DOCOMENT RESUME , / Al , ,---Iii:1341____69_8______.. 95 / CE, 009 178

. . AUTHOR WooSillard, Robert L.; Myers, Norman L. .). TITLE industrial Arts.Power Meclanics. Applying Scientific Principles to Poier, Energy, Force. InStructional Units. 4 INSTIT6TION California State Dept. of Education, Sacramento.

. PUB DATE 70 , . 'NOTE 145p.; Project conducted under National Defense. Education Act of 1958, 1)ublic Itaw p64 of the 85th Congress / EDRS PRIC2 EF-$0.83 HC-$7.35 PlusPostage: DESCRIPTORS Curriculum Guides; *Industrial Arts; Industrial

Technology; Instructional Materials; *Power . Mechanic's; Science-Instruction; Secondary Education; Trade and Industrial Educatipn;/*Umits of Study (SubjectcFields)

: * ABSTRACT lheci.hstructionaI unkits and related materials in this guide are designed fb assist in the prepi'ration.of coursesi'of - stUdy/instruction in (1)power mechanics spee±ficallye (2) power, mechanics whiCh seive as introductory courses in other areas of Industrial alr-t-Sc and (3)auXomotive'mechatics ihich also cover the broader aspectS of power mechanics. Each unit presents a broad coverage of the topicindicated by its title, coveri:the scientific - principle involved, suggests methods oX applications of the technical and scientific information, and listsfselected refe;tences to furtber technical and scientific, information. These references are\keyed by Nv nusbers jeil parentheses to the.c9Mplete list of selected references at the end. There.are 40 units prSented'under seven section headings: (1) Natural Power (muscle power, waterwheels, windmills, heat -collectors, and solar stills);(2) Mechanical Power (simple 44.d coound machines, lubrication, springs, clutches, and dynamometers), S.(3) Steam Power (steam engines and turbines),(4) Thermal Power " (h. -energy rate forming, powder-actuated tools, jet and roket -engines-, gasoline tes,ting, carburetion, two- and four-cycle engines, wankel engines, thermostats, and welding processe4, (5) Electrical Power (dry cells: primary cells,' storage batteries: secondary cells, generation cf electricity; transmission of electric.power, transformers, spark plugg, ignition systems, electric lootors, fuel cells, photoelectric cells, and semiconductor power rectifiers), (6) Hydraulic Power (jacksand preSSes,.machine tools, braking systems, fuel pumps, power steering, and air conditioner), and (7) Pneumatic Power (air-iaowered tools, spray guns, and vacuum pumps). Appendix A presents asrelatively brief"coursefoutlin for industrial artsAaomer mechanics, and appendix T a coepfenensive course outline for industrial arts autoMatiAe mechanics. Appendix C contains terminology

on the storage battery. Appendix D is assignment heets. 4JT) . 0

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Documents acquired by ERIC include many inforinal unpublishedmaterials not available from other seurces. ERIC makes every effort to obtain the best copy available. Nevertheless, items of-marginal reproducibility are often encountered and this affects the quality of the microfiche and hardcopy reproductions E,RIC makesavailable via the ERIC Document Reproduction Service (EDRS). EDRS is not responsiblie for the quality of the originaldocumenf. Reproductions supplied by EDRS are the bestithat can be madefrom, fhe original. f .1

Instructional Units

c Inctustrial Arts POWER IYIECHANIC I. Applying Scientific Principles to POWER ENERGY FORCE

Robert L. Woodward and Noriman L. Myers Consultants inlndustrial Arts Education Project Coordinaton

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DEVITMEN_T OF HEALTH, EDU ATION WELFAEfr NATIONAL INSTPTUTEQF EDUCATION THIS DOCUMENT HAS0 BEENREPRO- RECEIVED FROM DUCED EXACTLYORGANIZAiION AS OR iGIN- THE PERSON OR ATING IT POINTS OF VIEWOR OPINIONS STATED DO NOT NECESSARILYREPRE- SENT OFFICIAL NATIONALINSTITUTE OF EDUCATION POSITION ORPOLICY

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Proje t Conducted Under National Defen on Act of 1958, Public Law 864 of'the 85thCongress

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to. k Partially funded under provisions of the National Defense Education 2 Act,TitleAi,thispublication was edited and prepared +fur photo-offset production by the Bureau of Publicalions, Californk State Department of Education, 'and published by the DePartment, 7,21 CapitCil Mall, Sacramento, California 95814.

Printed by the Office of State.Prinling 1970

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, FOREWORD ' Courses in- industrial arts power mechanics are designed to provideopportunities for students to make applied use of technical information and scientific principlespertaining to poWer, energy, and force. Students are thus given the types of experience,s thatwill make their knowledge Kf technical and scientific information, Meaningful and useful tothem and that will cause them to acquire and use proficiently the skills involved inindustrial arts power mechanics. These . achievements willin turn intensify .the students' interest in industrial arts, science, and technology. Two studies conducted by the California State Department of Education Wereconcerned with the scientific content in 'automotive/power mechanics coursesoffered bf California high schools. These studies.produced information that wastOed to, develOp instructional material for the industrial arts -area of powermechanics. This information was used .by members of the NDEA IndustriaL Arts-Science Curriculum Committeeand the NDEA IndustrialArts-ScienceEditorial Committee during workshops conducted' under the provisions of the National Defense Education Act in thepreparation of the material for an :experimental edition of Industrial Arts Power Mechanics. 1 A copy of the eXperimental edition of Industrial ArtsPower Mechanics anda questionnaire were sent to each auto/notive/power mechanics teacher inthe highhools of California and to selected industrial artS leaders in other states: Theeducators wth. i.s!ted to review the publication and complete and return the questionnaires.SuggeSted change 3ted in /he returned questionnaires were usedinrevisingthe material presentedJnthe experimental edition.. he instructional units in this publication provide a sound basisfor the preparation of- co es of Study/instruction in (I)power mechanics per se; (2) power mechanics which servk as Introductory courses to, industrial arts automotivemechanics., electronics, and metals in grades nine through tWelve; and (3) automotive mechanics whichMake Ilse of the elements of 9,ower mechanics. I am certain that the, information presented if t Industrial ArtsP9wer Mechanics will be of great value in the detelopmenta of power mechanics courseswith the breadth, and deplh of content that is needdd and m which sound, efficient, andeffective instructionaFprocedures are emphasized:,

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Superintendent of Public Instruction NDEA COMMITTEES

NDEA IndhstriaL Arts-Scielice Curriculum Committee .. . The spacialists in autonyotive/power/ mechanics frOm the ten California colleges with accredited industrial ails ,teacher-education programs and the teachers, supervisors, and teacher educators who prepared the instructional drifts for industrial Arts Power Mechanics during a work sessiOn held at Fresno State College, December 19723, 1966, are asfollc4s: .., -Leslie L. Aldrich, Fresno State College; John C.bavis (retired), Fresno City Unified ,School District; Raymond E. Fausel, California State. College at Liz Angeles;Frank J. 1 Irgang; Sari Ttiego State College; Richard E. JohnSion; Washington High School, Fremont/ (formerly.at .Chico State College); Frank H. Jolly, Huinboldt State College, Arcata;Mark Jones, Tustin Union High School District; Angus J. MacDonald, San Jose StateCollege; Ted . A. McCoy, Hanford High School; Burton A. Pontynen,Pacific Union College, Angwin; Ernest J. ,Raws6n, California State College at Long Beach; James E. Rice, CaliforniaState. chroeter, Fresno State College; and Gerald Polytechnic College., San Luis Obispo; Frank E , Valente, formerly atiSan Francisco State Cbllege. A

1 NDEA Industrial cienc Editorial Committee t . The members of the teams of specialists in science and.speciali§,ts in industrial artswho, at work sessiOns in Los Angeles, Sacramento, and San Diego, On December 18722,1967, edited and augmented the material for- Industrial Arts, Power Mechanicsprepared by the NDEA Industrial Arts-Science Curriculum Committee, are as follows: 0. BrucpAkers, Burbank Unified School District; Ralph C. Bohn, SanRise State College; Joseph E. Freeland, Sacramento City Unified School District; Serafino L.Giuliani, San Diego pty.Unified School Distriet; Harold L. Marsters, San DiegoState C011ege; Richard L. Miller -(retire'd), Los Angeles Unified School District;Jack E.Reynolds, Sacramento City Unified School District; William B. Steinberg, San Diego City Unified SchoolDistrict; and DaVid a Taxis, Office of the Los Angeles County Superintendent ofSchools.:, \

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PREFACE

Industrial Arts Power Mechanics presents,a q of instructional un,itsxierived".frgnfe results' of two studies, a .serieof work sessiofs, and an evaluation O. an ex erime tal s. edition: , !,. OC. Members of the Central California'Autornotive"Technical committee, iVQhprepaTed the material for the experimentartdition of Industrial Arts,AUtoInotive1 Illechaiiics which was published by the California Stite Itlepartment,,of Education in1964, requested the Departnient to. conduct a study to determine the extent to which scientific principles are being apPlied in present industrial arts automotive/poWeri,icchanics coursesand the ways in which these principles can be applied to a greater extent in all, coursesin this area of industrial arts. The Department responded. by conducting two studies, onein 1964 and the , . - , other in 1965. c-r, The firSt seudy-sVuas conducted by having teachers ofautomotive/power mechanics in the high schoOls ofealifornia complete a questionna'ire that was designed to secure their Industrial Arts reactions to.the way in ivtlich scientiftc principles were employed in Automotive Mechanics. All the auto¬ive/power mechanics teachers whoresrlonded favored the covering of applicablescientific principles in the automotivepublication. The second study was conducted by having teachers of automotive/powermechanics in the tigh schools of California complete 2 questionnaire that Was designed to reportif the teachers applied a giiren set of scientific principles _in tlieir courses and, if so,how. In both studies the teachers-indicated a need for curriculuni material thatwould set forth ways of applying scientific principles and provide, instructional units covering thebroader area of power mechanics. A series of work sessions for the development of instructionalmaterial in industrial arts power mechanics which would apply,scientific principles relating to power, energy, and force was financed by funds provided under provisions of TitleIII of the National Defense Education Act. The first work session was held at Fresno State College 'onDeceber 19-23, 1966. Specialistsin automotive/power mechanics from the ten colle in California with, accredited industrial arts teacher-educatión programs were assistedby supervisors *and representatives, of the CentraL California Automotive TechRicalCommittee in preparing instructional units in power mechanics. These participants, listed asmembers of the NDEA Industrial Arts-Science Curriculum Committee in thispublication-, used the data obtained 4from the two studies, information presented 'in the CaliforniaState Department of Education publications Industrial Arts and Science andMathematics and Industrial Arts Education, and science textbooks used in the sChool systems located near the tencolleges represented at the work session to develop the instructional material.- Additional work sessions were held in Los Angeles,Saciamento, and San Diego on December 18;22, 1967, to augment anid edit the power mechanicsmaterial developed at the Fresno State College work session. Each work-session team wascomposOd of a-specialist in science, a specialist in automotive/power mechanics;and astecialist in industrial arts. The participants int these work sessions arelistedas members' of the NDEA Industrial Arts-Science Editorial Committee in this publication. Copies oithe experimental ethn Of Industrial Arts Power Mechanics andquestionnaires\. " for evaluating the publication were 1 i uted in September, 1968, to automotive/poWer-2 mechanics teachN-s and industrl arts supervisors and teacher educators in California and to selected industrial arts teachers *and supervisors in other states. Those who-evaluated the experimental edition and responded to the q0stionnaire became members of the National Power Mechanics' Review Committee. Changes sUggeted by them were taken into consideration 'in revising the material. The NDEA project was coordinated by Robert L. Woodward and Norman L: Myers, Consultants in Industrial Arts Education, California State Department of Ethication. The education profession in California, and particularly those Inembers working° in the, afea of industrial arts automotive/power mechanics, are greatly indebted toall the teachers, supervisors, and teacher educators who participated in the Work sessions and studies which ;esulted in Industrial Arts Power Mechanics., Industrial Arts Power Mechanics should be of invaluable assistance in the preparation of detailed courses of study/instruction in_power mechanics, in the revisioniof present courses of study/instruclion in 'automotive mechanics, and in the improvement of instruction in California junior high schools and high schools.

J. WILLIAM MAY MITCHELL L. VQYDAT Acting Chief, . Chif, Bureauof Elementhry Divisien of Instruction and Secondary Education

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CONTENTS

Page Foreword Preface

California's Industrial Arts Piogram 2 IntroductiOn - SECTION I ATURAL POWER Unit 1MuScle Power 3 UnirtWaterwheels J 4 Unit'3Windmills 6 Unit.4Heat Collectors . 6 Unit 5Solar Stills., ,011.04 . .. 8 .. . SECTION II 7 MECHANICAL POWER Unit 6Simple and Compound Machines, 9 1-3 Unit 7Lubrication . Unit 8Springs 16 Unit 9Clutches 1 17 Unit 10 DY,narpometers .1 19 .. 1 SECTION III STEAM POWER Unii-1,1 Steam Engines and Turbines 21 SECTION IVTHERMAL POWER Unit 12 High-Energy Rate orrning -23 ,- Unit 13PowIer-Actuated fooIs 27 Unit 14 Jet and ,Rocket Engines 30 . Unit 15 Gasoline Testing - ,, , 32 , 33 ` Unit 16 Carburetion , . , Unit 17 Two- and Four-Cycle Engines 35 Unit 18 Wankel Engines 38 URit 19 Thermostats 04 k 39 Unit 20 Welding Processes 41 , I\-- SECTION VELECTRICAL POWER- tinit 21 Dry Cells: Prirr;arl.i Cells 43 "Unit 22 orage Batterieggpcondary'Cells\ , 44 Unit 2Generation of Electricity , 53 -Unit 4 Transmission of Electric Power 60 /Unit 25 Transformers . 64 TIS...Knit 26 Spark Flugs --- 65 8

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r . 1 r .e. v ^ page .. _ Unit 27 Ignition-ysterns ., 67 Unit 28 E1eyrrie()tors 69

Unit 29e Fuel Cells e 71, Unit 30 Photoelectric Cells 73- 'Unit 31 Semicon ttor Power Rectifiers '74 . , I

I : "-SECTION VtHYDRAULIC POWER - Onit-32 Jacks and.Pgsses ...... :...... ",..... 77 --,- /. Unit 33 Machine Tools ... 78 Unit.34 Braking Systvms --7-9. Unit 35 Fuel Pumps 81 ,Unit 36 Power Steering 82 Unit 37 Air Conditioners 83' SECTION VII PNEUMATIC POWER -,43N. Unit 38 Air-Powered Tools 86. Unit 39' Spray Guns .... '.,.." , .88 Unit 40 Vacuum Pumps r 89 ( I 4 . Selected References . ' 92 .. 1 , Appendices ... 95 7 ApPendix A Power Mechallics Course Outline 95 1, Appendix B Autorrictiye Mechanics Cotirse Outline 97 - ° Appendix C Battery Terminology - 124 Appendix D Assignment Sheets .,. -125 ft Acknowledgments . 134

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A CALIFORNIA'S INDUSTRIAL ARTSPROGRAM graphic lofts,industrialcrafMmetals',power The industrial arts programirt.California schools of is an integral part of- the total programof edu- mechdnics, and woods. In a large school each, isoften taught ina cation and is designed Specifically tohelp prepare these ai'eas 'of instruction industrial-, different shop/laboratory; in a smallschool, several- studegts to meet the requirements of an shap/laboratory:' In each instance , which are taught in one "technotogicalculture.Inthisproln with special .i.kplication, the courses are taught by teachers involves study, experimentation; a.nd preparation in the field of industrial arts andin studentearn through participationin activities in machines, specially designed-and equippedfacilities. In' ihese. whiThthe Y use industrial-technical tools; helping materials, and processes, as well a'sEnglish, mathe- grades emphasis and attention are given to students kliscover and further theiraptitudes, abil-. matics,science, 41,ndsocialsciences,in iolving . ities, and interests. Provision ismade for"students meaningfiil probleins. skills and to profit from The four major purposes ofinaustrial Arts are to to acquire a variety of provide opportunity for each student todevelop ° participation increative actiifities. industry and iti In grades nine through twelve andten,through (I) insight and understanding of provides oppor- placeinouf society; (2)talentinindustrial- twelve, the industtial arts program related tunity fqr the high schoolstudent, regardless..of his technical fields; (3) problem-solving ability he So the maprials, processes, andproducts of indus- majorv to chotise the industrial artS courses _proficient and sate use c4 believes will be of the greatest.-value tohim in try; arld (4) skill in the Included in the to ls and machines.These- purposes are furthered againing the goal he is seeking. emphasisisplaced on program are elective courseswhich pvivide in- b a program in which automotive median- helping students acquire The knowledgeand skills struction in the broad areas of ics, \drafting, electronics, graphic arts,industrial ' basic to many careers. , power In kindergarten and grades onethrough six, the crafts,metals;pholraphY, .plastics, the established mechanics, and woods.hese courses are tabgkt by industrialarts program furthers the field of educatignal objectives and enriches theexperiences teachers with special preparation in inspeciallydesignedand pupilshaveinattainingsuchobjectives. The industrialartsarid this purpose equipped facilities. The advancedtechniques devel- industrial arts activities employed for the procedures emphasizeplanning: andconstructionthatis oped' in these courses approach that arise as the pupils used in ,industry. At this level emphasisis given to 'requited in meeting needs cutations .and participate in experiences'relating toFnglish, math-. practices and requirements of' oft SaienceA. The regular 'professions relating to each industrial arts area. ematics, science, ansj social for scientif- classroom'teacher has responsibility for conducting Challenging opportunities are provided ically and mathematicallyoriented students to. the elementary sehool industrial artsprogram. materials, pro- In grades seven and eight ofelethentary schools work and experiment with new . and, grades seven,' eight, and nineof junior high cesss, 4deacs,2 and designs. i" ithegral kn Isltie-and skills acquired and theekperi- schools, the industrial arts program is an t assist total program of ence -ined in.ithe industrial arts. program and often required part of the inclividdfals: tesilect careers wisely and topartii. educationforallyouth.) StUdents are 'usually experiences ipate succesSfully in programsof educaiion and guided through a series of introductory higher learning, in a variety of industrial arts areas.Included in the training offered by institution's of which provide instruction in industry, and government whichprovide further program are, courses careers. the broad areas of drafting,eleotricity/electronics, preparation needed for the chosen

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INTRODUCTION Industrial Arts Power Mechanics is designed to mechanics outline. Appendix C contains terminol- applyscientificprinciplesrelatingto, power, ogy on the storagebattery,N, and Appendix 1:Y energy, and force. The words power, energy, and° contains assignment sheets. force ohen h'ave different meanings when used in One of the purposes of Industrial Arts Power everYday langdage than when used in a -scientific Mechahics is to assist in the preparation of courses sense. In -a scientific sense these words are defined of study/instructionin (1) poWer mechanics as follows: specifically; (2) pOer mechanics which serve-as PoWer is th e time rate of doing work. introductory courses in other areas of industrial Energy is the capacity to do work. arts; and (3) automotive mechanics which also cover the broader dasp.ects of *power mechanics. Force is a push or a pull. Another purpose i to demonstrate theinter- Industrial arts power mechanics is the study of relationships of the instructional content-bLikidus- the generAi6ii and conversion of_g..nergy to power trial arts power mechanics with that of science. 42 andthe 'transmission, control and use of this Courses in power mechanics provide an instruc- power. Power Mechanics includes the study of (1) tional program that is much broader in content the development of power for industrial and home thantheconventionalautomotivemechanics use; (2) the control and measurement of power; (3) courses.Infact,power mechanic1iiploys a the transmission orpower through mechanical, selective coverage of many sources p ergy and fluid, and electrical means; and (4) thease of their application. power to accomplish work. Knowledge and skills relating to po-Wer mechan- Each unit In Industrial Arts Power Mechanics ics may be used in grades seven and eiht to presents a broad coverage of the topic indicated by augment courses in othelyareas of' industrial arts; itstitle,covers tile sciotific principle involved, however, it is recommended that'coufse's in power suggests methods' pf application of the technical mechanics not be provided below grade nine. and scientific information, and lists 'selected, refer- Introductory courses in power mechanics may be ences to further techniCal and scientific informa- offered in grade nine of junior high schools Dr tion. These references are keyed by numbers in four-year high schools.Itis reconimended that parenthesestothecompletelistof selected courses in power mechanics be provided at the high references immediatelY preceding the appendices. school le't;e1. Power mechanics may be offered at The page numbers listed 'after each Ice'5'ted number the high school level as an introduction to courses give further directioniorlocating pertinent infor- in_the indtstrial arts areas of autennotive meChan- mation. ics, electronics, and metals. Appendix, A ofthis publication presents a - Today's industrial technology requires knowl- relatively brief course outline for industrial arts e.dge and skills that are not,Adequately ,covered in power mechanics;,Appendix B presents a Compre- conventional automotive mechanics courses. It- hensive course outline for industrial arts automo- resommended that these -,conventional courses be tive mechanics. The outline on poNter mechanics is more selective in content relating to automotive keyed to the instructional units contained in the mechanics and include the broader aspects of 'text and to certain sections of the automotive power mechanics. 11 SECTION I NATURALPPWER

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-Una 1 . MUSCLE POWER"

k. gewever, such niZchines. cannot increase man The only power aqailable to primitive man was prdd ct his own . muscle.This muscle power madeit hbility to do work, which is defined as the make simple of the force: and the distancethrough whicit possible for hinpto travel, seek food, ce tools, and fight his enemies. The lever wasused by moves. Machines merely allowfife, trade of dist for "quick" force. For example, the wrencused mart during thiS eàrJy period.However, relatively e nut is great sources' of power wereavailable only when 'to loosen a nut is a form of le the muscles .Of many men were brought tobear stuck tightly, it ray be necessaryo use a longer other simple Machines wrench to increase the leverage. Acally, the work upon a single object. Later, se the wrench were used by man tomultiply his mus-Cle power. accomplished is not reduced, bec These were the wheel and pulley, theinclined handle is moved a° longer distan than the nut plane, the wedge, and the screw. (Refer toUnit 6, moves. The same amountof work has tieen done, but in a different, more gradual manner.Either "Simple and Compound Maehines.") force cap When man levned to domesticate andharness speed can be sacrificed to gain force, or animals, another source of muscle powerbecame be sacrificedto gain speed. use forceis available. However, human and animalMuscles required to move the parts of achine and to applied to simple machines limitedman's powel overcome frictioninthe machine, the actual ,for him mechanical advantageis never as great as the output. This limitation made it necessary effi- to seek other sources of energy.Among the sources theoretical mechanical advantage. Thus the of energy to be employed 'were waterand wind, ciency of '1nachineisalways less than 100 °which 'were used to turn waterwheels and wind- percent. mil s. Today, many sources of energy areused by Scientific Principles Involved: mail. Even though modern manhas cOuntless Work, Power, tnergy, Force lab r-saving devices and makes useof many sources of4iower, he still depends on muscle power for a In everyday language the term .workis Used to mental great number of daily activities. describe any actiyitj ir whicly musCular or .machthes" effOrt is exerted. In a scientific sense,howeyer, It should be tmderstood that simple done are devices to increastman's strength (muscle). work has a very cecial meaning:" Work is

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A.- ..- ., w4ign a force acts on niatter and changes'its motion always push,or pull an object. Some combinations or,vhen force Itioves an-olyeet against an appo#ng of forces just balance each other; as a result, the force. No matter how, long a 50-Round Idadris Held body on which they, act remains stationary. There- tin a persOn's shoulder, work is not being done in a force is inore completely defined as that scientific sense;dieupwaid force that,is exerted is lybichproduces or preyents motion or has' a erely counteracting the downward force of. the 'Tendency to do so. lo Work iA done in a scientific sense when the load-is raised to the'shoulder, Viben it is carried up Application of Principles a fligiit of stairs, or when it is dragged acress the I AAcledynamometer can be made td floor. In these cage's a forcelis exerted whicfi moves illustrate the use of muscle poWer to produce the object. Expressed in an equation, work (in electric power. The bicycle is held upright by foot-pounds) -= force (0 pounds) X distance (in a front-wheel block and balancing supports on et each side oftke rear-wheel axle. Two rollers Like the term work, the term power has a (approximately f*Our inches in diameter) are scientificPmeaning that differs from its everyday placed under the ar heel of the bicycle. meanings. When it is said that a person has great The front roller is the idle,and the rear rollers power, it usually means that the person has great is the driver. A pulley whel is attacheto strength. or wields great authority. In a sscientific driver roller. A belt from isulleyheel is, sense, however, power is the time rate of doing placed' around the pulley whee an auto-, \ work. A man does the same amount of work mobile alternator with a variable field control. - whether he climbs a flight of stairs in one minute (The pulley selected should /permit about or in one houe:but he does riot use the same 1,000 revolutions per minute.) All supports of amount of power. parts should be attached to a plywood base/ Matter acquires energy when workis done floor. The generatedcurrentisfedtoa. against iravity inraising.' matter to an elevated 12-volt storage battery fa stabilizing voltage. position or when work is done to set matter in A. bank of lights or other electrical load can motion. The energy thin acquired can be used to be employed to use up the electricity pro- do work. In mechanics there are two kinds--of duced by the alternator. Meter readings can enfty,kineticeviergyandpotntialenergy. be made and horsepower computed. IOnetic energy is energy due to 'notion of a mass. 2 Simplemachinesamongthetoolsand A moving automobile, a bullet leaving the fhuzzle machines in a facility 'can be identified and of a gun, z_spinning flywheel, a rolling ball, and demonstrated by stu-dents. (Refer to Unit 6, falling or running water all possess kinetic energy. "Simple and Compound Machines.") Potential energyisstoredenergy.The water impounded behind a dam has potential ealkergy. Selected References This energy becomes kinetic when it is-used to turn Note: The numbers in forentheses in this section refer to a waterwheel or turbine. The coiled mainspring of entries in the list of selected references that appear within this publication immediately after the text. a watchas-, potential energy because work was 4.

done in winaTiigt. Its potential energy becomes (9), pp. 80, 486-87; (13), pp. 58-64; (16), j,. 148;- kinetic as the sPri g unwinds. (22), p. 49; (24), pp. 452.-55; (26), pp..1-16; (27), Force is direct y related to work and energy. pp.42-49,120-42;(36),pp. 8-13; (37),pp. Force\is a push or a pull. Howeir, forces do not JO" 298-99; (63), pp. 493-97; (66), pp. 1-8.

U nit 2 WATER WHEEL

The waterwheel, sometimes ' calledagravity shot whe,the overshot wheel, and the breast wheel, is a simple mechanical device to convert wheel. The undershot wheel was one of the first water power to mechanical power (rotary motion) engines designed ,to do work. It was introduced against a resistance at the axle of the wheel. The over 2,000 years ago by the Egyptiais and the three general types of waterwheels are the under-, Persians. Undershot waterwheels are made so thai

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rs of the when the paddles at the bottom of thewheel are It is this Water pressure that turnsthe ro dipped into a stream or tiSer, the currentof water water turbines found in theelectricaLgower plants *exerts a force against the paddlesand turns the - located at the base of damg'. .wheel. Overshot ,wheels make use of waterthat-is directie3c11 the top of the wheel on thedownlkard side. t waterwheels, which are similar -tothe Undershot undershot wheels, are rotated bydi.recting water bvershot above the .center of the wheel on the downward side. The early waterwheels were,constructedof the wood; ir n parts becanie common during paddles at. Renaissa ce. (The force of tge water strikes against the the bottom of theorfcNrshot waterwheel (left) and at Witltile introduction of, hydraulic turbines in of the overshot the. the top on the downward side the early part of the,square inch a also has pressure. For about every34 feet below bottoni of the bag. I the surface of water:the pressure ismultiplied by 14.7 pounds per square inch (theamount of Selected References The pressure of deep water Note: The numbers in parentheses in this sectionrefer to pressure at the surface). entries in /the list of seiected references that appearwithin must be taken into considerationwhen designing this publication immediately after the text. huge dams. The thickness of thebase and the that they. ( 13), pp. 509-12; (16), pp.153-54:161; (26),PP- strength of the concrete must be such 395, 398-99. will withstand the pressure of thewater.held back. 8-13; (27), pp. 214-17; (46), pp.

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The U.S. Navy's hydrofoil gunboat is powered by Water jet and is cap- s4e r able of speeds in excess of 40 knots. Water is drawn through rear struts 4: into centrifugal pump and is then jetted through nozzlesniear the stern(Boeing Company, Seattle, Ar- Washington).

5cfra. 1 4 6

Unit WINDMILLS v

Windm,ills consist of a rotating element or.wheel of the current of wind without swing)ng the-entire driven by thedWind that causes the turning of a unit on a-vertical axis. shaft corinected qo equipment to perform useful work. Wit-Ian-tills are pra,cticaf when intermittent Stientific Principle Involved: pbwer is required, as in pumpin,g water to storage .11orsepovrr2Output qf Windmill tanks and 'generating electrical .iower for charging c. The available poweriin a current of Wind is dqe storage batteries in power-supply systerts. to the kinetic / nergy of the mass of airflowing;; The windmill was one of the earliest devices through a give4 areajer anif a time a windmill used toobtain -power from natural sources. SQJli,e the 'area conierned:the 'frontal area swept-Otit'by recordindicate thitt windmills were in existence- the rotating eieriient. At sea-level Codaitions-of air prior to the seventh century. The windmill Was in pressure and temperature, the available,horsepower usein Persia during thrltrith untury and in per unit of area s given by the equation-Hp Western Europe near the close ofethe twelfth 0.00(00214 X V3, where V is the wind velocity in century. feet per second. This equation givesIthe results of During the sixteenth century the general form of horsepower output of a windmill (area 100 square t14 Dutch windmill was stabilized. No essential feet, efficiency 30 percent) as follows: chianges were made until the start of the twentieth Wind speed in feet per century, when resear& showed the way for signifi- second 10 20 30 40 50 100 cant improvements in the form of sails or windmill Wind speed in miles per arms. Modern windmills.have tended toward high- hour 6.8 13.6,20A27.234,068.0 speed destns or types possessing wheels rqtating at Windmill horsepower 0.06 0.5 1.7 4.1 8.064.0 alargeA-giber of revolutions per minute for Application of Prindple maximum efficiency in operation. Present types of windmills are the multivane,,the 1. A windmill can be constructed for demon- propeller, and the S rotor. The'mffltivaned wheel, stration and use in generating electrical pdwer though the least efficient of the modern windmills, for charging storage batteries. has the most numerous applications in the United 2. A . cup-type anemometer can .be. used or States. The multivaned and propeller windmills constructed to check wind speed. possess rotors that revolve About a horizontal shaft, Selected References and hove it is necessary to orient the rotors,into Note: The numbers in parentheses in t.his section refer to the wind through the use of a vertical vane or entries in the list of selected referencestthat appvar within rudder. Since the S-rotor type of wheel is mounted this publication immediately after the texk on a vertical shaft, it is possible to-ta e advantage ( 1.3).pp. 228-32; (16), pp.152-53;r76),pp. 13-15.

-Unit. 4 HEAT COLLECTORS vs(

Itis safe to assume that the earth's supply of dispersion. Yet the energy reaching the earth is fossil fuels will last for at least one and one-half far greater than our needs. If only 1 percent of centuries and that the supply of uranium will last available ground area were used for solar power for a century beyond the fossil fuels. However, plants,theseplants would have atheoretical these fuels are Imited, and energy sources which capability to produce more power than all the arenot presently being used must be put to steam and hydroelectric power plants in the world. 'efficient use in the future. There are two major .probleins in making prac- The energy of the sun is the most obvious source t cal use of solar energycollecting it and using it -of energy. The daily supply is tremendous. In two low intensity. Heat energy at normal earth days the sun provides the United States _with temperatures is difficult to put to practical use. energyequalto "allour Jemainingfossilfuel .More researcand study are needed before solar reserves. Much of this enAgy islost,- however, energy becom sa major source of controlled because of clouds and other forMs of energy power.

4: r- 7

Conduction: Through motion,kinetic energy ,9 uses, though small,are note- 1. Some current is transferred fromAneeatom. or.molecureAo worthy. They are as follows: otheroms or moleculesadjacentlo.if: In 1. Solar cell& convdrt solar energy toelectricity., way heat_ travelsthrough a body by Even though the ouipsut islow,-sdlar cells are onduction. Metals are good heatconductors; used to power satellites andrkpyide power for nonmetallic substances are poorconductors. remote telephone boosters. , motidn, 21-Convection: The increased molecular 2. Solar evaporation pf seaweerhas been a due to a cise in temperature, causessubstances major.source of saltand,other oceanminerals to expand, therebyreducing ,theiF'density. for centuries.. Also, the yvaporationand con- When any portion of a gas orliquid is heated tlensation -of\ 'seawater as a sourceof fresh to- a higher ternpieraturethan the remaining water have been effective insmall a* experi- fluid;it' becontes lighter and- floatsupward. 4mental installations`..\ Theresulting 'movementisaconvection 3. S'Olar cooking units have beendesigned and ctirrent.. Heatis *distributedin gases- and manufactured( for -use in areas havinga-*&gb- liqpids by these convection currents. - .tstantial amouAt-)of avatlable sunshine. 3. Radiation: Heat in the formof .rafliant energy 4. SiDlar heating TOf homes hasbeen successful fia"yelsins, straight lines througly spaceand regions wherethere isan abundance o transparent materials. Radiowaves, infrared sunshine. light, visible light, ultravioletlight, and x-rays - radiant energy. When radiant 1 are all forms of Light energy, particularlythat of the infrared por- tion of thespectrum, strikes an opaque object, some of it isreflecied back into space and some is absorbed. Theabsorbed portion increases the kinetic energy ofthe atoms or molecules that make up thesubstance, thus increasing its temperature.

