-gage 1-52. Electric shavers do not require 3-prong 3. 18-gage gounding plugs because the 4. 20-gage 1. owner cannot use it ashore 1-47. What is the maximum acceptable resistance 2. original cord is fused to the housing between an installed grounding object and to prevent it from being pulled out the earth? 3. housing is of nonconductive plastic material and the cutting blades are 1. 1ohm isolated from the electrical compo- 2. 3ohms nents within the shaver 3. 6ohms 4. 3-conductor cord is too heavy and 4. 12ohms bulky which makes it hard to use

1-48. What is the primary purpose for repainting electrical equipment? Learning Objective: Recognize safe and 1. To prevent incipient corrosion unsafe working practices or conditions 2. To improve its appearance applicable to energized circuits. 3. To improve the insulation 4. To provide a means of identification

1-49. Portable electric cables should be con- 1-53. Which of the following is a safe practice sidered very dangerous if they are for members of an electrical crew?

1. more than 10 feet long 1. Wearing rubber gloves with leather 2. spliced at any place overgloves to remove transformer fuses 3. insulated with any material other 2. Placing a NAVSHIPS Warning Tag 3950 than rubber (3-63) on each switch of a circuit 4. red that is being overhauled 3. Placing 2 NAVSHIPS Warning Tags 3950 (3-63) on each supply switch of a circuit that is being repaired by 2 working parties 4. Each of the above 6

640 1-54. What is the first stop that you should 1-59. Who determines whether or not work is done take in replacing a 220-volt 15-ampere on an energized circuit? fuse? 1. Electrical officer only 1. Deenergize the circuit completely 2. Damage control officer only 2. Put on rubber gloves before touching 3. Enqineering officer only the fuse 4. Commandiny officer or his authorized 3. Remove and replace the fu!,e with representative insulated fuse pullers 4. Turn the switch off to the burned 1-60. Before work is started on an energized out fuse only circuit or switchboard, a Construction Electrician should check to make sure 1-55. What are metal locking devices used for? that

1. Locking switches in the ON position 1. the divition officer is present to stop them from tripping in case 2. a Hospital Corpsman is present in of a surge in power case of an accident 2. Locking switches in the OFF position 3. the safety officer is present to prevent them from being operated 4. man are stationed by circuit breakers accidentally or switches and telephones are manned 3. Securing circuits which ate no longer in use 1-61. What is the recommended procedure for 4. All of the above discharoing high voltage capacitors when checking a circuit? 1-56. After the power has been turned off and the switch locked and tagged, you still 1. Discharge once with a suitably should not proceed to work on the circuit insulated shorting or grounding bar until you have checked 2. Discharge at least twice, with a minimum 15-second interval your tools 3. Discharge when the power is turned the lights in the space off and again before starting to work the metering and control circuits on the circuit 4. the grease and oil fittings 4. Connect a jumper lead across the capacitor leads but be sure to remove 1-57. Which of the following circuit breakers it before energizing the circuit should be secured before work is started on a switchboard? 1-62. Which of the following practices must NOT be followed when you are taking The main circuit breaker to the measurements on electrical circuits or switchboard equipment? 2. The circuit breaker at the generator feeding the switchboard 1. Deenergize the equipment after taking 3. All circuit breakers leading to the the reading switchboard 2. Assign the responsibility of energiz- 4. All of the abcvt ing the equipment to an assistant standing by the switch 1-58. One of th(:acGitemelAs of a rear-service 3. Avoid touching the test instrument switchboard is caat while the power is on 4. Take the measurement directly by 1. the fuse box be behind the switchboard means of flexible leads or probes 2. it must be dusted every day 3. the rear of the switchboard be covered with an expanded metal enclosure 4. it be painted with bright colors to identify the circuits

Mit 1-63. Which of the following is NOT a requirement for working on live conductors and Learning Objective: Indicate fire con- equipment operating at 600 volts or less? trol and fire preventive measures.

1. Adjacent live or grounded conductors and equipment should be covered with insulating material or approved 1-68. The best way to extinguish an electrical rubber protective equipment fire is to turn off the power and cover 2. Bare or exposed places on one conduc- the fire with tor must be taped or covered before another conductor is exposed 1. foam 3. Two men should work together 2. carbon dioxide 4. One must maintain a body clearance of 3. sand 2 feet when working on energized lines 4. water

1-64. When you are testing a 2,000-volt circuit 1-69. How soon after the discharge of a fire to determine if it is alive and it is not extinguisher should you request a possible io recheck the voltage detector recharge or replacement? on a known live circuit, what must you do? 1. Immediately 1. Test the voltage detector on a live 2. After a damage estimate has been circuit in the electric shop before made work is started 3. At the next firefighting equipment 2. Ask personnel who have used the inspection detector if it is working properly 4. Within 1 week after the fire 3. Use a new detector 4. Check it two times, each with a 1-70. What should be done with wiping rags and different detector other flammable waste material?

1-65. When working on electrical equipment with 1. Place them in a cardboard box and operating voltages of 3 to 7.5 kilovolts, kecp the box behind the motors and 7.5 to 12 kilovolts, or 12 to 33 kilo- generators volts, you should maintain a minimum 2. Place them in a tightly closed metal distance of, respectively container and empty the container at the end of each work day 1. one-half foot,1 foot, and 2 feet 3. Place the rags so they may be reached 2. one-half foot,2 feet, and 3 feet easily and place other waste material 3. 1 foot, 2 feet, and 3 feet in a tightly closed metal container 4. 2 feet,3 feet, and 4 feet 4. Remove them from the work area and place them in a neat pile in an open 1-66. Under which of the following conditions area may work be performed with hot-line tools on lines energized at more than 5,000 1-71. When not in use, volatile solvents should volts? be kept in tightly closed containers and stored in a separate building or in 1. Rain is impending but not actually falling 1. a ventilated fire-resistant room 2. Snow is falling but rubber gloves are 2. the coolest part of the generator worn LOOM 3. Tools are dry and rubber gloves are 3. the supply room not worn 4. an area just outside the generator 4. All of the above room but protected from the sun

1-67. The world's most important protective agent is

1. a careful individual 2. a good safety training program 3. use of safety procedures 4. good safety equipment

ts.)

8 Assignment 2

Safety (continued): Bli.enrinta, Diagrams and Schematics; Special Tools

Textbook NAVEDTRA 10636-H: Pages 33-87

2-5. The main purpose for completing sections 22 and 24 of the Accidental Injury/Death Learning Objective: Point out some impor- Report, OPNAV Form 5100/1, is to tant aspects of safety training and identify information that must be entered on 1. recommend corrective actions the Accidental Injury/Death Report, OPNAV 2. identify the principal unsafe condi- Form 5100/1. tion or act that caused the accident 3. provide a detailed description of the accident L. determine whether or not a formal in- 2.-1. Sound safety training enabs a man to vestigation of the accident is required guard against hazards for which safety devices are impracticable. 2-6. What kind of information should you supply in section 27 of the Accidental Injury/ 2-2. Which of the following will be most bene- Death Report, OPNAV 5100/1? ficial in reducing accidents? 1. Your description of the accident 1. Never work on unfamiliar equipment 2. Your opinion as to whether the acci- 2. Memorize all safety precautions dent was caused by an unsafe act or not 3. Work slowly and deliberately 3. Your opinion as to whether or not the 4. Recognize hazardous situations accident was caused by an unsafe condition 2-3. Which of the following measures is the 4. Your opinion of what can ,e done or preferred method for making the men in what will be done to prevent accidents your electrical group safety conscious? likthe one being reported

1. Allow them to learn by experience 2. Provide them with safety reminders and your personal example Learning Objective: Indicate injuries 3. Restrict them if they fail to follw encountered in electrical work and recog- the safety rules nize procedures for rendering first aid 4. Send them to safety school to accident victims.

2-4. Completing the reverse side of an accident report (OPNAV Form 5100/1) provides the crew leader with a guide for 2-7. As a general rule in aiding accident victims, which type of injury poses the 1. summarizing safety lectures and movies greatest threat to life and requires the that focus on accident prevention most immediate treatment? 2. recommending action that will help prevent accidents similar to the one 1. Stoppage of breathing being reported 2. Wounds, fractures, and dislocations 3. describing the type of injurY 3. Shock L. organiziug a training program that 4. Serious bleeding (hemorrhage) will emphasize accident preventions

9 543 One of the symptoms of a person in shook 2-13. When giving a cardiac massage you should is repeat the application of pressure about

1. a weak pulse 1. 40 to 60 times per minute 2. constracted pupils 2. 50 to 70 times per minute 3. cold, dry skin 3. 60 to 80 times per minute 4. deep, fairl; regular breathing 4. 70 to 90 times per minute

2-9. Which of `IleA.)11,. is the most impor- Information for items 2-14 through 2-20. tant factor to rescue a man from You are first to arrive at the scene of contact wit:h Ln c-!c:,,ric circuit? a fire. You find the following casualties injured as indicated. 1. Securi., 'he olccuit quickly 2. Pu11in th an awly from the circuit Poindeer--right hand and forearm are quickly reddened ard Startiug art'ic;.al resuscitation as soon ao possiLe Anderson--entire left leg exhibits 4. Avoiding conttct with the live circuit symptoms of increased warmth, tenderness, and or witn th viti while he is in a reddish appearance. ,oact with it Stein--face, neck, and both arms are 2-10. What ftu:.t you do for the victim of elec- reddened and blistered; skin on both hands is trical si.c.:°k before beginning artificial completely destroyed and the underlying tissue re3pir;q.1:-.1,7 is black.

1. Admini:ter a s'imulant Laine--burn on his right leg from the Trea', him for shock knee down, is characterized by complete destruc- Cloar his mouth of foreign matterOr tion of the skin, with charring and cooking of r,cher obstructicn the deeper tissues. 4. Cover him with a blanket 2-14. Your main objectives in rendering first 2-11. Indications of a cardiac arrest include aid treatment to burn victims are to

1. cold and moist skin, weak pulse at 1. prevent infections, relieve pain, and the wrist, anc . shallow, irregular combat shock breathing 2. relieve pain, immobilize the burned 2. dilatea pupils of the eyes, complete areas,and apply antiseptics to the absence of pulse at the wrist, and burns weak or stopped breathing 3. combat shock, open blisters, and 3. contracted pupils of the eyes, complete apply wet antiseptic dressings to absence of pulse at the wrist, and the burns weak or stopped breathing 4. remove foreign materials from the contracted pupils of the eyes, weak burns, apply hot moist packs to the pulse at the wrist, and cold and moist burrs, and prevent infections skin 2-15. The calualty who is most seriously burned 2-12. When giving a cardiac massage, you should is place your hands one on top of the other so that the heel of the bottom hand covers 1. Poindexter the 2. Anderson 3. Stein 1. lower part of the breastbone and the 4. Laine fingers of the top hand point toward the victim's neck 2-16. The casualty who has only first degree ?. upper part of the breastbone and the burns is fingers of the top hand point toward the victim's neck 1. Poindexter 3. lower part of the breastbone and the 2. Anderson fingers of the top hand point toward 3. Stein the victim's feet 4. Laine 4. upper part of the breastbone and the fingers of the top hand point toward the victim's neck

544 2-13. Poindexter an i.LH, are ...xper,,cd'i:e4 ',;hich of the following is a necessary more pain than Anier:;on and prrytiee in the proper care o: blueprints?

in reat tx;t1 - Th,y.111 uiLd never be folded 1.):: Sh:11..;! aocito the ,,,enerai They :th,01Ld be kept out of sunlight ..edure of sh.:..ck tr,otment? Only pencil should be used to make notations on them him co.d iLaTh of the above hin by

Placiw, him in a sittdh,-, posit : refolding a blueprint, you should him :J.' mor,ibe b- able to see its identifying number without having to unfold the print. Ci.)tniow, or other for,i1:,n material adhering t,d a;-;e:'ly burned area - 0. Enowing the drawing number on a blueprint the body i;hoLiLd he enables you to properly Vile the print. The drawing number also serves to removed carefalLy, with a dter e pointed :;tick 1. identify the type of system described s,iuked loose in Warn .raLtwater in the drawing cleansed from the area with :Locip 2. indicate the overall sire of the and water ,-)bject described left aHne 3. help in locating a drawing referenced on another print Lf baitery arid spills on your skn, the first th:ng, you should do iJ 2-A). The quantity, stock number, and description of all items required for a wiring wipe the acid off with a ciean, dry job are listed in which part of the blue- rag print? .wipe the acid off with a ,:lean, wet rag 1. Legend

rinse the acid away with plent.y of ,... Title block cold, fresh water 3. Notes neutralize the acid with ammonia or 4. Bill of material baking soda 2-27. In planning a job, you are working from a drawing and need to know how many feet of conduit to order. Which of the fol- Learning Objective: Define the term lowing techniques would give you the most blueprint and identify its main part. accurate results?

1. Measure the lines on the drawing, and convert them to scale 2-21. What is the definition of a blueprint? 2. Trace out the conduits on the drawing, then estimate the length of each run 1. Information extracted from a drawing 3. Copy the dimensions of conduit from 2. A reproduction of the working drawing the drawing and add them of a schematic h. Refer to the schematic i0 he job 3. A drawing reproduced on blue paper only 2-28. What part of a print explains the abbreviations and item numbers shown on the print' 2-22. The main part of a blueprint for a machine is the 1. Legend 2. Block diagram 1. bill of material for the machine 3. Title block 2. title block 4. Scale 3. legend 4. graphic representation of the machine

Learning Objective:Point out procedures to follow in reading and caring for blueprints and identify symbols used on electrical drawings.

545 2 '9. Asstime you are reading an electrical 2-33. Which of the following is the standard blueprint and do uot .rstand the architectural symbol for a single meanings of various shown. fluorescent fixture? Which of thQ following standards should you consult to find the meanings of these 1. symbols? L )

1. Military Standards for Electrical o Symbols American National Standard inmtitute's Standard Y 32.9 3. 3. Each of tht, above

2-30. In learning to read an electrical draw'ng, you try to see the mental picture that symbols, abbreviations, and notes make. 2-34. The architectural syli,bol for a surface- Refer to table 3-1 of your textbook when mounted panelboard and cabinet is answering items 2-31 through 2-34. 1. 2-31. blob of the following graphic synlools repreuents a shielded capacitor? 2. 1

3. 1

Learning Objective: Apply electrical 2-32. Which of the following graphic symbols diagrams and schematics to internal and represents a pushbutton two-circuit external wiring and communications systems. switch? Q-Lla 1. 00 The following alternatives are for items w2-35 through 2-37.

A. Schematic diagram

3. CUD B. Plot plan

C. Wiring diagram 14. 0elo 0c/o D. Pictorial diagram 2-35. Which type of drawing is helpful in determining where the connections are to be made in an electrical circuit?

1. A 2. B 3. C 4. D

5,16 2-36. When used to illustrate a given electrical 2-43. The dotted lines in textbook figure 3-8 hookup, which type of drawings would show represent the sluse oumpohentts? 1. fencing 1. A, B, and C 2. underground conduit 2. A, C, and D 3. bondir; wire 3. B, C, and D 4. overhead duc:. L. A, B, C, and D 2-44. Which of the following is the standard 2-37. iwlich type of drawing gives you an idea architectural symbol for a lighting of what the equipment looks like? panel?

1. A 1. 2. 3. 4. 2.

2-38. Refer to textbook figure 3-5. What is the voltage and phase of the primary 3. main:, leading to the battalion's mess hall? 4. 208-volt,3-phase 2. 240 volt,1-phase 3. 21:0 volt,3-phase 2-45. The architectural symbol for a convenience 4. 120 volt,3-phase outlet is

2-39. The distribution system of textbook 1. figure 3-6 feeds three phase power to operate the motor pool lighting system and 120-volt motor. 2.

When answering items 2-40 through 2-42, refer to textbook figure 3-7. 3. LA 2-40. About how much No. 2 wire will be needed between the pole next to manhole 22 and 4. 1-117ril the pole near building 126?

1. 2,300 ft 2. 2,000 ft 3. 1,500 ft 4. 700 ft

2-41. If each guy wire is made up of 45 feet of 3/8-inch steel cable, how many feet of this cable and how many strain insulators are needed for the job?

1. 180ft of cableand 8 insulators 2. 225ft of cableand 10 insulators 3. 270ft of cableand 10 insulators 4. 270ft of cableand 12 insulators-

2-42. How much of the line poles will be above ground when they are set?

1. 29 ft 2. 35 ft 3. 40 ft 4. 41 ft

547 2-51. You are to install an electric range in 110/220 V the galley. Which of the following best describes the information obtainable from .1extboek figure 3-12?

t. Eush heating coil will be rated at 600 watts Each hcating eoil will be rated at 300 watts Each heatirg esil is wired to operate on 230 volts 4. Fach range unit should be fused for at least 15 amPeres

.1)-4 ALL (GROUNDED NEUTRAL Learning Objective: Point out advantages, BUSES) disadvantages, and applications of NAVFAC prepared standard drawings.

0 2-52. The advanced base drawings in NAVFAr -Th P-437 save construction time becah- 1. they are easier to use than she normal Figure types of blueprints 2. all buildings constructed SEABEES When ahswering L-c:1113 2-46 through 2-48, are basically the same refer to figure 3. they permit much work to done .11 an assembly line basis whe:. s3ver:L1 2-46. It is poshible to run a 220-volt, 3-phase similar structures are to bu:1! motor from this i.anel. 4. they provide a standard pia- shop installation 2-47. The panel board is el:lipped to handle six circuits but only two are in use. 2-53. Which of the following is a disadvantage of the standard drawings prepared by 2-48. A single switch is used to disconnect NAVFAC for use at an advanced base? power from all the convenience outlets. 1. A single master plan cannot be used 2-49. How are P and S of the induction coil for all buildings placed in series in textbook figure 2. They add to the time it takes to wire 3-I1A? buildings for heating and lighting 3. They create more installation prob- I. Energizing coil LR1 lems than they solve 2. Deenergizing coil LR1 4. They exclude detailed information 3. Taking the receiver off the hook on proper installation of equipment 4. Closing switch LJ1 2-54. Siudy the print in textbook figure 3-15. 2-50. Line lamp LL1 in figure 3-11A is ener- What do the numbers on the 50 ampers, gised 3-phase panelboard indicate?

I. when relay LRI deenergizes 1. Circuit breaker mounting bolt siz,.s 0. when relay LR1 energizes 2. The output voltage of each circuit 3. only when the transmitter is 3. he circuit breaker each circuit ties deenergized into from the main panel

2-55. Where on a blueprint would the electrician find information as to special instructions needed to complete an assembly?

1. Notes on the bill of material 2. Notes written in the margins of the print 3. Directly beneath the assembly number

114

5 4 8 i-62. Of the following types of power hacksaws, with which can you increase or decrease the pressure on the material being cut?