All opaque . r adiate some heat depending sorb on their temp ,and a,11 such some of the radiaenergy thatstrikes them.he amount of absorption orradiation depends mainly N on thesurfaceand color of the body.Rough, dark-colored '.6rfaces absorband radiate more heat. Smooth, light-coloredsurfaces _absorb and radiate less heat. Silicon-arsenic 4e-) A solar cell is composed of awafer of silicon-arsenic Sun's tays coated with boron. Focus of Scientific Principle Involved:Heat rays The tekrnperacure of a bodyis the measure of the motion bf its molecules.Molecules of all sub- stancespossess °kineticenergy, which maybe expressed by the formula KE =112Mr where KE is kinetic energy, Al is mass,and V is velocity. As the tvriperature of asubstance rises, the kinetic Reflector energy and,therefore, the velocity of themotion of its molecules increases. Solar cooking can bedemonstrate'd by Using a conduction, by convec- concave mirror or bright metallicsurface to convert Heat is transferred by the sun's rays to heat for power. tion, or by radiation:

6 Application of Principle 'should be exercised since very_high tempera- ., tures are possible. . 1. simple heat collector can be made fronr a . box which is painted a dark color, preferably VThe conversion of solar energy,,to electiiciff black: A' second 'collector box, painted:white, can be illustrated through the use of:solar " should also be made. A thermometer should cells. A 'solar motor assemblY can be built \--J be placed in each boi and the boxes placed in : 'which consists of a Pair of solar cells wired to bright sunlight. yhe temperature readings of a small motor. The motbr will operate when- each thermometer should be recorded at ever theoells are exposed to sunlight. periodic intervals. An appropriate gr'aph can beblOtted. Selelteferences fr 2. Solar cooking can be demonstrated by usiug a Note! The numbers in parentheses in this section refer to apeiltries in the list of selected references that appear within concave mirror or bright metallic surface. A this publication immediately after the text. match or small pieces.of wood can be ignited at the focal point of the mirror.flector. A (14), pp. 160-70; (16), -pp#177, 217-18; (26), pp. larger4rilt, designed to roast hot gs or cook 339-40;'(40, bp. 128, 398: 400, 401; (54IQc pp. other foocts,, 'can be billy with a bright, 551.53; (.59), p. 274; (66); pp.- 174-81 ; .(8.3771313. concave, iiefallic surface g a reflector. Care 182-eS, 193.

1 .Unit 5 SOLAR STILLS The available Supp1y of fregh water may soon bejis then condensed to/liquid/again. The condensa- inadequate for many cities and Countries in the tiOn takes place on any surface which is ,cooler world.v Many islands, such as the Virgin Island than the water vapor A"- steAi. All suSpended have inadequate supplies of,fresh water for di-in matter and any dissolved material which has a Mg and for irrigating crops. As a result, consider- higher boiling point than water are left behind. able effort has been expended to extract ocean water thai can be used as fresh drinking water. Application of Principle , One mefluid, often recommended for s wors at seas involVes the evaporation and, condensation A solar still may be.developed thco.dgh the use of seawater. Miring evaporation the water goes ..of a large, clear plastic bag, a black terwel, or other into the air in the ctantainer, leaving \the Salt and dar, absorbent material, and a collector.tray. The other. minerals ,behint. When the water is con- 'Plastic bag should be rigged as a canopY over the densed,itisfresh and free of salt and other black towel. The towel should 'be soaked in salt minerals. water. When the unit is placed in the sun, the solar This, method, known as the solar still method, is energy will be absorbed by the towel and the water inexpensive but impractical for large quaritities of will be heated and Aiporated. The water vapor water.Itis currently used as. an emergency or wl11 rise to the inside of the canopy. Since the air is -low-production methodof desaltingseawater. cooler within the canopy than at the towel, the Future improvements, might finditor a modi- water will condense on the inner surface of the fication of the system more practical to meet the clear plastic bag. Abcollector tray along the edge of growing demand for fresh.water. the canopy should l4e used to collect the small quantities of condensed fresh water. ScientifiC Kinciple Involved: Distillation of Water. Selected References Seawater is not satisfactory for drinking becaLese Note: The numbers in parentheses-in this section refer to of its high saline ,conteni_Distillation or evapo- entries in the list of seleckd references that appeari lin ration has long been usecr as a method tO obtain this publication immediately after the text. pure water. The process consists of evaporating or (8) pp.147-49; (13),pp. 213;.,336; (14), pp. boiling %Niger to form water vapor or steam, which 169-70;(43); pp. 172-73,186-89.

17 .( No.

SECTION N .MECHANICAL 'POWER

:;.).

4.40,

, , Unit 6 4- SIMPLE AND COMP.OUND MACHINES. tk. , . . /Machines are used to transform Energy, transfer ex,prt an, upw'ard force on the flag as a downward1 energy, multiply force, multiply speed,and change force is exerted on the other end. the direction, of .4 force. A generator transforms mechanical energy into electrical energy. A steam Mechanical Advantage orgasturbirm,, transformsheatenergylnto When a chain hoist is 'lied to lift a car engine, Mechanical entity. Machines are used to transfer the chain 'moves several feet to raise the engine a energy froth one place to another"; for example, in few inches. When a vile is tightened, the end of the an automobile theconnecting rods, crAnksbaff, handle is moVed (turned) further than the jaw of drive shaft, and rear axle transfer energy from the the vise is moved. When the lever of a paper cutter. cobustion in the cylinders to the rear wheels. is p'ulled ,down, the hand of the 'operator moves hinesare used to multiply force; thus, an farther th any point on the cutting edge. In each .. engine can be lifted out of an automobile'63, u,sing of these s and in countless others, a lesserforce a system of pulleys. The pulley systemmakes it is exerte, gain a greater force at the expense of possible to raise the engine by exerting a force haying toe rt thq lesser force over a longer which is smaller than the weight of the engine. distance. Each of-these machines provides Mechani- However, this smaller force must be exerted over a cal advantage. greater distance than the height through which,the 1.engine is raised, and the engine moves more slowly Scientific Principle Involved than the ckiain whichis, pulled. A machine, By the use of simple or compound machines, a therefor,.ktoduces a gain.inforce, but only at the personisableto multiply the force that hi expen.f speed. Machines arealsoused, to muscles are cap'able of exerting. When a 20-pou multipl ,5 eed; for example, a bicycle is used to force is exerted through a pulley arrangement o gain speed, but only by exerting a greater force. No' chain hbist to lift a 200-pound engine, the effor,tot. machine caf be used to gain both force and speed a person is multiplied teh times.Mechanical advan- at the same time. And machines are used to change tage equals weightsupported (W) divided ,by the the direction of a force, as when a single pulley at force' applied (F) in any meehanical device; or, to the top of a flagpole enables one end of the rope to put it. another -Way,. rnethanical advantage equals

.1 8 9 "10

W/F. The mechanical advantage then is ten. With its drIven by internal-combustiOn engines. In the vise the mechanical-advantage principle Oho m t instances the lever is used toincrease force. same except that it is achieved by a combinationof 'Scientific princ4le involved. A lever is a rigid 'two simple machines, the wheel and axle and the bar that is free fo turn about a fixed point called screw-or inclined plane. Likewise, the paper cutter the fulcrum or pivot point. A force applied to one cobines the lever and the wedge. mechanical advantage of force of a machine point on the, lever may, be used tp overcome resistant force at another point on the lever. The is ermedtheweticaloractual.Theoretical mechianical ady*tage is the ratio of the distance ratio of the force applied to the resistance thaeis the,effortforq moves td the distance the resist- overcome,is called the mechlnical advantage of.the ance force moves. Actual mechanical advantage is lever. The theoretical mechanical advanteg of a the ratio of the resistance force to the effort force. lever maOhe found by dividing the distance from The efficiency of any machine is the ratio of its 'the effort (force) to the fulcrum by the dis ance from the resistance (load) to the fulcrurn. Ievers actual mechahiyal advantagetoits, theoretical the mechanical advantage converted to d percent. are of tIgée classes. First-class levers have fulcrum 'betweenthefozces; some exaMples, 4( Simple Machines include' tin snips, pliers, and scissors. Second-class ---,levers have` the load or resistance between the .., There are six simple machines. These are the efföhr'and the fulcrum; pper cutters and %melding lever, the pulley, the wheel ahd axle, theirAiled ,tank trucks are examp 1 s. Third-stass levers" have plane', the screW, and the wedge. Other Machines the effort applied betw n the fulcrum and the are either modificationsof one of these simple resiStance..;iixamples arecalipers and.. tkeezers. machines or a . combination of two or more of These toolsiare familiar examples of the useof them. The pulley and the zlieel and axlele ,levers.Levers may be used to increase force, fundamentally leversi, while the wedge and screw distance, or speed. If the resistance force is greater are modified inclined planes.Many complicated ihan the effort force, then the effort fore Must "machines are combinations of simple machines. A combination of two or more simple machints Load called a compound machine. A drill press is an Effort veample ot a compound,machine. Many of the simple machines are foundlin the drill press. Lever ' ,The lever was one .of ttie first simple Machines known to man. In making use of leverage, he found that the tusang effort exerted depended on (1) the amount of:force applied; and (2) the of the

lever arm.:The ,ame form of simple leerris still used to ,move heavy objects. In modern ma'chines many other more -complexforms of this simple sed in gaining mechanical advantage or speedz, ovement. Some examples of todls ,(hiachines) that use the lever princi le are tire , Effort jacks, scissors, haminers, bo e s, pliers, tin snips, crowbars, vise handles, wrenches, hand-lever plinches, paper cutters, drill presses (feed handles), and squaring shears Jtreadles). Pushing, pulling; ulcrum raising, or lowering Of handles on most tools are first-class lever (top) has the fulcrum Itabnen the _applications of the principle of the lever' Moving effort applied end the load (e.g., prying with a °the accelerator,-clutch, brake pedals, turn-..ncfpcator.1" CroWbar)m second-class lei& (center) has ihe Wed levers, and manual gears rs are examp(es of beween the effort applied and the fulcrum (e.g., the apPlication of the er in automobiles. Operat- mdping - a wheelbarrow); and athird-classlevei ing' cranks and k starters are examples of the (60 om) Itas the effort applied between the fulcrum application ofe lever principle found in other and the lopl (e.g., using a broom).. 11

o, 4. V move _through a greater distance(faster) thathe Wed e , resistan The work done by theleverf thn, Mambas found many applications of the princi- therefore, never be water than the amoqht of ple. of the wedge. The great force that canbe work oduced by the effort on the lever. If the exerted/by-this simple Machine makeslit useful in work done by the lever were greater than tçjat put (1) se arating or fpreing .on ' thing awayfrom in,thelever would be an energy-creatthg or anoth r(bythe o chisels,knives, perpetual-motion machine. splitti Wedges, nd edges d to lift heavy objects and( locki i .orholdingobjects Whed and Axle q. together (bthese of wegtes in hammer handles; The wheel serves a number of purposes. Like a pegs, nails, her fasteners thatre driven into materials; cork in bottles; and gears ô wheelsthat fixedpulley,a road wheel oil anautomobile 1, supports a load and permits itto move in a are pressed on the endsof shafts). direction parallel to t14-Toad surface. When power Scientific principle involved. The wedge -is an from the engine kuses the rear axle -to turn, the 1 object that has a greater ss section at one end rear wheels act aslevens to move the.load they than at the other. As a wed e is moved intheC support. The wheels als6function 0 levers when - sprockets; pulleys, difection.of its smallet croSs sect sn, a greater force the brakes are applied. Geatt, otion by its sides.: windlasses, and winches are examples of thewheel is exerted at right angles to this _ Th wedge is a rny=of, thc? Med plane, and its and aZIe. mechanica &al:1W 4r,{ ainedinthe same Scientific prieciple tvnvolved. When in mtion,, manne f a wedge; :A..-4.14* ditnches.. and its .o., the wheel isa conringously rotatinglever. The cross sectip, 2 inches,.it will center of the Wheel is theftilcrum.A wheel that, hve a calcli .-st, tage of three. like t-a front wheel on a-scar, merelyrolls aV J suplorts a load has a meclial.kical advantage of one. Pulley Drive wheels on poWered ve`.tcles usually haite a Pulleys ai4 Alit$,Its,as wellas sprockets and mechanical advantage of less than one. Andwheeils-e chains, areusedin driving all types of equipment. with brakes have h similar mechanicaladvantage% The drill press, lathe (wood and niethQ, jig saw, The amount ef,mechanical advantagedepends on milling machipdiCkainApist, block and takleand the wheel ragius' rear axle ring-gear radius,brake' many otheOleKices would be rendereduseless, drum, or digleixa iust A cable or ropewindlass is a Athout the iimple machine known as the. pullek wheel and axle W th d mechanical advantage greater, The pulley provides a means of transmitting, than one. The amount ot mechanicaladvantage mechanical power from a single driving source to gained by a windlass depends on the diameterof one or ta drivenmechanisms. The pulley, as the drum and the length -*the dativing handle. used with ia chain/ hoist, provides amechanical advantage; imakes easier the lifting of a heavy Inclined Plane Object, such as an automobile engine. Pulley and ;The inclined plane is a great 1elp toworkmen kbelt combinations, as found in the drill press, are provides: used for obtaining desired speeds. Pulleys andbelts because of the mechanical adva, tage it frominternal- Oil drums and other heavy objects canbe raisedor areusedtotransmit ,power lowered by means of an incline. The sameprinciple cOmbustion engines to drive electric generators and is involved in the grading of roads andmountain fans of vehicles and stationary units. trails and ja the ascent and descentof winged Scientific principle involved. A pulley, whichis a 14 - aircraft in flight. i wheel that turns readily on an axle,provides a l . . through a belt or Scientific principle involved. An inclinedplane means of transfming power end or side chain from one location to another.With this consists of a plane surface- with one work Nmhigher than a plane earallel to theearth's surface. transfer of power, it is possible to accomplish object is at a location rernoved from the sourceof power. In echanical advantage is gained when an .fixed moved up a slanted surface-rather thanwhen it is ' the lifting or moving of an object, a single lifted vertically. As an example, a 3(10-pounddrum pulley merely Changes the direction of-force. In a incline that rises Veet pulley .system with one movabledulley, the force can be rolled up a 12400t A combination of at one end by a calculated foice of100 pound. moves twice as fast as the load.

2 0 pulleys of vdying .sizes may be used to increase or hat provides enough mechanicalradvantage to turn decrease speeds beyond the speed 7f the driving the front wheels easily yet 'requires a minimum Source. The law governing this principle is that the number of turns of the steering wheel for the ratio of the speeds at .which the pulleyS turn convenience of the operator. Consideration -must inverselyproportionalto, the diameters of tht be given to the diameter Of the steering wheel, pulleys. As an, example, an 8-inch pullex at the which is rigidly attached to the steering shaft; to *living so rce will make one revolution Nor every the ratio of the gears in the steering gear box; and tw? revolutins of a 4-incVriven pulley. to the length of the levers, which move the wheels attheirpivotpoints. Power assistance (power Screw s4ering) is often built into an automobile to assist Certaindevices areregulated with adjUsting the' driver in exerting greater force in turning the screws. As adjusting -screws are turned, force is wheels. applied to control the space between the parts or ,- to provide the resistance \that may regulate the Scientifietionciple Involved - flow of gas,liquids, or electricity. The correct The function of a-machine is to conrrt energy setting is determined by the amount the agiusting to.--itteful work. the steering system of an auto- screw?s turned and, in some cases-, can be'hecked Mobileis aimachine that enables a person to with an electronic instrument or a pressure gauge. .multiply ihe force produced by his muscles. The A few tevicesthatuSeadjustingscrews are* lever iS a rigid bar that is free to turn about a fixed oxyacetylene regulators, padding ca acitors, painot- point. -Vie arm or end to which force is applied i .spray, guns, automobile carburetors micrometers, the effort arm; the arm that moves the load is tile and compass. Clamps and vises m1ce use of the resistance arm. The mechanical advantage, which simple 'machine known as fle screjv. A corrimon depends oil. the lengths of the two arms, .may be clamping operation, is holdin rial firmly in a increase ;by lengthening the effort arm or short- drilkpress vise while the stock is being drilled. The eningt t?e resistance arm: The gear is a form of handle oA the vise acts as aleyfr, multiplying the lever. It)) is a series of levers around a Circle used to mechanical advantage, oftjiscrew. The total transmit continu us force to another gear. 'One mechanical advantage of.uchadeviceisthe gkar of tvpair Mabe the resistance trm and the prothict of the mechanical advantages of the twR other theffort arm. The wheel *idly attached to simple machines. i an axle is also a form of lever. The rim of the wheel is like a series of levers and is more convenient to \Scientific principle involved. A machine screw is use than a sintle lever. AcombinatiOn of two or , a cylindrical Updy with a h'cal (spiral) grow tilt .more simple; machines, such as the lever, g9rs, and into its surface. For practicaurposes a scr6T may wheel with axle, is a compound machine. In almost be consideredn inclined plane in the form pf a allcases thetotal mechanical advantage of a helix. The screw must resist tension (strain) and compoiind machine is the product of the mechani-% shearing (cuy4). In its application 'as a simple cal advantages of the simple machines of which it is machine,thestrewis machined to precision coMposed. accuracyinbothfit(orrectsize) andpitch (distance bet een threads). The fit of the screw determines h6v much friction will take place as Application of Principles the screw is trned. With too much friction, the Oarnples of simple and compound machines screw is diffi ult to adjust; with too little friction, canbeidentifiedqtriongthe hand tools and the screw is d ficult to keep adjusted. The pitch of 'components of machines in the facility as well as in the screw threa determines how finely a particular the systems of internal-combustion engine units. ( instrument can be adjusted. If the fit and the pitch Simple and compound machines can be demon- are not correct, the effectiveness of the adjusting strated by using-(I) a yard or meter stick as a lever screw is decreased. to lift weights; (2) weights, levers, and spring scales to show mechanical advantage arid torue; (3) brake pedals' on automobiles to illustrate classes of Compound Machines levers by disconnecting ihe brake pedal from th4r An engineer designing a steering system for an master cylinder and connecting a spring scale or automobile must devise a set of levers and gears---t-e-rque-Avserreh- to the pedal; .(4) a spring scale 2 1 13

Selected References- connected tothe rim of a steering wheel to Note: The numbers in parentheses in this settioh refer to measure the force necessary to steer the vehicle; entries in the list of selected references that appear within (5) input and output. traWsmission shafts to deter- this publication immediately after the text. ., ( 13), pp. 436-53; ('22),pp. 448-516; (24), pp. mine gear ratios; (6) the rolling of a grease drum ,up. 132-46; (26), pp. 5-; (27), pp. 131-42, 353; ( 36), a ramp to demonstrate the in'clined plane; and(7) a pp. 9-13; (37), pp. 2-32; (55), pp. 3-30; (66), pp. wood or metal wedge to seCure tool heads. 104-10; (69), Chaptr 10, Chapter 15.

Unit 7 LUBRICATION , For the pro* lubrication - of a four-cycle SAElOW, S. E20W,and SAE30. internal-combustionengine, 3theoil used must The A ericanl Petroleum Institute (API) has prevent rotating and sliding metal surfaces from devised a s stem for classifying motor oils accord- coming into contact while underheavy shockloads ing to en ine service 'requirements. This classi- and widely varying temperatures. Internal liquid fication s stem provides six service ratings, three resistance to flow prevnts oil from being squeezed for gasolin renginpstancrthree for diesel engines. froM between movineihetal surfaces of bekrings, The...Tint ler in each designation indicates the cylinder walls, and valve trains. This property of oil type cif engine: for the gasoline and LPG engine,\ is commonly refened\t7 as viscosity. . and D for' theesel engine. The second lettePain . eithh.designation indicates the type of service. The 2 , Viscosity of Oils ng;ee service Patgsifor gasoline or spa:lc-ignition Viscosity Of oils must be discussed in terms of ines' are (1) " for severe service; (2) MM for (I) bOdy, or the, resistance of the oil film to dium serviceran(3) ML for light service. puncture; and (2 )jluidity, or-the ease.with which tA Viscosity Index (VI) evaluates oil in terms of oil flows through dIs,ribution lines and coats metal viscosity change caed by variations in tempera- ' su, rfaces. These characteristics) can be considered ture. The adopted VI rating scale goes as bigh as oPpositis since the more duid/ty an oil shows:the 300. The higher the VI number indicated, 'the lesS the oil viscosity varies with temperature. In a very , less, body it has. Modern1gines require an oil with great fluidity because ofose tolerance but with cold climate, the viscosily index is very important. body Iresistive to breakdown nder the heavy loads It 'may be necessary, for..ëxarnple, to start an and temperatures imposed by high horsepower engine at. below zero degrees F., but in a few

. minutes' have oil temperature witliin the engine at 'output: . ,-. The yiscositys of an oil can be determined by a 200 degrees F. In this situation'the oil must not be but devicecalledaviscosimeter. The viscosimeter so thick at starting that it prevents cranking, not so thin at operating temperature that engine determinens. the `time: it takes a measured quantity, t of oil at a'. certain iemperatur ,-, to flow through a danresufts. ( 01 companies .blend oil with additives to give metered orifice. . Temperature affectsoilsby increasingtheir the pioper weosity index for the type of service vicpsity as the temperature drops and decreasing for which the oil is intended. Multiviscosity oils, in t en- viscosity as the temperature rises. According wide use now, are premiuni oils that have a high VI to the viscosity rating system of the Societyof rating., The viscosity of an oil used in an automo- American Engineeis (SAE)0ower numbers indicate boile. engine has muchtto do with the life of that a thinner oil, higher numbers a thickeroil'. Winter engine. Manufacturers?' recommendations should be grade oils have a W after the SAE number to followed carefully in selecting and using oil. indicate that the oil was tested at zero degrees F. With the development of improved lubricating and 210 degrees F. The three automotive winter oils and more efficient oil and air filters, automo- grades are SAE5W, SAE1OW, and SAE20W. Auto- tive, manufacturers hav liberalized their recom- motive oll not tested at zero degrees F. is rated as mendationsforoil/changes. When favorable SAE20, SAE30, SAE40, or SAE50. Oils can have operating condition'sexist, some manufacturers multiple ratings-, such as SAEIOW-30. This number recommend that oil should be changed every two means that the oil can be substitutedfor grades months or after 4,000 miles of operation, which- 2 2 14 . - 2\

'ever occurs first. Other snanufacturers favor an oil 2. Sh0w-the.effect of cold-On the cranking of an change every two months or after 6,000 miles, engine by cooling a small gasoline engine with whAthever occurs first. All recommend that for dry ice. Compare how difficult this engine is mine adverse drjving conditions, such as start- to start with different grades of engine oil in and-stop driving, cold-weather driving, or 'driving the crankcase. through dusty areas, the oil should be changed I Contpare the visAity of various:Oils) by a more frequently. simple device. Placeoils to be testedin plugged test tubes, each of which contains a' arnall steel ball. Place the test tubes in a rack Seimitifie Ptingiple Involved: so that all can be rotated at the same- time. Fluid Friction and Viscoilty The more viscosity an oil has, the longer will When a liquid (id) is set -motion; internal it take for the oil to reverse in the test tubes structures (molecules e at different velotities. and for the steel ball to settle to the bottom.. Friction is involved as these structures slidepver or rotate around each other. This friction is known as Selected References viscosity. , Note... The numbers in parentheses in this section refer to , Aliquidis made. up of moleculeS in motion entries in the list or selected references that qppear within which are of different sizes for different liquids. this rhiblicationlmmediately after the text.' Liquids Avith large molecules tend to have a higher (4), p. 37; (20), pp. 260-90; (21), pp: 338-45;(22):/ viscosity' than liquids with small 'molecules. This pp. 5; (27), pp. 225-26; (66), pp. 39-43; (69), sheriomenonxmight be eXplained by comparing the Chapter 5; (75), Chapter:10, pp. 1-2. larget Molecules to rocks and the smaller friolecules to fine sand. It is much.easier to force.ipild of Unctions o Lubricating Oil ....sand to flow than a pile of rocks because ro Lubrican s are used to slow dAn wear and to tend to pile up and resist motion. with reduce fØetion between two-,moving surfaces-. The 'different-sized molecules can be mixed to obtain a lubricating oil used in Aire four-cycle internal- desired yiscosity.. The smaller molecules can be combustionengineperformsatleastseven thought of as little bearings that fit in with the functions. It (1) lubricates moving -parts.to reduce larger molecules to provide a "ball-bearing" effect wear; (2) *reduces frictiorfand powerloss; (3) io reductthe resistance4o flow of the larger prevents spot overheating-by absorbing heat as it molecults. circulates;(4)seals- piSibn rings,pistons, and The rn1 lar structure of a liquid is always'in cylinder Alls to prevent loss of-gases on the power motion; ac ve the mplecules are is determined stroke; (5) absorbs sherck in bearings; (6) dissolves by tern ture. The lower the temperature, the lacquerlikesubstanops and shspends other by- slower and Owe together are the molecules. The products of brokett-down oil and worn metal higher the 'EMIrature,the morrapidly (,,and through the use of detergents and the oil-fdter farther apart 'th olecules ve. The more action (helps keep engine clean); and (7) neutral- 'activity displayed by t mol les,' the less is the izes acids (formed in the breakdown of oil by heat energy that will be necesi o cause the liquid to which would damage metal parts) through the use- Mow. The opposite is true for lower temperatUres._1 of additives. If the temperature is raised too high, the molecules Cylinder walls,pistons, and piston rings are tend; to get so far apart that, for all practical exposed to ttte high heat .of the burning fuel-air purposes, the viscosity of the liquid maydisappear. mixture (particularly on the power stroke). This heat will evaporate some of the oil coating on Application of Principle pistons and cylinder walls. The oxygen from the 1. Obtain several different SAE grades of oil. unused air in the fuel-air mixture, together with the Provide a funnel with a small metering orifice. high temperature will partially burn part of the oil Neat measured quantities to a given tempera- coating the exposed surfaces7 leaving carbon. The ture (such as 200 degrees F.) and time the heat also "craCks" some of the oil molecules, flow throughthe furmel. Co61 the same causing the formation of additional carbon. sample% in dryyice or in) a refrigerator to a Lubrication of the two-cycle engine is quite given temperature (such as 32 degrees F,). different frorh the lubrication of the four-cycle Compare the rates of flow. engine. Since the fuel mixture must travel through

2 3 15' -A r I the crankcase, a, reservoir of oil cannot be stored Dry, Gieasy, and Viscous Friction there. Theintricating oil isiixedtith the gasoline Friction is a force which resists motion and and is then "lotft to the gas tank. (Two-cycie convarts the energy of motion into. heat. The engine manufac4urersare now developing and "drag'due to friction depends on the roughness of marketin'g 'enginewith .oil-mqtering devices that the surfaces in contaa, the amount of'surfacel and eliminate the .nèç2for premixing the oil apd the force holding them together. Friction is Yoth a gasoline.) The lubricating oil for all craqccase parts help and a hindrance inthe operation of an enters the crankcase as art -of the fuel mixture automobile. It helps a person,to hold and turn the Millions . of tidy p11 droplets suspended _ in e steerifig wheel. Without friction the brakes would mixture of gasol. e and air sçttle on .the m ving not work aid the tire§ would not have traction. .` The steering wheel, brakes, and the tire tread are parts in the cranlEcase,proird- g .lubrication. N. all &Signed to increase ihe effectiveness of this Scientific Principle Involved: helpful friction. Effect of Heat on Hydrocarbon MoleculesV Illowever, fiction in the automobile engine and tge capacity along thepower train wastesi energy an0/`-causes Heat is one fOrm of energylandhas wear. The use of machined andpolished\rnoving of doing work (both useful arid destructive). High parts, bearings, and proper lubrication all help to temperatureisusedin petroleum refineries to decrease the amount of friction. They enable the break .large hydrocarbon 'molecules into smaller gasoline. engine (and., power train) pads to last longerj1 ones (cracking) in order to obtain more the automobile to perform more efficiently. The carbon and hydrogen 'atoms of the, hydro- There are three types of friction: dry, greasy, carbon molecules are .teld together by chemical and viscous. Dry friction occurs when two dry bonds. When heat is added and the temtsrature is surfaces rub together/ The friction betw-een the thereby raised, the atoms begin to vibrat tretch- brake lining and the brake drum is one example of ing the bonds (very much like bouncing a ball tied dry friction. Greasy friction 'occurs when a small to a rubber band). When the vibration becomes too quantity of oil or grease is applied between the two violent, ,tke bonds begin to break. It contacting surfaces. Greaseis applied to auto- mobile door latches and the front wheel suspension Application of Principle system. Viscous friction occurs between the layers IDemonstrate the effect of heat on lubricating of a liquid, The lubricating oil in an automobile oil by dipping one end of a I-foot welding rod engine is forced between the' movMg metal sur- in oil, holding the rod with Ow, and heating faces.Viscous., frictionis thus substitutedfor the opposite end with a torch. The heat sliding friction. travels along the rod, and the oil begins to smoke (evaporate). Continued heating pro- Scientific Principle !nvolved: duces a black, sticky coating on the rodfrom Dry, Greasy, and Viscous Friction the oil (carbon and lacquerlike substances). Atoms and molecules make up solids, liquids, Test and compare various brands and viscos- . and gases. They11 behave as though they were ities of pils.Also test used oils (crankcase very tiny balls. The surfaces of highlypolished, solids appear tO be perfectly smooth. However, drainings-). 2. Check the acid content of used oil by placing photographs of these surfaces, taken with an a small quanfity of crankcasedraMMgs on a electron microscope, show "hills and valleys." The "hills" of one contacting solid surface tend to fit piece of metal. into the `!valleys" of the other, causing friction (resistance to movement) between solid surfaces. Selected References The molecules of greases are larger and move about Note: The numbers in parentheses in this section refer to more slowly than those of oils(atthe same entries in the list of selected references that appear within temperature). The constant movement of the this publication immediately after the text, molecules prevents /the formation of permanent (4),pp. 36-42;(21),pp. 299, 302;(22),pp. "hills and valleys" between layers of greases And 172-79;(27),pp. 68, 225-26;(36),pp. 111-12; oils. Friction in both oils and greases should be, (66),pp. 102-3; (69), Chapter 5, pp.2-7;(75),, and is, less than solid friction, and _oil (viscous) Chapter 10, pp. 1-10. friction is less than greasy friction.

2 16

r" pplicatimi of Principle orecord the stajtiig foice and theanoving force for each bl 4. Cover the long,iflat surface 1 Measurerelativefriction l, usingseveral blocks of the same size (but of different with oil andwrepeat theexperi4nent. Again materials),aspringbalance,along,flat observe and record the starting force and surface, grease., and lubricating oil. Tie-a string, moving force for each block. to each b1ocin order to attach *the, spring 2. Measure the force *needed on the steering' balance. Test ach block for all three types of wheel of an antomobile to turn thecfront friction (dry , greasy, vikous). Place a block wheet. Place different surfaces under the on the long,flat surface with the spring front tires. balance attached to the block. Pull.the swing balance steadily until the block 'begins to _Selected References' rtiove. Read° and record this "starting force" Note: The Atinbers in parentheses in this section refer to entries in thi lisof selected references that appear within (pull). (The difference between the starting this publication im ediately after the text, ancl moving force is the friction.) Test the bJock47ö,r dry friction and record the date of (13),pp. 440-41,' -46; (1), pp. 81-82,95-98i; te mg intable. Coat each block with grease' (22), pp. 49-51; (27), pp, 225-26; (66), pp. 38,86; ndrep-eattheexperiment. ',Observeand (69), Chapter 5, pp. 2-3:.

Unit8 SPRINGS

, Mechanical energy can be stored in a spring and automobiles hydropneumatic devices are used- to itised in many ways in machinery, engines, watches, limit -the speed of the spring action. toys, and other;cils. A spring has the capacity Springs are classified according to their shapes. to store energy release it when needed. Springs The three main types of springs are the flat or leaf, are made of steel -or brass. One of the most spring,'the helical spring,,and the spiral spring. The frequent uses of springs is to supply motive power flat or leaf spring, which is made -of.pl_ates isor 'in a mechanism. A good example, of this is found in leaves, has the special advantage of both Fling or the windup toy. When the toy has been wound up and the lever has been activated, the toy moves . ab9ut, releasipg the stored enerly of t e wound spring. The Valve springs in an automobe engine are also used to supply motive power or ergy. The spring pusheS or holds the valve firmly i-..t1.3e valve seat of the engine until the rotating cani------mechanism of the engine forces the Valve lifter to- open the valve. When the lifter stops pushing on the valve, the spring t..2n, pushes the valve back into the valve seat. Another use for a spring is to return displaced mechanisms to their original position. Examples are a door-clOsing spring or the spring on a cam follower. The- coil or leaf spring on the car frame is connected to the axles of an automobile and is used to keep the body at a certain level with respect to the road. As the automobile moves along a highway and irregularities move the car body up and -down, the springs help return/the body to its original position. These same springs act as shock absorbers on the automobile so that the bouncing If the pointer attached to the spring returns to the effectisabsorbed by thesprings andisnot zero mark after the weight is removed, the spring is .transmitted to the rider in the car. In modern perfectly elastic. 2 5 4. 17

polling at right angles. The helical spring consistsof Application of Principle a wire Wound in ahelix.It can be used for 1. Employ, springs as a tneanS ofabsorbing, compression, such as a valve spring, or fortension, storing, and imprting mechanical energy.- ' such as a brakeispil9g. The sp"&al spring is awire or Activities inVolVing the measurement ofthe band wound in a spital ,that produces atorque; energy in springs mightinclude thefollowing: such as:the spring found in'a recoil deviceused in a a.. Test the tensionof a scteen door spring laWnmotor starter. . with a scale and recordthe pounds pull at, various lengths as the spring isstretchAi. Scientific Principle Involved: Elasticity b. Test compression springs, such asintorffal- ,When aforceisappliedtoa -solidbody, . . combustion enginevalvesPrings°,, on .a distortion of. the body occurs. The greaterthe valve-spring tester: again noting the force fOrce., the greater_ is the deformation. lnan elastic required to compress' the spring and the substance. the_displacerRent of 'the atoms and change in the length or htiglkt of thespring. molecules of the substarice.,urider,:gress :sets c. Check the torque on torsion bar with fortes of attraction and repulsion Which resistthe either a: scale and lever or a torquewrench. distorting force and tOnd .to,restore thebody tO its, be 2. Pursue the method by whichthe spring is original size and phape. A .sUbstance is said to- follows: force, called r, a ct 'rat e d . Some of the methods are as perfectlyelasticiftherestbriiii Sa. Use a cam (like that used in the internal- "elastic reboil," is equal and OPpoSite tothe force . 'combustion engine) to actuate, thg valve. causing the distortion. If the body does not resume b. Apply pressure, either hydraulic or ,pneu- its normal shiapeancl,, size on removal of the matic, to push on a valve (for example, distortingforce,its"elasticlimit"has 'been dIP styli and brass, check valves in a fuel pump). exceeded. Certain metals, such as c. Use a twistingeffort, such as the torsion which possess desiratle elasticproVertimAte- used demons ate spring Ina Sizes to bar or curtain roll, to \ for making springs of various shapes action. withstandLthe forceseAbf compression, tension,and tsion for w ich they are designed. 3. Gather a variety of springs andid ify them ooke's law states that within the limits as to -type (helical,spiral, or leaf); fu ction p fect elasticity, strainkdirectly proportional (to absorb, store, or impart energy); orforce tress. This is the princole uponwhich a spring which they countErta t or react to(compres- baranceoperates:the amount thes, gis sion, tension, or torsio ). Stretched (or compressed) ft, directly pro to the force applied.TM.* if 600 pounds wilk Selected Ref nces° compress a coil spring 3inches, 1,200 pounds will Note: The numbers in parentheses in this sectionrefer to compress it twice as far, or6 inches. entries in the_list of selected references that appearwithin From the standpoint of,,e9nservation of energy, .. this publication immediately after the text. the spring ispractically 400 percent efficient_ of the energy *), pp. 133-37;(22), pp.517-31;(27), pp.190-91; because it can return practically all 16, p. 7, stored in it on distortioJTts elafticlimit is not 69), Chaptet 15, pp. 7-16; (75), Chapter Chapter 39, p: 1, Chapter 40, p. 4,Chapter 42, p.3. exceeded.