. I. Hydraulic 2. Moshr,rtical 3. (lravity 4. Feed

he 2-63. What should be the pitch of a power hacksaw blade for cutting a solid piece el' brass stock?

dror,m 1. 4 teethperinch 2. 6teethperinch

r : :1 3. 10teethperinch t,y 4. 14teethperinch

1. _-64. in ope-ating power-al-uisted hammers, you tir,r,,t,t v1 7, will need one pistun for pins and '.rother tr,:. ::w iI. fo- studs, unless there is a difference fe-1 ::erew in the lengths of the

- . ri(1 s,qr Lit( rwrim parts 1. stud shanks pne grihder the result or 2. stud threads 3. pins 1,1hrleatifh, 4. spa,_:ers

excess i :;10;..,1 uleb.rloading /tic pri.t.;;;ur.! Learning Objective: Identify fundamentals The att'ichmeht011N prWIIMIlt[Cpavement of operating and caring for portableair breaker Col. ,ee.ting asphalt and frozen cc-3pressors and power earth augers. .oundis a

::pahe 2-65. The pressure drop in air line hose over a long hIstahce is taken care of by the 4 installation of

,r following in a good practice I. two air compressors in series

a pneumatie pavem,ult . two air compressors in parallel reak, 3. an air manifold

1. Takihg bites oC 4to 6 inehen behind Hefer to textbook figure 14-21. Which of 1.1,e working rq,, the following tanks should be performed

Taking bites .)/' 1 A, inehes Ln on an air compressor daily? Front 01the w,,rking face holes with the moil polht 1. Change the compressor oil kreaking eonerete wit.h 2. (irease the engine p,int 3. Inpneet the compressor oil filter cartridges 11,,t ,opitt.INK urr the pavement breaker 4. Clean the radiator and cooler coren

when the nv,1 I pd 1,1tr,,lai,h con- y(,11 NV, likely to end up with 4 ',L.P. Which of the following devices prevents troken the clutch from being engaged or disengaged while the air compressor engine I. riviI point 1n running?

01/111k. 1. ilhlfter mechanism Ii retainer bJ I 2. Electric clutch 3. Built-in safety Interblock 4 "rletion disk

5 4 9 2-68. In starting up an air compressor engine, 2-71. Which of the following are routine pre- you can eliminate the warmup steps after start checkpoints for the earth auger? the first daily startup: 1. 04..1 levels in the engine crankcase 2-69. Which 01 the following is an indication and transmission that the cartridge of an air cleaner 2. Supply of fuel and hydraulic oil used with a Worthington air compressor level needs replacement? 3. Coolant and battery water levels 4. All of the above 1. A red flag pops up 2. A green flag pops up 2-72. After crankin3 an auger engine for more 3. The aspira'or plugs up, sou ding than 30 seconds, you should wait 1 minute an alarm to allow for cooling of the I. The cartridges plugs up, soundi ; an alarm 1 battery 2. starter 2-70. Which of the following is the reason 3. generator for the safety statement, "Never use I. engine oil benzene, kerosene or other light oils to clean compressor intake filters, 2-73. Refer to textbook figure 4-29. The cylinders or air passages"? purpose of the spirit level is to

I. They form a highly explosive mixtJre 1. level the auger engine under compression 2. level the auger shaft 2. They form a gum and cause parts to 3. plumb the auger shaft wea L. plumb the auger engine 3. They form a varnish and will plug up fuel lines 2-74. Support jacks are used to dampen 4 They form a varnish and cause the bouncing of the earth auger when cylinder ringn to stick it is being operated in hardpan or rocky soil.

16 r r 0 Assignment 3

Test Equipment, Control and Protective Equipment

Textbook NAVEDTRA 10636-R: Pages 88-128

3-4. How must an ammeter be connected in the line to measure current? Learning Objective: Identify principles and techniques of measuring with an amme- 1. Across the line ter, voltmeter, megohmmeter, phase sequence 2. In series with the line indicator, and special purpose testers. 3. Parallel h Series-parallel with the load and line

3-5. The maximum current-carrying capacity of 3-1. What does the accuracy of test equipment an ammeter is called its depend upon? 1. polarity 1. Its 2. rating 1'. Your test procedures 3. calibration

14 3. The treatment or the instrument . current flow 4. Each of the above 3-6. Which of the following factors would limit 3-2. When measuring ah unknown current with an the current-measuring capabilities of an ammeter which is capable of meastll'iug timmetcr? several different ranges, you should make lhe first measurement with the meter set 1. Size of the inutrument at, 2. Range switch 3. Connecting terminals I. the higheSt range it will measure 4. All of the above 2. a range slightly higher than you estimate the current to be -3-7. Why is a shunt sometimes used on an the range where you estimate the funny:ter? current to he the lowest ange it will measure 1. To give more accurate readings 2. To create a voltage drop 3-3. After using the ohmmete,' scale of a multi- 3. To extend the range of the metf.r meter, what should you do to guard against h. To calibrate frequency dishcharging the battery in the multimeter?

I , Turn uflthe multimeter P. Turn the meter to d-c supply positive 1. Turn the met, e!to d-c supply negative Allof' the above

l'(

5 5 I 3-8 . of the in a diffei.eh,- -1;. 4f,r a capacitor with a Vibro- be tween the tr:oter tior mer:ohmmot,.r. Six seconds after d= acting the the needle stops moving

1 A voltmeter t.a. ah ?,,t; i'5t,irmitethe value of the =Lmmeter had rl..,rt %hah A voltmeter tan mca:,:re a-c ah

% tiiiiiter tan meahdre bott a-e idJ1 . A v.ul'vieto. mdst --:t.-ttod it .% F

!. I : i r a ! lo: '41 tt tb- .1te; rit .o

eutal(2CLI: in ,obri . .cOL A voitmeter md.:t b- A wi'Al ; 4L M,,Y ,r may tot t- 'to.d Wtet is the roa:,.'n for Xeeping r,-rterds of a dl.dht tdeor::'ormor tehts?

.rebeduling of further tests is

di., i ent

. enatge in insuJation resistance prr,perty functioning equip- the v :nest

sio.er -AP,re.; i . A ,.;rattal deterioration in insulation

: i r-!:iitanee',inbe more easily noted f.he wi Jr- pubtieations recommend it ',he meter :; 1( (I)! liofer to textbookfigure5-2:.t. You are ',r.-:f1.t.t'f .1! instructed tr, cheek the phase sequence or ..,.! rw,;:71; nit, alternatorFirldmake the liook- up. After eunnecing the phasesequence '1.,, iter A to XI, B to Y1, and C to Zl, ;r1.t tt. rioter r,Atitenin the counterclockwise ? ti recti,di. When youCONNUctthe meter loatA1,r,7., P,to'1,andCt.)Z.,the N;e1,el Whieh of the i . A 1 I it, re:, I et,,ekw I se. A I1 ,,,,hheeti, aro made ,orrect h=o,Xing dp? t.i ' ff.' "t. XI, Y1, 7, 1,0Vol

! Xi , Z1 ,zto Yi X Y1, Z tr) Z)

, !, 1 II Art ,-f 1;, 'tv,p 'I' !t1;a:,, ' 7 , t t,(

I t , mord w thth, i ' /I. cl,rr.,!.. :;noip-Arminl pi,he V,I,,t,r1,i1.1Tester111,/P:01,",:', " 1 i ' itrn IN!i^ eurehietfw by mann:; 411. i'

! I t I vt.pi ,tup 'et! i' t, iin'.'1, I '1,H1 n

i I. ' I, ,,,111.fic Boat. It.wisfer r lo A . r /WI. I

' .11'1!,11,,! wit 1,11enable the 'if t 11. /,-Iht, ,cittlI altlf. I tvliffitt'l ILIAntiI 1,yrw

1,,1 . I ittpl . i.oWer ! ' ; ,

r, 3-18. The chief functios of the 1W1-1A tester In answering items 3-23 and 3-24, refer is to measure the to table 5-1.

1. amount of power used by a load at - When using the Wheatstone bridge to given voltage measure a loop resistance of approxi- 2. peroent of the load that is shared by mately 1,200 ohms, at what position do eaoh phase of a three-phase power you set the MULTIPLY BY dial? dource 3. resistance of protective devices due 1. 1/100 to corroded contacts 2. 1/10 4. time it aked a protective device to 3. 1/1 open a circuit at a given current 4. 10/1

In answering items 3-19 and 3-20, refer 3-24. With the MULTIPLY BY dial on 1/1, you to figure 5-31 of your textbook and balance the Wheatstone bridge with a adsume that you are testing a ground. reading of 3 on the thousands dial, 8 on the hundreds dial, 3 on the tens dial, 3-19. RI is adjusted until the currents in and 1 on the units dial. What is the what two windings cancel each other? actual resistance in the loop?

1. Primary of T1 and secondary of Ti 38.31 ohms 2. Primary of T1 and primary of T2 2. 383.31 ohms 3. Primary of T2 and secondary of T1 3. 3,831. ohms 4. Primary of T2 and secondary of T2 4. 38,310. ohms

3-20. The unkhown ground resistance is read on 3-25. When preparing to make a loop resistance tent uf a pair of conductors with the portable Wheatstone bridge, what connections must you make?

4 1. Connect the two far ends ofthe pair of wires together 3-21. What is the maximum permissible resistance Connect the cable sheath tothe ground between sulid erth ground UN4 the light- point ning arrester ground on a distribution 3. Ground one wire and connectit to system? binding post Xp h. Reverse the wireu connectedto line I. 1 ohm binding pouts X1 and Xp. P. 5 ohms i. 10 ohms What galvanometer indication tells you 4. 15 ohmh that the Wheatstone bridge lu balanced?