Unii, 9 CLUTCHES

isto permit the position (engaged),itprovides the link which The purpose of a clutch the rear coupling or uncoupling of a power source(engine, dilows power- to flow from the engine to the *drive unit. In an automobile wheels. In the uncoupled position(disengaged), it or motor) and does not permit power to flow. When the clutch is withstandard (not automatic) transmission,the it possible to transniit the power disengaged, the gear may be shifted easily:When clutc es the clutch is gradually engaged, withthe auto- from engine through the power train to the smoothly in the . mobile in gear, the vehicle moves wheels. e clutch utilizes the'scientific principle of frict on. When the clutchisin a coupled selected direction. 2 6 vo 18

ClassificationS of clutches "and examples of each together? The hub of the friction disk is splined to include (1) the disk clutch, used in automobile the transmissiori shaft. Depressing the clutch pedal transmission coupling; (2) the cone clutch, used in releases the spring presure, and uncoupling takes standard transmission synchronizers and engine- place. The flywheel,preisureplates, and the lathe controls; (3) the overrunning clutch, used in 'friction disk' then' turn independently. Releasing starter drives and automatlic transmissions; (4) the the clutch pedal engages the unit's, and the vshicle sprag clutch, used in 'autVmatic transmissions; (5) moves. the ratchet-dog clutch, used in automobile bumper jacks; and (6) the centrifugal clutch, used in Scientific Principle Involved: motorcycles, lawnmowers, and go-carts. Sliding Friction All automobile clutches are similar in constiuc- One scienV principle involved in the-operation tion and opera ion; they are classified as single- or' of a clutch sliding friction. This friction acts multiple-dis he single disk is most widely used. parallel to Ahe' surfaces which are sliding over one Frictional 4ontact in the clutch is made between another and in the direction opposite to that.of the. two smooth, metallic driving surfaces and facings motion. The degree of friction depends upon the riveted to a driven disk. Pressure springs hold the (r:oaterials and their surfaces. Sliding friction occurs flywheel, pressure plate, and thefriction disk betw.een the brake lining and the brake drum on a

_Clutch cover

Throwout lever -ClutCh adapter

Plate

Adapter Housing Reknse yoke

Pressure plate

("f Lever Driven disk Throwout bearing

Complete pressure plate

The illustration presented above gives an exploded view of the clutcfpunit used in the three-wheel Cushman gasoline truckster (Cushman Motors, Lincoln, Nebraska). ,

2.7 19

by the car. It -also occurs when twofacings on the clutch bicycle as increasing pressure is applied are pressed between theflywheel and the pressure rider's foot on the Kdal. plate. When the friction becomes greatenongh 3. Tan the tuning knob on a radio toeither the between the two surfaces, slippage is almostnil. extreme left or extreme rightposition; con- tinue turning the knob and note theslippage The two most important factors in this frictional of the force are the nature of the surfacesinvolved and that occurs. (This is an application Clutch friction-clutch principle.) the force pressing the surfaces together. engine and efficiency is, therefore, dependent on the clutch's 4. Check cone-clutch assemblies on ability to transmit power from the driver tothe woodworking lathes. .driven through friction and, conversely, onits 5'. Examine,disassemble,andreassemblean ability to separate the driven from the driverand automobileclutchassembly.Identifythe avoid friction. various parts and study their functions. Selected References Application ofPriCciple Note: The numbers in parentheses in this sec&nrefer to entries in the list of selected references thata0ear within 1. Raise an automobile with ,abumper jack. this publication immediately after the text. Examine the ratchet-dog clutch andobserve it (4), pp. 155-56; (22), pp. 391-405; (27), pp.64-66; as it operates in thejack. brake on a (39), pp. 1'7-18; (55), pp. 38-45; (60), pp.49-50; _ 2. Check the operation of 'a coaster bicycle;this overrunning clutch stops the (66), pp. 104-5; (78), pp. 356-63.

'Unit 10 DYNAMOMETERS

The dynamometer is a deviceforldetermining Electrical-load dynamometers dnd, occasionally, (twisting in hydraulic-load dynamometers, are availablethat the actual horsepower (hp) or torque dynamom- foot-pounds) that is available at thecrankshaft of couple the engine unit directly to the engine or at the driving eter for very accurate engineevalliation. an -internal-combustion dynamometers wheels ofavehicle.Dynamometers may be The frictional and hydraulic-load grouped as follows atcording to the threemdhods couple the crankshaft of the engine to alever arm is placed used to provide load: ) the use of an electrical that bears on a weighing scale. The engine generator, using an electrical load;(2) the use of under load at a given rpm by thefrictional-brake load; and unit or hydraulic pump while the leveris pressing liquids under pressure, using a hydraulic in foot-pounds is deter- 43.). the _use. of..a _mechanical .slisv An the scale. :The torque . mined by the simple fbririitla"Whiell states 'that using a frictional load. length in For the testing of automotive-typeequipment, torque (in foot-pounds) equals lever arm feet, scale reading in pounds. Thus, Hp =t6rque X the electrical-load dynamometerhas proven most the rpm of engine33,000. (The figure 33,000 comes practical. This unit is constructed to measure careful power available at thedriving wheels ofthe vehiCie. from James Watt's determination, based on FloOr-motinted rollers connected to an electrical measurement, that a strong horse cando about., generator are driven by the wheelsbf the vehicle. 33,000 foot-pounds of work per minute.) The voltage and amperage (wattage) outputof the generator circuit is instrumented toindicate the horsepower or Scientific Principle Involved: horsepowq and torque at any given Horsepower engine reVolutions per minute(rpm) according to 746, or watts Work can be accomplished by sliding,rolling, the formula Hp = volts X amperes Work is 746, 1 horsepower equaling 746 watts. lifting, or ,rotating anything having mass. done when a force acts on matter andchanges its Inthis testingitisnecessary to take into by a consideration that the power actually measurable motion.. Ai7; force (energy) can be supplied would be much natural phenomenon (such as wind) orby a at the crankshaft of the engine mechanical device (such as ari engine or anelec- greater' than at the driving wheels because of the force power losses in the power-transmissiontrain. trical motor). In relation to power output, a

2 8 20, must have a time factor or rate of doing work. 4. An experimentalor demonstration 1.dyna- Power represents a mass being displaced over a mometer for small engines can be constncted distance in a certain period of time. Power is a similar to the one illustrated. function of the time it takes to accomplish work ..0 (force X distance moved). 1kor the use of science When this type of 'dynamometer is used, the and industry,ithas cebeenetablishedthata engine must be started with no load" on the hortepower represents he, lifting of 33,000 pounds generator. Once-the engine is operating at peak 1 loot in 1 minute. The formula is exPressed as Hp performance, the electrical load is thrown into the = weight in pounds X distance moved in feet circuit. The students can (a) record the voltage and 33,000 X time in minutes. amperage; (b) mUltiply theSe readings to deteAkine the wattage output of the engine-gperator; and (c) APplication of Principle divide this product (wattage) by 746 to determine I. A simple dynamorneter for small 'gasoline the horsepower. engines of about1 horsepower can be con- tri one high school the students calculate the structedy' irom a typical 12-volt automotive actual horsepower of automobiles" and test the alternator or direct-current generator with a performance of "tuned" and "untuned" engines by regulator. A variable ,resistor or caron pile of making use of a highway going cher a hill of known .1or1 ohm capable of dissipating at leait elevation. By knowing the height of the hill, the 1,500 watts should beprovided, for the total weight of the vehicle, and the time re4pired generatc% load circuit. A tachometer suitable to accomplish this run, the students figure the total to the engine should be provided with an foot-pouutts of 'work accomplished per minute; by accurate voltmeter and ammeter. At a given dividing the total foot-pounds of work per minute rpm the load should be adjusted to give 'a by 33,000, the Students figure the average horse- slightdropinvoltagewitha maximum power actually developed. amPere indication. 2. A hydraulic dynainometer can be constructed A Selected References *by driving a hydraulic pump or water pump Note: The numbers in parentheses in this section refer, to with a small engine and measuring the pres- entries in the list of selected references that appear witizin sure and, flow developed through an orifice at this publication immediately after the text. a given rpm. 3. A frictional dynamometer can be constructed (4),p. 33; (11), pp. 98-100; (20), pp.,371-74; (22), from an automobile brake and a scale. Mea- pp. 54, 253-54; (26), p. 304; (27), p. 125; (47), pp. sure the foot-pounds of torque produced at a 82-83, 171-72; (66), P. 86; (76), pp. 34-37; (78), given rpm. pp. 52-54.

Flywh1 cord Model engine 'tch 0-10 ammeter

J Coupling

"7\

1.5 volt cell Bicycle generator0-10 AC voltmeter Lamp

2 9 SECTION III STEAMPOWER

Unit 114 STEAM ENGINES AND TURBINES - When water is boiled and changed into steam, sets of blades, causing therrotor to turn.The water expands about 1,700 times. If this steamis diameters of both the rotor and the stator are collected in a closed container and, is not permitted largerneartheoutletendtoallowforthe to expand to its full volume, the pressure (andthe expansion of the steam. The pitch and size of the boiling temperature of the water) will increase blades vary throughout the length of the turbine so When this pressure is released, it has the potential that the expansive force of the steam isused to do work. In this way heat energy (used toboil efficiently. - thewater)canbe converted into mechanical Steam also has other valuable functions. It can ..eilergy. The steam ,can be used todrive the piston be used to heat buildings and clean automotive or of a steam engine or tà difre-lhe blades of a ste/am turbine.,Since the generation of steam is usually Live steam done by burninglhe fuel outside the engine, most steam engines and steam turbines are external- Slide valve Flywheel combustion engines. Wood,' coal, or oil is used as fuel. Nuclear power plants use heat from a nuclear ( ,13_;) r/ reactor to produce steam. The steam turbine has become one of man's most important sources of power. Approximately 80 percent of all electricity used in the United States is generated by steam turbines. Many ships use steam turbines to drivetheir giant propellers. In a large steam turbine, tile two main parts are Exhausted Piston Steam\\ the rotor and the stator. 1e rotor is a long shaft steam on Which are mounted wheelscontaining a large In the steam engine of James Watt, the steam pushes number of sets of blades. The stator, which encases the piston first on one end, then on the other end, so the rotor, contains a large number of fixed nozzles. that there is power when the piston slides forward as Steam from the nozzles exerts pressure against the well as when.it slides backward.

21 3 0 22

industrial equipment. At one time the-steam engine was the source of power used in automobiles.At present, in an effort- to use fuel more efficiently and reduce smog, experiments are being conducted to develop a compact steam engine or turbine that can save as a source of power for theautomobile., Scientific Piinciple Involved:c- Conversion of Heat Whenevea gas 4 trappe&in a °confined con- tainer and the temperature is increaSed, the pres- (sure increases., This pressure 'can be used to apply a forcer *Ilia can move pistons, rofate b1a4e4, or provide force for other purposes. Steam engines and turbines are heat engines using external Com- _ bustiom. They are able to change heat energ5( to mechanical energy. Application of Principle 1. Demonstrate that the energy of steam can move an object. Punch holes diagonally from The. energy of steam can be made to move an object. each other near two corners of a metal (spice) can. (These holes should be about one-half turbine. (The turbine can consist of a few inch above the bottom and just around the blades mounted on a small shaft or a squirrel- corner on the broad surface of the can.) Put cage-type blower.) about. two tablespoonfuls of water in the can and close the opening in the tap. Hang the Selected References can by a thread. Apply heat to the bottom of Note: The numbers in pazentheses in this section refer to the can. entries in the list of selected references that appear within 2. Construct a simple steam turbine by using a this publication immediately after the text. - pressure cooker or atin can to generate (16), pp. 154-61; (26), pp. 11-22, 73-88; (2.7), pp. steam. Fasten a small tube to the pressure 271-76; (36), pp. 15-18; (37), pp. 347-53; (43), pp. cooker outlet or outlet of the constructed 144-69; (44), pp. 74-101; (66), pp. 142-48; (73), boiler and direct the steam- to the blades of a pp. 14-20.

1 0.00

3 1- 9

SECTION IV THERMAL POWER

- Unit12 `f-- HIGH-ENERGY RATE FORMING

High-energy rate forming.has developed from an medium used to conduct the shock waves is usually interesting curiosity to a metalworking reality. air or water, but oil, plastics, powdered talc, and There are extensive possibilities for the application clay are also used, The charge may be shaped to ot this prodas in a wide variety of industries. direct the shock waves to specific areas of the High-energy rate forming of metals now includes blank.. Explosive forming is used in extruding, the operations of forming, sizing, flanging, engrav- forging; shearing, and blanking. Metal and ceramic ing,compacting, welding, hardening, and con- powders have been successfully compacted by the trolled cutting. Some of these operations are used technique of explosive forming. commercially; others are still in the experimental Electrohydraulic forming is sometimes referred stage. The material used inthese operations may be toas .hydrospark forming orelectric-discharge in bulk, plate, sheet, or powder form. There are forming. The discharge of an electLic spark under four methods/ of high-energy rate forming: explo- water produces a shock wave with sufficiAat energy sive,electrohydraulic,electromagnetic,and to form metalparts.Forces equalto 6,000 pneumatic-mechanical. horsepower (hp) within 40 millionths of a second Low and high explosives are used in explosive are possible at present Theequiprpent used in forming. Low-explosive powders do not actually electrohydraulic forming consists basically of a explode but bum at 'a rate of several hundred feet high-voltage power supply, capacitors. for storing per second and are accompanied bythe, rapid the charge, a discharge switch, and a coaxial evolution of gas. Expansion of the gas: throug,h electrode. The force can be varied by changing the either air,or some other medium, such as water or a voltage. The advantages of electrohydraulic form- hydraulic plunger, forces the blank to the contour ing over many other forming proceSses are greater of the die. Low expIosives are used in a closed safety, inbre precise control, and lower cost. chamber. High explosives detonate in a few mil- Another conceptinhigh-energyformingis lionths of a second and produce shock waves magneticforming.Electrical energyproduces whose magnitude is in millions of pounds per magnetism which acts as the forming force. The square inch (psi). The charge .issuspended in a magnetic pulses, lasting only six millionths of a medium over the materialto be formed. 1 he second, exert pressure up to 560,000 pounds per 3 2

23 24

square inch. Magnetic forming has three classifica- which employs a2 caliber cartridge (blank) as tions of forming:compression, expansion, and The power source. The explosive-forming device has hammer. This forming method has the .distinct fvur parts: frame,I bolt, exPlosion:chamber, and advantage of forming material'without mairing or die.(See the as mbly drawing.) Power loads scratching thesurface, thus eliminating further (cartridge-type powder charges) are available in finishing operations.' It can perform as many as 600 various ratings: extra light, light, medium, heavy, forming operations per hours Magnetic forming is extra heavy, and magnum. Medium loads are used to (1) form tybing into precise and difficult satisfactory ,for use, with sheet metals such as shapes; (2) expand tubing into bushings, hubs, and .015-inch tinplate, .030-inch gnnealed copper, and split dies; (3)"swage inserts, fittings, and terminals .035-inchsoftaluminum.Efficiencycanbe into many,different parts, including rope,, cables, -increased by pulling a vacuum in the die cavity; .and other parts; and (4) coin, shear, and blank. however, the unit works well enough with onlyair The Hyge machine, built by Convair and used relief holes hi the die cavity. for pneumatic-mechanical formipg, is actuated by The frameis made frourtwo pieces of SAE 1020 2,000 pounds per square inch of nitrogen. When fold-fmished steel measuring 5/8" X 2" X 6". The the compressed gas is suddenly released from its- two pieces should be clamped together during apiston-column storagechamber,itdrives 4 drilling to maintain alignment. Four pieces of . assembly at high velocity into a liquid medium % -inch steel pipe are used for the frame spacers. which acts against the blank inthe die..The The four spacers must be precisely the same length rrochine also has been used to qtrude tungsten, to prevent distortion of the frame. The top plate, forge ferrous and nonferrous allOys, and compact' base plate, and four spacers are assembled and ceramicandmetalpowders.Advantagesof secured with four if" (16 NC) X 5"machine pneumatic-mechanical forming over many other screws. forming processes are the elimination of explosives as the. power source and the high repeatability of The bolt assembly is made from a %"( I I NC) X the operation. 3" alloy steel hexagon-head cap screw. The firing )pin and firingpin retainer are made from an Scientific Principles Involved: oil-hardened' drill rod and both are heat-treated to Work, Power, Energy, Force 52Rc (Rockwell). If heat-treating facilities are not The four methods of high-energy rate forming available,parts 1 and 2 may be made from coveredinthisunitdealprimarily with the heat-treated SAE 4140 steel.This materialis scientificprinciplesrelatingtoenergy,force, Omachinable and tough enough to serve the purpose power, and work. Energy is defined as the ability well. The firing pin retainer also serves as the bolt to do work (or the capacity for ,doing work). In handle. The die-centering pin at the bottom of the mechanics there are two forms of energy, kinetic frame is a modified %" (16 NC) X 1/2" round-head and potential. Kinetic energy is energy dile to the machine screw and keeps Ihe die centered in the motion of a mass. A moving automobile, exploding frame. gunpowder leaving a shell, compressed gas released Theexplosion chamber is made from 1020 steel. from a storage chamber, and an electrical charge Itis important to maintain reasonable concen- leaving a capacitor all have kinetic energy. Poten- tricityinall machined parts and to leave the tial energy is stored energy. A coiled mainspring of cartridge chamber undersize for later reaming by a a watch and a charged capacitor have potential gunsmith. The die cavity is also made from 1020 energy. ForCe produces or prevents motion; It is steel. The size of the air relief holes is determined also defined'as a push or pull. Work is done whep by experimentation. force acts on matter and 'changes its motion 6r When all pairts have been completed and before when force moves an object against an opposing heat treatment of the firing pin and firing pin force.Poweristherateof doing work. In retainer (if a drill rod is used), the unit should be high-energy rate forming, the work accomplished assembled, and the assembly should be checked by depends upon the energy which produces the a qualified gunsmith. In particular he should check force. the firing pin length, check the head space, and Application of Principles ream the chainber for .22 caliber. The charge for High-energy rate forming can be demonstrated this service varies, but generally is less than the cost through the use of an explosive-forming device *of a chambering reamer.

33 25 =p.

The material to be formed should be cut tp AThe =expended .power foad may be extracted with a 21/4"-inch diameter and placed between the explo- 6-inch piece of -1/8-idch brazing rod. sion chamber and the die. A power loadshould Seitcted References 4 filen be inserted ihto the chamber, this assembly 4 Note: The numbers in patentheses in thislection refer to should be placed in the frame, and the bolt should entries in the list of selectiti references tha appear within be turned down securely. this publication immediately aftfr the text. For safetythe unitis so designed that the pp. 436-50; (16), p. 91;(27), pp. 120-31; explosion chamber is recessed into a counterbore (13), in the (tie cavity, and the bolt enters a counterbore r45), pP. 1-88.491), pp. 13345: in the explosion chambex. It is practically-impossi- Note: A 60--Paie book, High-Energy Rate Form- ble to discharge a powerridad unless all parts have ing and Testing, (No. R-96), can be purchasedfrom been securely and properly assembled. the American Machinist, Reader's ServiceDepart- N.Y. .The power load is discharged by strikingthe ment, 330 West 42nd Street, New York, firini pin sharply but lightly with a small hammer. 10036, fOr $2.00.

;#111111 w ," 00 0 Caution: Place explosive-forming device behind wireglass screen or in-metal or wood container before firing. IAimpsMACHINE SCREW 4 STEEL. 13'100IA PIPE 4pAL. 12FILLISTCR HCAOCAPSCREW STECL IIB.451PLAT CA7020 10LOWER CAS/NG CA7020 AIR REL/Ef HOLES' aDIE CAVITY 7MATERIAL TV BE AVRA4CD 6UPPER CASING EF /020 Developed by FIRING CHAMBER Frank P. Accurso, Merritt College 4TOP PLATE' CF/020 Hcx.Newo CAP SCRCW STEEL Peralta Junior College District,,Oakland A7R/NG p/N Rer4INER STCCL f/RING P/N- MAT TREAT m/LLRoD p. NO autr NAME aforNormle Drawings by EXPLOSIVE-FORMING DEV/CC Sterling C. Lowe, EncMa High School SCALA. San Juan Unified School District, Carmichael DC3ION1.0 BY F ACCUOSO OR BY STERLING c LOWE SlIEEr 1 42 I°

3 4 26

AIR RELIEF HOLES. SIZE 125PfAM C'BORI ,PJ8 DP \DETERN/NED BY ExPeRmiNrArI A ovl a DRuii

t$L DRILL DP

3 4.

4L -11ivr i-//NC -14

.493- 414 ell11111a 1-111 MACN/NE To FIT DRILL 22 CAL POWCR 3.I CHARGC .040 OR/41.

. t

/41/455 MACHINE SCREW 4 S7L-TL 13 1/40/,4P/PE 4 GAL. faLareR ilrAD CAP XRf ISTEEL II 8.45C PLATE. /CF 1020 10 LOWCP CAS/NG /CI /0.20 9 A/F1 REL/17 lioLcs D/E cAwne 7 n'ArtRiAL To as CORNER 6 (AVER CASING CF/020 S F/P/N6 CHAMBER TOP PLATC i CF /020 3 HCX NEAP CAP SCREW 1 .S7TCL

84 Z F/R/A/43 P/N RATA/A/CR /irceL / PR/AI6 P/N- HEAT TRLAT 1 DRILL rap naerNAM.. owl pomp. EXPLOSIIY-FORMING DEVIC£ DEVGNED BY F ACCL/RSO SCAIS- FLAL DR BY STERLI AIR C LOW Elearr L.0 2 27

Unit 13 POWDER-ACTUATED TOOLS Among the most interesting of the recently 3. Uk an extension only when the safety developed tools are powder-actuated tools. Thes% control rodis accurately .setto prevent tools use energy from the firing of a powder charge firing at an angle. to drive a fastener into cOncrete or ,steel. Many 4. Make sure before firing that the fastener attempts were Made to use explosive energy for does not have sufficient_ power to' drive this purpose as early as the turn.of the century, but completely through the material. not until 1945 was ameihod developed that was 5. Always set the, fastener 3 inches or more commercially practical. Today, labor on hundreds from the edge oftoncrete. 7 of fastening jobs is greatly. reduced by powder.- 6. AlWays set the fastener1/2 inch ot more actuatedtools.This Method makes use, of a frOm the edge of steel. stud-driving tool, a powder charge, and a fastener 7. Use only a factory-recommended fixture (stud). Powder-actuated tools have two primary for any special fastening as described in the functions.First,they set threaded studs into manufacturer's instruction manual. concrete and steel for fastening removable installa- 8, Allow at least 30 seconds before removing tions. Second, they drive nail-like studs through a tool flop-the work surface in the event it materialsintoconcre eandsteelfor making does not fire; then remove the powder permanent installans. charge and dispose of it safely. Since powdectuated tools make use of the 9. Be sure the tool is unloaded when not in high-pressuregases developed by the confined use. If au operator decides not to fire the burning of powder (nitrocellulose propellant), they tool, he must unload it. are potentially as dangerous as any other formof 10. Never fire into cast iron, tile, high carbon explosive. However, improvements in these tools steel, or other hard or brittle materials. since they were first introduced have, made them relatively safe to operate as long as the prescribed Despite 'theTarry 'hundreds of applications precautions are observed. Because safety is such an performed daily by a powder-actuated tool, there the importantfactorinoperating powder-actuated are only a few simple basic rules that govern tools, all operators must 'be certified before they system and make it possible for the operator to do 'inay fire an ex'Plosive tool. To obtain a certificate, good work. These rules are as follows: an operator must pass a written test onthe safe I.Know the material to be penetrated. If a operation and careof the tool. ..;'"The first safety practice to be observed is to read common nail can be hammered into the and understand the instruction manual provided base material, don't use a powder-actuated for the particular powder-actuated tool before tool. attempting to operate the tool. These manuals 2. Select the proper fastener, for the job. describe the components of the stud-driver, the Consider wily the section -of the faStener loading and firing cycle of the tool, the parts list thatis to be imbedded under the work and parts numbers, the use of the extension, the surface of the material since the section use of the shield,e proper maintenance ofthe aliove the work surface of the material will tool, and the particular precautions to be observed. be determined by application requirements. All of the safety precautions presented in'a manual When selecting a fastener for concrete, are important and must beObserved in order to choose one that will penetrate into the prevent injury to the operator or to a bystander. concrete a minimum distance of eight times Certain of ,these precautions take precedence oyer the diameter of the shank of the fastener. others. 'The general sequence of importance of .A light-duty fastener with a shank diameter of %2 inch must penetrate 1 % inches; a these precautions is indicated in the safety instruc-, tions that follow: heavy-duty fastener with a shank diameter 1. Use a positive guide to insure alignment . of 14 inch must penetrate 2 inches. When when setting a fastener through a previously selecting a fastener for steel, remember that prepared hole in steelt the whole pointof the fastener must 2. Always fire from a iully shielded stosition appear through the reverse side of the steel as protection against ricochet. plate.

3 6 28

3 When selecting a* powder charge to set a tain a balance in the relationship of the fastener into either steel or concrete, or power of the cartridge to the length and when determining how far to insert the diameter of the fastener shank. If a fastener stud into the barrel, always use the weakest is selected within the aoper limits that pdwder chargeiltr insert the stIl a fair is,eight diameters into concrete or the distance into theIarrel for the first fasten- whole *point through the reverse side of ing. Learn the color codes some manu- teel thecorrectholdingpowerswill facturershaveplacedonthepowder generally result. charges, for the different colors ,designate g.k powder charges of varying intensity. The Scientific Principle Involved: Expansion of Gases colors should ,be memorized for immediate recognition. The power of the charge is The propelling force of the powder charge indicated by the color of ,the wads in the (nitrocellulose, the successdr to gunpowder/black mouth of the cartridge case as well as on powder) results from the rapid burning and evolve- the box or container in which theyAare ment of hot, gases that exert a sustained forward packed. force or pressure on the missile or projectile. The 4. Know the holding power of the fastener. A rapid conversion of the powder charge into hot powder-actuated tool is designed to main- gaSes that have a larger volume than the volume of *

In concrete In steel

Threaded stud The powder-actuated tool (above) utilizes the energy Threaded stud frOm a power source to set threaded studs or drive into concrete into steel pins through materials into concrete or steel (USM - Fastener- Companye Shelfon,, Connecticut).,- -- -

0 0

'10 4 0 0 0 0

0 ° o 0 o 0 c, 0- 0 0 -0. 0 0 . Dri ll! pin through Drive pin through Drive pin through Drive pin through wood into concrete wood in toteel steel into steel steel into concrete 3 7 the originalcharge overbalances the restraining Selected References pressure of the surrounding matter. Note: The numbers in parentheses in this section refer to entries in the list of selected references that appear within Application of Principle this publication immediately after the text. Since the powder charge and fastener are poten- tial adangerous as ammunition, the powder- p. 91%;,H8),Article 47;(27),pp. 237-38; ac uated t ol must be operated by a person with (16), (61),pp. 133-45. . 'an operator's certificate. A qualified teacher, con- struction worker,, or manufacturer's representative should demonstrate theuse of this tool. The Note:Operators' manuals publishedby,the explosive-forming device (referred to in Unit 12, manufacturers of Drive-it, Ramset, and Remington "High-Energy Rate Forming") can be used to powder-actuated tools can be obtained from local cl ie monstrate thepropellingforce of u powder suppliers of industrial equipment and -concrete harge. fasteners.,

\ _ 0,01041".71.1=% The caseless"power-cap"(right)isusedin a newly developed powder-actuated tool to drive pins and studs into concrete and steel. It - reduces fastening-cycle time; burns cleaner, with no residue; and eliminates cartridge case ejection. It works as follows (see below): (1) cap in position, firing pin armed; (2) firing pin releases, squeezing cap against anvil;(3) heat tragsfer begins; and (4) capis completely consumed, energy is ported khrough anvil into barrel, activating piston ram (USM Fastener Company, Shelton, Connecticut).