I. Pointer movement to the Left or negative side of the meter and back to hoarning Objective: Pecogn1ze the purpose zero or a Wheatstone bridge and techniques or 2. Pointer movement to th( right or posi- using the dridge to measure loop resist- tion side of the meter and back to ance of a communleatIonn eIrcuH- zero

I. No deflection of the met,/r 4. A full scale deflection to either nide m,r the meter 3-PP. Tho pnrpon,. or the Wheatstone bridge

shown In textbook r1w,urf. 5-34 Iii to

1. indicate the ronIntance of IL clreult directly In ohms without any need tut. calculations locate cable faults apprOXIMatvly Iii communication and powl.r cables by meanurIng resistance in the cable wires mensilio the magnitude or the .iptive power In an electric cirou.t 4, detct the difference in potential betwmen two points if n ,IroniL

19 3-29. What is the .-,..sistance from test point X2 Learning ob,lective: Recognize principles to the fault? and applications of the regular Varley loop test, three Varley test, and Murray 1. 1594 ohms loop test. 2. 2313 ohms 3. 2714 ohms 4. 3010 ohms

3-30. How far is the fault from binding post 3-27. The objective of a -egular Varley loop X2? test is to locate a

1. 60.5 miles 1. ground in a high resistance loop when 2. 61.7 miles the unbalance is1 ohm or less 3. 63.1 miles ground in a high resistance loop when 4. 65.3 miles the unbalance is more than 1 ohm 3. cross in a high resistance loop when 3-31. In making a three-Varley test you set the the unbalance is more than 1 ohm MULTIPLY BY dial on 1/4. To obtain the cross in a high resistance loop when resistance from the test set to the the unbalance is 1 ohm or less ground, you multiply the difference between the decade dial readings of the second and third tests by

1. 5 2. 8 3. 3 SHORTE)vt 4. 4 xa In answering items 3-32 and 3-33, refer to textbook figure 5-38 and assume that you are using a three-Varley test. You are using the 1/9 range on the MULTIPLY BY dial and you have obtained the following information: Ri = 3,500 rigure 3A = 4,100 R- = 9 600 3 ' To arrh4er items through 3-!.0, refer What 10 Xa? to figure 3A and apply the formuta: 3-32. la (r x R) - (A x R). A + B 1. 270 2, 550 3. 1250 Lt A = L. Then R, the decade dial read- 4 1570 B I Lag of he meter after the loop in If the dirtance to the far end of t. balanced will equal 3-33 cable run is 61 miles, what is the d. trine(' to the cleat? loop resistance (r) minus twiee the resistance ,J Xa 1. 7 mile:, loop resistance (r) MiNUOthe resis- ;?, 35 miles twice xa resistasce (r) plus the resin- 3. 43 miles 55 miles tmnee xa 4. the resistanee la IC you need to use A/B ,1 and the resit Lance in the faulty wire Ls greater than fn answring items and i-iu, use the the good wire, what measu; dc you take following information: nloro.e the bridge In the Varley 1 rosintance e 6,wo ohms (r) t..t, of figure 5-38? ohms

A , I I. Direonnect the goGd'ire Ground the good wire 1)1 t.tiv t, nhor Put n remlutnnee in series with the r,1111,ti 1,rat. r cahle 'Un good w:re I n 1,n 110, i/10 range on the MULTIPLY HY dial 3-35.. Assume thLt you are using the Murray loop 3-38. Connections between the test set and the test shown in textbook figure 5-39 and cable are made with a 2-wire test cord. you have set the :111:3IPLY BY dial at M100. Where do you connect the ',est cord on the Also, assume that the length of the loop cable end? is 30 miles and you have obtained a reading of R = 1,400. Determine the distance: 1. To the grounded conductors Da (from point X2 to the ground). 2. To the grounded conductor and a ground rod 1. 12 miles 3. To the cable sheath and the grounueri 2. 16 miles conductor 3. 22 miles 4. To the grounded conductor and a call 4. 28 miles clamp

3-39. To what terminals on the test set dc connect the other ends of the test coi, Learning Objective: Point out the purpose of the cable repairman's test set 1. 1 and 3 1-51, and identify principles of locating 2. 2 and 3 a ground in a telephone cable. 3. 3 and 4 4. 4 and 5

3-40. If the fault has a resistance of ovel _00 3-36. What is the purpose of a cable repairman's ohms, to what test set terminals 10 yo, test set? connect the test cord leads?

1. Tu locate faults in PBX connectors, 1. 1 and 3 regular connectors, and reverting-call 2. 2 and 3 switches 3. 3 and 4 2. To measure the magnitude %,f the actire 4. 3 and 5 power in an electric circuit 3. To locate an open circuit in communica- 3-41. How should you hold the exploring coil tion and powerlines to locate the round? 4. To locate accurately u short in a cable after its approximate location is 1. Parallel to the cable determined 2. Parallel to the cable and move it along the cable toward the grotulued 3-37. You know or a.e able to find the following point infordati- a' a cable t1-,t hal a fault! 3. At right angles to the cable A. ITie6/1,e fault h. At right angles to the cable 7nd B. The resanue of gocd eona...cto,.s move it along the cable nes.- 'be C. The reristance of fa.ilty onCuctorn grounded point

D. Approximat J on of tbo fault E. Length of the eabie 3-142. When the exploring coil i rL ,ver the

F. Equipment ,:omieeted to'11,. eable grounded point, the tone i y,:r receiver Which items of inforwil ;on are e!.nentlal. :n pinpointin'g d cable :ault with the 1. increases cable repal.man',1 tont set? 2 disappears 3. increases then decreases I. A, 4. do creases then increases P. A, d, E 3. li, D, E If the gro,Ad is of n. b high resistance 4. D, E, F 11.5 tO make the absol.de location uncercain, whet is the proper Info..lati,n for Items;-3d Urough IP Refer to texbook Figure 5-4. Lcu ar- I. Make a blainly visible mark at the cuwe repairmarit, going ' approximel location rtnl then repeat a jo,..nd in a 51-pair to1ec,,,de cable tbe tr!:tn from the ()Ur,' end of the that nr.,'; been located with a Wheat;:ht, bridge. cable The ground In solid and eoncerna or,- wire only. 2. Repent all of the tests,hat you ma(!e previously 3. Reset the tone switch to position 2 and repeat the nts h. Bonet the tone ,,,witch to position 2 and repeat the tLsts but from the opposite end of the cable 3-48. In the alternate method of locating a split pair, one conductor of each pair Learning Jbjective: Identify principles is connected to the test cord leads. of locating short circuits, crossed wires, After you pass the exploring coil over and split pairs with the cable repairman's the split, the volume of the steady tone test set. you hear through the receiver will

1. increase only 2 . decrease only 3_44. How should :,.1 locate a short in a paired increase decrease cable with the cable repairman's test 4. ston iilmentarily, then remain steady set?

3-49. You are to. t wet spot in a cable. 1. Set the tone switch on position 1 After tho c.,...cring coil passes over the and connect the test cord to the two wet spot, *,e voliune of the tone you hear faulty wires through er will 2. Set the tone switch on position 2, connect the test cord to the two- 1. increase only faulty wires, and use the exploring 2. decrease only coil 3. increase or decrease . Use a test cord containing three insu- 4 neither increase and decrease lated wires and connect them to three separate cable wires 3-50. There are two methods of connecting the 1. Cet the tone switch ON position 2 but tone unit of the test set to a cable for Ao not use the exploring coil tracing a wet spot. In one of these methods, the two leads in the test cord 3-45. Refer to figure 5-46 in the textbook. In are connected lo what way does the locating of crossed wires differ from the locating of a 1. one wire in each of two pairs of .rounded wire in a paired cable? wires 2. two groups of wire, selected at ran- The tone switch is let on position dom, and strapped together The test cord is connected to termi- 3. two wires selected at random nals 3 and 4 on the tone unit 4. one wire, selected at random, and 3. The exploring coil is held at right the cable sheath angles to the cable The exploring coil is not used

-46. Hofer to textbook figure 5-48. In locat- Learning Objective: Identify procedures ing a split pair, what procedure must you and techniques of locating and tracing follow at the far end of the cable that buried communication cable with the cable is under test? repairr- '1 test set.

1. Connect the two wirer that are split Connect the split pairs to ground 3. Short out the four wires involved 3-51. You are using the cable repairman's test 4. Disconnect the four wires involved set 1-51 and component parts necessary and make --Ire Done of them is in for tracing buried cable. How can the

contact 1 another tone volume be increased when the exploring coil is connected directly to the 3-47. For your initial tracing of a cable to receivers via a terminal strip? locate a split pair, you have both conductors of one pair connected to the tent 1. By increasing the source voltage in cord leads. After you pans the exploring the test set coil over the point locating the split 2. By connecting an amplifier between pair, the volume of the tone you hear the exploring coil and the receivers through the receiver will 3. By changing the tone switch from position 1 to position 2 1. increase only 4. By changing the test leads from the d. decrease only high resistance.lugs to the low 3. Inerease and decrease resistance lugs at the set 4. be steady SOUND SOUND LEVEL L EVEL

No- REGION OF F LR.T REGION OF FAULT -

SOUND SOUND LEVEL LEVEL

...... -REGION OF FAULT REGION OF FAULT

Figure 33

3-52. You are uninit, the htray '!urrent method PP14()A.A I 'UN IPIACC I I Ouk.I D (b12.3 of tracing a buried cable. Which of the --- LN a figure z^ Illuotritte.; the graplin _L change in t;oundrh_; p,u appr,atch, :1[J ST1 11,, 10 then pe.ns wier the cable? XII

1.4--

III, PH To 93 f T 'N. t SI iI N,.. c TO TS i I It 3-5i. Th- ihacti.)h rr(m a hearty p,cwerIlhe precl!Ide:; the or :tray carreht to 0 trace a buri,d ,:able. An alternat, 100 method Cur tracihg the cable th.,h,l,pt the llm:e of current from a OVIliritAD POOR 1. ducter olameter 2. power circuit arialy7.er 3. Wheatutonfm bridge 4. cable repairmau':: Figure 3C

;-bh. AL which point nhould the neareot ground rod be located from thu buried cable in figure 3C?

1 .

h. 3-55. While attempting to locate the vicinity 3-59. How are grounds indicated on the Tela of a buried cable with test set 1-51, Cable Model 262? you should start by holding the exploring coil in what position? 1. Shorted light goes out 2. Indicating light comes on 1. Horizontal and parallel to the cable 3. Indicating light flashes 2. Vertical and parallel to the cable L. Shorted light flashes 3. Perpendicular to the cable 3-6o. Before identifying a certain wire in a 3-56. Assume that you have found the general cable with a Tela Cable test set, an location of a cable with test set 1-51. operator must have What type of tone will indicate the exact location of the cable if the ex- 1. an assistant standing by to deenergize ploring coil is held in the horizontal the circuit position and passed over the cable? 2. an assistant at the point where the cable is terminated 1. A steady rise in tone until maximum 3. the circuit energized tone is received 4. the circuit deenergized 2. A steady rise in tone and then a sharp decrease in tone 3. A tone that changes from constant to pulsating Learning Objective: State the purpose of 4. A tone that changes from low pulsating electrical protective devices and indicate to high constant techniques of locating common faults in fused circuits.

Learning Objective: Identify operating principles and techniques of the telephone 3-61. The purpose of electrical protective test set AN/PTM-5 and the Tela Cable Model devices is to 262 test set. 1. govern the amount of power delivered to any electrical load 2. prevent power interruptions 3-57. The purpose of the telephone test set 3. prevent short circuits (AN/PTM-5) is to 4. prevent dangerous amounts of power in a circuit 1. identify *Jingle leads or pairs in a cable without breaking the individual 3-62. In locating the cause of trouble in a conductor insulation defective circuit, the first thing you 2. identify single leads or pairs in a should do is to cable without breaking or opening the outer sheath 1. test the circuit with a voltage 3. locate open or shorted leads in a tester cable without breaking individual 2. trace the wiring conductor insulation 3. disconnect the black and white wires 4 locate open or shorted leads in a from the source of power

)4 cable without disturbing the position . check the circuit for visible of the conductors signs of trouble

3-58. In what position should the probe tip be held when you are checking conductor pairs with the telephone test set?

1. Between the pair, nearly parallel to the conductors 2. Between the pair, at right angles to the conductors 3. Across the pair, at right angles to the conductors 4. Squeezed tightly against the pair with the fingers

214 220V

SWITCH---4w SWITCH---10"' (CLOSED) (CLOSED)

FUSE FUSE (IN) (IN)

TESTER HOT WIRE TESTER (VOLTAGE) (VOLTAGE) r:ONNECTED

WIRES DISCONNECTED

SHORT

TEST A TEST B

Figure 3D

3-63. Figure 3D illustrates how you can use a 3-65. In disconnecting and connecting the wires voltage tester to test for a short cir- from the terminals in the fuse box, you cuit. The circuit has a short if the should disconnect the tester shows 1. hot wire first and connect it first' 1. a reading when you make test A 2. neutral wire first and connect it 2. a reading when you make test B first 3. readings when you make tests A and B 3. neutral wire first and connect the 4. no readings when you make test A or hot wire first 4. hot wire first and connect the neutral wire first a When answering 3-64 and 3-65, assume w that now you are trying to locate a fault in a single-phase 2-wire circuit.

3-64. Before you begin any work on the circuit, you must make sure that

1. the switch is opened and all fuses hre removed 2. the hot wire is disconnected at the fuse box when an open cirruit is suspected 3. the hot wire is disconnected at the fuse box when a short circuit is suspected 4. both wires aro disconnected at the fuse box

5 5 9 3-70. Oxidation on a fuse or fuse clip is an Learning Objective: Recognize operating indication e' poor contact between the principloo and applications of fuses fuse and fia,e and circuit breakers. 3-71. Sections of electrical. circuits in substations are often conveniently made oafe to work on by 3-66. What components in a substation, in addition to feeder line breakers, protect 1. installing circuit breakers at im- trar.smission lines from the effect.o -f portant wire junctions short circuits? 2. placing several more generators than are needed in the sibstation I. Low voltage feeder breakers 3. installing all circdit cables in 2. Low vG:tage feeder fuses parallel. 3. High voltage circuit breakers 4. placing the high voltage eircui's 4. High voltage fuses underground

3-67. Fuses eombined with gang-operated air- 3-72. What causes an electrically operated air break switches ale safe to use with eircuit breaker to open when an excessive transformers having a capacity of current flows through it?

,750 kVA i. A fusible link melts, causing a :,000 kVA coiled spring to open the contacts 7,500 kVA 2. An electromagnclt forces the contacts 10,000 kVA open 3. An electromagnet trips a release 3-68. What action takes place in or is initiated mechanism allowing a coiled spring by an expulsion type primary cutout fuse to push the contacts open when a serious overload occurs? 4. Current through a high tension spring causes it to expand and open the con- 1. A second fuse in cut into the circuit tacts A high resistance is placed in series with the load 3-73. The main contacts of high current circuit The fuse resets itself breakers are not burned when they open or The fuse link melts and opens the close due to the circuit 1. bypass action of the arc contacts 3-69. Cuppose that in an automatic reset repeat- 2. quenching action of the arc quencher ing cutout, the first and second fuses section blow but the third fuse does not. There 3. actions of the bypass contacts and is reason to believe that this situation the arc quencher section was caused by a ma6cetic field which flows under the arc runner short circuit in one of the distribution transformers permanent open in the transmission line temporary fault in the distribution system source generator with an excessive voltage output

). 6

160 Assignment 4

and Prote,:tive ETdipment

book liA711DTRA Piti-,;e:; 128-174

4-4. Which of the following is most likely to cause a relay.magnet to chatter? Learning Ubjective: Indicate procedure for maintaining and inspecting power 1. Burned contacts oireuit breakers. 2. Open coils 3. Rusty magnet sealing surfaces 4 Shorted coils

4-1. leilpit must you do before servicing a 4-5. When manually onerated circuit breakers cireuit breaker? normally remain in an open or clogged position over a long period, how often Wipe off the surface of the circuit should they be tested? breaker mechanism Direct air from an airhose in order 1. Twice a year, or more often to remove dirt or dust from the 2. Once each year mechanism 3. Once every 2 years 3. Deenergize all circuits including con- 4. Once every 5 years trol. circuits to which the breaker iS tel 4-6. Assume that you installed a circuit 4. Look for corrosion or pins and bearings breaker in the spring of last year. its first overhaul is due no later than Ilef,rL working en fixed-mounted circuit breakera, what switches should you open? 1. spring of this year 2. fall of this year l. ALI awitchea in the entire switchbcard 3. aprtng or ,.?Itt year circuit 4. "a-1 f noy,c year

. All generator circu1t breakera ;. All switches ahead of the breakers 4-7. The fir..t:1,1:117 that you must do before 4. Alt bua tie switches circuit breaker that is in use 4-. Aasume that inspection of copper circuit breaker ecntacts reveals a blackehed aur- 1. ground the equipment fiwe. What is the correct maintenance 2. remove all fuses durca for these contacts? 3. warn people who are using tne circuit h. notify the electrical supervisor of 1. 'dipe the black coppfr eylde off the your plans contacts with a clean cloth :land the contact surfaces with fine sandpaper 3. Wipe the contact aurfaces with inhibited metbyl chloroform 4. 1n..h or the above, if necessary 4-8. Your are cautioned NOT to trip the con- 4-14. The arc contacts of a power circuit tact mechanism of an oil crcuit breaker breaker should be replaced when they after the contacts are lifted from the become oil in order to 1. badly pitted or burned 1. facilitate the finding of damaged 2. slightly discolored parts 3. brittle 2. minimize the possibility of rust 4. bent forming on the contacts 3. avoid electrical shock 4-15. Which of the following is an acceptable 4. prevent mechanical shock damage to method of determining the condition of breaker parts arc contacts in powe- circuit breakers?

4-9. If paper tank liners in oil circuit 1. Remove the arc chutes and observe breakers have absorbed moisture, the the condition of the arc contacts liners should be dried by 2. Without removing any part of the breaker, observe the arc contacus 1. baking them in an oven with a dentist's mirror 2. placing them in the sunshine 3. Disassemble the entire breaker and 3. blowing air on them with a fan observe the arc contacts L. storing them in a cool room 4. Observe the condition of the arcing tips and assume that the conditin 4-10. How can the CE tell when the thickness of of the internal contacts is the sume a circuit breaker contact has fallen below the required minimum? 4-16. How often is it recommended that oil in oil circuit breakers be tested? 1. By consulting minimum contact thickness tables in the manufacturer's instruc- 1. E-dery 3 months tions 2. Twice each year 2. By taking 1/2 of the original thickness 3. Annually as stated in the manufacturer's in- 4. Every 3 years structions 3. By applying a general rule tying 4-17. The oil in power circuit breakers must be replacement tc years of usage filtered until the oil has a minimum di- 4. By using the figures stamped on the electric strength of breaker frame 1. 18,000 V 4-11. What type of contacts do radial-,;Tast 2. 22,000 V interrupters have? 3. 26,000 V 4. 30,000 V 1. Arcing 2. Rolling 4-18. When oil from circuit breakers is being 3. Butt tested for dielectric strength, the 4. Sliding spacing between standard disks in the tester should be 4-12. How much metal can be burned off contacts or radial-blast interrupters before it 1. 0.01 in. becomes necessary to replace them? 2 0.10 in. 3. 0.15 in. 1. 1/32 in. 4. 0.20 in. 2. 1/16 i. 3. 3/32 11). 4-19. You are checking the condition of the oi] 4. 1/8 in, in power ..:ircuit breakers. Which of the following signs is an indication that the 4-13. The usual maintenance for the main con- oil must be filtered and tested for di- otacts of crone-blast interrupters consists electric strength? 1. Carbonization 1, applying a light coat of oil to the 2. Dirt contacts 3. Moisture 2. replacing damaged contacts 4. Each of the above 3. cicaning and aligning contacts 4. turning the contacts slightly to expose a r surface 5 6

28 4-20. The reeommended agent for cleaning external surfaces of power circuit breaker bushings Learn.. '4.ive: Identify operating pril ,f riLgnetic and thermal over-