= Eight' tinfes actual size

(2) (4) 30

Unit JET ANDROCKET ENGINES Jet and rocket engines are internal-combustion closely follows the abofe description. In the engines. They operate through the application of turbojet engine, air is brought into the front Newton's third law of motion: For every action of the engine by a compressor. The com- there is an equal and opposite reaction. burned. pressor forces the air into the center section 'gases leave the engines with greatforcef The of The engine, where fuel is added and ignited. -. opposite reaction is an equal thrust in a forward The burning fuel increasei the tenwerature direction. As a result the jet or -rocket engine is and the pressure in the chamber. rie gase,, pushed (thrust) forwara, carrying the plane or therefore, exert a heavy force in Ali directions. rocket with it. The comptessor prevents the gas from es4p- Jet and rocket engines operate identically in ing out the front. As the gas escapes out the relation to Newton's law. Howeger, they differ in rear, it drives a turbine. The onlyfunction Of the way their fuel is prepared for combustion. A the turbine is to drive the compressor. As the jet engine sucks in air from the atmosphere and gases escape out the exhaust, *forward paii mixes it with the fuel for burning. A rocket carriesvi is given to the engine.. This pusli it'Oea its own air in the form of an Oxidizer and operates thrust, which is measured in riouna. Tust in space, where there is no atmosphere. is, therefore, the forward push (force) result:- The jet engine is defined further as one which ing from the pressureinthe combustion propels igelf by the same gases that convert the chamber. In the turbolirop engine the corn-t4 fuel's thermal energy into mechanical work bustion gas turns, a propeller as well as a turning the air compressor turbine. compressor. Propulsion power inthis case There are three types of jet engines using the comes from' the propeller: The .exhausting gas, . same basic principles of operation: the turbojet, depleted of most of its energy in *rating the turbofan, and the ramjet engines. they are the prop and the turbine, adds little thrlist to described as follows: the turbovop engine. 1. The turbojet or gas turbine engine is thought 2. The turbofan engines one of the most widely of as a "pure" jet engine because it most used engines, modifies the operation of the I

, k,

WWWWWW

A steam catapult is used to launch a jet aircraft from the USS Coral Sea (U.S. Navy photograph). 3 9 31

turbojet engine. The turbofan engine is able tion. However, the larger portion of the energy is to process greater quantities of air, provide use-dto rotate the airplane propeller when the increasedthrust,and . operateatlower 'turboprop engie is used or to rotate the wheels of temperatures. This improvement is accom- the automobile when the gas turbine is used. plished by providing, a bypass around the Stientific Principle Involved; combustion chambei, for a portion of the Newton's Laws incoming air. This air is shunted to t14 rear of the engine, where it combines with the heated Gas confined within a container exerts pressure gases. The mixing of the gases makes more equally in every direction. As long as the container efficient use of the available heat, producing is sealed, the forces resulting from the pressure are greater thrust. in balance. If the pressure is relieved at any point, however, the force at that ,point will drop. As a 3. The iamjet engine does- not even use a result the force opposite the reduced force will compressor, .has no moving parts, and requires cause movement or apply an unbalancedforce in a high speedbefo e it can operate; it cannot be direction opposite that of the relieved pressure. started from re .The forward motion of the This same principle can be identified in a different engine bringin the air. The shape of the manner: for every action there, is an equaland corn tiochamber prevents the air already opposite reaction. In the case of gas pressure, relief in the chamber from being compressed by the of the pressure (by opening the chamber at that incoming air. Fuel is added and ignited, an'd point, exhausting the gas) proqices an opposite thrust is produced in the same inanner as in and equal reaction. The reaction is a push away the turbojet engine. The incoming rush of air from the point at which the pressure is released. prevents the forward exhaust 'of the,burned gas. At high speeds the ramjet engine is more Application of Principle efficient and trouble free than the Aurbojet 1. Newton's third law of motion (for every engine; however, the ramjet engine cannot be action there is an equal and opposite reaction) used 'when the plane is standing still or is can be demonstrated by filling a toy balloon traveling at slow speeds. Future Jet engines with air and releasing the balloon. The bal- may take- advantage of bothturbojet and loon goes forward (reaction) with a force ramjet features. A combination engine called proposed. It equal andoppositetothe force of the a .turborarnjet engine -has been escaping air. would take off and operate as a turbojet 2. The principle of jet and rocket propulsion can engine. When sufficient speed is reached, it be taught by constructing a small rocket, would operate as a ramjet. using a CO2 cartridge as the engine. The The rocket engine uses the same principles of rocket can be operated on a string on the operation' which control the jet engine. However, it school grounds. The most important consider- operates ,independept of air, carrying a supply of ation for a good flightisto get a hole , both fuel.and oxidizer. Since the "reactionprin- punchedin the cartridge and the rocket ciple" of motion does not require atmosphere, the released before much of the CO2 escapes. rocket engine operates effectively in space. In 3. Thethrustof a CO2cartridgecan be operation,Oxidizer andfuelareignitedina measured by attaching the - cartridge to a combustionchamber. The resulting gases are cle wheel and checking the movement of heated to a very high temperature, producing a therheei with a dynamometer. high pressure. As the gases escape from the rear of the engine, a strong forward thrust propels the Selected References rocket. Note: The numbers in parentheses in this section refer to entries in the list of selected references that appear within The same principle of operation that is applied this publication immediately after the text. to the turboprop engines of planes can beapplied 4o gas turbine engines inautomobiles.' In these (1 ), Volume5,pp.918-25, Volume 7,pp. ,engines nearly all of the force of the escaping gas is 1237-39Volume 10., pp. 1859-62; (7), pp. 13-14; egorbed by 'thlurbine. The turbine serves a dual (-9), pp. 119-20; (13), pp. 192-99, 519; (22), pp. function. Part o the energy is Used to drive the 75-77; (4): pp. 238-43; (26), pp. 233-88; (37), PP. compressor bringing in the air needed forcombus- 383-91; (54), pp. 507-14; (55), pp. 81-108. 4 0 32

Unit 15 GASOLINE TESTING

Two tests usedin comparing the power of volume) has a rating of 50. Iso-octane and heptane gasolines are the Full Load Power. Test and the are reference fuels used to test and rate unknown Fixed. RPM Power Test. The units used in the fuels. measurement are foot-pounds of torque (fpt). A single-cyclinder engineis generally used in Scientific Principle Involved: testing the power of gasolines. The engine fuel- Conversion of Energy supply system must be equipped with a quick- Gasoline (chemical energy) is useful as a fuel for change systeM, which can be made by fitting the internal-combustion engines becauseitis easily fuel line with a glass jar lidin a way that will evaporated and very flammable. A mixture of permit the person performing the test to rapidly gasoline vapor and air provided by the carburetor interchange jars containing samples of different entersthecylinder,thepistonmoves up to gasolines. compressit,and an electric spark ignites the The engine is equipped with a tachometer, and compressed mixture. The burning is a fast chemical the load is applied by a dynamometer. Readings of reactionthatproduces carbon dioxide (CO2), the revolutionS per minute (from the tachometer) water vapor, and a large amount of heat (heat and foot-pounds of torque (from the dynamome- energy). The heat produced expands the CO2 and ter) are made and recorded for each sample of water vapor, forcing the piston down. The down- gasoline for full load power and fixed rpm power. ward movement of the piston (mechanical energy) Directionsforperformingthetestsareas turns the crankshaft. follows: The dynamometer makes use of friction to 1. Full Load Power Test. Adjust the throttle and measurethe torque (twisting rotationalforce) dynamometer until maximum readings for produced by an engine. Force is a push or a pull both rpm and fpt are observed. Record these which tends to produce movement. Friction is the readings. resistance to movement which is observed when 2. Fixed RPM Power Test. Adjust the throttle to_ two surfaces make contact. maintain 2,000 rpm while increasing the load -40 on the engine with the dynamometer. Rpcord Application of Principle the highest fpt reading which can be obtained I. Samples of various grades and brands of without dropping below 2,000 rpm. gasoline should be given the Full Load-Power Test and the FiNec PPM Power Test. The Today's best gasoline engines reach an efficienc cmiagdmmoitOt recorded reading. hould be compared to of 25 to 30 percent. Higher efficiency of th determine whatsignificantdifferencesof engineisobtainedby increasingthepressure power have been demonstrated, ,and the vari- (compression) of the fuel-air mixture in the cylin- ous differences in automobile engine design der just before it is, ignited. However, high com- and conditions which affect its fuel require- pression raises somelidifficult practical problems, ments should be discussed. Some of the such as making pistons and valves fitperfactly... factors which should be in the discussion are Also, when the pressure on the gasoline vapor is compressionratios,carburetors,gasoline suddenly increased by the compression of a piston, octaneratings, spark coils, capacitors, dis- the gas gets hot. In fact, under high compression tributorpoints,sparkplugs, and ignition the fuel mixture gets hot enough to explode before wires. Note: Poisonous carbon monoxide is the siiark ignites, causing engines to knock. Chem- present inthtexhaust gases of a running ists have developed a gasoline that can be highly engine. Good ventilationisa "must" to compressed without exploding too soon. High- prevat carbon monoxide poisoning whenever octane gasoline is highly resistant to knock; low- an engine is bfng operated indoors. octane fuel knocks easily. A gasoline is 4ated by 2 A fractionatmg tower can be assembled to the use of an octane-rating number (ONR). Iso- distill petroleum. Note: It is unsafe to heat octane is given a rating of 100 because it is very petroleum with an open flame above 75 resistant to knocking. Another fuel, heptane, is degrees C. Rubber tubes must be connected given a rating of zero because it knocks easily. A from the fractionating tower to the collecting. mixture of .half iso-octane and half heptane (by bottles. Petroleum warmed to 40 degrees C.

41' 33

will produce a vapor.sthat when condensed C. will be pentane gasoline; to 75 degrees C., Hexane gasoline hexane gasoline. 75° Selected References To collecting bottles Note: The numbers in parentheses in this section refer to entries in the list of selected references that appear within Petane gasoline \ this publication immediately after the text. (16),pp.100-101,166-67; (22),pp.49-59, 165-77; (69), Chapter 6, pp. 1-38; (75), Chapter Petroleum 20, pp. 1-8.

Unit 16 CARBURET1ON

Most American internal-combustion engines use operation from Partly open to nearly wide- gasoline as fuel. Gasoline is obtainedfrom petro- open throttle. When the throttleis opened leum and is composed primarily of hydrogenand wide, a metering rod and jet assembly allow carbon compounds. By the mixture4ofcorrect more gasoline to pass a point andprovide an amounts of gasoline and air and theignition of this enriched mixture. mixture in an engine, power is produoed todrive a 5 Accelerating pump circuit. This circuit caries vehicle. The mixing of gasoline and air in con- the engine through the closed throttle to trolled amounts is known as caiburetion.The open-throttle transition period. The transition device on automobiles and other unitsdriven by period is ofter referred to as a "flat spot" in internal-combustion enginesthat performs this engine performance. function is called a carburetor. Thecarburetor 6. Choke circuit. This circuit is designecl to cause performs seieral specialized functions. Thenamei the carburetor to deliver great amounts of and_ brief_ descriptions. of these functions are as fuel for starting_ when the_engine is cold. The circuit can be controlled electrically, thermb- follows: statically, or manually. the float 1. Float circuit. The major function of carburetor circuit is to keep the bowl filled with gasoline. A great deal of air passes through the full, the and engine. Air is likely to contain a gyeat amount As the lexel of gasoline approaches entered float rises and cuts off the ingress feed; when of dust and grit. These impurities, if they the float drops, the valve is opened, allowing the engine, could cause ssrious enginedamage. All air entering the engine through the carburetor must the ingress feed to open. cleaner. Air cleaners 2. Idle and low-speed circuit.eThis circuit oper- firstpass through an air ates when the throttle is`-closed ornearly contain fdter material (fine-mesh metal threads or closed. At this time only a small amountof ribbons, special paper, cellulose fiber, orpoly- air can flow through the carburetor airhorn urethane) or oil reservoirs to remove dust and grit (air intake), causing a limited mixture to be from the incoming air. supplied to the engine. Scientific Principle Involved: 3. High-speed, part-load circuit. As the throttle Bernoulli's Principle is opened for high speed, it moves past the loyi-speed port in the carburetor and allows When a 'fluid is undergoing a change invelocity, air to pass the air horn in a sufficient quantity the pressure, measured at right angles tothe highest tofurnishamixtureadequateforthe direction of flow, is lowest at the point of demanding conditions. velocity. A venturi is built in the air tube leading to 4. High-speed, full-power circuit. This circuitis the jets in a carburetor. The air moves through the designed to do what its title suggests. The venturi, causing a low pressure as it reachesthe area of the tube, where thediameterisless ./mixture supplied is satisfactory for engine

4 2 6 34 .6

r Idle-adjustment needle

High-speed adjustment needle

'High-speed adjustment spring

Choke shaft

Return spring

Choke valve 6 Throttle valve Choke-valve ball 0 Choke-shaft spring Throttle shaft Needle and seat

Float-lever pin

Bowl \

1 Bowl nut

The illustration presented above gives an exploded view ofthe carburetor used in the three-wheel Cushman truckster and haulster (Cushman Motors, Lincoln, Nebraska).

4 3 35

High speed Lower pressure Needle valve Idle valve' Low speed Low speed Venturi Choke butterfly Higher pressure::z1=-- Higher pressure

Gasket Throttle Float butterfly Nozzle Gasket

The venturi (left)is a constricted tube which causesthe velocity of the air to increase and the pressure to decrease. A carburetor (right) illustrates the use oftheventuri (Briggs & Stratton Corp., Milwaukee,Wisconsin).

(constricted). The air pressure in the liquid con- 2. Students canconstruct a minikure wind tainer (bowl) forces the gas to flow intothe tube tunnel to measure static and dynamic pres- and mix with the air, where it becomesatomized. sures in the venturi.

Application of Principle Selected References

1 Small, single-cylinder engines lend themselves well to experimentation involving the degree Note: The numbers in parentheses in this section refer to the entries in the Fist of selected references that appearwithin of combustion efficiency and its effect on this publication immediately after the text. engine's operating conditions. Students can vary(a) thethrottle-valvesetting;(b) the 127-71; (27),pp. Choke-v7esetting;and(c) themixture (20),pp. 244-57; (22),pp. setting.hey can then observe the results in 224-25; (36), pp. 113-16; (69), Chapter 6, pp. smoothness of operation speed and the quan- 140; (75 ),Chapter 21,pp.1-16; (78),pp. tity and Color of exhaust smoke. 193-214. S

Unit 17 TWONNDFOUR-CYCLE ENGINES The source of power for internal-combustion, cylinder pressure to less than atmospheric reciprocating engines is heat-formed by theburning pressure or by applying aninitial, higher of a combustitYle mixture of petroleumproducts pressure to the fuel charge. and air. In a reciprocating engine thisburning takes 2. Compression. The mixtureisreducedin placeinone or moreclosedcylinders, each volume, or compressed. containing a piston. EXpansion resultingfrom the 3. Power. The mixture is ignited by atimed heat of combustion applies pressure onthe piston. electric spark (gasoline engine) or by the heat This pressure forces the piston down,turning a of compression (diesel engine). The burning shaft by means of a crank and a connectingrod. fuel-air mixture expands, forcing the piston In the gasoline engine, the fuel is ignitedby a down and thus convertingthe generated spark; in the diesel engine, by theheat of com- chemical energy into mechanical energy. pression. The series of events thattakes place to 4. Exhaust. The burned gases areexhausted run the engine may.dccurIn one_ revolution of the from the cylinder so that a neW cycle can crankshaft (two-stroke cycle) or in tworevolutions begin. -00,1 of the crankshaft (four-stroke cycle).The operat- The diesel engine differs 'from thegasoline ing cycle consists of the following parts: engine in that 'in the diesel engine airalone is 1. Intake. The mixture of fuel and air isdrawn drawn into the cylinder during the intakestroke or forced into thecylinder by reducing the and is then' comjaressed to a much higherdegree.

4 4 36

Ic The air is heated by compression. Instead ofan Direction of rotafion electric spark, a finely atomized charge of fuelis injected into the combustion chamber, whereit combines with the heated air, causing ignition. The power and exhaust strokes are .almost identical to those of the gasoline engine. Each movement of the piston fromtop dead center (TDC) to bottom dead center (BDC) is referred to as a stroke. Thus, forevery two strokes (1 ) of the piston, the craashaft makesone complete nirection of rotation revolution, meaning that there will be two-revolu- Jib tions of the crankshaft for each completefour- Compressed charge strokecycle (intake, compression,power, and

(2) Direction of rotation a Expanding gases

Direction of rotation Exhaust gases

Intake Compression

Exhaust

(4) The two-stroke cycleofan intemal-combuvion engine takes one revolution of the crankshaft

exhaust). For the purpose of intake and exhaust, valves are installed in the combustion chamber. The opening and closing of the valves must be synchronized with the movement of the pistonon appropriate strokes. In a two-stroke-cycle engine, the four events take place in two strokes of the .piston orone revolution of the crankshaft. Thus,a compressed fuel charge is fired each time a piston reaches TDC; Power Exhaust each downward troke is a power stroke. The The four-stroke cyde of an internal-combustion engine incomingfuel-airmixture must be somewhat takes two ievolutions of the higher in pressure than the lowestpressure existing crankshaft in the cylinder. The piston is usedas an air pump 4 5 37 for this purpose; the engines are called "crankcase- b. Draw on engine sehimatics (provided by scavenged." teacher) the flow of air-fuel and exhaust on each of the engine types. Scientific Principle Involved: c. Identify valves, ports,pistdns,rods, and Expansion of Gases other internal parts.. A very important principle in the operation of d. Determine the firing order of an engine. the two- or four- cycle engine is the expansion of e. Find the compression' iitio of anengine by gases or the conversion of chemical energy to heat using actual measurements. energy to mechanical energy. Energy is defined as f. Determine engine cUsplacem4it by measur- the capacity to do work. The energy is stored in ing the bore and stroke. the molecules of gasoline. When the fuel is ignited, 2. Calculate actual pressure odie top of a energyisreleasedand producesheat, which piston as a result of the expCnding gases. increases the pressure of the gases above the piston. Selected References The piston is pushed down in the cylinder. The Note: The numbers in porentheses in this section refer to downward movement of the piston turns the entries in the list of selected references that appear within crankshaft. this publication immediately after the text. (4), pp. 27-29; (13), pp. 464-66; (22), pp- 3848; Application of Principle (26), pp. 113-18;(27), pp. 271-72; (36), pp. 19-20; 1. Have students do as follows: (56), pp. 3-12; (66), pp. 17-19; (67), pp. 17-20; a. Disassemble and assemble two- and four- ,(69), Chapter t, pp. 7-22; (72), pp. 4-31; (75), cycle engines. Chapter 4, pp. 1-12.

o 1-

'".4^

-1

...... ,...

t4,I 4- ,,tt..-.0.- 21.

Single-cylinder, air-cooled, two-cycle engines are used to power a saw, pump, bicycle, and spray-gun compressor (Orline Products, Los Angeles, California). 4 6 38

Unit 18 WANKEL ENGINES Therecentlydeveloped Wankelinternal- combustion, and expansion .for the power strq,ke combustion engine is relatively' small, lightweight, until the exhaust port is uncovered. The exhaust and ineXpensive to manufactuce. It sis extremely cycle then takes place, again with no speed- versatile: there is almost no limit on compression restricting valve mechanism. The entire operation ratio, maximum revolutions per minute, type of cycle is thus completed. fuel feed, and method of cooling. The Wankel engine is capable of rimning at high speeds for long' periods of time. It is very successful in cutting down friction by a reduction in the number of moving parts. As the rotor "piston" of the Wankel engine turns, it forms chambers between the three sides of the rotor and the wall of the housing. The shape, size, and position of the chambers are constantly being altered by the rotor's rotation. Cycles of intake, compression, power, and exhaust are going on simultaneously around the rotor when the engine is running. There are three power impulses for each rotor revolution. As the rotor opens the intake port, which has no speed-restricting valve mechanism, the fuel-air mix- During the combustion cycle the rotor of the Wankel tureis drawn in. The rotor continues turning, engine turns and forms chambers between the three closing the intake port by passing beyond it. Then sides of -the rotor and the wall of the housing thecompres§ionbegins,follgwed by ignition) (Curtin-Wright Corp.).

..

The new Wankel marine engine 'uses twin rotors.

4 7 39 !-

flywheel provides a torque which resists thisaction Scientific Principle Involved: uniform rate Movement of Inertia also. The flywheel tends fo maintain a of crankshaft rotation. A body continues in its state of rest oruniform motion unless an unbala=d force acts onit Application of Principle (Newton's first law ofimotion). A wheelmounted on an axle will not start to rotateunless a torque is The Wankel engine, which has not been adopted applied to the wheel. A wirel which isspinning for use in any American vehicle, is beingused in will continue to spin at constant angularvelocity NSU sports cars and marine engines'manufactured unless a torque acts on it. In both cases thewheel ii?Germany. Several companies have been licen* law of to manufacture theengine,including Curtiss- isin equilibrium. Thus, Newton's first and motion also applies to rotary motion. Wright in the United States,_ Daimler-Benz A rotating flywheel helps maintain a constant others in Germany, Perkins in England, andKogyo an ular velocity of thecrankslat of a Wankel or in Japan. Most of these companieswill provide conventionalinternal-combustionengine.The drawings and photographs on request. m ent of inertia of a flywheel islarge. Torques it do not produce rapid changes in its Selected Referenqes angular mo entum. As thetorque from the Note: The numbers in parentheses in this sectionrefer to combustion in each chamber or cylindertends to entries in the list of selected references that appearwithin accelerate the crankshaft, theflywheel provides a this publication immediately after the text. torque which resists this action. But asthe torques (27), pp. 88-89, from each chamber or cylinder wherecompression (22), pp. 78-80; (26), pp. 209-12; is occurring tend to decelerate thecrankshaft, the 108-9; (46), p.86. b

Unit 19 THERMOSTATS

A thermostat is a device that is used tocontrol that turns the heater on or off at thedesired change in temperature. A' similar unit is used in theelectric temperature. It responds directly to a iron is temperature and is usually set so that itmaintains a iron so that the circuit is broken and the desired temperature level. Most thermostats are shut off when the proper temperature isreached. If the iron becomes too cool; the thermostatcloses usedto open or close electricalcircuits or to control the flow of liquids or gases. the electrical circuit and the iron heats up again. Thermostats are used in the home tocontrol the In the automobile engine the thermostatis temperatures of heating systems, airconditioners, placed in the top of the block ttclose off theflow 'refrigerators, electric irons, stove ovens,and elec- of coolant when the engi e is cold. Thisclosure temperature tric blankets.In the automobile a thermostat causes the engine to r1ch operating restricts the flow of the coolant inthe radiator more quickly. The thermostat operates avalve so coOlant to the set untilthe correct temperature of theengine is that, when the engine warms the reached. The automobile heater, as well asthe temperature of the thermostat, the valve opensto refrigeration system, uses the Niermostatasa perrhit normal circulation. Coolant thermostats are temperature-control device. of various types which normally use the expansion One of the most common thermostats uses a of a liquid or wax to control-the engine tempera- bimetallic strip that operates on the expansionand ture. One type, called a bellowsthermostat, con- When the tainsaliquidthat evaporates with increasing contraction of twO different metals. inside the temperature changes, the twometals expand or temperature and causes the pressure contract unequally. This causes thebimetallic strip bellow to expand and push the valve open. to bend in the form of an arc.The bending of the Another type, called a butterfly thermostat, uses a wax pellet, which alsoexpands with increasing strip can be used to open or close a circuit. permit- the In a home-heating system thethermostat is set temperature to open the valve to to open or close the circuitcontrolling the valve coolant to flow through the radiator.

4 8 40

Scientific Principle Involved: Gases and vapors are particularly useful in thermo- Thermal Expansion. stats because their molecules, which are uniformly distributed, exerttheir pressure, equally inall Heat is the kinetic energy of randomly moving directions to all parts of the sealed container. molecules. Adding heat to a substance causes the molecules to move more rapidly and produce a greater tendency for the molecules to overcome Application of PrinCiple their mutual attracting forces and to move farther. apart. Differentsolids have individual rates of I. Secure one or more thermostats from auto-a expansion and, different melting points because mobiles, a container for boiling water, a they are composed of unrelated molecules which thermometer, and a heat source. Suspend the are bonded together in different ways. Liquids also thermostat and thermometer in the container have various exppsion rates and boiling points; of water and increase the temperature of the but liquids in general expand more than solids water. Note the action of the thermostat as under the same changes in temperature since liquid the temperature of the water approaches the molecules move :more freely. The molecules of temperaturestamped onthethermostat. gases are so far apart and free to move that the Record the temperature at which, the therm- thermal expansion rates for gases are many times stat begins to open, continue io observe the greater lhan those' for liquids or solids. action of the thermostat, and record the y temperature at which it is fully open. Discuss Thermostatic i.oxilrolsinthe form of spiral the_ thermostat as' a means of control in the springs, sucli as those used to actuate the heat-riser cooling system of the internal-combustion valve in theSutornobile exhaust system, depend on engine. the expansion of the metal in the coil to relax the tension of the spring. 2 Conduct the same type of experiment by using the spiral spring found on the heat riser Since brass expands about twice as much as in the exhaust system of the automotive-type steel, bimetallic bars made of these inexpensive internal-combustion engine. Note that the metals, bonded together, make sensitive thermo- application of heat to this spring will cause it static controls which can also conduct electricity to actuate the control valve, an action that and withstand high temperatures. can be readily observed when heating the spiral spring in the automatic choke on a

(1) . carburetor. Qbserve that when heat is applied Bimetallic to this spring, the choke valve moves from the strip closed to the open position. Contact 3. Note other applications of thermostats in )-41 Contadi spring points electricirons,circuit breakers, and many other heat-controlled appliances. Obtain the thermostat from an electric iron orl circuit (2)' breaker from an automobile electrical system Bimetallic and either connect these units into an elec- 7-- strip 4 trical circuit with a sufficient load to actuate Contact them or apply heat directly and observe their Contact spring / points action.

The two different metals in the thermostat expand Selected References unequally when the temperature rises, causing the closed contact points (1) to open (2). Note: The numbers in parentheses in this section refer to entries in the list of selected references that appear within this publication immediately after the text. Thermostatic controls which operate on the principle of thermal expansion of liquids and gases (22), pp. 194-95, 349; ( 26), pp. 146-47; (27), pp. are generally more sensitive than those dependent 233-38; (46), pp. 211-12; (47), pp. 267-71; (66), p. on solids because of their high expansion rates. 47; (69), Chapter 4, pp. 9-11. 4 9 41

Unit 20 WELDING PROCESSES

Welding is the process of joining metal parts by called hard soldering since the piece to bebrazed is directing heat to melt and fuse partstogether. not melted. Instead, the brazing rodis melted into called the edges of the pieces to be joined. This processis When heat alone is used, the operation is there is very fusion welding. In some welding processes pressure used in repairing broken parts because will be is used to help join the metals. Many weldsrequire little danger that any of the original parts that extra metal be added to the weldby melting a damaged. metal rod into the molten puddle. Safety Instructions Industry uses welding to fasten parts together permanently andto make repairs on broken 1. Obtain permission from your teacherbefore equipment. Many buildings, bridges, and ships are using welding equipment. fabricated by welding. The automobile has parts 2. Make sure you have ample ventilation. that are welded together; in "tooling up"for an 3. Be sure that you wear welding goggleswhile automobile, the manufacturer spends considerable using oxygen-acetylene welding equipment. time in arranging for special weldingequipment to All assistants and observers must also wear fabricate many ofitsparts.As a means of welding goggles. fabrication, welding has proven fast, dependable, 4. Wear a helmet with a proper observation and flexible. It has made possible thesimplification window, a pair of treated gauntlet gloves, and of design and the elimination of costlymachining a treated leather aprolwhile using' electric processes. The three most commonmethods of welding equipment. All assistants and observ- welding are gas, arc, and resistance welding. ers must also wear thisequipment. rolled down- Gas welding is accomplished by mixing oxygen 5. Keep your sleeves and pants cuffs and acetylene in the body of a weldingtorch and and wear a leather jacket while using electric then lighting the 'gaseous mixture atthe tip. The welding equipment. oxygen-acetylene flame produces a temperatureof 6. Make sure that welding equipment is working 6,300 degrees F.After properly adjusting the properly and that it is used correctly. flame, the welder heats the metal part byholding Scientific Principle Involved: the flame near the metal until amolten puddle Kinetic Molecular Theory forms. Then he applies the welding rod tobuild up -- the weld. One of the advantagesof gas-welding Heat is the kinetic energy of movingmolecules. special Chemical energy released on_the burning of acety-. equipment is that through the use of a- of torch the flame can be used to cut metals. lene in the oxyacetylene torch is the source In arc welding the electric power comesfrom energy used in gas welding. Inthe electrical-arc either an electric generator or atransformer. One weld, the heat energy 'is produced by the acceler- cable from the source of power is connected tothe ation of electrons and ions in the electricalfield; in metal objectsto be wMded, and the otheris the resistance weld the heat is due to the resistance connected to the holder that clamps theelectrode. tor the movement of electrons in the metal. The The welder strikes an arc bytouching the metal purpose of using heat in weldingis to increase the part to be welded yvith theelectrode. The arc temperature of the metals to the pointwhere the produces a temperature of about 9,000degrees F. kinetic energies of the molecules and atomsof the The operator feeds the electrodeinto the joint, metals aresufficient to break the bonds which hold forming a bead as it is moved along thesurface. these particles together in the crystalline structure the Spot welding, whichisusually a method of of the solid. When these bonds are broken, freely in resistance welding,is employed a great deal in metal fuses and the particles move more industry to join sheet-metal parts. Thepieces of theliquid state. On cooling, the particles lose positions metal areplacedtogether and clamped under kinetic energy and.resume relatively fixed pressure between the tipsof two electrodes. A in the solid state. When these effects occur onthe large amount of current passes betweenthe elec- localheating of pieces of metal heldclosely together at the together, as in spot or seam welding, theresult is a trodes and fuses the metal pieces of more point where the current passes throughthe metal. strong, solid bond without the addition Brazing, involving the use ofgas-welding equip- metal. Addition of molten metal, such as in gasand ment, is not considered a methodof welding. It is arc welding, allowsbonds to form between the 5 0 42

added metal and the fused metal from the surfaee 'skillsinvolved in the welding and brazing being welded. The molten metal flows into small process. spaces between the metal surfaCes by capillary 2. A demonstration of both the gas- and arc- action caused by intermolecular forces of cohesion. welding processes should include the setup Inbrazing, a different metal with a lower and adjustments necessary for each particular melting point is used as the bonding materhl. The welding operation. metals to be brazed are preheated (but not to the 3.An aid which will allow the development of melting point) in order to increase the molecular the necessary manipulative skills without the motion, which promotes better penetration of the actual use of electrodes, welding or brazing molecules of thesolid metal sinfaces by the rods, or oxygen and acetylene is a 1-inch molecules of the molten metal. The bonds in solids dowel or stick approximately 14 to 16 inches between unlike molecules (adhesion) can be as inlength. A holeisdrilledin which an strong as or stronger, than the bonds between like. ordinary graphite pencil will fit snugly. The molecules (cohesion). The molten metal used in hole should be at an angle which approxi- brazing flows into the small spacing between the mates the position of the welding torch. or metal pieces by capillary action, which is due both' electrode. By an adjustment of the length of to the strong attraction (adhesion) between the the pencil to correspond to either a torch or molten metal and the solid metal surface and to an electrode, the tfasic patterns and strokes the high surface tension (cohesion) of the molten may be practiced oira piece of paper. metal. Selected-References Note: The numbers in parentheses in this section refer to Application of PrinCiple entries in the list of selected references that appear within 1 The most effective aPproach to the applica7 this publication immediately after the text. tion of welding and brazing is to learn the (34), pp. 27-41, 237-51; (47), pp. 276-79, 342; basic technical inforimation and acquire the (87), pp. 30-33.

1 SECTION V ELECT' F.,721 POWER

Unit 21 DRY CELLS: PRIMARY CELLS One of the most common sourcesof electro- longer life than theordina'ry zinc-carbon-ammo- chemkal energy is the dry cell (primarycell). nium chloride dry cell. Electricaldevices suchasflashlights7 portable Scientific Principle Involved: - radios, and warning flashers on thehighways are Conversion of Energy conlrenient usually powered by dry cells, which are by and flexible power suppliers. Regardlessof size a ... The dry cell produces an electric current zinc-carbon single dry cell produces 1.5volts of converting chemical energy into electrical energy. direct current (DC). The cell is mostoften made The conventional dry cell- consistsof a negative from (1) zinc, which is one of theelectrodes and electrode(zinccase) and a positive electrode (2)-a carbon rod, (carbon_ iod). Electrons must pass from the nega- serves as the shell or container; (external circuit) which is the other electrode and extendsthrough tiveto the positive electrode the center of the cell; and (3) anammonium before electrical energy is produced. Achemical The'top of substance (ammonium chloride)in' the zinc con- chloride paste, which is the electrolyte. ions and the cell is sealed to prevent evaporationof the tainer reacts with the zinc, forming zinc moisture in the ele'ctrolyte, and the zincshell is liberating electrons. This reaction is very slight Proper care untll the positive and negativeelectrodes are usually encased ivteel or heavy paper. circuit and intermit/pt: Use extends the lifeof this sourCe connected together in a circuit. When the hasbeencompleted,Cilie chemicalreaction, of electrical e41.g. from the In recent y, e dry cell has beenimproved. increases, and the electrons steadily move negativeto the positive electrodethrough ihe One of these irriprovements is the so-called mer- bubbles cury cell. The negativeelectrode of this cell is external circuit. At this time hydrogen made of an amalgam ofpowdered zinc and attempt to form a coating on thecarbon electrode. shape. The depolarizer is Another chemical (manganese dioxide) isprovided mercury, pressed into bubbles in order that composed of mercuric oxide and graphitepowder. to dispose of these hydrogen the chemical reaction may continue.The move- The-zinc-mercury amalgam cuts down local action, of the and the graphite helps reduce theinternal resis- ment "of electrons will cOntinue until most tance 'of the cell. Mercury cells de aconsiderably zinc is consumed by the reaction. 44

Metal regardless of theirsize,deliver1.5volts. cover However, larger cells deliver more current. A Negative Positive freshNo. 6 drycelldeliversabout 25 terminal terminal ampereos, a penlight cell about three amperes. Expansion The ammeter.te'st should be made only when Asphalt necessary, and then as quickly as Wssible, gasket space Insulating because the drain of the current reduces the Wax seal life of the cell. Note: Deteriorated cells are -washer likely to expand or leak. They should be Paper Depolar- removed from flastlights and other devices. washers izing mix When dry-cell-powered equipment is stored, Asphalt Carbon the batteries should be removed. A dry cell coating electrode should be put into use before the expiration Zinc can date that is stamped on the label. Paper 2. The chemical action of a supposedly dead cell jacket Paper may be restored temporarily by punching a, separatdr number of holes in the case and letting it ...... --stand in water for a short time. However, .cells Paper restored in this manner are of little practical washers use beCause they are only partially restored, their life is short, and they leak. 3. Dry eells in various states of deterioratiga may be displayed, attention being directed te swelling, perforation of the container, and A cross-sectional view of a zinc-carbon-ammonium corrosion. Cells may be cut in half° to show chloride dry cell shows the components (National Carbon Company, Inc.). their internal structure. Selected References Application of Principle Note: The numbers in parentheses in this-section refer to I. Fresh dry cells and cells that are in -various entries in the list of selected references that appear within this publication immediately after the text. states of deterioration can be given an approx- imate test by cbnnecting them in a circttty (13), pp. 481-82; (14), Op. 212-14; (26), pp..292, with a 1.5-volt light bulb and observing 297; (27), pp. 458, 461, 465-66; (36), p. 50; (47), intensity of the light. A more accurate test PP. 228-30; (49), Volume 3, 276-79; (54), pp. can be made with a battery tester which 331-32; (65), pp. 41-42; (66), pp. 155-56; (86),pp. measures volts and amperes. Zinc-carbon cells, 40-41.

Unit 22 STORAGE BATTERIES: SECONDARY CELLS The storage battery is an electrochemical deviceforce (emf) of each lead-acid cell is approximately forconverting chemicalenergyintoelectrical 2.2 volts. energy. It consists of a number of storage cells connecteVn series. A storage cell is a secondary or Lead-Acid Battery voltaiccellthat can be restored or recharged Active materials within the lead-acid battery repeatedly. Storage cells of three types are now in react chemically to produce direct current (DC) general use: the lead-acid cell, the Edison cell, and whenever lights, radio, starting (cranking) motor, the nickel-cadmium cell. Thelead-acid storage cell, or other current-consuming devices are connected used in the batteries of automobiles, airplanes, to the battery circuit. This current is produced by trucks, motorcycles, and other equipment requir- the chemical reaction befween the active materials ,ing a portable source of electrical energy, is by far oftheplatesandthesulfuricacidof the the most widely used type. The electromotive electrolyte. 5 3 45

4.

Plate strap 'ep, 'casting

Negative -plate" gtoup

Separator Element

Positive plate group

An interior-construction view of a trical 12-volt lead-acid storage batteeyillustrates internal cell connections (Delco-Remy Divisimj eneral Motors Corp.).