1. a dry rag Lon . soapy water 3. oil 4. an emery cloth

. What is the best recommended method of 4-21. What cleaning agent is recommended for overcoming burnout of the operating coil removing dust and carbon inside a magnetic of electrically cv,-.erated breakers ,2aused airblust circuit breaker? by an operator ho'ding the control_ switch closed too long? 1. A dry rag 2. Soapy water I. Lubricating the mechanicm 3. Oil 2. Installing an auxiliary switch 4. An emery cloth 3. Replacing the damaged coil 4. Puttinv a sign on the switch to remind 4-22. What is the recommended method of prevent- the operator ing moisture from collecting in a magnet airblast circuit breaker? 4-27. Which of the following actions should you take to r,medy the failure of an a-c con- Wiping dry with a rag frequently trolled power circuit breaker to latch L. C'.eaning with a solvent regularly closed? Tr.3:,f. ling air blowers in the breaker 1. Adjust closing re:lay 4, InsteDing heaters in the breaker com- 2. Test rectifier partment 3. Install larger incoming wire 4. Charge battery 4-23. What is the recommended maintenance for treating burned contacts of large trip 4-28. When an overload occurs in a magnetic type coils in oil circuit breakers? relay, the increased flux around the coil will lift the iron plunger into the center 1. Replacing the contacts of the coil. 2. Readjusting the contact airgap 3. Reducing the current through the 4-29. The current at which a magnetic overload contacts relay trips may be increased by

. -eaning with fine sandpaper 1. lowering the dasnpot 4-24. The speed of the closing motor of an oil 2. raising the dashpot circuit bretker is varied by means of 3. addirg oil to the dashpot

1. an auxiliary control breaker 4-30. A thermal overload relay will finally open 2. a variable line switch the contacts when the '. a variable resistor 4. a variable inductance coil 1. heater coil reaches a specific temperature 4-25. Infrequent operation is a cause of con, 2. splitter arm moves tact:, overheating in power circuit 3. solder melts breakers. One way to overcome the over- 4. tube assembly rotates heating problem is by 4-31. A thermal overload relay is adjusted to

.... replacing the breaker with another hav- trip at a predetermined value of overload ing a large current rating current by 2. reducing the operating voltage to the contact relay 1. changing the relative poFition of the 3. adjusting the closing relay contacts u. replacing copper contacts with new 2. raising and lowering the dashpot silver-to-silver contacts 3. rotating the splitter arm 4. moving the relay heater coil

56d 1:ci take placeto cc C rovcr:.-,0

:.arn 1.ientify 4,pera'.! phne-ra.Mr,

t!,,1 N. -)1arity E mut;t p tiarit

'ts":1,11tw. I'7... 1!t 1 curnero_ aniii ,what ..e m!:!re%!er.1,, with epe...t gynerat,r! t'r '!re larity E and F the thrDvh !.ne revere with reape:st t- th- p.:art!..y H Therr.la: pha---:'a:iure relay in.Huated when rc,lay

P '' '' p,,wer relay ,-urrent iN Lhe d-c rela exceelo ,urrent in the reactor .!-rrentin any one of the d-e r-lay c,T i !: .1e:-.5 than in any of the.clrer

currentin one pair of A-c relay

ii less than currert in another pair current is reversed through any of the rectifier bridge units

.36. whul, ia the basic differ,-nce, if any, between a system ground and an equipment ground?

U:ystem ground is the grounding of noncurrent-carrying metal parts equipment grounding is the gr,.nding of the hot side of the equipmer,t System ground is the grounding of one of the current-currying conductors and equipment ground is the grounding of noncurrent-carrying metal, parts of a wiring system 3. There 13 no different._ except equipment ground protects personnel and system ground protects equipment 4. There is no difference; both grounds are designed to protect personnel

NAVFAC requires grounds to be provided in ac:,rd-nce with the National Electrical Flgure e except that individual transformer and lightning arrestor grounds must not In answering items 4-33 and 4-35, refer be above 10 ohms to ground. to figure A.

4-33. Oscillations in the induction disk of the timer element of the relay are damped by

1. A 2. B 3. D 4. E

30 564 - 1;1 rTtryn-c. i t r ,,,nt 1 1. r whn h doe: currentto rho a !ake art,,r

pardl rc,11' '

! 11;.t art1:1:, :; I 1111 i . i eit i ;;tr.conta,ft.;

.rt,w711 .; t:;

:LC!. I I': 1;) 1 ; ;. ' I - t;1* ri coil1 a*, the 11;it rc,t lii,t 0:"

tto'..:1;11;; ; a it;,1

ir; t,0tOt ,r

r or roller 1; 1'1;1 i It ') rtrIrin.t npeed by ,rlin).7

le.;.; resistance in !he I.no tep: until ;he not.-r 1;rt.'t.,1 itrarallo: acrc s the t'o rodu:e the voltae 1r,ttl the or 0 runni;Ig rull speed .nain contacts in parallel with the starting reristrs a :ircui like the one in a primary re,Jitor cntri'llor but wit.h-it uccel- c

) anwer :t cc 4-.- and rfer tc of your textbook.

the filow:tte conditions of Iht! F and P .act:'rs cau.;es line CO:V_Sc*,3 hl, iD, a.:d R3 to clo;el'

1. open

PA cn

. w F s;:r- r,rev-n!tr-i frc:m b_th beir4t clo.o.1 at the same time by

wh:ch a mechanical interlock a 16-ampere control fuse 1. tintF and R contactor coils w. i:t'en, :1 ' ! 7 the overload relays

Ora-; /vivantage af an autotransformer starter ti,at

the motor is connected to the line 7oltage at all times it utilizes capacitors and transformers in parallel to raise starting current high starting line currents can be reduced more than with resisI.or starters it can be utilized for starting loads that are heavy enough to requiie resistor starters

063r - r 11-Mt ;t

a I

t' 1 'ut t t wi't.tt ...,t,

t.' t.

.; tt'tt

1:1 t; t'

Ito:, 1 tl.' nec

vcr.,:trd fre p.cc.Wt .._ttct

:tutt

. 0 hitt,it!

tact

use.t :n heavy duty .7.-n- leo e uipment that rema.ns el.,sed for er.ten,le I ;:eriols is the M: fr-m silver conta.-t cocTer contact carbon conta-t alaminmum contact

. ing The mir,imum value of controller contacts c : :u "alls within the range of

:tar startin,:. .015 to :.020 in. f a m._-t-r firot aTTlying 2. 0.015 to 0.030 in. lat-r 10. iercent of 3. .,.°20 to 0.030 in. a:.t. .0.020 to 0.040 in.

Reiay: diff-r-;,* c:ntroller magnet coils should be re.:ti_ttance th." :ine dried cut by A .:tar ,7r1hodticd; tied t,a de:ta ii,jrinecticn in the ctItit.illor 1. baking them in an oven standing then in a warm room t. Th.l motor io startoi on a dt!Ita wini- 2. ing connetion ani later is cnanged 3. sending current tnrcugh them to L. letting them lie in the sunshine or Windiugs of a motor having delta con- under a sun lamp nections are changed to star connection:-; at first and later back to delta connection 32

56 , Why ttt5 1 jolt ow i totter. .. .1 i n

n I I I c 0 11 ry cyni I. t 1 t h a t t (1qui }:Ut.1,1 ,11

W1 !111:1.1R1.0phycj cal 1 1.r.ti

.;1.; proyeat tho tcr

o t provor,* overt oat i t he c lit rt.I ,121,".11! \

1 1 a ! Ito tit w1 th i a safe elect ri cal 1 imit

aotaate 1110 contact mochari.;m,, tert;, atare-actuatet switcht.:t tet.et

expansin ct metalin the hollows expans,Ja of ghs or vapor 1a the sensing balb expannion or en, or vrijcn II tho bellows pressure on the helical tu1,0

,! ,e f 11 ,wihg .tymbc!... represents Assume that a pressure si'th ..loses at :hbutto- switch whose only function 300 psi and opens at 1)0 p aer you toone:g1to, a cintuit when the push- make certain adjustments, Or wttch td.1,wa? clLsel; at 35J ps: and opens 5, psi. What Nind or kinds of adjust:- you 0"----10 make?

Range only Differential only Tomp::rature Range and differenticl

8-8 To ensure accurate adjustment o therr switches, 1. :s necessary to - 1. compensate for different rates of temperature changes 2. allow a minote or two for the ;t to reach the temperatul'e of the srround- Learning Cbjective: identify operating ing air. ga or liquid principles cf phctcelectric ccntrol relays, ;. make djustme:,ts very slowly while

switct,os, pressure-and temperature the switch ": ir operation actitit,1 witches, anl automatic boiler 4. check operation11 the sw..tch throug.n an entire cyc .. after making the initial adluImerr

4-69. A change in thi.. wk,ter lece ,-,aused by an 4-t)3. The phctotube type of light sensitive cell imbaJ-n-e of fluA, flowing into e..nd r,ut generates enough epergy to operate the of at team generetin,-, equipment is pho -cell relay directly. det., by a level control cr float cc: .rol which ct.:,.3es other devices to A self-generating photronic cell should -rstore to balance or cut off operate within what limits of current to th iotl supply. be a useful control device for street ighting?