The battery perfornisihree functions in automo- Safety Instructions tive applications. First, it supplies electrical energy 1. Obtainpermissionfromyourteacher for the starting motor and ,for the ignition system beforeservicingorchargingastorage as the engine is started. Second, itintermittently battery. supplies current for the lights, radio, heater, and 2.i4se proper instruments for testing a storage other accessories when the electrical demands of battery. these devices exceed the output of the alternator. 3. Avoid overfilling a battery, especially if it is Third; the battery acts as a voltage stabilizer in the to be charged. electrical system. Satisfactory operation of the 4. Use water and baking soda (a neutralizer) vehicle is impossible unless the battery performs to clean off the top of a battery. each of these functions. 5. Remove and transport, a battery with a The internal constriiction of a lead-acid storage battery lifter. battery is such that a highly. reliable power source 6. Handle battery or acid with care. Wash is provided. Two types of plates, one positive and immediately any part of your body or The other negative, are the basic units. These plates clothing that comes in contact with ackd. consist of chemically active materials contained in 7. Wash hands immediately after handling a grids. The grids are flat, rectangular, lattice-like battery. castings. Each grid is designed specifically to hold 8. Wear goggles when using a charger. the active materials. Once the grids have been 9. Provide ample ventilation when using a pasted with the active materials, they are called charger. plates.During the manufacturing process these 10. Remove cell covers before charging a bat- plates are then said to be "charged." Charged tery, unless the covers have other instruc- negative plates contain sponge lead (Pb), which is tions upon them. gray in color. Charged positiveplaies contain lead 11. Keep open flames and sparks away from a peroxide (Pb02), which has a dark brown color. battery being charged. 54 \ 46

12. Turn off charger before disconnecting leads plates cause a.. .mbalance whic1 is corrected when (wires) from charger to battery. the circuit is completed and t electrons move _13. Replace cell covers before moving battery. through the external circuit to the positive plates. 40. Scientific Principle Involvea: Application of Principle Conversion of Energy I. A lead-acid cell can be made by placing parts Electromotive force (emf) can result from the of two ciliates (positive and negative) from a immersion cf. certain pairs of dissimilar materials discarded storage battery in a dilute solution into the proper electrolyte. The lead-acid storage of sulfuric acid. When the plates are immersed batteryis a combination of negative plates of in the electrolyte, little or no chemical action spongelead(Pb)andpositiveplates of lead occurs. However, when the plates are con- peroxide (Pb02 )immersed in an electrolyte of nected in series with a 1.5-volt lamp, chemical sulfuric acid (H2SO4 ) and water (H20). When the activity will take place. Note: The use of an terminal posts \re connected to form a complete acid-resistant container of glass or plastic will circuit, a movement-of electrons will result from make itpossibleto observe the chemical the chemicalactilbn.This chemical reactionis activity. between the active materials of two different kinds 2. A simple voltaic cell can be made by inserting of plates and the electrolyte. a strip of brass and a strip of galvanized iron (of a clean copper penny and a silver dime) -into a lemon. Check current flow between strips or coins,with a galvanomenter. Selected References Note: The numbers in parentheses in this section refer to entries in the list of selected references that appear within this publication immediately after the text. ( 7), prt 37-39; (9), pp. 229-30; ( 13); pp. 481-82; ( 16),pp. 24447; (22),pp. 200-204; (27), pp. 466-69;1'33), pp. 24-27; (37),p. 415; (4,7), pp. 23342; (65), pp. 44-47; (66), pp. 15 -541; (69), Chapter 19, pp. 9-14; (86), pp. 45-49 (87), p.53.

Each cell in a lead-acid storage battery_has a potential Electrolysis, 1 of approximately 2 volts (actual potential is 2.2 volts .41 per cell). Batteries containing three cells connected in Electrolysis ise deco osition ifg' a chemical series are 6-volt batteries; six cells connected in series compound by mea s of e e 1 eney. Electrol- are 12 volt Applications requiring highor voltages use ysis has been put to ma yseful purposes in combinationsofbatteries,suchastwo 12-volt industry; such as in the mnufacturing of chlorine batteries connected inseries to obtain a 24-liolt and fluAne gases, in electroplating, and in the syste extracting of ialuminuiritnd certain other metals from their. ores. However, electrolysis can occur During the chemical reaction the'oxygen (02) of where it is not desirable; for example, during the the lead peroxide (Pb02) of the positi4 plates charging Of a storage battery. If the rate during combines with the hydrogen (Ht2 ) of the sulfuric charging '(amperage rate of current flow) is too acid (H2SO4) to form water (H20); the sulfate high, the battery will heat, producing an excessive (SO4) from the sulfuric acid (H2 SO4 ) combines amount of explosive gas (a mixture of hydrogen with part, of the lead (Pb) of the lead peroxide to and oxygen) by electrolysis. These gases are also form lead sulfate (PbSO4 ). Alsp, a chemical change produced when the battery is overcharged (when takes place at the negative plates. The lead (Pb) of charging is continued after the battery has a full the negative plate combines with the sulfate (SO4), charge). When a storage battery is being charged, of the, sulfuric acid (H2 SO4 ) in the electrolyte to the manufacturer's recommended charging rate form leadsulfate (Pb504 ), which is .thei same should bc followed; the charging shOuld be done in material as the positive plates. The excess electrons a well-ventilated area, away from heat,sparks, and transferred from the positive plates to'the negative open flame.

5 5 47

Refer to the safety instructions previously men- charged. An 18-inch length of 11/2 -inch Pipe is tioned in this unit. capped at one end. The cap is drilled and tapped for a 14mm spark plug. This unit can Scientific Principletwolved: be mounted on a stand.- One terminal of a Electrolysis storage battery is connected by a length of No. 12 wire to a primary terminal of a 12-volt cell(cell of a storage When an electrolytic ignition coil and the cannon barrel (pipe). The battery) is connected to a direct-current source, other battery terminal is connected with No. such ,as a battery charger, the cathode (negative 12 wire through a push-button starter switch plate) becomes negatively charged and the anode (positive plate) positively charged. Positive ions to the other primary terminal of the ignition acquiie electrons coil. The high-tension terminal is connected move to the cathode, where they to the spark plug. Then the cannon barrel is from the cathode and are discharged. Negatively placed for about five minutes over a cell charged-ions move to the anode and are discharged opening of a battery thatis charging and by giving--,up electrons to the anode. The loss of gassing freely. The cannon is then removed electrons by the cathode and the acquisition of a and placed at a demonstration location. The like number of electrons by the anode is, in effect, starter button is pressed to ignite the accumu- the conduction of electricity through the cell. The lated gas. conduction of electricity through an electrolyte, 2. A simple means of capturing the gases pro- together with the resulting chemical changes, is duced during the charging of a storage battery called electrolysis. is to insertin the cell openings of the battery J rubber stoppers (with a hole in the center of Application of Principle each stopper for a glass elbow for the end cell The explosivenature of the hydrogen and and T joints for the others). The glass tubes oxygen gases produced through electrolysis when a are connected in series by the use of piecesof storage battery is charged can he demonstrated by rubber tubing. This series hookup is then 'capturing the gases anci igniting thew in a safe connected by a rubber tube that leads to a manner. The demonstration can beconducted as shallow pan partly filled with water. If all follows: tubing connections are tightf and the battery is I. A "cannon" :an>e constructed to demon- charging, gas will bubblt slowly from the strate the potential hazard of a spark igniting submerged end of the tub' g. After sufficient gas given off from a storage battery Deing time has elapsed (Aen niinutes to half an hour) for the gases from the -battery to replace the Spark air in the tube, gas samples may be collected Cap plug in small jars or wide-mouth bottles (2 to 8 Pipe barre ounces in capacity) by water displacement. So that the gas can be burned or exploded safely, the inverted jar is lifted from the pan, covered with a glass plate, and placed right side up on a table. At arm's length from the jar, theglass plate is removed and a burning match is thrust into the mouth of the jar. Pure hydrogen pops, then burns quietly with an almost invisible flame. pydrogen mixed with oxygen or air explodes with a pop or ashriek, Switch depending on the composition of the mixture. Note: Use only a small, wide-mouth bottle or Ignition jar for this demonstration.- Do not collect gas coil 'in a large container and do not explode gas in a confined space, such as a bottle with a narrow neck or a bottle with a stopper. Do not attempt to light the gas at the end of the Storage battery rubber tube.

5 6 48

Selected References centimeter) of a liquid is called its density. When Note: The numbers in parentheses in this section refer to thedensityof oneliquidis -compared toa entries in the list of selected references that appear within standard, the relationshipiscalled the liquid"S this publication immediately after the text. specific gravity. All liquids are compared to water, (9), pp. 46-47; (13), pp. 280-81; (27), pp. 498-506; which is given a specific gravity of 1.000. If it is (37), p. 294. found that 1 cubic centimeter of iron weighs 7.6 times as much as 1 cubic centimeter-et .3kater, it is said that the specific gravit;of' iron is 7.6. An Hydrometer Test object placed* a container of liquid is buoyed or Each cell of a lead-acid storage battery contains lifted by an amount equal to the weight of the balanced quantities of positiveactive material, liquiditdisplaces;thisiscalled Archimedes' negative active material, and sulfuric acid. The principle. The denser the liquid, therefore, the sulfuric acid is diluted with water, and the solution greater isits buoyant force on the object. For is called the electrolyte. When the cell is fully example, as sulfuric acid is denser than water, a charged, the active materials are free of sulfate, and mixture containing more acid, as in a fully charged the strength of the electrolyte is at its maximum. battery, will buoy a floating object higher than a When a cell discharges, the active materials react mixture contitning less acid, as in ,a discharged with the sulfuric acid in the electrolyte, and lead battery. A hydrometer uses a calibrated (specifi- sulfateisformed on the plates. This reaction cally marked) float that measures the density or gradually lowers the strength of the electrolyte. specific gravity,of a liquid compared to pure water. Since the strength of the electrolyte varies directly Thus, this instrument will measure how much acid with thestateof the charge of the cell,this is mixed with the water in a battery by weighing strength offers a convenient basis for- estimating the mixturethat is, more acid makes the float the state of the charge. To determine approxi- rise higher and less acid lets the float sink deeper. mately the state of charge and how much energy is The markings on the calibrated float give the availablefrom _abattery,one needs only to specific gravity of the mixture compared to pure measure the specific gravity of the electrolyte. water. Specific gravity can be measured by means of a battery hydrometer. In the taking of a specific gravity reading, itis important that the float be freely suspended- in the fiquid, not touching the Do not draw Hold tube vertical. walls, top, or bottom of the barrel. It is important in too much also that the eye be approximately at the liquid electrolyte. level when the reading is taken. Specific gravity readings are affected by temperatures; 80 degrees Float must F. is the accepted standard. For every 10 degrees be free. of electrolyte temperature above .80 degrees F., four gravity points (.004) must be added to the gravity reading. This addition compensates for the loss of gravity caused by expansion of the liquid as its temperature increases. For every 10 degrees of Take reading electrolyte .temperature below 80 degrees F., four at eye level. gravity points must be subtracted from the gravity reading. This subtraction compensates for the gain in gravity caused by the contraction of the liquid The hydrometerisused to measure the specific as its temperature decreases. gravityofthestoragebatteryelectrolyte Refer to the safety instruction previously listed (Delco-Remy Division, General Motors Corp.). in this unit. Application of Principle Scientific Principle Involved: I. Information concerning the hydrometer can Specific Gravity be applied by testing a storage battery (prefer- All liquids have weight; some weigh more than ably one recently removed from an automo- others. The weight of a unit volume (e.g., cubic bile). In the performance of the test, care 5 7 49

must be taken to avoid spilling the electrolyte 6. Make sure that the cable terminals are clean because it contains sulfurid acid, which can and tight at the engine or frame and also at burn a person's skin or destroy his clothing. If the cranking motor switch and solenoid. spilling should occur, the acid should be Overfilling washed off with plenty of water. The hands should always be washed immediately after a, CorrosionFrayed or broken storage batterY has been handled. Loose Dirt cables 2. A hydrometer can be used to measultest hold-down antifreeze-solutions and crude oil.

Selected References Sealing Note: The numbers u parentheses in this section refer to compound entries in the list of selected references that appear within Cell defect this' publication immediately after the text. connect& (7), p.39; (22), pp. 357-58; (27), p. 207; (47), p. corrosion 237;(71), p. 28; (86), p. 48. Cracked case Cracked Low Battery Installation and Servicing cell cover electroly té- A storagebatteryisdesigned to withstand normal operating conditions; however, excessive The importance of periodicbattery service mechanical abuse.will lead to early failure. Mechan- cannot be overemphasized. Witha reasonable ical abuse often occurs during installation. So that amount of attention and care, the useful lifeof the a battery might be properlyinstalled, recommen- battery can be greatly extended; neglect and abuse, dations for installation are given as follows: however, will shorten its life. Any servicing and maintenance program should include the following 1. Before installing the battery, check for proper battery polarity with respect to the .vehicle's points: specifications. "Ground" polarity is usually 1. Inspect the battery thoroughly for defective indicated.Avoid reversedpolarityduring cables,til3ose connectors, corrosion, cracked installation by marking cables as to their 9aTes covers,andloosehold-down polarity when removing the old battery since devices. reversed battery polarity may cause serious 2. Check the electrolyte level periodically, par- damage to the electrical system. Remember ticularly in hot weather, and add pure water if that thepositilie battery terminal post is necessary to bring the liquid to therequired larger than the negative terminal post. Note: levelineachcell.OVerfilling shouldbe Wheninstallingbatteries,disconnectthe avoided, as this will cause the loss of electro- "grounded" cable at the battery terminal first lyte, resulting in excessive corrosion, reduced and reconnect it last to avoid damage to the battery performance, and shorter battery life. battery and wiring by accidental "grounds!' Allowing the electrolyte level to drop below Be sure that the battery carrier and hold-down the tops of the plateS will cause the exposed device are clean and that the new battery rests plate material to become dry and chemically level when installed. ihactive.Also,thehigh concentration of 3. _Tighten the hold-down device until it is snug; electrolyte remaining in the battery will cause however, do not drawittight enough to permanent damage on the plate area below distort or crack the battery case. the electrolytelevel, causing poor battery 4. Be sure that the cables are in good condition performance and shorter,life. and that the terminal clamps are clean. If the battery requires the addition of -5. Clean the battery terminals with a wirebrush an excessive amount of water in normal ser- before attaching the cable clamps. Do not vice, an overcharged condition is indicated. pound the clamps onto the battery terminals. Some water usage is normal, usually 1to 2 When tightening cable nuts, use the wrench ounces per batterY per 1,000 milesof service, carefully to avoid twisting and damaging the depending on the type of service and prevail- cell cover. ing temperatures. If the water usage becomes 5 8 50

ex essive, high battery temperatures or a high Battery Testing 1 volt ge-regulator setting should be suspected , The storage battery may be tested to determine as t e most likely causes. If very little water is if itis in good condition or if it is defective or used\ over threeor four thousand \ miles of worn out and must be replaced. Before the service,anunderchargedbattery may be performance of any electrical.checks, a visual indicated. Allowing the battery to remain in inspection should be made to reveal any obvious an undercharged condition for excessive per- defects. If the case or covers are cracked or if the ods may result in plate sulfation and perma- battery has unusual odors or is otherwise damaged, nt damage. The cause of the undercharged the battery should be replaced. condition should be immediately -corrected in, The light-loadtest and the hydrometer test order to insure optimum battery life. (which was explained earlier in this unit) should be 3. periodically, clean the liatterytop, posts, performed on batteries having individual cell cov- cable clamps, carrier, and hold-down device ers.The light-loadtestissimple, quick, and with a diluted, ammonia or soda solution to accurate; it should be applied to batteries before remove corroiion and other foreign material. they are charged. Otherwise, defective cells m4r After cleaning, flush with clean water_ and pass the test and . cause a false diagnosis. An apply a thin coating of petroleum jelly to the expanded scale voltmeter (one that has .01 volt per- cable clamps and posts to retard corrosion. scale division) is needed for this test. Tighten the hold-down device so that the To check the electrical condition of battery cells battery will not shake in the carrier, but avoid using the light-load test, fffst check the electrolyt over-tightening to avoid- possible damage to level i41 each cell. If necessary, raise it to the the battery case. propeN level by adding pure water. Then, if the battery is . Refer to the safety instructions previously listed in the vehicle, place a load 4:1,the battery by in this unit. holding the starter switch on fer three, seconds or Scientific Principle Involved: until the engine starts. If the engine starts, turn off Corrosion and Oxidation the ignition immediately. If the battery is out of the vehicle, place a 150-ampere load on it for three The term corrosion may be.used to denote the seconds. Next, turn on the headlights (low beam); chemical change which takes place when a metal or, if the battery is out of the vehicle, place a combines with oxygen. (Examples include the 10-ampere load on the batte formation of an oxide scale on steel heated in air fter one minute, with lightsstill on or the 1 mpere load still and of hydrous oxide rust on iron exposed to connected, read the voltage ofach battery cell water or damp air.) Chemical change also occurs with a voltmeter, noting the ext voltages. It is when metal comes into contact with an acid. The necessary to remember only the highest and lowest heat given off by an internal-combustion engine, cell voltages. moisture in the air, and the spilling or spraying of The condition of the battery can be determined" an electrolytecause the corrosion of battery bynotingthe differencein terminals, cable clamps, and holders. voltage readings between the individual cells as follows;-:= Application of Principle I. If any cell reads 1.95 volts or more dnd there Skills can be applied and knowledge extended is vt difference of .05 volt (axe' divisions) or through the installation and servicing of storage more between the highest anctlowest cell, the- batteries.Servicing can be made of batteries battery is defective, damaged, or worn out installed in automobiles or recently removed from and should be repliced. them. 2. If any cell reads 1.95 volts or more and the Selected References difference between the highest and lowest cell isless than .05volt(five .divisions),the, Note: The numbers in parentheses in this section refer to entries in the list of selected references that appear within battery is good and sufficiently charged. this publication immediately after the text. 3. II cells read both above and below 1.95 volts (4), pp. 110-11; (22), pp. 359-63; (69), Chapter 19, and the difference between the highest and pp. 13-14; (71), p. 28; (75), Chapter 36, pp. 19-24, lowest cell is less than .05 volt (five divisions), (78), pp. 247-57. the battery is good but requires charging.

5 9 51

If all cells read less than 1.95 volts, thebattery was explained earlierin this unit) may be used on batteries. In the specific-gravity cell-comparison state of chargeis too low to test accurately. regardless of Boost-charge and repeat the light-load test.Boost- test, the specific gravity of each cell, state of charge, is measured.*interpreted. If charge all 12-volt batteries rated at 100 ampere- between hours or less at 50 amperes for 20 minutes(1,000 specific gravity readings show a difference the highest and lowest cell of .050 (50points) or ampere-minutes). tharge all other batteries,both defective and must be 6-and 12-volt, at 60 amperes for 30 minutes(1,800 more,the batteryis ampere-minutes). If none of the cells comes up at replaced. 1.95 volts after the first boost charge, thebattery The "421" test is a specific, programmed test' Batteries which do procedure consisting of a series of timed discharge should be given a second boost. condition not come up after a second boostch4re-should be and charge cycles that will determine the the of the battery with a high degree of accuracyin a replaced. If the charger being used will not give The "421" testers, ratespecified, charge for an equal number of very short period of time. ampere-minutes at the next lower rate available. which are manufactured by a number of different For purposes of the light-load test, do notboost a suppliers, automatically subject the battery to the battery more than the amount indicated.If the programmed "421" test. The "421" testeg; when battery is found to be good afterboosting, it used in the procedure as outlined in the chartthat should befully recharge& by the slow-charge follows,- will in two or three minutes accurately method before being placed in service. determine the Condition of any 12-volt unit regard- of. The"421"test,thespecific-mvitycell-, less of size, in 'or ,obViof the Vehicte, M any state comparison test, and the hydrometer test(which 'charge, and at a0-temperatufe.

. ., .ACTION EXAMINATION OR TEST WHAT-TO LOOK POR - . 5 ...:".. Cracked cases and covers REPLACE BATTERIES ' ... 1. VISUAL INSPECTION % . .- - . b.Electrolyte level betew top Lowelectrolyte level may cause permfent dam- NOTE:t1 novisual detects are fatltOprO7 ''. age to batteries. Fill with water to per level. - -, Otplates. .--e ceed to Test 2:- . ' anckproceed with carefUl testing of battery, to - ir ,7, s ..0-- determine if diiMage has occurred. i:-. . , ,. .. . t ° LoW electrolyte level indicates that the.batkr ,. . has leen negtected flit an extended petted'.of' r ,.. . `! and/or the 'battery is being 'subjected to .-: ,.7. time , -,..,.:.., overcharge-inWhich,case The charging ststem . 4. should be ghecked for coc(eAt voltage setUng, . ' ," .1, . - %.,-,°. ....,,, (/ - '' ' ` i, REPLACIVBATTERIE$lf terminals are loose . ? ). c.Otheribuse.4 ltiri,'-'- J.: pr bent:sailing compound, removed,cell Covers --° . 91 - S.. - . damaged by . I damaged, plates or separators , 8. f \ insertion of probes;,toolst etc"6-* c.--in'' ,-4- ' - V . 4 "4..1., Batteries designate air Bad by gEPLACF.MATTERIES.,. _, 2. '.'421."flit . . , tester. \ ' .1 4 NOTES4 e. ,...--..."' .. . Batterrei designated'as Gog4t.nd .4, TURN TO'SERVICE:== I A.Do,: not charge units prior etcr-raking.- . -i.Its ,cab1s and top should' be clean ,add . -' 7 r with no owner complaint ot- test. poo,r4terformanCe:Th ' atteries shId be. hut, least a-75%state-of- , indication'Of. .';t ' e . . charge. . .,, , Aeites ri are produced by asunV--1.,p, e ..,11, . berf different manufacturedfollow - ,_,... , -4--,.-, ... 'i . , .l, th directions for;tester'operation. ' :t Pro-ceed to Step ?-, . C.--Eie.,.cdrtaiivio gbtairi clean and tight ;.Batteries disignated as Good by grre performing this tester, but arg still questionable cohniiptions ..-; i tept because of okner coMplaint or .4 : , age ol2bafte . , --- " - r readingA mupt be made im- . D. A 1 ' . . pediately after Micator light -iornes . i :.'- - . , .t..., _..,_`-t , a. -$401454 or more variation,REPLACE BATTERIEk, .:-.,PECIFIC GRAVITY/HYDROMETER) ..betwarrihighest and lowests ,:;. 7 '1'TEST .. ' . .,' 4 . . - i,..)tells. NOTE: DITJP1QT arge battery prior. to . . making tit ' li. .-.., , ;. b.Less than .56-points variation. RETURN TO SERVICE hicihest and lowest Posts, cables and top th4Ig'be cleanand,' , ..., between (bait 75% state-M- the battery should be in at . . 1.' cone^ .. ' ' .` .407 charge.' . . .

e416t 6 0 A 52

Refer to the safety instructions previously listed the ampere-hour rating is 60 a.h., the charge rate in this unit. should be 4.2 amperes or, for all practical pur- poses, 4 amperes. If the an-were-hour rating of the Scientific Principle Involved: battery is unknown, the charge rate should be 5 EMF and Capacity Rating amperes for passenger-car type batteries and 9 The lead-acid storage battery for automobiles .amperes for heavier batteries. Charging periods of with 6-volt electric systems is three 2.2-volt cells 24 hours and more may be needed to bring the connected in series. The emf is approximately 6.6 battery to full charge. The battery is fully charged volts. Six cells are connected in series to make up when the cells are gassing freely and no change in the battery for 12-volt systems. specific gravity octurs over a- one-hour period. The quantity of chemical energy stored in a Sulfated batteries (that is, batteries which have battery depends on the magnitude (greatness) of stood in a discharged condition for long periods of the charging current and the time the current flows time without recharging) may require three or four to bring it to a fully charged state. The capacity of days ,of slow charging in order to bring the battery a battery is usually rated in ampere-hours. One to a fully charged condition. Batteries which are having a capacity rating of 90 ampere-hours could permanently sulfated can never be restored to a .supply a current of 1 ampere for 90 hours, 2 normal operating condition, regardless of the rate amperes for 45 hours, 3 amperes for 30 hours, and of charge or the length of time the charge is so on. applied. ApplicatiOn of Principle The fast-charge method supplies the battery with a high charging rate for a short period of time. The procedures provided in this section can be Charging rates of 40 to 70 amperes are common, used in testing storage batteries installed in vehicles with charge periods varying from I % to 3 hours, or recently removed from them. depending on battery type and size. The high Selected References charging rate may be continued for as long as there is no electrolyte loss and the electrolyte temper- Note: The numbers in parentheses in this sertion refer to entries in the list of selected references that appear within ature does not exceed 125 degrees F. Because of this publication immediately after the text. the short charging period and the high charging (22), p. 204; (26), pp. 298-99; (27), PP. 469-72; rate, the plates are not fully converted to lead (33), p. 26; (47), pp. 234-35; (65), p. 198; (86), peroxide (Pb02) and sponge lead (Pb). This defi- pp. 46-47. ciency means thata battery cannot befully recharged by the fast-charge method although it can be substantially "boosted" or recharged. For Battery Charging the comPlete recharging of the battery, the fast- There are two basic methods of rechArging charge procedure should be followed with a slow batteries. One is the slow-charge method and the charge for a few hours. When fast chargers are other is the fast-charge method. As the names used, the safeguards built into the charger by the imply, the methods differ in the length of time the manufacturer should never be ignored or circum- battery is charged and in the amount of charging vented as these safeguards Pare intended to protect current supplied. Before any battery is recharged, thebattery from damage. Itisimportant to the cells should be checked and water added ; remember that an explosive mixture of hydrogen necessary to bring the electrolyte to the proper and oxygen gases is formed when any battery is level. Periodically during the charging process, the being charged. As the mixture escapes through the temperature of the electrolyte should be measured; battery vents, normal air circulation usually carries and if the temperature exceeds 125 degrees F., the the explosive mixture away. But if circulation is charge rate must be reduced or temporarily halted poor or if the battery is being heavily charged, the to avoid damage to the battery. The electrolyte explosive mixture may acciimulate near the bat- temperature should never be allowed to exceed tery. Since a spark or flame can ignite the mixture 125 degrees F. and causean internal battery explosion, care The slow-charge method supplies tl)e battery should be taken to avoid sparks atm] flame near the with a relatively low charging rate for a liong period battery. of time. The charging rate shoulebe 7 percent of Refer to the safety instructions previously listed the ampere-hour rating of the battery. Example: If in this unit.

6 1 r 53

of electronsisreversed.All rechargeablecells Scientific Principle Involved: and Chemical Change depend on a reaction of this type. When a lead sulfuric acid battery is connected to a charger, the The sulfuricacidelectrolytecontains both reactions are reversed. When charging is complete, hydrogen ions (H-1-). and sulfate ions (SO4 ).The both plate§ are restored to their original compo- negative plate, which is sponge lead, reactswith the sition, and the elearolyte is restored to itsoriginal sulfate ions in the electrolyte to produce adeposit concentration of sulfuric acid (hydrogen andsul- of lead sulfate. During this 'reaction electrons are fate ions). This process is illustrated in aformula as circuit to released; they move through the external follows: provide electric power for the starter,lights, and other electrical equipment of theinternal-combus- Discharging tion engine unit. The lead peroxide of thepositive Pb02Pb2112 8042PbSO4 + 21120 plate reacts with the hydrogen and sulfate ionsof Charging the electrolyte to form water and, a depositof lead sulfate. Application of Principle When the external circuit is open, the movement of electrons is interrupted,, causing bothchemical Charge lead-acid storage batteries and make tests reactions to stop. If the circuit is closed for along under "Hydrometer Test" and "Battery period of time without the benefit of acharging T g" in this unit. current, the reactions will continue untilthe plate Selected References surfaces are covered with lead sulfate and mostof from Note: The numbers in parentheses in this section refer to the hydrogen and sulfate ions are removed entries in the list of selected references that appear within the electrolyte. The sponge lead of thenegative this publication immediately after the text. plate and the porous lead peroxide of thepositive plate provide greater internal surface, areasfor (4), pp. 105, 1 1 1 ; (7), pp. 3940; (9), pp.229-30; chemical change and collection of thelead-sulfate (22),pp. 362-63; (26),pp.172-73; (27),pp. deposit. 466-67; (33), pp. 24-25; (47), pp. 24042; (54), PP. Certain chemical reactions that produce a move- 332-33; (65),pp. 45-46; (75), Chapter 36, pp. ment of electrons can be reversedif the movement 21-23; (78), pp. 242-43; (86), pp. 4649.

GENERATION OF ELECTRICITY Unit 23 0

This unit deals with (1) magnetos; (2)direct- which is then stepped up to a highvoltage by (3) alternating- means of a separate coil.High-tension magnetos current generators and alternators; the current rectifiers; and (4) generatorregulation. produce voltage of sufficient value to jump spark-plug gap without the use of a separatecoil. Magnetos The difference between a magneto and a gener- ator is that while the generator has anelectromag- A magnetoisa device which generatesand distributes electricity for igniting the compressed netic field requiring an outside source ofelectricity fuel-air mixture in the combustionchamber of to excite it, the magneto uses permanentmagnets internal-combustion engines used to operate vehi- forthisfield.Magnetoignition systems have cles qd portable or stationary equipment(for certainadvantages over the battery-demanding example, lawn mowers, motorcycles, chain saws, . systems. The magneto systems are moreportable hotter portable lighting systems, and outboardmotor- and lighter, and they provide a spark that is boats). as the engine speed increases. The magneto generates the electricity,steps up There are two types of magnetos, the low- the .low voltage to a high-t9sionvoltage, and tension type and the high-tension type. Magnetos the are classified .further according tothe part of the distributes it to the cylinder (or cylinders) at has its correct instant. These operations aredone without magneto which is revolved. A magneto that the aid of a storage battery. Certain magnetos are 'windings on a rotor which is revolved in amagnetic low-tension types; they generate a lowvoltage, field is known as a shuttle-wound magneto. In the 62 Spark plug north pole and a south pole). The reason for this' phenomenon is that a magnetic force (or field) existOmtween the opposite poles of a magnet. This magnetic fieldis compospd of invisible lines of Armature force (magnetic flux). There are two types of magnets, permanent Coil magnets and temporary magnets (electromagnets). Pole piece The earliest type of permanent magnet was the *;r4.4kMagnet natural one* of ore and was used as a compass in navigation. It was called a lodestone (lead stone). ,7V zetaI 45.8% \Contact points Now, permanent magnets are manufactured. Two common shapes of manufactured magnets are the Plunger bar magnet, which has a pole. at each end, and the Capacitor horseshoe magnet, which is a' bar magnet that has Flywheek been bent into a U shape so that the pole,s are close together. Originally, manufactured magnets were made of high carbon steel. Now, high quality permanent magnets are manufactured from alloys The magneto of a small engine produces electricity of steel and tungsten, chromium, and cobalt; from when the flywheel is rotated by the pulling of a rope alloys of nickel and chromium; and from ceramics. wound ar,ound a pulley attached to the crankshaft These magnets not only are stronger bat retain (Briggs and Stratton Corp.). their magnetism for much longer periods. inductor-type magneto both thecoiland the The movement of electrons (flow of current) magnet are mounted in stationary positions; move- can be caused by revolving a coil of wire in a ment of the magnetic field is obtained by making and breaking the magnetic field. A newly devel- Spark Spark oped magneto, known as a revolving magnetic x/ _L _L design, has been made possible by new types of -zt ="' Ground magnets. The coil of the.magneto is mounted in a Ground Alagnet pole stationary position, and one or more magnets are Magnet pole revolved between the pole pieces of the magneto. A magneto, in a sense, consists of two simple Primary circuits; one is called a primary circuit and the winding otherasecondarycircuit.Both circuits have Secondary windings which surround the same iron core, and Ground ittwitrdw4 the magnets in the flywheel or rotor act on both winding circuits. Current can be induced in each circuit by Capacitor aftBreaker changing the magnetism in or around the coils. The points primary circuit, which has relatively few turns of Ground heavy wire, includes a set of breaker points and a \1414,Magnet capacitor. The secondary circuit, which has a coil 3 with many turns of lighter wire wound around the outside of the primary winding, includes a spark Ground ----Cutout switch plug. A permanent magnet is mounted in the The schematic diagram given above presents the flywheel or rotor; as the flywheel rotates, the components of a flywhdel-type magneto used in an magnet is brought into proximity with the coil and outboard motor (Evinrude Motors). core. magnetic field.In a conventional generator the Scientific Principle Involved: magnetic field ..isproduced by passing current Magnetism through the field coils, which in turn produce the Every magnet has a north pole and a south pole. magnetic field (electromagnets). In the case of the Like poles repel each other (two north poles or magneto, the magnetic field is produced by means two south, poles); unlike poles attract each other (a of pbrmanent magnets. Magneto ignition systems

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Lighting switch

Speedometer bulb

Headlight Bulb High-tension coil Magneto Taillight -144118*-0 Spark plug

4/ shown A flywheel magneto provides electrical currentneeded to operate th& engine and the electrical components in the motor-scooter wiring diagram (Lamretta:Innocenti Motor Division). have distinct advantages. They do notrequire any (13), pp. 482-90; (15), pp. 13-22; (19), pp. 28-33; storage battery or other source of current,and the (26), pp. 159-61, 306-9; (27), pp. 510-32;(9), intensityof thegeneratedvoltagedoes not Section VII, pp. 1-3; (32), pp. 15-18; (33), pp. decrease but increases -with the enginespeed. 55-58;(47), pp. 57-61, 188-89; (52), pp. 5, 9; (53), Magnetos are particularly popular forinternal- PP. 19, 85-86;(54), pp. 293-94; (57), pp. 193-204; combusion engines where a storage battery is not (62), pp. 6$-77; (65), pp. 20-29; (69),Chapter 3, needed for starting or lightink. The recentdevel- pp. 18-21; (75), Chapter35, pp. 23-29, Chapter opment of permanent magnets of greatlyincreased 36; p. 27; (79), p. 20; (81), pp. 25-27; (84), pp. strength has improved their performance. 46-47,; (85), Appendix; (86), pp. 12-19, 104. Application of Principle

1.Place a magnet under a sheet of glass or a Direct-Current Generators and Alternators piece of cardboard. Sprinkle iron filings on The automobile must have some sourceof direct the glass or cardboard and tap lightly.The current (DC) to operate the starter, ignition,lights, iron filings will show the form of the mag- and electrically operated accessories. A storage netic field. battery will furnish this electrical energyfor a 2. Locate permanent magnets u ed in the com- limited tim. A direct-current generator, which ponents ot small engines d, automobiles converts mechanical energy provided by theengine (magneto, radio speaker, andcompass)...: to electrical energy, has been usedfor a number of 3. Check thepermanen9 magnet in a speedom- years to keep the batterycharged. Dema.n- ds of the , eter. electricalsystem of modern automobiles have 4. Service or repair a magneto.. placed a heavy strain on the generator. For this reasonthedirect-currentgeneratorhasbeen Selected References replaced in many vehicles by the alternator (alter- Note: The numbers in parentheses in this sectionrefer to .nating-current generator), which has the advantage entries in the list of selected references that appearwithin when the this publication immediately after the text. of producing current at low speeds even

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engine idles or the car is moving through slow traffic. The alternator produces alternating current Negative brush Commutator (1) (AC) much like that available in home electrical circuits. A rectifier is used to convert this alter- Pole of field DC nating current to direct current. Manufacturers' electromagnet Positiveoutput directions should be followed when direct-current brush generators and-alternators are installed and tested. Scientific Principle Involved: Electromagnetic Induction An electric potential is produced when a coil of wireispassed through a magneticfield. This principle is used in the automobile generator to / produce current. When the armature (rotor) of al generator isturning, the coils pass through the magnetic flux of the fieldcoils, producing an alternating current in the coils of the armature. 0 - The current alternates because the armature coil DC input approaches the magnetic field from one direction and leaves in another. This movement causes the current to flow first in one ifirection and then in Brush another, thus producing alternating current. The Slip direct-current generator uses a commutator made rings (2) AC output of segments arranged on the armature so that they Brush contact the brushes at the proper times during the rotation. This contact causes the pulsating current A basic direct-current generator is identical to a basic toflow in only one direction in the external alternating-current generator except that one has a circuit. The alternator uses slip rings and collects commutator and the other has sliprings.If the the alternatinecurrent, which is then converted to commutator (1) is ieplaced by the slip rings (2), the direct current with a rectifier. Unlike the magneto, generator's output will become alternating current which uses permanent magnets, these generators instead of direct current. use field coils, which are electromagnets (temp- orary magnets). The electromagnets produce the

Field Armature Brush arm Field terminal terminal Pole coil Pulley and Brush Insulation shoe Insulated fan brush holder

Grounded brush holder

Commutator Armature

The illustrations presented above give an enCI view and a sectional view of a direct-current passenger-car generator (Delco-Remy Division, General Motors Corp.). 6 5 4' 57

Brush holders and Field 'terminals Battery Aluminum foil terminal brush assembly field winding Rotor poles Positive silicon rectifier diodes Slip rings

Cio Pulley

Fan 4, 3-phase stator- winding assembly Nega tive silicon rectifier diodes Nig The illustrations presented above give an end view and a sectional view of analternating-current generator (alternator) (Delco-Remy Division, General Motors Corp.). properly oriented magnetic field when direct cur-(10), pp. 7, 12-21,24; (13) 82, 490; (22), PP. rent is sent through the field coils as part of the 215-25, 377-83; (24), pp. 72-73; (26), PP. direct current produced by the generator is sup-173-79, 316; (27), pp. 5 (33), pp. 71-85 ; plied to these coils. (38), pp. 152-53; (47), pp. 189-213, 218-22; (51 ), PP. 5I I ; (54), pp. 321-26; (62), pp. 111-17; (65), Application of Principle pp. 200-201; (66), pp. 158-59; (69), Chapter 19, 1.The relationship of the field strength to the pp. 1 /-__4; (86),pp. 105-8. generator output can be shown by placing a variable resistor in the field circuit and regu- , lating the amount of direct current supplied Rotor to the field. Crankshaft 2. A generator can be designed, constructed, and operated by a group of students.