1. 2 to 2. 2 to 4 A 3. 1/2 to t mA 4. 1/2 to 4 mA

567 photoele.'tric comburion contr,i ee..monly work.; on the principle that the

,,, ! re lay r,. 10.0 e .1 t he Wh-n prop,iriy act cireiit. to burra.'r (Ten.' ....; . relay when prote..y the'ircnit .' ' ' " . r, to tlx c rc y .".':e.. r the oel.i's ;lit:7mlto make 1,' 1,- i .1: .:,rew ; t.' within thecell which,in turh, opera-

, t he re 1 ay " w. e,"work apytihr, t. ; 1: 1 :4',.1i device.: r, the writ..:. prec,.'olre whiv, Sn.. r,ttowinkr, !ump.: uf has the same functi.41 as the lhotoelt . tle:71 Whenth.' prop'r :embul.tion c)htrel? .; : 1. l'hotocenductive COE eo.sLien c)nt. 1. Presalre limit :;witch . 1. L,e.row Pro teeto re I ay :!.' , frame, :Ln . 4 . Pyrostat

;..'hy is thc pret,..t Jreluy a' electromauletic suiteh on many firetube " . ' w Sico:n;,a.::::. type boilers? f" 're a.- ,k 7iech- 1. To tie toget:.er the burner ce,,erajI controls and the shf, .! mbvstion controls

2'. To provide an interlock betwc m 'he burner and burner contro?3 O. To cause emergency shutdowt of the burner in response to safety corn . bustion controls 4. To perform all of the above

314 Assignment 5

5-4. When mixing an electrolyte, you pour the acid into the water. Identify prir'ole3 f rganioing an aud listingui3h between 5-5. You wear gloves on both hands when filling racti,'es. a blowtorch with fuel.

5-b. 1-fore s.:arting to work around a rotating machine, you remove your finger rings and ele.'tricar reya'r shop should NOT be wrist watch. a3 5-7. All Navy instalictions must ,round some neral i.iqu' for repair and appliances. Local authorities may decide mainterance of electricai equipment not to ground otner. The supply voltage orero: electrical parts for that represents the division between the elipment two classes of appliances is d orage d-pot for the conduit and wire t, be .1sed in nes,4 construction on the 1. 50 v ,o3ite 2. 100 v oreroom and issue room for tools 3. 150 v -,ed :or electrical equipment repair 4. 200 v and maintenance 5-8. Which of the following electrical appli- a shovaan receives repair parts, such ances must have their cases or enclosures as ball bearing assemblies, he should make grounded? it a prac'ice to 1. Food mixers plao them in storage without di9t'orb- 2. Record players idg their wrappers 3. Soldering irons inJ:Aact them to ensure they are of the 4. All of the above pr)per size and in good condition, then 37,ore them 3. inspect the, treat with preservative, and then store 4. store them near the euipmont on which they may be n-cded

To answer items 5-3 through 5-6, determine whether an item describes a good shop L..a.-Aice or a poor shop practice. Erase block 1 n the Lnswer sheet to indicate a good practice; erase block 2 to indicate a poor practice.

5-3. To keep from damaging repair parts, you leave them in their original containers until ready to use.

5 6 9 5-l14 What step should you take just beforls resurfacing pitted collector rings with a Learning otleotive; ii,,cognfte techniques commutator stone dressing tool? iisads,mbl:ng a g'ia.taltor or motor and

re r ing ammo.. t.f r ar co I lee tor ri rigs . 1. Clean the collector rings with a solvent Polish the collector rings with oiled canvas Assume that you are sent out to a sub- I. Let the generator cool off station to repair a 3-phase a-c generator 4. Run the generator under load that is inoperative. To save yourself time and labor, your first effort toward 5-15. When turning a commutator on a lal t, how repairing the generator should be to ex- can you keep from twisting the bars? plore the possibility that the source of

the trouble is a L. Use a cutting depth of 0.01 inch or less sudden change of atmospheric conditions 2. Run the lathe slower than the rated 2. defective manufactured part spPed of the generator neglected routine maintenance action 3. 3. Run the lathe faster than the rated 4. poor housekeeping habit speed of the generator 4. Use a feed of 0.10 ipm

9-1 . In breaking down an a.o generator into its comionent parts, you should use a rawhide 9-16. Which of the following tools should you or rubber mallet in order to use to remove any insulating mica that protrudes from slots between commutator 1. withdraw the rotor bars? 7. work the end bells out of the frame 3. mark the end bells and the frame 1. A power-driven flexible-shaft under- 2. remove the bolts holding the end bells cutter in place 2. A slotting tool 3. A cutter improvised from a hacksaw 5-11. After removinc, s-misealed ball bearings blade from motor end which of the fol- 4. Each of the above lowing actions should you take? 5-17. When measuring the air gap at the commu- I. Use an approved cleaning solvent on tator poles to determine the amount of the bearings before storing them commutator wear or misalinement, how many 2. Store the bearings in a piece of clean points of reference should you measure on waxed paper until they are ready to be the stator with respect to a single refer- reinstalled ence point on the rotor? 3. Be careful to apply pressure only to the outer race 1. Five 4. Each of the above 2. Two 3. Three 5-12. You should wear canvas glove: when removing 4. Four a rotor from a generator to prevent the keyways from 5-18. The surface of a commi4ator c&be cleaned with a 1. scratching the field coils

2. nicking the pole pieces 1. canvas wiper only 3. scoring the commutator bars 2. canvas wiper or a toothbrush 4. cutting your fingers 3. toothbrush or a strip of fine sandpaper 5-13. A blue or green discoloration on the 4. st/ip of fine s.-...:dpaper or a canvni copper surfaces of a commutator should be wiper removed with a

1. grinding resurfacer 2. dressing tool 3. lintfree cloth dipped in approved solvent L. strip of canvas moistened with light oil

570 5-19. Pitting ,'Ilused by ele,:trolytic action 5-:74. when seating a b:-ush, you should place on the :nirface of collector rings can be the sandpaper between the brush and the prevented by commutator with the rough side toward the

1. reversing the polarity of the rings 1. commutator and pull the sandpaper in every few days the opposite direction of normal 2. changing the brushes every few days commutator rotation 3. che,:king the rings ortt2n and changing P. commutator and pull the sandpaper in them when they become worn the direction of normal commutator 4 polishing the ringL; with a crocus rotation cloth 3. brush and pull the sandpaper in the opposite direction of normal commutator rotation 4. brush and pull the sandpaper in the Learning Objective: Identify practices direction of normal commutator in maintaining and replacing brushes on rotation d-c motors and generators. 5-25. The finishing steps you take to complete the job of seating the motor brush include

5-20. The grade of brush used in a motor or 1, turning the sandpaper over, sandpaper- generator is determined by the ing again, and touching the seater to the heel of the brush for a second or 1. :tize of the motor or generator two 2. load and speed of the motor or 2. touching the seater to the commutator gentrator for one or two seconds, vacuuming the 3. time in service dust that results, and cleaning the commutator 5-21. Br.:hes should be rgdaced when they are 3. lifting the brush, inserting the worn to within seater between brush and commutator for a second or two, and cleaning the 1. 1/8 inch of the metallic part, or commutator more than 75 percent of the original 4. pulling a finer strip of sandpaper length of the brush between brush and commutator once or 2. 1/8 inch of the metallic part, or twice, vacuuming the dust that results, more than 50 percent of th,, original and cleaning the commutator length of the brush 3. 1/4 inch of the metallic cart, or more than 75 percent of the original length of the brush 4, 1/4 inch of the metallic part, or more than 50 percent of the original length of the brush

5-22. You can calculate brush pressure by

1. dividing the brush contact area by the spring pressure 2. subtracting brush contact area from the spring pressure 3. dividing the spring pressure by the brush contact area 4. subtracting the spring pressure from the brush contact area

5-23. When seating a brush, you should use a brush seater and

emery paper c. a file 3. sandpaper 4. an oilstone

571 Learning Ob1ective: Identify principles = = = m =1 = and 1)ractices in the maintenance and :0!Air of generator or motor ball bearings C:3 =3 = = mCD =3 and armatures.

CDEN=3E:Dm= 5-28. The type of boaring used in motor construction is primarily thrust or radial, depend- = = CD CD m =3CD ing mainly on whether the

1. rotor rotates clockwise or counterclockwise A motor is mounted verticialy or horizontally 3. drain holes on the bearing housing = CDC= are accessible or not, bearing housing is, or is not, dis- -77 = CD CI =cJ c=3 assembled to renew bearing grease 5-29. %latch p-ersonnel should be familiar with the normal operating temperature of + cEJccJEJ generator bearings in order to detect any sudden change in bearing oil temper- - I= CI = (:=3 ature. 5-30. When pressing a bearing onto a shaft, you must apply pressure to what part of the bearing?

Figure 5A 1. Cage 2. Raceway 5-26. Are the brushes in A and B of figure 5A 3. Inner ring staggered correctly or incorrectly? 4. Outer ring

1. The brushes in A and B are 5-31. What kind of solder do you use for staggered correctly soldering banding wire? 2. The brushes in both k and B are staggered incorrectly 1. Pure lead solder 3. The brushes in A are staggered 2. Pure tin solder correctly, but the brushes in B are 3. Lead-alloy solder staggered incorrectly Tin-allpy solder 4. The brushes in A are staggered incorrectly, but the brushes in B 5-32. One method of determining whErl type of are staggered correctly winding an armature has is to measure the variatichs in Lhe resistance found at 5-27. Brushes may be set on the no-load neutral different plars around the commutator. point of a commutator by the mechanical You can 1-ead this differenre on a low- method or by the reversed rotation method. reading ohmmeter or use a milliammeter In either method the brushes are posi- connected tioned on the commutator at a point where minimum voltage is induced between the 1. parallel with a rheostat and a 6-vot batterY 1. adjacent commutator bars 2. parallel with a rheostat and a 12-volt 2. commutator and main-field pole 'iatte]'y 3. commutator and armature 3. in series with a rheostat and a 6-volt 4. commutator and windings hatterY 4. in series with a rheostat and a 12-volt batterY

5 7

38 5-33. On a simplex wave winding the maximum 5-38. Assume that the test shown in textbook A.Naneter rending will he indicated when figure 7-30 reveals voltmeter readings the probes are placed an commutator seg- that increase or decrease and are alter- ments that are approximately how far nately po,;itive and negative. What is apart? indicated by such readings?