3. Generators can ,*be .checked, serviced, and repaired. 4. A 6- or 12-volt light bulb can be connected to each end of a generator field coil; when the coil is lowered into the field of an operating growler, the bulb will light up. The rotor-type alternating-current generator used in Selected References motorcycles is composed of a stator with coils which are wound around iron cores and a rotor madeof Note: The numbers in parentheses in this section refer to is attachedtothe entries in the list of selected references that appear within. permanentmagnetswhich this publication immediately after the text. crankshaft (Honda Motor Company, Ltd.).

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Alternating-Current Rectifiers Four selenium Alternating-current generators (alternators) pro- rectifiers Direct current duce alternating current that is used in the home, Alternator in industry, and in the electrical components of automobiles and other units driven by internal- combustion epgines. -However, direct current is required for (the operation of 'certain components Alternating of many electric/electrodic devices, such as the current electricalsystems of internal-combustion-engine units, the circuits of radio and television trans- mitters and receivers, and measuring instruments (meters). Therefore, the, alternating-current output of alteinating-current generators must at times be changed or rectified to direct current. This change A full-wave or bridge rectifieris used to rectify or rectificationis accomplished by the use of alternating current produced by alternators. In the s selenium, silicon, magnesium-copper sulphide, or diagram presented above, four selenium rectifiers are copper-oxide rectifiers or electron tubes, which interconnected to provide direct current during both furnish a one-way path for electric current or halves of 'the alternating-current cycle (Honda Motor movement of electrons. Company, Ltd.). The ilicon rectifier or silicon diode rectifier is one of the most recent types of rectifiers to be developed. Because of its small size, it is built into the frame of the automobile's alternator. Plate- type rectifiers .1re relatively large in size and are mounted externally. Single-phase alternating current would result in a pulsating current. To provide a much smoother flow of current, alternators are built with three stator circuits which, in effect, give overlapping pulses of alternating current. When these pulses are rectified through diodes, a comparitively-smootIV flow of direct current is obtained.

Scientific Principle Involved: (2) Rectification The process of changing alternating current to directurrent is called rectification. When a silicon diode rec-ffierisplacedinseries with a load (elec.:tn. al device) in a circuit and is supplied with an alternating current, the current islloWed to %. flow in only one direction. This type of rectifier, . whichiscalledahalf-wave rectifier,provides (3) 'sA pulsating direct current. For one half of each cycle Yiy of alternating current, the current flows through the rectifier and load. During the other half-cycle, Rectified current the current cannot flow through the rectifier, so In the diagram of a single-phase alternating current that no current floVis through the circuit. Capaci- (1); the positive half wave is represented by (a), the tors can be used to smooth out the pulsating negativehalfwaveby(b).Inthethree-phase current, however, full-wave or bridge rectifiers, alternating current (2), the phase outputs overlap but which use both halves of each cycle, or three-phase do not coincide. The three-phase alternating current alternators produce a smoother direct-current out-, depicted in (2) is shown as rectified direct current iW put. (3). .59

Application of Principle some alternating-current .generators.The cutout relay closes the circuit between the generator and I. Locate rectifiers in the generator circuitof battery when the generator is producing current; it by automobilesandotherunitsdriven opens thiscircuitsothatthebattery cannot internal-combustion engines. discharge through the generator when the gener- 2. Disassemble, clean, check, and, if necessau, ator slows or stops. Certain alternating-current repair generators used in the electrical system generators, because their design makes them self- of internal-combustion-engine units. limiting, have no cutout relays and no current 3. Mount a 1/2-horsepower, single-phase motor, a regulators. The rectifying diodes or transistors in 35-ampere alternator, a regulator, and a stor- thecircuit (transistor systems) prevent reverse age battery on a piece of plywood.Charge the current or discharge of the battery through the battery by driving the alternator with the generator. motor. 4. Use an ohmmeter to demonstrate how a CruetiaoyutCurrentVoltage silicon diode rectifier will have low resistance Battery regulator regulator in one direction and high resistance in the other. 5. Demonstrate magnetic fields by placing sev- eral coils around a cardboard tube and pulling a piece of iron through the tubeby turning bn --each coil in turn. c -f, Selected References Note: The numbers in parentheses in this sectionItvfer;.to entries in the list of selected references that appearwithin this publication immediately after the text.

(5),'Pp. 1-15; (13), pp: 489-90; (22), pp. 217-22, 381-83; (24), pp. 195-99; (26), pp. 174-75; (27), 645-48;. (33),pp. 81-83,177-80;438), PP. 152-56; (47), pp. 172-78, 409; (51), pp.21-23; Generator (53), pp. 23-25; (65): pp. 285-90; (69),Chapter A conventional three-unit regulator is used with a 19, pp. 25-29; (75), Chapter 31, pp. 1-22;(86), pp. generator. , 135-36. Scientific Principle Involved: Generator Regulation Electromagnetic Switch Both alternating-current and direct-cbrrentgen- The cutout relay, voltage regulator, and current erators require a regulator whichprevents the regulator areswitches operated by an electro- generator from producing excessivevoltage/cur- magnet. The cutout relay consists of twowindings rent. Without regulation, a generatorwould con- (coils) around a core and a flat steel armature, tinue to increase its output as speed increase,duntil mounted on a hinge above the core. A contact it would be producing so much currentthat it point on the armatgre, is positioned justabove a would overheat and burn up. If anunregulated stationary contact point that is coortected tothe - generator were connected to theelectric circuit of battery. When the generator is-not operating, a an automobile or toother units drive,n by an spring holds the two points apart, keeping openthe internal-combustion engine, thestorage battery circuit the generator and battery. When would be greatly overcharged and theelectrical the gene ator begins to operate, currentflows devices couldbe damaged. The direct-current through one winding, induces voltage in the offer generator uses an externalresistante to control winding, and creates a magnetic field around the voltage and amperage output. Variousdevices are core. Thecarmature is pulledby the electromagnet This used to regulate alternating-current generatorsby and the contact points cpme together (close). placing resistance in the generator fieldcircuit. action completes the circuit between the generator. Cutout relays (circuit breakers) are a partof the ,and the battery. When the generator stops,current regulation system of direct-current generators and begins to flow, from the battery to the generatot.

6 8 This 'yeversal of current flow creates -a reverse the armature springs up, the circuit between the magnetic fieldin one winding which bucks the battery and the generator opens. magnetic field in the other winding. The weakened magnetic field can no longer hold the armature Applicatio.n of Principle down and keep the contact points together: When I. Locate regulatas in the generator circuit of automobilesandotherunitsdrivenby Junction internal-combustion engines. Battery blcick Switch 2. Clean, check, and, if nectssary, repair regu- SAT IGN lators (cutout relays, voltage regulators, cur- rent regulators, and transistor systems). Selected Iteferelices Note: The numbers in parentheses in this section refer to - entries in the list of selected references that appear within this publication immedktely after the text. ( 4), pp. 124-27;45), pp. 1-15; (7), pp. 42-44 (13), pp. 486-87; (19), pp. 226-37; (22), pp. " ,5-32; (26), pp. 309-11; (27), pp. 519-24; (33), p. 60; (36),pp.85-96; (47),pp. 321-29; (65),pp. 198-202; (66), pp. 154-55; (69), Chapter 19, pp. 20-23; (75),Chapter 33, pp.1-23; (78),pp. The alternator empleivs a transistor regulator. 286-329.

Unit 24 TRANSMISSION OF ELECTRIC POWER Both the storage battery and the electric gener- them up at the other end. When the number of ator- (alternator) have positive and nevtive ter- electrons at one end of a wire exceeds the number minals. The positive terminal, which has a shortage at the other ehd, an electric field is set up between of electrons, ittracts electrons. The negative ter- the ends of thewire. Thisfieldcauses free minal, which has an excess of electrons, repels electrons in the wire to move from the negative electrons. When a circuit is completed between the end to the positive one. This movement of ,elec- terminals, electrons move through the circuit. They trons isthe Row of electric current; itisthe will move as long as there is a complete circuit and electromotive force (voltage) that creates the elec- as long as the electromotive force is maintained. tric pressure that causes the current to flow. The originalelectronsthatstart out displace electrons in the next atoms, and so on along the Application of Principle length of the circuit. The movement of electrons is I. Use a proper meter to check the electro- called an electric current,. motive force (voltage) Of a storage battery The.modern gutomobile has an alternator and a and a generator. storage battery to supply, the electrical system. 2. Use a proper meter to determine the positive Electrons move (or current. flows) through wires to and negative terminals of ; dry cell andf the ignition and lighting systems and through storage battery. cables tothe storage battery and the starting (cranking) motor. The internal current flow in the Note:- An ammeter must always be connected in electrolyte is a movement of positive and negative series with the circuit. To make a series connection ions in opposite directions. requires breaking the circuit to connect the meter. A voltmeter is always connected in parallel .or Scientific Principle Involved: across the circuit. The circuit does hot have to be Electromotive Force broken 4o- that voltage can be measured. Use A device such asiVtOrage battery or an-electric direct-Orrent meters to measure direct currents generator provides the electromotive force which and vottVes. Direct-current meters must always be removes electrons from one end of a wire and piles connected with the correct polarity. Use alternat- 6 9 1 6 (.5

61 ing-current meters to measure alternating currents Scientific Principle Involved: and voltages. Electron Theory An atom is composed of particle's of matter ' called protons, neutrons, and electrons. The pro- tons and neutrons form thenucleus, which is the Ammeter in series center of the atom. The electrons are arranged with the circuit Load outside the nucleus in an orderly manner. Each atom has an equal number of protons and elec- trons. The proton carries a positive (÷) electric charge, the neutron carries no electric charge, and the electron carries a negative () electric charge. A normal atom has no electric charge because the p(itive charge of the protoin the nucleus is Load canceled or neutralized by th egative charge of the electrons outside the nucleus. The protons in the nucleusa jnhot easily be moved; however, the electrons can be disturbed and even pulled away from the atom. When this occurs and electrons are taken away from a neutral Selected References atom, the atom has a positive charge and becomes Note: The numbers in parent&ses in this section refer to positive ion; that is, the atom hils more positively entries in the list of selected references that apfear within this publication immediately after the text. charged protons than negatively charged electrons. Conversely, if extraelectrons are added toa (13), pp. 490-91; (22), p. 201; (26), p. 296; (27), neutral atom, the atom has a negative charge and pp. 463, 560-61; (33), pp. 152-64; (47), pp. 22-23, becomes a negative ion. 34-35; (62), pp. 15-19; (66), pp. 150-52. Some atoms hold their electrons very tightly. Substances made up of atoms of this type are knownasinsulators;electrons do Rot move Conductors and Insulators through them easily. These substances A.O.usually A conductor is a material that readily allows a nonmetallic. Other atoms have electrons that are flow of electrical current (movement of electrons). held very loosely. Some of these electrons jump Metals are good conductors of electricity. Silver is rapidly from atom to atom as "free electrons." the best conductor; copper and aluminum follow, Substances made up of atoms of this type are in that order. For this reason wires, cables, straps, called conductors; electrons move through them and bars used in transmitting electric power are easily. The best conductors are metals, such as made of copper or aluminum, and silver is used in silver, copper, and aluminum. When electrons are the manufacture of many electronic parts. Solu- taken from atoms ina conductor, the atoms tions of salts,acids, and bases arefairly good become charged positively, and the electrons from conductors. nearby atoms are attracted to them, moving into An insulatorieamaterial that will not readily spaces left by the departed electrons. This action is conductelectricity(resisting the movement of repeated along the entire length of the conductor. electrons). Rubber, glass, porcelain, mica, anther, A positive chargeplaced on any part of the oils, and sulfur are good insulators. Rubber and conductor causes a movement of electrons from plastic serve as insulating shields around wires used atom to atom within the conductor. This move- to conduct electricity. Power lines are attached to ment of electrons is called an electrical current. insulators made of glass or lain. Pure water is , an insulator, but water fro cet is not because Application of Principle itusually contains small i. ,of dissolved 1.Check the amperage of circuits using an impurities. ammaer, a1.5-volt dry cell, and the typep The movement of electrons can be stopped by and lengths of wires that follow: an open circuit (a switch in the"off" position or a a. Five feet each of No. 22 copperaluminum, . break in a conductor) or shorted or groundedby a and nichrome wire, connected separately in conductor that is not a part of the intended circuit. circuits 7 0 62

b. Five feet of No. 18 copper wire, and then electrons). Resistance is the opposition offered by five feet of No. 28 copper wire the circuit to the flow of current (movement of c. One foot of No. 28 copper wire and then a electrons). Current is the movement of electrons. ten-foot piece.of No. 28 copper wire Ohm's lawstatestherelationship of voltage, 2. Attempt to operate the starting (cranking) current, andresistanceasfollows:Voltage = motor of an automobile by connecting a small current X resistance. gauR conductor, such as a length of No. 16 Ohm's lawplays an important roleinthe copper wire, .between storage battery and checking of automotive and other electric circuits. starter. When electric meters are used to measure, the 3. Inspecttheelectrical systems of a small voltage, current, and resistance in a circuit, Ohm's engine unit and an autdthobile. law is applied. Voltage is meakired in volts, current Selected References in%mperes (amps), and resistance in ohms. The symbols orlettersusedtorepresentiroltage, Note: The numbers in parentheses in this section refer to entries in the list of selected references that appear ,within current, and resistance are E foe voltage, I for this publication immediately after the teit. current, and R for resistance. The relationship 6 Voltage= currentX resistancecanalsobe (13), p. 491; (27), pp. 430-31; (33), pp. 16-17; expressed as E = I X R. When the voltage and (47), pp. 10, 25; (54), pp. 316-19; (62), pp. 59-67; resistance are known-, the amount of current is (63), pp. 162-67; (65), pp. 96-1Q1; (69), Chapter 2, found by using I = E R; when the voltage and pp. 5-7, Chapter 19, pp. 4-5; (75), Chapter 30, p. current are known, the resistance is found by using 2, Chapter 36, pp. 4-12; (81), pp. 17-18; (86), pp. R = E 'Some practical examples are given as 5, 53. follows: I. A headlight has a resistance of 4 ohnis. When Voltage, Current, and Resistance itis connected to a12-volt battery, how Voltage (E) or electromotive ford (emf) is much current will it draw? electrical pressure that will cause electrons to move (current to flow) in a closed circuit. The force is I = E R; I = 124; I = 3.amperes the repelling force caused by a surplus of electrons 2. A 12-volt battery delivers 100 amperes to a and the attracting force caused by a deficiency of starting motor. What is the total resistance of electrons. Electrical pressure or potential differ- the starting circuit? ence is measured in volts. It is the voltage which causes the flow of current in a cl sed circuit to R = E R 12 ÷ 100; R = .12 ohms provideheatandlightand op rateelectrical 3. A poorlyconnectedbatterycable has a equipment. resistance of 1 ohm. How much voltage will Current (I) is the rate of the elec ron movement. be required to push 300 amperes through this Current may be simply described as the rate of bad connection? movement of electrons in a circuitj. The basic unit E = I X R; E = 300 X 1; E = 300 volts of measurement for currerit is thie ampere. Elec- trons move from negative to positi e in a circuit. Resistance (R) is opposition to t e movement of Application of Principle electrons (flow of current) and \is measured in I.Voltmeters, ammeters, and ohmmeters can be ohms. All components in a circuit, including wires, used to measure electrical conditions in cir- have some resistance. Electric motors, appliances, cuits. An ohmmeter is used to measure the and other electrical devices have resistahce. Resist- resistancA of an open circuit. A voltmeter is ance is the property limiting the flow of current in used to Neasure the voltage drop between a closed circuit. two points in a closed circuit and the total circuit voltage. An ammeter is used to meas- Scientific Principle Involved: ure current flow in a closed circuit. Ohm's Law 2. Aff%per meter should be used to determine The movement of electronsinan electrical sources of resistance in the starting circuit of circuit occurs when voltage overcomes resistance, an automobile, including (a) corroded termi- causing current to flow. Voltage is the pressure nals; (b) broken insulation; and (c) frayed or that causes the flow of current (movement of broken wires.

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3. Determinetheresistancesof resistors by R1 R2 - reading the color codes and checking with an ohmmeter. Selected References . Note: .3T.he numbers in parentheses in this section refer to entries in the list of selected references that appear within this publication immediately after the text. (1 3),.pp. 490-91; (26), pp. 299-303; (27), p. 473; (33), pp. 36-38; (47), pp. 31-32; (58), pp. 15-59; (62), pp. 15-16; (65 ), pp. 70-95; (86), pp. 53-71.

Series and Parallel Circuits Electrons move (current flows) from a high- potential point (excess of electrons) to a low- potential point (deficiency of electrons). The path or -paths followed by theelectrons or current is called' the electric circuit. All circuits must contain a sôbrce of electromotiveforce to bring about the difference of potential that causes electrons to R1 move (current to flow). This source may be an electric cell, a mechanical generator, or another device that provides electric power. All paths of the circuit lead from the high-potential (negative) end of the electromotive source to its low-potential (positive) end. The electrons (or current) in a circuit follow paths provided by solid conductors, liquids, gases, vacuums, cr any combinations of these.Its path may include electric lights, heaters, motors, or any Electrons move from the negative side of the power other of the many devices requiring electricity. source(EMF) through the resistances and back to the The three general types of electric circuitsart positive side of the source. In the series circuit the (1) theseriescircuit, which provides asingle, electrons, move through resistors R1 and R2 (load); in continuous path for electrons to move (current to the parallel circuit, through R1 and R2; and in the series-parallel circuit, through R1 (in series) and then flow) from the negative side of the electromotive- through1R2 and R3 (in parallel). force sôui to the positive side; (2) the parallel circuit, whici provides two.or more parallel paths for electroniovement (current flow) from nega- Application of Principk tive to positiv; and (3) the series-parallel circuit, a I.Trace, check, and measure cir&its in elec- combination of the after two. trical systems and devices. 2. Hook up serieso,parallel, and series-parallel ScientificPrinciple Involved: Direct-Current Circuit circuits by using lengths of wire and light bulbs or other resistances to prove the rela- In a series circuit the current flow is the same in tionships between voltage, current, and resist- all parts of the circuit; the total resistance is equal ance in th'ese circuits. tothe sum of the individualresistances; and voltageis equal to the sum of the potential SelectedReferences differences across -each of the individual resist- Note: The numbers in parentheses in this section refer to the voltage is the same entries in the list of selected references that appear within ances. In a parallel circuit this publication immediately after the text across all resistances; the total currentis equal to the sum of the currents through its branches; and (13), pp. 493-94; (19), pp. 19-22; (26), p. 303; the total resistance is equal to the voltage across (27), pp. 454-91; (33), pp. 44-49; (47), pp. 40148; the resistances divided by the total current in the (62), pp. 21:46; (65), pP. 114-19; (66), pp. 15 2-53; circuit. (86), pp. 55-57.

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Unit 25 TRANSFORMERS

Transformers are most often used where elec- will be increased. Thus, thereicrofthe voltage trital voltage needs to be either increased or induced inthe, secondary coil or coils to the decreased. Power transformers used to increase or voltage applied to the primary coil is the same as decrease voltage are classified as step-up or step- the ratio of the number of turns of wire in the down transformers. A very common application of secondary coil to the number in the primary coil. a step-down transformer can be found in the model traintransformer or the doorbell transformer, where the120-volt alternating current used in Scientific Principle Involved: home electrical circuits is reduced from 8 to 24 Electromagnetic Induction volts. An example of a step-up transformer used to An electric current flowing in a wire produces a increase voltage is the transformer connected to a magnetic field around the wire; the greater the neon sign which will increase 120 volts to the movement of electrons, the greater is the strength several thousand volts necessary for the operation of the magnetic field. A coil of insulated wire of the sign. Many electronic devices, such as radios, carrying an electric current becomes an ,electro- stereos,tape recorders, and television sets, use magnet whose strengthis determined in direct power transformers to increase or decrease voltage proportion to the amount of current and the to the desired amounts. number of turns of wire in the coil. Using a Power transformers consist of two or more coils permeable steel core also greatly increases the of wire wound around a laminated metal core. The strength of the electromagnet because the core winding carrying the current from the source of itself becomes a strong temporary magnet. Revers- electrical power is called the primary winding. The ing the movement of electrons in the coil reverses other winding or windings which carry the induced the magnetic field of the coil. voltage are called secondary windings. A trans- Moving a magnet perpendicular to a wire pro- former may have one o'r more secondary coils duces the movement of electrons along the wire. which step up or step down the voltage. Moving a magnetic field through a coil of wire The two leads of the primary winding are induces an electromotive force in the coil. The connected to the source of power, which must be strength of the electromotive fin ce is in direct an alternatingcurrent or an interrupted direct proportion to the rate of change of the magnetic current. The current through the secondary coil or field and to the number of turns of the coil. coilsis known as the induced current, and its Reversing the magnetic field reverses the direction voltage is known as the induced voltage. If the of the induced voltage. number of turns of wire in the secondary coil In a power transformer the changing magnetic equals the number of turns in the primary coil, the field that is produced by the alternating current in induced-voltage Will be the .same as the voltage the primary induces an alternating electromotive applied to the primary coil. If the number of turns force of the same frequency in the secondary. in the secondary coil is less than the number in the Since the rate of change of magnetic flux is the primary coil, the voltage will be reduced; and if the same for both the primary and secondary windings, number of turns in the secondary coil is greater the voltage atio is the same as the ratio of turns of than the number in the primary coil, the voltage wire in t coils.

100 volts 200 volts 200 volts 20 volts AC input AC output AC input AC output 1 100 turns---- ',00 turns primary coil 14;-200 turns 2,000 turns econdary coil primary coil secondary coil

The step-up transformer (left) and the step-down transformer (right) show the direct relationship of the number of turns of the coils to the voltage. 40,

7 3 65

' - . . Li - In an laetion coil ntAutomobile, the Voltage . increased;j.and .the direction of LimpflOW 12 vofis) ot the stoilage battery is trans- 4s: (indicate 'dr deflectiod. oftfie/7.needle).- t'ornied hF stepped .up to the (high voltage requ'd chanses ,ilirection _Of the _16g/it As to dike the current j nip theparkIplug 'giip3Th qchange-. Itt ignition doil has a P friary 'c' cuit Made 'up-of A 1 pl1icillustratión QfThowan-1'6100f winning of a fAv 1l1ndIed tsQfje1ati.ve1y.he -devflop Ohlrett field can be ircuititiade up of a .bh -Aifed ±y coq ting_the"'tion.coil of an wire and, a secondary Nry .44 the high tension of manY tholisands of turns fine *ire. Wh - autontObile t distribator contact. points cse and rrentil$wf. lead tea:,a sparplug/. A stler15 appears at the in the primary circuit, amagnetiOie *Ws up., k4hig p.as the flow of electricityis When the dis1ribut.orontact errupted. automotfve ignition capacitor current stops flowing, the, magneticfield;collapseS. plaCed acrs* the sWitch,olianges:the spark as The collapsing magnetic field indupes highvOltcge it arcs the gap, :this thange 'demonstrates an in the secondary winding: This inductionireates increaSe iriNoltage. the high-voltage surge that isconducted ,thfough 3. The 1011owing °.'13jocednre can beused to the distributbr rotor and,cap to a sparkplug.. illustra-tec4 decreasein voltage: first, connect a The increase in voltage in thestep-up trans- doorbell transformer to the ordinary 120-volt former and the autornobile ignition coil is accom- house current; then connect a voltmeter panied by a corresponding decrease in current so across the output terminalsand observe the that the power output (volts X amperes) cannotbe voltage, which should be approximately 15 greater than the power input. Thesedevices are volts (depending on the specific transformer highly efficient (95 percent or better) sincelosses used). of energy are relatively small in the form of heat Selected References due to resistance of the windings, eddy currents, Note: The numbers in parentheses in this sectionrefer to and hysteresis in the laminated and highly perme- entries in the list of selected references that appearwithin able core. this publication immediately after the text. N. Application of Principle (4), pp. 82-85, 104; (12), p. 379; (13), pp. 1-93; I. Electromagnetic induction can bedemon- (15), pp. 13-22; (22), p.239; (25), p. 200; (26), pp. strated by connectirig a coil of wire to a 32429; (27), pp. 559-60; (33), pp. 91-98; (36), pp. galvanometer and moving a permanent mag- 56, 92, 102-3; (47), pp. 337-52;(53), pp. 85-88; net past or through the coil of wire. Induced (54), pp. 325-27; (65), pp. 135-49;(66), p. 53; (69), voltage increases as the speed of the magnet is Chapter 3, p.3.

Unit 26 SPARK PLUGS travels Spark plugs, which producehigh-voltage sparks electricity (the voltage boosted by the coil) found in down the center electode and jumps the gap tothe to ignite combustible fuel mixtures, are block devices such as furnaces, heating unitsof steam other electrode. Then it travels to the engine and back to the coil through "ground."The fuel cleaners,and internal-combustion engines. The spark plug consists of a steel shell inwhich is mixture is ignited when the electric sparkjumps is a the gap between the electrodes at the propertime fastened a porcelain insulator. (An insulator stroke. nonconductor, a material through which electricity near the end of the compression Spark plugs are classified according to aheat willnot pass.) An electrode runsthrough the center of this insulator andanother electrode range which indicates theirability to transfer heat shell to a from the firing tip of the insulator to thecooling extends out from the bottom of the steel transfer is position close to the center electrode.When the system of the engine. The rate of heat spark plug is used in the ignition systemof an controlled basically by the distance the heat must automobile, the shell is screwed into thecylinder travel to reach the cooling medium. A "cold"plug, head, and the *ire from thedistributor is con- which has a relatively short insulator nose, trans- nected to the top of the centerelectrode. The fers heat very rapidly into the engine'scooling

7 4 JP.

66

system. Such a plug is used in heavy-duty or 5. Clean the exterior of the plugs in sOlvent to continuous, high-speed operation to avoid over remove grease and dirt. Allow to dry. heating. A "hot" plug; which has a much longer 6. Cleanwiththesparkplugcleaning insulator nose, transfers heat more slowly away machine. from its firing end. Thus it runs hotter and burns 7. Open the spark-plug electrode gap and file off coMbustion deposits which might tend to foul the electrodes to obtain clgan, bright spark- theplug Iluring prolongedidle or low speed , ing surfaces. operation. Because the operating temperatures of 8. Reset the spark-plug gap to proper specifi- spark plugs vary in different engines and under cations,usingthe wfre-type gauge and different engine service conditions, the plugs are bending the side electrode only. made in several heat ranges. 9. Use a sparkplug cleaning and testing machine. Compare sparking efficiency with Scientific Principle Involved: a new plug. Ionization of Gases 10. Place the spark plugs (with new gaskets) Dry air at atmospheric or higher pressures is 'back in the engine, tightening them to the, such a poor conductor of electricity that it can for recomniended torque. practical purposes be considered an insulator for low voltages. The atoms that compose the mole- cules of any gas occasionally lose an electron and Terminal nut become positive ions. Thus, there are always a few Stud positive ions and free electrons present in the air. A higher percentage of theseelectrically charged Cement particles is normally present in heated gases, such as the compressed fuel-air mixture in the combus- tion chamber of a gasoline engine. The high voltage 'NO-- Insulator of the ignition coil produces strong electrical forces k on the electrically charged particles in the gap Center between the electrodes. Free electrons accelerating electrode rapidly toward the positive electrode collide with molecules of the gases, causing further ionization and a movement of electrons across the gap. Rapid interactions among the ions and molecules of the Seals gases result in the release of heat, light, and sound energy in a spark discharge similar, but on a smaller scale, to the discharge of lightning between a cloud A-Shell and the earth. This energy released in the gap of the spark plug is sufficient to ignite the fuel-air mixture in the combusion chamber. Inside Application of Principle gasket . Compare the test results obtained on a spark plug cleaning and testing machine, using a new and a used spark plug. Remove, test, clean, and reinstall spark plugs apording to the procedures that follow: I. Loosen the plugs for one or two turns with aspark-plug wrench or a deep-socket wrench. Ground 2. Blow the dirt out of spark-plug ports. electrode Spark gap 3. Remove the plugs the rest of the way, 4- _keeping them in their respective order. It isessential that the spark plugs be the right type 4. Analyze visually the condition of the spark for the engine in which they are used (Champion plug (normal, oil-fouled, too hot, too cold). Spark Plug Company, Toledo, Ohio). 7 5 67

p..40-, Selected References 386-88; (27), pp.44142; (47), p. 25; (56), Note: The numbers in parentheses in this sectionrefer to (66), pp. 60-61; (69), Chapter 3, pp.9-12; (75). entries in the list of selected references that appearwithin this publication immediately after the text. Chapter 35, pp. 15-23; (78), pp. 336-38; (81), pp. ( 2), pp. 1-35; (4), pp. 80-81;(22), pp. 237-38, 285-92.

Unit 27 IGNITION SYSTEMS The purpose of the ignition system is todevelop High-compression engines require a higher volt- and deliver high-voltage electricity sothat the age at high speedsfor efficieat ignition of the fuel. spark plugs in the engine cylinders can deliver a In the cori,Ventional system thepoints open and high-voltage spark to ignite the air and gasoline close quickly, and the primary coildoes not.have system time to build up to a very highvoltage. Other mixture at the proper time. The ignition life of consists of a battery, ignition switch,ignition coil, defects found in this system are the limited distributor, spark plugs, and wiring. the points and capacitor, along withthe main- The very high voltage needed to jumpthe gap of tenance necessary to keep these units inworking the spark plugs is obtainedfrom the ignition coil. condition. This coil is a step-up transformer that steps upthe The transistorizedignition system eliminates voltage to over 20,000 volts. The batterysupplies these defects and provides far moredependable the vojtage to the _primary circuit ofthe ignition service than could be obtained fromthe conven- coil. However, since pure direct currentcannot be tional system. The transistor, which iscapable of used to induce a voltage in thesetondary Of a handling large amounts of current, switchesthe transformer, it is necessary to start and stopthe primary circuit on and off so that thepoints carry battery current. only a very small current. Since thepoints carry. The starting and stopping or opening andclosing of the primary circuit of the ignition coilis done by the distributor, which is usuallydriven by the engine camshaft. The distributorhasa set of Secondary &intact points that are opened and closed by a Primary rotating cam wii,ich has the same numberof lobes as the engine has cylinders.The camshaft, which is Ignition driven by the engine, rotates at one half thespeed coil of the crankshaft. This opening and closingof the Distributor contact points by the cam startsand stops the of the ignition coil so Resistance current flow in the primary wire that voltage is induced into the secondarycoil. A lee' capacitor (condenser) is placed across thepoints to prevent the burning of the contactpoints and to Spark Solenoid reduce arcing. plu The distributor delivers the highvoltage pro" duced by the secondary of the ignition coil tothe Switch correct spark plug at the propertime. This delivery is accomplished by the rotor in the distributor.The rotor attached to the distributorshaft is connected directly to the output of the ignition coil.As the it moves from one rotor turns in the distributor, Battery contact point to the next inthe distributor cap. Starting motor Each of the contacts in the cap isconnected by a high-tension cable to a different sparkplug. Thus, The ignition cal in a typical ignition circuit isshown as the rotor turns,it distributes the high-voltage schematically, with the magnetic linesof force surges first to one sparkplug, then to another, and indicated(Delco-Remy Division,General Motors so on, according to theengine firing order. Corp.). 76 68

such a small portion of the total current, arcing gases in the fuel-air mixture in the combusion between them is eliminated and a capacitor is not chamber.Sufficientforceissuppliedtothe required. However, a special coil with a higher charged particles (ions) by the electric field to turns ratio and current rating must be used. produce enough energy in the spark discharge Some transistorized ignition systems do not use across the gap to ignite the mixture, producing a contact point in the primary circuit. Instead, a heat energy in the expanding gases as a result of magnetic pickup coil is used to time the transistor the chemical reaction in the burning fuel. , current flow for the primary circuit. A permanent The magnetic pickup coil used in some transis- magnet ringismounted onthetopof the torized ignition circuits operates on the principle distributor shaft. This magnet has the same number of electromagnetic induction, which producesan of teeth as there are cylinders in the engine. Inside electromotive force whenever the flux through the of the permanent magnet is a pickup coil that is coil changes. However, since this current is rela- wound around a steel core; which ilso has teeth. tively small, timed voltage pulses are used tovary Each time the teeth align, the magnetic lines of the bia n the transistor base to control the force from the permanent magnet cut through the amplitude othe current through the primary turns of wire in the pickup coil. This activity circuit. produces the same effect in the primary circuit as Ignition systems used on internal-combusion does the opening of the contact points. The engines may be'- categorized as (I) the hot-tubeor specialized transistorized circuit connected to the glow-plug types used on model airplane and diesel pickup coil acts as a current amplifier and switch engines;(2) the magneto type; (3) the transis- to turn the primary coil circuit off and on. torized ignition; (4) the capacitor-discharge type.;,j (5) the pulse pickup type; and (6) the conventional Scientific Principle Involved: automotive-type ignition system. There are many Electromagnetic Energy other applicationsforignition systems which employ the same basic principle; an example is the When the primary circuit of the ignition .coil is ignition- system used for automatically firedgas interrupted by the opening of the points in the furnaces, heaters, or steam cleaners. distributor, the magnetic field produced in the core of the ignition coil collapses rapidly. /The change in flux induces a high electromotive force in the Application of Principle secondary winding, whose voltage ratio, compared The students can do the following things: to the voltage of the primary, is the same as the ratio of the number of turns in the secondary 1. Measute the voltage in the primary cirucit winding to the number of turns in the primary. (approximately 6 to 12 volts in the automo- The capacitor (condenser) consists of two con- bile) and cotnpare it to the measured second- ducting plates separated by an electrical insulator, ary voltage (approximately 25 to 30 thousand usually two strips of metal foil separated by wax volts, as measured with an oscilloscope). paper wound into aroll.Itoperates on the -2. Measurethevoltageinas many ignition principle that an electrical charge placed on one systems as are available and compare their plate of the conductor induces an opposit charge primary and secondary voltages. in the other -plate, which is connect o I easure the amperage flowing in the primary These opposite charges on the plat lirAi arid secondary circuits of the conventional, other so that additional charge I the charging plate. When the primary curren transistorized, and imagneto-ignition systems. the induction coilis interrupted, the collapsin Compare the amperage flowing in the primary magnetic field induces a current in the primary of each system and discuss the implications of winding as well as in the secondary. Rather than this comparison. arc across the points, the primary current charges emonstrate glow-plug ignition by connecting the capacitor. The capacitor then discharges back a model airplane glow plug _to a 6-volt battery through the primary coil when the points are again and observing the small coil of wire as it on th make, becomes red hot. Tile high voltage on the center electrode of the 5 Examine and repair various ignition systems spark plug produces a high rate of ionization of the and their individual componehts.

7 7 69

Selected References (16), pp. 249-53; (19), pp. 397-429,461-64;(22), (27), Note: The numbers in parentheses in this section refer to PP. 233-43;(26), pp. 112-13, 117, 163-65; entries in the list of selected references that appear within PP. 620-24;(33), pp. 268-79; (36), p. 110;(47), this publicatiop immediately after the text. PP. 353-54;(66),pp. 99-101,111; (81),pp. 1 (4), pp. 80-95; (12), 'pp'. 436-43; (15), Pp. 15-22; 243-3 Il.

U,nit 28 ELECTRIC MOTORS

An electric motorisa device thatcohlrerts are trouble-free and do not usethe commutators or electrical energy into mechanical energy. Because brushes found in direct-current motors. Induction of its ease of operation, efficiency nvenience, motors require a starting system in order to get and economy of operation, it is useexte them rotating. There are a number of different industry, in business, in the hom and in th systems used for this purpose. One ofthe most automobile. Electric motors range in sizeom very mon methods of starting aninduction motor is small motors used to run electricclocks' to very through the use of two sets of stationary windings. large motors used to operate industrial conveyor- One winding is called the running winding and the belt systems. \ other the starting winding4he starting winding is Electric motors have a variety of characteristics, automatically disconnected from the circuit after each of which is selected to meet the requirements the motor is in motion. that it must fulfill. The automobile,has several The universal motor is used wherevariable different types of direct-current motors. One starts speeds are desired; it can be found in electric (cranks) the engine, another operates the blower of mixers and sewing machines. A rheostat is used to the heating/refrigeration system, and another raises controlthe speedof a universal motor. The synchronous motor is used where constant speed is and lowers the windows. clock, which uses a syn- The motor used' tostartthe enginein an desired. The electric automobile is a series-wound motor in which the chronotis motor, has a stator and a rotor with field coils are connected in series with the armature multiple poles. coils. Series-wound motors have the advantageof Scientific Principle Involved: ccleveloping a tremendous torque, which is essential Electromagnetic Induction when starting an automobile engine. Shunt-wohnd motors, which have the field coil connected in An electric current towing in a wire produces a parallel with the armature coil, are used where magnetic field around the wire. -If the wire is constant speed is desired, such as forblowers. placed atright angles to a magnetic field, the Anotherdirect-currentmotor is calleda interaction of the two magnetic fields produces a .compound-wound motor since it has one field coil force on the wire, tending to move the force across in series with the armature and another inparallel the magnetic field. The amount of theforce is with it. The Compound-wound motor combinesthe directly aroportional to the strength of current in starting torque of the series-wound motor withthe ° the wire,. the strength of the magnetic field in constant speed of the shunt-wound motor.A which it is placed, and the length of the wire.The rheostatis used to control the"-current flow iv directionof theforceisdetermined by the order to vary the speed of a direct-current motor. direction of the movement of the electrons in the The alternating7current motor isused exten- wire and the direction of the magnetic field in sively in the home and in industry, where alter- which the wire is placed. This interaction between nating currentisreadilyavailable. Alternating- magnetic fields is the underlying principle for the current motors are usually classified asinduction, operation of all electric motors, where the attrac- fields of universal, and synchronous motors. tions and repulsions between the magnetic The induction motor is the most common type the armature (rotor) windings anjd the field (stator) used to operate industrial equipment such asdrill producethe torque which tuyfis the motor. The presses, lathes, and grinders. Householdequipment, torque of the motor depentWOn the strengthof the such as washing machines, dryers,refrigerators, and current, the number windings in the armature, disposals also uses induction motors. These motors the number of tus in each winding, and the

7 8 70 strength of current and number of turns iii the the direction of rotation by reversing the current in fieldcoils.All direct-current motors utilizea ither the armature or in the field windings, but commutator and brushes to change the direction of not in both. The series-wound direct-current motor current flow in the armature coils at just .the right can be operated on alternating current because, instant during the cycle in order to maintain the both the armature and the field windings change rotation. Directyrrent motors may be reversed in polarity simultaneously in step with the alterna- tions in the current. The induction motor operates on alternating . current only because the motor depends on the alternating magnetic field produced by the current Field in the stator to induce an alternating current in the rotor conductors. The current induced in the rotor isoppositeindirectionto the stator ,current; therefore, their fields are in direct opposition to each other. However, since a torque is necessary to produce rotation, the starting coil must have a current which is out of phase with the stator current. Thi§ change of phase of the stator coil is accomplished by either a capacitor, or an induction DC input coil, which causes the current to either lead or lag - the impressed toltage. When the rotor approaches near-synchronousspeed,thestatorcurrentis . interrupted, and the alternations in the main stator coil which are out of phase with the induced Field current in the rotor will continue to supply torque to maintain the rotor at near-synchronous speed. The synchronous motor is a constant-speed motor because its speed of rotation is determined by the frequency (cycles per second) of the alternating- current power suppliedto the stator and the number of poles on the rotor, in accordance with the formula rpm = f X 120 p, where f = frequency of alternating current incycles per DC input second and p = number of poles. Variable speeds are obtained in direct-current a n d universalalternating-current/direct-current motors by controlling the amount of current with a rheostat. Field Since the electric motor is similar in construc- tion to the electric generator, the rotating motor produces acurrent which opposes that being supplied to the motor. This opposition accounts for the fact that more current is required for starting an electric motor than for operating it at its designed speed.

Application of Pirinciple I.Laboratoryactivitiesinvolvingallof the DC input various types of electric motors would be The diagrams show the wiring of (1) a direct-current virtually impossible. However, a list could be series-wound motor; (2) a direct-current shunt-wound made identifying electrical motors by their motor; and (3) a direct-current compound-wound type and utilization, such as AC, DC, induc- motor. 7 9 tion, synchronous, series, shunt, and others; 7 1

necessity for variable speed andthe precise and the advantages and disadvantagesof each be applied means of accomplishingsuch speed. The could be discussed. Skills could various components, such asthe brushes, and the understanding oftechnical informa- throuartisassembly, testing, commutators, andrheostats,which make tion extended possible the varying of the speed of anelectric and study of the various circuitsinvolved. which indicates the motor, can be physically examined. 2. A simple demonstration which must relationship between the amlunt of current 4. Opposed to an electric motor, is operate at an infinite numberof revolutions required and the load applied to the motor synchronous motor must toa battery an per minute, the obtained by connecting maintain continuous revolutions perminute. internal-combustion-enginestartermotor engine, and The rpm of the Synchronous motoris con- which litas been removed from the alternating measuring the amperage requiredby the trolled by the frequency of the current and the number of polesin the motor. free-running starter motor. Next, the ammeter which is connected toa starter motorwhich is An example of a synchronous motor installed on an engine,' the engine isstarted, should be examined is an electric clock. and the amperage required to turnthe starting Selected References motor now that the loadof the engine has isnoted. The two amperage Note: The numbers in parentheses inthis section refer to been added within readings are compared and theirimplications . entries in the list of selected references that appear this publication immediately after the text. are discussed. involves varying 3. Another common application (22), pp. 205-14, electricmotors,Sewing (4), pp. 120-23; (13), pp. 497-98; thespeedof 183-84; (27), machines, as well as automobile-heaterand 366-68; (24), pp. 193-94; (26), pp. (33), pp. 136-51; (47), pp. 356-403; air-conditioningblower-motors,utilize pp. 549-55; speed. The (54), pp. 397-99; (65), pp.186-92; (69), Chapter motor which requires a varying 34, pp. 3-15; (86), pp. circbits of such motors could beanalyzed and 19, pp. 31-32; (75), Chapter discussed, such points beingdiscussed as the J08-12.

Unit 29 FUEL CELLS .1 a fiat, new action n the cell is the productionof water, wliich Scientists are Working constantly to the proper electro- electricalpower. One muste removed to maintain methods for generating bncentration. The voltage output is approxi- method thdt has great promise isthe fuel.cell. This lyte develop electrical power matyly 1 volt per fuelell, Because of the high cost cell has been used to 11, its use is limited at the inside spacecraft -that have carriedastronauts into of producing a fuel esent time. outer spaese aft the smallest active element Fuel cells produce a continuousflow of electric- In Gemini space These cells create of the fuel-cell battery is the thinindividual fuel ity by meaxis of chemical action. inches wide. Each electric energy with greaterefficient}, than do cell, which is 8 inches long and 7 A fuel cell can cell consists of anelectrolyte-electrode assembly most other electrical generators. distribution, produce electricity as long asit is fed fuel 'along with assOciated components for gas batteries work on a current collection, heat removal,and water can- with oxygen or air. Dry-cell for the Gemini, 32 similar principle but cannot befed continuously trol. In the fuel-cell battery cells are series-connected to form amodule. Termi- with fuel. of the two outside The fuel cell consists ofelectrodes; an electro- nal plates installed on the ends and an oxidizing cells in the -module serve aselectrical connectors lyte; a fuel, such as hydrogen gas; module has its own agent, such as oxygen. In thehydrogen-oxygen fuel for the external circuitry. Each electrodes, and the hydrogen and coolant manifold aswell as its own cell, catalytic nickel is used for modules containing electrolyte is potassium hydroxide.Oxygen is fed water-oxygen separator. Three hydrogen to the a total of 96 singlefuel cells are installed in a tothe positive electrode and cylindrical container to form a compactfuel-cell negative elec+rode. The resultof thj chemical 8 0 72

battery. The three modules are electrically inde- conductor, the porous nickel in the electrodes pendent and are connected in 'parallel through serves as a catalyst by breaking-down molecules of connections to the main electrical bus. The fuel- thehydrogen and oxygen gases into separate cell batteries may also be connected in parallel atoms, helping to speed up the chemical reactions voith the reentry batteries. Fuel cells are highly at the electrodes. Since thd electrodes do not enter efficient; they have an overall thermal efficiency of into the chemical reaction in this cell, they do not more than 50 percent. They arecapable of deteriorate as in the conventional electrochemical producing more electricity per pound 'of fuel than cell. all but nuclear devices. The fuel-cell batteriesare In Gemini spacecraft, ion-exchange membrane silent,, fumeless, and operable without moving fuelcells convert the energy of the chemical parts. reaction of hydrogen and oxygen directly into electricity. Unlike conventional batteries, fuel-cell Scientific'Principle Involved: batterieswillcontinueto operate as long as Electrochemical Effeet hydrogen and oxygen are fed from an external The fuel cell is an electrochemical cell in which source. The structure of the fuel cell contains an the energy of the chemical reaction between, anode and cathode, which are in contact witha oxygen and a gaseous fuel such as hydrogen, solid plastic electrola, (ion-exchange membrane) natural gas, ,or carbon monoxide is converted thatpermitsthe Mrchange of hydrogen ions directly into low-voltage, direct-current electrical between electrodes. In the presence of a metallic energy.htge hydrogen-oxygencell, hydrogen gas catalyst, hydrogen gives up electrons to the load passes through the porous nickel electrodes and (where they do useful work as an electric current) reacts with the hydroxide ions of the electrOlyte. while releasing hydrogen ions, which migrateacross This reaction forms water and gives up electrons'to the electrolyte to the cathode.. There the ions the electrode. When an external circuit iscom- combine with oxygen and electrons from the load pleted to the oxygen-fed .electrode, these electrons circuit to produce water, which is carried off by,4b. move to this electrode and enter into the chemical wicks to a collection point. Ribbed metal current- reaction, where the oxygen reacts with water to carriersarein confact with both sides of the form negatively charged hydroxide ions. These ions ele-ctrodes to conduct the produced electricity. The replace those which were used up at the hydrogen- fuel batteries and'the fuel and oxidant supplyare fed electrode. The net result of these reactions is located in the spacecraft-equipment section. Total the combination of hydrogen and oxygen to fprm consumptionisapproximately 0.9 pound per water in the cell and the movement of electrons kilowatt hour. Fuel and reactant flow is regulated 'from the hydrogen-fed cathode to the 'oxygen-fed to delivery pressure by a dual pressure regulator , anode.Inadditiontoacting as an electrical and relief valve. By-product water from the fuel- Output: .9 volt, Pressure regulator

Pressure regulator

(Oxygen Electrodes Electro The hydrogen-oxygen fuel cell uses catalytic nickel electrodes and an electrolyte of potassium hydroxide:

-% Hydrogen tank

Oxygen tank Separator pump Condenser Water vapor

81 73

ollowing book, which was writtenby cell battery provides a pressurereference for the for the Joseph W. Duffy: Power: PrimeMoller of Tech- reactant gases. . ne'ogy (First edition). Bloomington,Ill.: McKnight Application of Principle & McKnight Publishing Co., 1964. exotic Fuel cells are classified as one of the more Selec ted References power sources in use today.Most of the fuel cells experimentation Note: The numbers in parentheses this section refer to produced are used for scientific entries in the list o f selected references that appearwithin and military or specialized industrialapplications. this publication immediately after the text, One source of information concerninglaboratory activities relating to various typesof fuel cells is (26), pp. 331, 336-39; (27), pp.468-69; (36), pp. contained in the laboratory manual (pp.135-40) 82-85; (64), p. 81; (66), pp. 186-89.

Unit 30 PHOTOELECTRIC CELLS needed, the photoelectric cell turns the carlights Some modern automobiles haveautomatic head- switches. These on. The photoelectriccell,whichis mounted, light dimmers and automatic light the light. This devices are operated by aphotoelectric cell, which behind the windshield, is exposed to radiant energy into a flow of cell is connectekto,a transistoraMplifier circuit is used to convert relay. This relay is electric curren t. which operates a sensitive fhe first photoelectric cells used the photo- connected to a power relay that turnson,the car electric vacuum tube as thë, controldevice. The lighting syst&-... current for photoelectric tube can provide electric Scientific Principle Involved: operating devices that will turn onburglar alarms,_ Photoele tric Effect opendoor;-priek-up sound in the sound motion- picture projectors, and control avariety of devices. Photoelectric devices lepend on theabsorption ultraviolet) by Certainmaterials(suchaspotassium, sodium, of incident light (infrared through selenium, and cesium) will give offsmall quantities electronsinthe sensitive material to alter the of electrons when held inordinary light. When electric characteristics of thematerial. According light is focused on the material in the vacuumtube. to the quantum theoryof light, photons are the attract the electrons which are small bundles of energy or quantaassociatill with a positive anode will of the photon emitted. The current flow in thephototube, which light radiation. Since the energy by an amplifier. depends on . the frequency of thelight wave, is very small, is usually increased frequency) have The output of the amplifier canbe cortnectO to a photons of ultraviolet light (higher more energy than visibleand infrared light. When relay that will turn a circuit on oroff. material absorbs a photon of Most present-da3'i photoelectric cells usesolid- an electron"' in a voltage can be radiant energy, it may be released from itsbonds state materials in which _a.smaIl of motion will produced when light shines on thematerial. These within the material, and its energy depend on :low much energy itabsorbs from the solar cells, called photovoltaiccells, use two types of material which generate a voltageat a junction between the materi* when lightshines on the Selenium or cesium.strip surface. A good exanfijle of such adevice is the light meter used in photographic meterswhere the output of the cellis connected to a sensitive -4 galvanometer. The stronger thelight, the greater is the voltage produced by, thecell. The increase or decrease of thecellVoltageisdetermined by Photons reading the needle movement in thegalvanometer. The automatic headlight switchused in the, Galvanometer automobile tupis the car lights on oroff according . tothelightlevel. As evening approaches and\ Light falling on certain metals, such as selenium or daylight is reduced to the point wherelights are cesium, produces an electric current.

8 2 '

74

. photon and how much of that energy was used in P-typAlaterial allow'sthe more energetic, clectro'ns breaking the bonds. The magnitude of the photo- to move across the barrier info the N-type material, electriceffectisdetermined by the intensity where they are free to move and deliver electrical (number of photons) of radiation absorbed. power in the external cikuit. Inthe vacuym or gas-filledphototube, the Application of Principle sensitive. element (cathode) is coated with a metal, such as potassium or cesium, which emits electrons 1. Demonstrate the characteristics of photo- voltaiccells- by connecting acell(silicon, from the stirface when subjected to incident light.. selenium, or the like)to a, mhliammeter. These photoelectrons areaccelerated toward a., positive anode in the same, way as in the =yen- Expose the cell to ordinary light and observe the action of theinilliammetei. (0-1). Vary the tional electron tube. . Photocells which use a single semiconducting intensity of thPlight and note the meter material, such as selenium or cadmium sulfide, readings also vary in direct proportion to the depend on the photoelectric effect to produce intensity of light striking the photovoltaic cell. . pairs of free electrons and positive holes within the 2. Use an ordinary lightmeter to measurei, di1the material. This increaseinthe number of free elettrons and positive holes results in the propor- availablelightWlientakingphoiographs. tional hicrease of conduCtance of the cell in the Record the readings as the meter is ex osed -,, to direq and indirect light in yarying d es. . battery-powered circuit. Also note the change in themeter rea mg as Photovoltaic cells, such as file solar cell, use two thecolorof thesubjector b ound different semiconducting materials in contact with changes. each other to form an N-Pairier. In the N-type material, such, as selenium- siliCon, conductiob is SededReferences ,..due to excess free electrons; in the P-type m'aterial, Note: The numbers in parentheses. in this section refer to

such as borpn-silicon, conduction is due to the< entries-in the list of selected references that appear within excess RositiveAholes. This separation Of electrical this publication immediately after the text. charges produces an electricalfieldacross the (9), pt 152; (13), pp. 576, 577; (16), PP. 307-8; barrier. When lightisabsorbed atthe barrier (26), pp. 339-42; (27, pp.333-34, 352, 458; (,?3),- region, new pairs of free electrons and positive pp. 27, 281-83; (3 ,p. 513; (47), Pp. 39, 253-57, holes.are produced by the phOtoelectric iffect. The . . . 405, 4519; (54), p431, 448; (65), PP. 6465; increase in thedonumber of free electrons in the p. 7. r

Unit31 SEMICONDUCTOk POWER RECTIFIERS ain electronic circuits itis desirable to Vacuum tubes cati be used as rectifiers, but in convert alternating current into direct current. many. devices they are 'being replaced by 'solid-state Such devices as radio receivers, television sets, semicOnductors.ThesesemicondUCtors,called stereos, and tape recorders ,all require a source of diodes, will permit current to flow through the directcurrent. To obtain the necessary direct conducting material quite easily in one directOn. current from an alternaVg-current power source', When the current is reversed,- the semiconductor each, of these Pieces of equifment uses a rectifier. offers, a great deal of reOstralice to the flow of

The rectifier changes the alternating current into current. Thus, the sernicohductOr diode, will permit .

direct current. current to flow in one directigIn only; and when. . Inthe modern automobilethealternating- connectedinan alternatingkurrent circuit,.. the current generator, called an alternator,also must output from the diode iS diret current. -havethe' alternating-current output -.rectifiedto Theearly.,seniicondUct powerrectifiers direct curient so that the storage .batter'y can be' copper oxide, copper sidfi e, and selepium were keptcharged.Withtheincreasedelectrical known as dry, rectifiers. 'At the present time demands inthepitomobile, the alternatoris germanium or silidon Ireeiwhg used for solid-state replacing the direct- ent generator because ofits rectifiers, which are usually hIiited in the, slip- efficiency and generat ng,capabilities at low speeds. ring end of the alternator. 8 3 75

.,,. . t'r <1 : sIl'a-ktitler inan chal-ge.Germaniunl, withthil..type of crystal When a single diode is used stryclure,'IsAalle14.*ype, or eleTtron-rich german- alternating-current circuit, the o tput,Atdt ng through the diode, will be pulses,,of,direct. nt. *um. N-type4er4tiium consists of germanium to Ohly thiritig half the !orhich are added ual numbers of free electrons Direct current will floW tharges so that the net charge is alternating;turrentcyclesinc e.. the diode will anit bound direction only. So that zero. permit Current flow in one those of a muchsitoOther direct current "can be obtained, it Atoms With three electrons,' such as full-wave aluminum and gallium, will act as acceptors.When is possible to 'design a circuit called a added to german- rectifierthatwillrectifyboth halves of the minute traces of aluminum are alternating: cycle. The output prOvides a much ium, each alumin xn,atom ts a single electron smoother flow of current sipce two pulsesof direct from a neighbo Akanium atom, leaving a hole current are.produced for each cytle Of alternating in the electron -A from which the electron ctirrent. Such a circuit; called a hridge-rectifier is acquired. T he equifalent of a positive trap into which an electron sv.kem, uses four diodeg.p charge since it re,.In the automobile it is very desirableto'have a can fall. As an electronfilKfhe hole, it leaves Which another electron fairly smooth direct cutient forchart: ses-. another hole behiml into thereftiee ...the can fall. In effect, thep,the hole (positive charge) -Three stator windhgs are,, y99 leaving alternatoraridajé connected in :.A detacheS itself and becomes free to move, connv. ,...... his behind the aluminum atom with aunit negative connec a"delta.7' structure is arrang ent enableS the generator td p 41 Ice a charge. Germanium with this crystal threeliasealternaling -Current which provides calledP-type,orhole-rich germanium. P-type overlapping cyclek..-4 ;alternating current.The germanium consists of germanium towhich is 'tput of the threirlitase 'Qurrent is connected to added an equal number of free positiveholes and :solid-state diodes _so th'at '.t_lie otaput from the botind negative charges so that the netcharge is Since zero. rectifiers is. a faiily eppstant.,threct- current. good con- diodes produce,' heat-b.wl:,leo` i*y aretOndutting Both P-type and N-type crystals are qevices called ductors, and each will+duct equally well in *talent, it is fiecesgary,'-fo use special joined Reat sinkS t& allgOrb this jeller_6. The,ididdes are either direction. When the two types are together, however, atfelectric barrier isestablished Oaced inside the siitteffiatoi,, and the heat sinks which the have largeradiating Surfaces to allowthe heat to be where their surfaces rrieet. The plane at . P-type crystal meets the N-typecrystal is called the ? radiatedinto the air, itirrOunding the generator. ' P-N junction. The free holes of theP crystal cannot s Scientille,frinciple Involved: pass through the electricbarrier at the P-N junction Rectificatieon With Semiconductors to reach the N crystal; thefree'electrons of the N reach the P 0 Silicomandgerri*ium are quite similar in their crystal cannot cross.the P-N junction to structure and oheniraf ;behavior. The atomsof crystal. A small potential difference impressed acrossthe :. bothelements' haVe fotir electrons bound in the .., the junction se wayin -theirrespectivecrystals.hiits pair enables the free electrons to cross transistor functions germanium is the more versa- P-N junction tile semiconductor. Germanium acquiresthe diode property of rectification and thetransistor pro- petty of amplification through the presenceof certain impurities inthe crystal structure. Two types of impurities are important;,oneis known as a donor, the other as anacceptor. .. Arsenic and antimony, are typical donorelem- ents. When minute traces ofantimony are added to germanium, each antimony ...atomdonates one *1'417, electron, to the crystal structure.Four,of the five Millianunete. electrons arepaired, but thefifth 'electronis S. relatively free to wander like the freeelectrons of a A small potential -difference impressed acrossthe metallic conductor. The detachedelectron leaves P-type and N-ty crystals enables the free electrons behind an antimony atom with aUnit positive to cross the junction and pass into the P-crystil. 76

. and pass into the P crystal. Similarly, the holes cAnnect the p*tive lead of the ohmmeterto cross into the N crystal. The apparent movement positiw:lead of the diode. Reverse the ,ef holes isin the opposillt sense to the actual connectiotis when checking a positive-case 1.:Atovement of eleclrons which fall iri.the holes of diode. AlthaUgh there may be a wide varia- the P-type crystal. Thus, an electron movement is tion in the ftref.istance of different diodes, the established across 'the P-N junction and in the ohmmeters;reading shouldbeconsistently external cirucit. above 3004'oliins. If"the reading is below 300 If the battery connections are reversed, the free ohms, the "diode has probably been shorted electrons in the N crystal and the free holes of the and should he replaced. P crystal are attracted away from the P-N junction. 2. Check an open circuit in a negatite-case diode The junction region is left without current carriers; by connecting the negative lead of the ohm- consequently, there is no conduction across the meter, to -the positive lead of the diode and junction ahd no current in the circuit. the positive lead to the negative case of the Itisthe junction which has the distinctive diode.Reverse the connections when check- property of permitting electron movement in one ing -a Positive-case diode. If an infmite resist- direction with ease when 6 small voltage is applied ance iindicated by the ohmmeter, the diode in the proper sense. Thus, the P-N junction is the has an oPen circuit' and should be replaced. rectifying element.of,semiconductor.crystals. Note: If the diode is good, there will beno ot . Jcurrent flow when the ohmmeter is connected Application of Principle as indicated previously. However, reversing A characteristic of solid-state rectifiers, such as tie connectionson the diode will cause a the diodes used in automobile alternators, is that current to 'pasS throalkkhe diode. they will allow current to flow in one direction only. This characteristic may be demonstrated, and, Selected References at the same time the diode may be checked for Note: The:numbers in parentheses in thiesaction,refer to opens and shorts, by using an ohmmeter. entries in the,list of selected .rgjerences that appear within this publication immediately after the text. I. Select a diode, either positive or negative case, from an alternator. If a negative-case diode is (22), p. 220; (26), pp. 348-49; (7), pp. 621-23 selected, connect the negative lead of the (33),pp. 269-70; (47): pp. 433-39; (65),pp. ohmmeter to the case .of the diode. Next, 268-70; (75), Chapter 31, pp. 7-8.

8 5 9

SECTION VI HYDRAULIC POWER

Unit 32 JACKS ANDPRESSES Through the use of hydraulics, the strength (muscle power) of a person can bemultiplied thousands of times. For example, itis possible through the use of hydraulic jacks for a person to lift a part or all of a house. Hydratilictools are used extensively in the automotive industry.When- ever a heavy force mustbe applied or a heavy weight lifted, a hydraulic tool has beendesigned to provide the means. A hydraulic jack or press consistsof large and small: cylinders connected at their base by asmall tubeor internal passage.. A piston fits into each cylinder. When a force is applied to thehandle at the small piston, a pressure isdeveloped in the released, the reservoir valve isepened to the small cylinder. The pressure developeddepends on liquid flow from the cylinder (21bick*in,to4. the l .... 04, A the area of the small piston and theforce applied. reservoir:, '. This pressure is carried through thehydraulic line The force is determined by the pres io the large cylinder. In this cylinderthe pressure is area of the pistons.Fat example, the 4 applied to the large piston, forcing it to move. has an area of 1squ e inch and is In the simplified diagram of aIlOraulic press, a directly to the larger piston,hich has ane lever is attached to the Smallpiston. As the' s4nall 100; squgre inches. If aArce .200 poundi piston is pushed down, some of the liquidfrom th'e applied to the small piff3n, a essure of4:00'- ..iii. small cylinder (1) is forced into ,the largecylin- pounds per squ e inch is develope his pr4stire' der (2). This pressure raises the large piston asmall is transmitted to rger cylinder, which,lkka amount. As the lever .is worked uriand down, it piston area of 100 square inches.his piston fs,SW I pumps the liquid from thereservoir and fotces it therefore, pushed with a farce,. 20,600 iouri4,, into the. cylinder (2). When the pressureis to be; (100 sq. in. X 200 lbs. per -in.) Thitgain,, ifi ; ,10 8

77

td" 78

forte (from 200 to 20,000 pounds) is made at the Pressure applied anywhere on a confined liquid' expense of distanee moved. If the small piston or gas is transmitted undiminished in eyery, direc- moved 5 inches, the large piston moved 5/100 Of tion. The force thus exerted by the confined liquid an inch. The output force coldd be doubled by of gas, acts at right angles tO every portion of the decreasing the size of the small piston and cylinder surface of the container and is equal' upon equal' tik 1/2square inch. Ho'iveVett_;;OepdistanCelnoved areas (Pascal'S principle). would be halved. The force of 200 poundgapPlied.tO the small Application -of _Principle cylinder is easy to obtain. Most jacks, presses, and T. The mechanical.asivantage of hydraulic jacka 'cranes have handles which are used tb apply the,7r-'' can be determMed by Meas !and cOmpar- - forceto the small cylinder. These handles are ing the distance the. small !brie pistons °. arranged as levers and multiply the applied force at. move. the _expense of distIonce. The 10-ton (20,000- .0,-04r- . pound) jack used as an example is relativelY small, 2. Different weights pan be placeeedit the jack to but 60- and 80- ton jacks are available. The output show that a resistanCe is, necessary:to piodw forceis very high; however, Movement is quite a mechanical advantage. A comparison of slow.because of the tremendous mechanical 'advan- force applied to the weight lifted can also be tage needed to multiply a 50- to 100-pound force calculatedbyoperatingthe jatie handle to an 80-ton force. through a spring scale. The efficiency of the jack can be shown by a comparison of, the Scientific Principle Involved: theoreticalmechanical advantaii andthe Pascal's Principle actual mechitical advantage. A hydraulic pump or set of cylinders does not ",pump" pressure. It merely produces a flow of 3. Hydraulic devices can be disassembled and hydraulic f19,id. Pressure is generated only when a assembled to assist in understanding the oper- restglction or load is placed in the circuit. If the ation of each part.: The ekact theoretical !,flow encounters negligible resistance, the devel- advantage of thehydraulic parts can be ppe& pressure is negligible. As the resistance force provided by the measurement of piston sizes. increases, the pressure within the system produced Selected References r by the puinp (or cylinders) increases to meet the resistance- force. The mechanical advantage pro- Note: The numbers in parenth ses in this section refer to . entries in the list of selected referinces that appear within duced by a set of hydraulic .cylinders is equal to this publication immediately afte, the text. , 1i'e-tAtio- of the surface area of the pistons. This natio- determines the ratio of distances moved by V>,pp. 3-6; '(27), pp. 200-202436), pp. -54-60; each ,cylinder, another measure of the mechanical (69),. Chapter 18, p.2; (75), 51,p. 4-5; .advantage. Pt. -(803, pp. 463-72,

,c- .* Unit 33 MACHINETOOLS

use hydraulic systems to In many applications hydraulic'systems are (nore 'cOntr of Machining operations. fefficient than mechanical linkage or a train of Hyds vide rapid, acturate, and ears.In addition, hydraulic systems are more efficZn ricate :machffia functions. exible in ternhpf load, speed, , and mechanical %.: yydrail d to s and machines, advantage. The basic system consists of an-electric (relies on iCan't com- motim driving a .hydraulic pump and Other rotating p.resSed.._ Ligui*und sit the pres- parts of the machine. The hydraulic pump operates sure throughoall Tarts oft, e id.4hts basic a hydraulic system consisting of control valves, wpro&rt 'allowsthe Use' of a liquid to transmit ylinders, and gaujes or sensing devices. Both otver. sourOe -to the., desiredpoint of Verticalandhorizontal motion 'oftables and cation means of: traniission lines (pipes ma6hine platforms-can be operated and controlled by the hydraulic-system.. ' 79 t'A

Shaper hend Operating cylinder La* -.Outing tool

Work hr

1 Trip dogs control stroke length \ \ \\ \\ o, Reversing lever

Speed Control Reversing valve

- Reservo*

Simple valving permits accurate control of ahydraulically actuated shaper.