I. One pole pitch I. A short ir a simplex winding Two pole pitcbe.s 2 A short in a duplex winding 3. Three pole pitohes An open in a simplex winding 4. Four pole pitches 4. An open in a duplex winding

5-31;. Blue sparks that pass around the armature 5-39. During a growler test, you hold a hacksaw of a running machine indicate an open blade directly over the top slot of the armature coil. The sparking occurs armature to test for a/an because, as the segment to which the open coil is attached passes under a brush, I. grounded coil the brush 2. shorted coil 3. opened coil 1. opens and closes a circuit d. bu:ils the coil insulation 5-.40. Assume that you are making emergency 3. shorts out the coil repairs to a d-c motor that has a short- 4. grounds the coil circuited armature coil. In order to keep the motor in service until the coil 5-35. In the bar-to-bar test, measurements are can be replaced you will have to taken with which of the following instruments? 1. disconnect the coil at one end only 2. cut the cdil at one end, then install I. Milliammeter umper between this end and the other 2. Millivoltmeter irnd of the coil 3. Ohmmeter 3, cut the coil at both ends and install 4. Each of the above a jumper between the risers from which the coil was disconnected 5-36. Which of the following voltmeter readings indicates a real ground in a d-c armature? 5-41. Before stripping an armature you must record the initial winding data. After 1. Low voltage before and after rotation recording the data, your next step is to of the armature 2. Low voltage before rotation of the 1. disconnect al.d remove the coils armature, and normal voltage after 2. perform a bar-to-bar test to determine rotation what type winding it has 3. Normal voltage before rotation of the 3. remove the banding wires

armature, and low voltage after I4 . unsolder the coil leads from the rotation commutator 4. Normal voltage before and after rotation of the armature 5-42. The armature wiring should be tested for grounds, opens, or shorts after the coil 5-37. How will the voltmeter in textbook figure ends are soldered to the commutatcr 7-30 read for open simplex arnature coils segments. and for shorted simplex armature coils? 5-43. When do you put snrink rings on a commu- 1. Minimum for both open and shorted tator? coils 2. Maximum for both open and shorted 1. Afterthearmature has been baked coils 2. Beforethearmature has been baked 3. Minimum for open coils and maximum 3. Afterthecommutator has been tightened for shorted coils 4. Beforethecommutator has been tightened 4. Maximum for open coils and minimum for shorted coils

39 573 In fur;w..ria4 it.qm; .-44 and 5, refer 5-49. An open circuit in the field winding of t, t.X1 Tabh. a d-c generator that is carrying a ioad will be indicated by 5-44. ilk immer,;ed in oil can be used as wb:Lt class of insulation 1. excessive armature current 2. heavy oparking 3. loss ad and voltage 4. r the generator L. A sta'

Coils ar... ylassified as shunt field coils 3. F 5-50. 4. H or series and commutating field coils, with one difference being that the former 5-5. What classes of insulation material are consists of many turns of fine wire while conoldered fragile and should be handled the latter consists of few turns of heavy with care? wire.

Y,u can discover and locate an open a-c 1. B and F 5-51. 2. F and H stator winding by taking resistance readings of the 3. H and N B and N 1. eoil ends

')-46. The maximum number of times that the 2. phase terminals windings should be dipped and baked 3. intert,oies during varnishing is 4. phase terminals, then the coil ends

After you have rewound stator coils and 1. five 5-52. two taped them with insulation, you tin the Your next step 3. three free ends of each coil. 4. four is to test for

5_4(. Refer to textbook table 7-3. A high- 1. continuity and grounds potential test can be made on a d-c 2. shorted turns and grounds generator when the rewinding is complete 3. continuity and shorted turns and the insulation resistance has been measured and found to be higher than 1 5-53. The trouble that shorts an entire pole- megohm in the phase group can be readily located by means of 1. armature alone 2. armature circuit less the armature 1. an ammeter 3. complete armature circuit 2. an ohmmeter 4. complete shunt ideld circuit 3. a compass test 4. a balanced-current test 5-48 In performing the high-potential test you maintain the full voltage required for 1 5-54. The balanced-current test is made with minute. Then you should reduce Cie voltage to one-quarter of the correct value within 1. an industrial analyzer 2. a low voltage d-c source 1. 10 seconds 3. an ohmmeter 2. 15 seconds 3. 20 seconds 4. 25 seconds Learning Objective: Identify principles and techniques of maintaining motors and generators. Learning Objective: Indicate principles of trz.,ubleshr)oting field coils and stator coils. 5-55. A motor that stalls while starting or fails to start probably has a

1. worn bearing 2. grounded winding 3. faulty centrifugal switch 4. burned-out winding

40 57 I 5-56. Why does the uccumulati)n f dirt, mois- 5-61. What is the cffi.iiensy and toxicity or ture, ant oilin gencrator und motor trichlornethylene as compared to type ventilutioi, ducts cause local. or gonera1 LI dry ci oninri ng solvent? overheating? L. Toxicity is less and officiency is 1. Resistance to the dissipation of heat greater is decreased 2. Efficiehey is lens and toxiity is Resistance to the dissipation of lxat the !raple is increased 3. Toxicity is greater and efficiency 3. Moisture and dirt Corm a nonconducting is greater paste Toxicity is less and efficiency is

4. Oil and dirt form a nonconducting 1,!512. peste 5-62. 22 ,lch of the following safety precautions 5-51 che accumdlation of iron particles on should you take when using a solvent fcr .1-tor or generator windings !s particularly cleaning electrical equipment? becausF the particles will punc- 1,..re insulation as a consequence of being 1. Have a fire extinguisher on the scene for immediate use I. removed with a dry rag 2. Use safety type po-rtable lights if 2. agitated by magnetic pulsations additional lighting is required 3. disturbed by air circulating through 3. Remove vapors with exhaust fans or the windings portable blowers 4 absorbed by moisture or oil 4. All of the above

5-58. Suction cleaning of motors and generators 5-63. By what means are shaft current.: kept is preferred to other methods because it from flowing through the outboard bearing lessens the possibility of damage to the of a generator on which the bearing pedestal is insulated from the base and 1. insulation the bearing oil piping? 2. commutator 3. brushes 1. Insulating shims under the pedestal 4. soldered parts 2. Insulated holddown bolts and dowels 3. Insulated couplings in the bearing 5-59. When blowing dust from a 25-kw generator inlet and outlet oil piping flanges with compressed air, you must be sure to 4. All of the above use which of the following? 5-64. What technique should you use to clean 1. C:.ean dry air oil and dirt from uncoated copper contact 2. A suction blower at an opening opposite surfaces? the air jet 3. Air pressure of less the 30 psi 1. Varnishing 4. All the above 2. Sandpapering 3. Silver polishing 5-60. What substance can be used in an emerge Ly 4 Moistening with an approved solvent as a cleaning solvent for electrical equipment? 5-65. New motors or generators are delivered from the manufacturer with the grease 1. Water cups removed from the bearitig housing 2. Alcohol and replaced with pipe plugs. Where 3. Benzine should the grease cups for 1,he new motors 4. Carbon tetrachloride or generators be?

1. With the responsible maintenance personnel 2. With the onboard repair parts or special tools 3. With the other grease cups in the workshop or toolroom

575 5-66. Where should grease dups forit motor be Arsume that you are taking air gap kept when aro not heing used te measurementr on a six-pole d-e generator. grease bearings? Which of the following measurements should you take if one end (A) is acces- 1. In the worksnop or toolroom in the sihlo and the qcooibility of the e.er custody of responsitle maintenance end (B) is siffidult? personnel

In A bag attached to tse mot r 1. At end:; (A) ant 01), 2 mr.,2annrmcnts S. On a wire attachod to A pipe plug spaced approximately 90° 4. ON a wire attaehed to tho motor At end (13), 6 measurements rpabed apprc,ximately 60°, at end (A), 2 5-07. In the abstce of other instructions, at measurements 911° apart wh,it snsuld you maintain the oil in 3. At end (A), 4 measurements :p(ieed an oil-lubricatel, ball bearing actor approximately 900; at en('(B), houSing? measurementr 900 apart

,Inproximttely level with the top or Assume that you are filling the oil laby- the bearing rinth of a ring-oiled rleeve bearing that 2. Almost level with the bearing inner fiLted to a 3/4-inch armature shal't. rine, at the lowest point The bearing housing is not fittt.d with an Level with the center of the bearing overflow gage or an oil filter g,ge. You Approximately level with the highest have filled the labyrinth to the proper point f the bearing inner ring height when the oil ring dips into the oil to a depth of approximately 5-Cd. To what extent sn.,uld you run a motor adding grelre too the mstor bearings? 1. 3/8 in. P. 1/2 in.

1. Intermittently 3. 3/4 in. 2. Continuously 4. i 1/2 in. 3. 3 minutes 4. 10 minutes 5-73. Which of the foliew, separates the bearing surface from the rotating 5-69. Bearings that require a silicone grease journal? lubricant normally operate at a minimum temperature of 1. An oil seal 2. The bearing housing

1, 82° C 3. An oil film 82o F 2. 4. An opening at the top of the bearing 90° C 4 900 F 5-74. At what maximum temperature can sleeve bearings and the outer races of ball 5-70. Why is it a rare prao-Are to take air gap bearings be allowed to operate? measurements on ball hearing machines? 1. 90° C forslid,ing contact bearings 1. Machine construction prevents bearing 2. 120° C forrolling contact bearings wear on class Ainsulated motors 2. Machine construction assures bearing 3. 150° C forrolling contact bearings alinement on class Hinsulated motors 3. Air gaps are too large to measure h. 120° C forrolling contact bearings with a feeler gage on class Binsulated motors 4. Air gans ere too small to measure with a feeler gage 5-75. In case an attachment plug has no cord- grip, you tie an Underwriter's knot in the cord to

1. adapt the plug to fit a 2- or 3- slot outlet receptacle 2. eliminate tension on the terminal connections in the plug 3. ground the connected equipment properly

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