Scientific Principle Involved: Pressure gauges can be placed in the, system to be Pressure Transmission by,Liquid determine the system's pressure. Cylinders can measured and the pressure converted to force to changes, 1) Liquids, when subjected to pressure determine the force being used to produce a transmit the pressure 'dhange to all partsof the particular motion. Machines can be adjusted as (PascarsLprinciple). This prin- fluid undiminished follows to demonstrate the hydraulicprinciples: ciple maY also. be statedas follows:Pressure ',..applied anywhere on a confined fluidis trans- 1. The speed of the machine can be changedby . nutted,undiminished in every direction. The force restricting liquid flow, thus exerted. by the confined fluid acts atright 2. An increase inpmure can be demonstrated anglesto' every portion of the surtice of the by increasing the 4ork load. container and is equal upon equal areas.Note that fluids may be eitherliquid's or gases; Pascal's Selected References of matter. principle applies to both of these states Nati: The numbers in parentheses In this sectionrefer tq gimes in the list of seledted references that appear within Application of Principle MO publication immediately after the text. Devices in which liquidi are used totransmit 4-58; pressure,suchashydraulicpresses,lifts,and (6), pp. 3=6; (27), pp. 200-202; (36), brakes, can be examined, tested,and operated. (69), Chapler 18, 15.2 ;:80), pp. 463-72.

Unit 34,'41dc44.11AKING SYSTEMS ship <9Devices for retarding or stopping,rnotion are electric curreica ;reversing)" the rotation of found in many pieces of equipment.Tir 1§.isic type propellers, reversing the pitch of *plane prd- tightened 4round or pellers, closing the clam-shell doors of jet engineS, of bilking operation is a band the face of a wheel. a pad pressed against awheel in inZitiort Big or pressing a disk moverrlarof In ,the:brakins syms,of vehicles that move on can be assisted by regulating the and fluids (liquids or gases), controlling 'theflow of wheels (sUch as aufornobiles, motorcycles,

8 oters), the friction between brake drums and A practical applicatiop. ot_force distribution brake shoes or'between pads and metal disks slow* through liquid pressure ifound in the four-wheel the rotation of the wheels; however, itis the hydraulic brake systemf the automobile. When friction between the tires and the road that results force is applied to thfoot pedal, a pressure is

in the stopping of the vehicles. , transmitted equally throughout the system to each The application of hydoulic force is almost wheel bythe employment of the mechanical universal in the brakMg syitems of modern auto-- advantage of levers. At the road wheel hydraulic mObiles. The modern hydraulic system is a combi- cylinders convert force through mechanical linkage nation of mechanical, linkage and force transmitted to the brake shoes or friction pads. Release of through liquids to the brake shoes or disks. Power pressure on the foot pedal reduces liquid pressure brakes use a pneumatic cylinder,operated by the in the systeny and spring tension returns to the engine vacuum to increase the ease and efficiency original position all components, such as pistons, of the braking force. The efficiency of the braking springs, and shoes. force continues to grow in importance as autoino; bile'speed increases and automobile safety receives Scientific Principle Involved: greater attention. Pascal's Principle Total force 0 the force acting against the entire area of a particular surfageL A liquid exerts a total Confiectirig tube force against the entire ar'a of the bottom and Cylinder sides of its container. Since liquid pressure equals v rzr force per unit area, total force equals the product 1) \I of the average pressure on the area times the entire Piston r area. . Friction pad The principle of the transmission of force by a liquid can be illustrated as follows: If a force of 50 pounds were appliedto a piston at 'a master ,,Brake disk cylinder whose area was 2 square inches, the 50 ) pounds of pressure would be distributed equally so that each square, inch would prodUce 25 pounds of force. ree applied at each wheel cylinder (1) MI disk brake is "n a released would be 2 ttRunds,if the cylinder hadip area of" Affake is in an applied position oneOquare ,Forcecanbe inciiised by hidraWm pressure (3) from the master enlarging the.d meter of the output cylinderor by increasing the p essure per square inch (psi).

7; e pedal Brake lining .4Y Brake shoe ri7/4 Brake drum IAAA Adjusting link !my '4 Brake line

Wheel cylinders Retracting springs

A schematic of .vrtlpical hydraift mtem shows how brake shoes are aCtivated to press brake lining against the brakaiums. .the 8 9 81

Application of Principle 4. Determine the compresSibility of air asaim.- pared to brake fluid by alloWing air to be Instruction relating to basic hydraulic principles admitted into the system. can be furthered thoroughactivities involving the -service and repair of automotive hydraulic brake Selected References systems. Some of the.activities students can per- form are as follows: Note: The numbers in parentheses in this section re r to entries in the lis0 of selected references that appear'hin 1. Measure the pressure developed in a brake this publication immediately after the text. system. (4), pp. 146-50; (90), pp. 108-11; (22), pp. 571,-80, 2. Calculate the force developed at each brake 587-94; (27), pp. 200-202; (36), pp. 54-60; (63), p. e. 658; (69), Chapter 18, pp. 1-10; (75), Chapter 41, 3. Service and repair automotive'brakes. pp. 1-14, Chapter 51, pp. 1-5,(78), pp. 504-18.

- e .

Unit 35 FUEL PUMPS The fuel pump is a simPle example of the fuel Pump contains a, flexible metal bellows that is -hydraulic pump usedinalmostallhydraulic operated by an electromagnet. applicAions. Power steering in the automobile is . Certain internal-combustion engines make use of anothWapplicatidn of the hydraulic pump. M?nY the fuel-injection system. Instead of a carburetor this system uses a series of injection nozzles and a machines, jac ,and automobile lifts use hydrauL... lies as their p ncipal. form of power. Production' high-pressure fuel pump to spray the fuel into the processes in in liar plants make extensive use of air entering the engine cylinders, .hydraulics. Scientific Principk Involved : The hydrauliC fuel pump is designed tb, supply Atmospheric Pressure gasolinetothecarburetorofaninternal- combustion engine at alonstant low presSure:' It is Eiquids will always flow to.palance a pressure a positiVe displacement pUmpusing a -d!aphragm differential. When the prealdie withip the fuel driven-by a spring to develop andkaintain ptessure pump chamberisreduced belOW atmospheric on the ,putlet side,Jpperationv the diaPhragm of pressure (14.7 ,pounds per sqUaLe inch)by the the fuel pump iS piilled,back on theintakestroke action of the' diaphragm', atm"spheric pressure 'by the action of Ihe enginc camshaft.As: the within the.gasOline tank=pushes thgasoline from laphragnz, MO* back on the intake stroke, a the tank itito the fuel ,pump chaber, 'balancing ial vacuurp is" produced in the fuel chamber. the -pressurewithinthe tank 41 fuel pump %, pheric Pressure acting on the fuel in the tahic., chamber at atmospheric pressure. v.tpushe it thiough the fuel lines, past the inletvalve,. - cr.:in'11-iefuel pump chamber. When the laphragin is,itleased, a springkkated behind the idiaphragii-i pushes the:diaphragni forward, placing a pressure:pi approxiinately -.6. pounds per square inch on thettfuejcin khe chamber. This pressure forces the "etakgainst the inlet valve, closing it. When the dA..*. tor needle valve opens, relieving the pressureri...,ilieji-12'61,Ii.etWeen thg,flieI pump and carburetor, ffie.,:iiiaPhragni...moves fatSivaid,-piishing Cam ,-_ Diaphragm fuel through 't ,e, -kinstier Olv'e.--and..4rit6r-c,the, carbii= 'and ...:diaphiairti,..,maintain an retOr. Thes ting Arni'' almostciipst nt -pressurecit(Tthej.'fuC: theieby .: providingWa continuous suppir-,0P fuelto .. the' .. Pivot

, carburetor.'- ,-.., ..c n pre nted above shows a typicalfuel An electricfuk,::pump is used on, some heavy- 4 the movem nt tof the diaphragm duty equipment, suCh as trucks andbuseS: This produces a partial vacuum.: ,.-. * . e t ° ., 9 0 ,.., ,...... ,,,-.1;,. 82

Application of Principle pump. Operatic .the fuel pump and compare I. Disassemble and assemble a fuel piimp, study- the obtained vacuum With the manufac- ing the operation of each component part. turer's specifications. Determine the operating characteristics of the c. Conduct the pressure test by attaching a total pump and the contribution of each part 'pressure gauge to the outlet side of the fuel to the operation of the pump. pump. Operate the fuel pump and compare 2. Testthefuel pumps inthree ways for -5the obtained pressure with the manufac- volume, vactibm-; and pressure fir as follows: turer's specifications. a. Conduct the volume test by disconnecting Selected References theoutletlineof thefuel pump and Note: The numbers in parentheses in this section refer to pumping gasolineintoa measured con- entries in the list of selected references that appear within tainer. Run the engine at idle speed on the this publication immediately after the text. fuelremaining inthecarburetor.In a specified time compare the output with the (4 pp. 61-64; (22), pp. 127-32; (27), pp. 200-202; ,,ernanufacturer4Vecifications. (54), pp. 222-24; (69), Chapter 6, pp. 1-10; (75), b. Conduct the Vacuum test by attaching a Chapter 26, pp. 1-4, Chapter 51, pp. 1-5; (78), pp. vacuum gauge to thf, inlet side of the fuel 180-81.

't Unit 36 POWER STEERING

I'feeringan automobile by moving the steering Pump inlet wheel manually has become more difficult because a return of increased weights and the use of wide, low- pressure tires. Ratios between the steering wheel Oil filter .and road wheels have bten increased to compen- satefor the greater force needed to turn the Return line automobile. A method of obtaining additional ?kir forceto turn the wheels isthe power-steering Valve spring filMinAii- chamber I assembly. Power steering isfr hydraulic systemp.. designed to assist the driveirin turning the wheels Control valve ATif tof the automobile. During the pasfjfears a number OutIA portk 4of systews have evolved. Each, however, consists of Inlet oil a hydraalic pump driven by the automobile engine. Pump Ting NO' V.& passage The hydraulicfluid,under pump pressure,ts Vane controlled by a series of valves which direc,t t e Rotor fluid to the proper chambers to assist the driver itv turning the automobile. The vane-type powNsteering pump provides addi- The hydraulic pump is the heart of any hydrau- tional force to aisisttin turning the whadls of an .1ic system. The pump develops 'no power of its automobile (Ford Mytor to.). own; it simply converts work applied to its drive shafts into the movement or a volume.of oi1 under largequantitiesof, water through the 'cooling -pressure. The volume is expressed in gallons per system. If the ystem is restricted, as it is when the minute (gpm) and the pressurein pounds per engine is cold and the thermostat is closed, the square inch (psi). The two types of hydraulic pump will simply rotate4without, movement or in usearethepositive- displacement of water.. pumps common Oto, zlisplacementpump , andthenonpositive- Allpower-steering systemsusea positive-. displacement pump. The nonpositive-displacement displacement pump. For each revolution of the pump uses the centrifugal force caused by rotation pump shaft, a specifiC quantity of flu% is dis- ,to move large quantities of fluid at low pressures. placed; i.e., pumped into the outlet line. Positive- The automotive-engine water pump isof this di,splacementpumpshavetheadvantageof design. When permitted to operate f,reely, it moves (1) capabilityforpumpinghighpressures; 6).?

.4

7". 9.1 83

volumetric (gpm), andrelief-valvesetting maximum (2) minimum size; (3) relatively high installation of an efficiency; (4) relatively small change inefficiency system pressure. By the throughout the pressure range; and (5) greatflex- engine tachometer, a decrease in enginespeed at ibility of performance. Most power-steering pumps will be noted when the pump is operating glOtoday's vehicles are based on a vanedesign or a maximum pressure. -.modification of this design. 2. Through the use of selected powersteering Some 'power-steeringsystemsuseasimple components or purchased hydraulic pumps, hydraulic cylinsler connected to the steeringlink- motors, and cylinders, a numberof devices age to assist the turning.In these systems fluid can be constructed as follow: under pressureis pumped to one side of the cylinder. The pressure of the fluid in thecylinder a. A drill-press vise canbe made to operate forces the piston to" move within thechamber. hydraulically by the use of a hy4Milic Since the piston is connected to the steeringlinkage, cylinder and pump. the movement of thepiston helps turnthe automo- b. A hydraulically operated cancrUsher can bile wheels. In some cases the pistonis stationary be built through the use of ahybiraulic and the cylinder ieconnected to thelinkage. In this cylinder and pump in addition to acham- case the movement of thecylinder -assists turning. ber to hold the can being crushed. Scientific Principle Involved: A pencil sharpener can be operatedhydrau-. Pressure Transmission by Liquids lically through the use of a hydraulic pump HOraulic fluids under pressure exert a force in Q.and a motor. every direction within aclosed container. The force resulting from the pressure is determined' Selected References the pressure and the surface area onwhich pressure is applied. whenthe pressure is applied to Note: Thernumbers in parentheses in thissection lefer to stationary piston and movable entries in the list of selectedregsictielithat:41p-ecir, viThth a movable piston (or this publication immediately aftertlieleit. 11- cylinder),theresultant forceisequalto the inch (psi) times the area Of the pressure per square . pp.19Q-91, pistOn, measured in the same units (squareinches). (6),pp.3-6, 21-24, 45-48; (22), 546-60;(27),pp. 200-202;(36),pp. 54-68; (63), p. Application Principle 37; (69), Chapter 17, pp. 2t-24; (75),Chapter 11, 4 pf:. 3-4, Chipter 39, pp. 10-14, Chapter 51, pp. 1. Power-steering sys s can be tested onthe automobileforcweratingpressure,flow 1-5 ; (78), pp. 464-7 Is,

)?. Unit 37 AIR CONDITIONERS air' conditio9iers are designed to refrigeration units and industrial air conditioners. Automolfile when a liquid make theinteriorclimateof the automobil4;, These systems use the principle.thar comfortable during summer driving.This comfort changes to a gas, heat energyis.required. The heat surround- is attained by removing both heatand water vapor for this change of state comes fmn..the li-frorp the air automatically. As the temperature of ing materials and air. The chanigetakes place ,at a the..aiLis lowered, the ability of the air to hold constant teinperatulb. 'TheteMiieiatUre, at which is;. however, water 'decreases. The air.reachesits coldest temper- this'change'iafstatetakes'rylace when it passes . dependent uppn the;4press,Ore .placed abovethe ature in the car and air conditimer IneteaSes, ithe temperature over the cooling coils(evaporffor). Water vapor in liquid. As the presstre deposited on the cooling at which the change of state occursincreases. the air condensq and is chemical coils. The water 'is collected atthe bottom of the Freon-12, an :odorless and nontoxic condenseclowater to the consisting of carbon, fluorine, andchlorine, is the coils, and a hose carries the as a refriger.antin ground dn4r the automobile. most common liquid used the same automobile air conditioners. At atmospheric pres- The automobile air conditioner uses boils at 21.7 degrees F. w principle ofoperation as that used by most ome ;csure Freon-12 (F-12), 84

below zero. At a pressure of 42 pounds per square outside tempefature,ishigher than noted, the inch, F-I2 boils at 45 degrees F., which is a more condensing pressure will increase to maintain a practical temperature for air conditioning. Each temperature of 20 to 30 degrees F. above the pound of F-12 which changes to a liquid removes outside temperature. 70 British thermal units of heat. The heat comes When the gas is condensed into a liquid, the from the surrounding air. Since heat is a form of liquid flows back to the evaporator inside the energy, the removal of this energy from the air automobile. Through the use of a valve or restric- lowers the tem erature of the air. tor, the pressure is reduced to around 45 pounds In this process the refrigerant is changed from a per square inch. The refrigerant can again evapo- liquid to a gas The gas is carried to a compressor, rate remove more heat from the interior of the where the pressure is raised to 150 to 160 pounds au mobile. The aik-conditioning cycle is contin- per square inch. The boiling temperature is, there- uo s; the refrigerant' is changing state in both the -fore, incrased to115 to 120 degrees F. This ev porator andcondenseratalltimes during temperatiife is above the normal air temperature. ope'lration. Since the refrigerant is just "a carrier of The high-pressure, high-temperature gas is pumped heat energy," itis never expended. It need be to a condenser next to the automobile radiator. At replaced only if the system develops a leak. normal summer temperatures of 85 to 100 degrees The heat pump, sometimes usedfor home F., air passes over the radiator, removing heat from heating, is a reversal of the air-conditioning.cycle. the condenser and gas. As heat is removed, the The evaporator is outside and takes heat from the refrigerant changes back \iiitoaliquid.If the outside air and discharges it througli a condenser Liquid/gas J11111111111111111111111111111111111111111111111111111

cmnmi Evaporator

1111111111111111111118.11111

munolummummmmuumn111111TIMIIITIF

\ Liquid Expansion valve

Gas

Compressor

Gas Liquid/g,as

0111011111111111HCondenser 1111111111110111 Receiver/ drier

1111111111111111111111111111111111111111111111111111111111111111111111111111

The state of the refrigerant at ceiain points in the air-conditioner unit is indicated in the 9 3 85 into. the home. In 'the summer the system canbe 'teaching system can be developed by obtain- reversed through the use of valves to coolthe ing a refrigeration or air-conditioning system home. 5 and providing it for student Use. Scientific Principle Involved: 2. Gauges' can be put on both the high andlow Heat Transfer sides of the unit to determine the operating pressures andtemperaturesatwhich the During the change of state,of a liquid, heat change of state is taking place in the evapo- energy is either absorbed orexplided at a constant temperature. This form of heat transferis called rator and condenser. "latent heat of vaporization." The amountof heat 3. Possible leaks can .be checked through the use being removed or _added depends uponthe sub- of a leak detectOr'or a solution of soap and stance. Water has a higher latent heatof vaporiza7 water orr'dll joints. tion than any other cominon sub.stancgjIt takes; compressor can be disassembledand assem- 970.4 Brit ish therjnalitin itof liev.`to.,00141e bled and the operation of the compressor pound of watseild,!One -poundPf ste'ain. Water studied. would make an exdgIrexit refrigerAt exceptthat in order to get water toboil at air-conditioning Seleoted References temperatures of 40 to 60 degrees F.,the wate-r must be)inder a v*Itium of more than20 inches of Note: The numbers in parentheses in this section refer to since a very entries in the list of selected references that appear within *tnercury. This pressure is inefficient this publication immediately aftercthe text. large compressor would be required tooperate- the system. (13), pp. 263-65; (22), pp. 602-4; (27), pp.279-80; Application of Principle (28), pp. 1-369; ( 36), pp. 68-74; (54), pp.555-58; I. An automobile air conditioner canbe used for (69), Chapter 20, pp. 1-12; (75), Chapter 48, pp. student demonstration and activities. Alsooa 1-9. .

9 4 .

(4e ,r. SECTIOI* VII PNEUMATIC POWER

ram j17

Unit 38 AIR-POWERED TOOLS

'Air-powered (pneumatically operated) tools aremakes use of the relationship between pressure'and particularly useful because they are relatively light volume. This second method is used to operate and small, run cool, and have vafiable speed and pistonand rotary-vane motors, the two most torque. A few of the operations that can .lie common types of motors used in air-powered performed by air-powered tools are drilling, sand- toojs. 114.gyse*ools use,reciOocating parts to accom- ing, grinding, chipping, tightening, (Yid hammering. plishwbfk. '-'Exarntlesof thesetools are the Other devices commonly found in industrial arts sheet-metal nibbler,and the impact wrench used to that depend on compressed air for their operation tighten or loosen lug nuts-on automobile wheels. are spray guns,Aliutomatic-feeds on'printing presses, lubrication equip4indnt, lifts, and- jacks. In order Scientific Principle Involved: that this flexible sOurct of power can beaulised, an Mechanical Properties of Gases adequate supply or compressed air, is needed and Two types of motors used-to pow4 air tools are hose connections should bd conveniently located in the rotary type and the percussion Cir_reeimpating the facility. type. In thefirsttype a rotor, wIth:rnes is, Air motors in air-powered tools require .a pres- surrounded by a hoUsing,. usually ,rharLA.-of cast sure of approximately 90 pounds per square inch aluminum. Air) enters the housing, push& on the for efficient. operation. A satisfactory source for vanes, and rotates a central shafti The drill chuck obtaining this air pressure is the compressor in the or grinding wheel is fastened to the end of the ,automotive or woodworking facility; the com- central shaft; In the second ./ype compreSsed -air pressor usually provides a prtssure of .150 pounds entersa cylinder and moves piston,. that is per square inch. An -air-powered tool is comprised connected , to or strikes .inother part- such As- a of an air motor, housing, valve with lever, 'gears, chisel or riveting hammer. The, pressure of com- spindle, and attachment to do the work. Motion in pressedair and gases is frequtly measured in air-powered tools is produced in several ways. One atmospheres. One atmosphere oressure is equal methcol makes.use of high-velocity air directed at a to 14.7. pounds per square inchfandard atmos- paddle or turbine wheel. The forced air causes the pheric pressure). When air is under a pressure of wheel to rptate like a waterwheel. Another method 4(several atmospheres; it can exert a great 'expansive 9

8 ,1* 87

A

Throttle 1.;;+e' . lever (1) Housing

I. Inlet 7 bushing Valve stem I Cali Air (1) I =regulator t c=s Valve plug

2-14-5,102_ Lower-end Upper-end Cylinder , plate plate sleeve Ho,sing Bearing ° Bearingg / . Rotor

Rotor blade

(2) Air . regulator , Valve seem / / . . Valve sleeve Es Trigger l 0,. \ CIii;i0 0Gliaj Qo Q4 o,lo Inlet bushing

Photographs and exploded views illustrate unitsand compoileifts of airpowered tools (screwdrivers, nutsetters, . and drills):° (1) lever handle and (2) pistol handle(Stanley Air Tools).

o..

9 6

88

a a. . , . force, -and this force can be transmi Reciprotating air or gas compressors operiateon, distance throughfong-walled,tutre the same principle as the bicycle pump but with design changes madeln the interest of ruggedness, efficiency, and durability.. . Application of Principle 1. Instructionrelatingto pneumatics can be extended and reinforced through the use of air-pctwered tools hi power mechanics and Ball-check . automotive mechanics activities. .- valve 2..An understanding of how the scientific princi-, ples relatidg to pneumatics'are applied can be Hose gained through the,disassembly and assembly f air motors or air-powered tools. Emphasis / sh .uld be placed on understanding,the func- epumpisthesimiilestpositive- tioof the entire unit and the operation of displacement compressor. The piston; secured to a eacpart in relation to the complete assem- handle_by a long rod, has a cup-shaped leather face bly. , opening downward, when the pump is in use. The ., downward motion of the piston causes sufficient Selected References initial pressure to open up thicQup and produce a Nate: Th nuers in parenth ses in ibis sectio, . refer to tight seal between the leather and the cylinder entries in ha lis1 of selected r ereneeselhat appear within wall. Air is forced through theball-check valve into this publication immediately aftç the text. the tire. . The upstroke Of the piston creates a partial '(3), PP- 1-47; (13), pp. 277-78; (25), pp. 20-49; va'cuum inside the cylinder, permitting atmospheric (31), pp. 1-16; (41), p. 1941; (42), p. 972; (49), air to flow past the cup leather and filling the Volume I, p. 143; (54). pp. 211 , 233-34; (63), pp, cylinder with air so that the cycle may be repeated. 16-46; (69), Chapter 18, p. 1; -474), Chapter 50, The flexible cup leather actually serves the func- p.I 9, Chapter 51, pp. 61. 1" tion of a check valve because it opens to admit air Note: Additional information on air-powered tools into -t e cylinder (on the upstroke) but prevents be obtained from (1) Stanley Air, Tpcils, 4525 thees air from the cylinder (on the F.stone Boulevard,' Souih Gate, California; or .downst oke as air pressure-forces the edges of the ) nley.Air ITools, 30520 Lakeland Boulevard; lea he tight inst the inside of the cylinder. Wil6w ,Ohio 44095. ;

; Unit39 - SPRAY GUN

Compre'ssed air is passed through a tube leading An orderly p ocedure for the use of a sprayrin to the nozzle of a spfay gun. The rapidly moving is given as follo - air in this tube passes over the open end of anbthei. 1. Inspect athe parts to be sure that they are tube which leads from a vented contaitter holding a clean. liquid. The pressure on the open end of the second 2. Reassembl the spray gun. tube is lowered by the rapid air flow in the first 3. Fill 'the paint cup with properly thinned tube. The air pressure on the surface of the liquid 'and strained paint. in the vented container forces the liquid to flow 4. Connect the spray gun to the regulator. intO the' air stream, where it is ,atornized beforea 5. Setthe regulator tothe recommended reaching the spray nozzle. pressure. A hand-held fly sprayer (with the hand pump tol 6. Test the spray-gun paint pattern on serap--- nply the air stream) can be uselio, demonstrate material" principlece operation. The tube supplying the 7. Adjust the paint-control valve and air pres- .1uid from the ventercontainer is easily seen just . sure as needed. - in front of the opening from the air..pump. 8. Hold the nozzle 6 to 12 inches from work. 4

9 7 4 89 bri

Spray thepaint with even, overlapping 4 3strokes. 10. Empty the spray gun of unused paint and thoroughly/ clean the gun and parts in paint thinner./ , /

,Scientific Principle Involved: Sernoulh's Principle Whfri afluid (gas or liquid) is undergoing a change in velocity, the pressure (measured at right angles to the direction of flow) is lowestAt the , point of highest velocity. A venturi (constriction) is built into the air tube leading to the nozzle of a spray, gun just before the top, of the tubefrom the stay Rot. The air must speed up toflow through the verituri,causing ,a very low pressure as reaches the top of the paint tube. The air pressure in thevented paint pot forces paint to flow up the paint 'tube into the air stream, where it is atomized. Another application of Bernoulli's principle found, in the carburetor of the internal-combusti When the trigger of the spray gun is pulled, com- engine. The air passage through a carburetor is pressetoir travels from the compressor, through.the partially constricted at the point where gasoline is hose and spray gun, and out the nozzle. The air mixed with air. This constriction increases the passing through the gun is atitsdkhest velocity at speed of air, lowers ifs pressure, and permits more the point where it meets the liquiom the tube of the container. The air pressure at the point Where the rapid evaporation of ihe gaso1ine. air and liquid meetis Jower than the air pressure in Application of Principle the corftainer. This difference iii pressure causes the 'liquid to rise in the tube and to enter into the air r The suj1ent will gain valuable experiences and ° stream. The liquidis atomized and then expelled skill in thact,t 'se of a spray gun. from the nozzleIDeViliiiss do.).,r s ) Selecte4 References , (9), p. 100; (13-h--pp. 516-17; (26), p. 151; (2 )), /owe:Theumbers in parentheses in this section refer to pp. 223-25; (49) Vplume 1,pP. 155-56, Vi1me entries in e list of selected references that appear within this p ation immediately after the text. 10, p. 580; (75), ChaVter 50, pp. 71-28. , 40010e

Unit40 = VACUUM,PrUMPS

Pneumatic power can be produced through the blades are moved by an air-powered motor which use of compressed air (asexplained in Unit 38, uses the pressure differential between -the atmos- "Air-Powered Tools") or4 a vacuum pump and pheric pressure and the engine's intake-manifold eased atmospheric pressur . vacuum is a positive form vacuum for operation. The vacuum i of power. The soce of this'Power is the weight of whenever thengine is rapidly accelerated oIput air, which is 14.7 pounds per square inch (psi). To under a heavy loaci. *hen these conditions oc .tise this power, a vacuum pumpmust reniove the the pressure differentialdisappearV and the a air from one end of a piston so that the air pressure powered motor no lo er has' a pressure differen an' act on the other end to force it to do- work. tial for operation. So tit a continuokUsidifferential Vacuum pumps are usedinthe operation of can be provided, a vacu m pump isplued between windshield wipers, power brakes, power clutches, the windshield-wiper *tor and the intake ,mani- I and door locks in the automobile. \ fold. The vacuum pumslaintains a sufficient Atmospheric pressure is used in the o eration 4-- vacuum (11 inches of mercury; tp,51/2 ROunds'. many , automotivewindshield wipers. he wiloer below atmospheric pressure) to opeiate the wiper 9 8 90

V motor:. Since this vaduum- is less than the normal from the wipqr motor to the, manifold. When the. intake-manifold vacuum, the wiper blades operate manifold vacuum drops,-ai. it does during open .somewhat more slowly during acceleration and throttle and full power operation, the ump acts as under other conditions requiring maximum engine a booster, maintaining a minimum vacuum for, power. The vacuum pump is an integral part of the windshield wiper operation. fuel pump and operates in an identical manner: Pneumatic systems may_ to1!.,, tiply a (See Unit 35; 'Tile! Pumps.") The air flows from force developed by a man s mac e. An the windshield-Wiper motor through the vacuum excellent example ,of a pneumatic power ooster is pump into the' engine intake 'manifold. When the the automobile power-brake system. As vehicle qngine vacuum is greater,than the vacuum devel- weight, power, and speed are increased, the effort oped by the vacuum, puMp, both the :inlet and needed to stop the automobile is also increased. outlet valves remain open, and the air flows rreely The variable factor used' to determine the rate of

Vacuum outlet q. Vacuum inlet pipe Vacuum diaphragm Diaphragm spring

Vacuum inlet valVe assembliei

Seal

VacuuM outlet Bushing ZR" valve assemblies Rocker arat

Vacuum litnk Fuel link

Fuel diaphragm spring I Rocker arm return spring Fuel diaphragm

411

Fuel inletake assembly Ou lift valve Inlet screen Pulsator diaphragm

A icombination fuel and vacuum pump shares a common housing and rocker arm (General Mhtors.Corp.). 7

9Or 91 decelerationis the pressure applied on the brake Atmospheric pedal. So that quicker braking can be done with pressure less movement of the pedal, a pneumatic booster Vacuuth has been addedtothe system.: This booster multiplies the braking foice applied' tg the brake Pedal. As a 'result, a small force applied to the braiepedalprovidesahighpressure on the Push rod hydraulic fluid in, the master cylinder' that rapidly Master cylinderBrake, brings the car to, a srop. The power-brake system line uses the pressure differential developed by the PistonVacuum intake manifold. The booster consists of a cham- Booster ber, valves, and a piston or diaphragm. Atmos- Brake pedalcylinder pheric pressureis admitted on one side of the The schematic of a power brake shows how the diaphragm by the movement of the brake pedal. control valve (1) can apply either engine vacuum or The intake manifold vacuum on the other side atmospheric pressure to section j(2)' of the booster produces a pressure differential on the diaphragm .cylinder. so that the diaphragm moves toward the vacuum. Since the diaphragm is connected directly. to the 3. Pump operation can be measured by attaching master 'cylinder, this motion operates-the brakes and stops the vehicle. Valves are used to control a vacuum gauge to the inlet side of the pump. isoperatedby hand, the the braking pressure and to balance the pressure on Asthe pump pressure will drop (the vacuum will increase) both sides of the diaphragm when the brakes are to a pressure which counterbalances a mer- released. cury.column ap'proximately II inches high. Scientific Principle I,nvolved.:-- 4. The force resu)ting from the .operation of a Atmospheric Pressure' power-brake twit can be dvtermined for a _The vacuum pump. uses the principle thM gas number of differentpress,. differentials. flows from high-to low pressure in an attempt to This determination will requirc lisassembly balance the pressure. Atmospheric pressure will (or the use of a cutaway.). CakuLtions may pass into the windshield-wiper air motor inits also include the mechanical advaciage of the effort to balance the vacuum. The air will then !baster -and wheel cylinders in order to deter- . e chamber.of.the vacuum pump since mine the available.stopping force. travel to t 5. A itiower-brake booster assembly can be dis- theactionof the diaphragm has reduced the .pressure bew .atmospheric pressure. When the a4embled and asseMbled to determine the 4iaptiragin,bm veos up on the exhaust stroke, the function and operation of 'each part as it pressure.is increased/thus, a flow of air is produced contributes to the operation of the power- from the chamber. 4 brake boosterassembly. AppliCa don of Principle' Selecjed References I. A Vacuilm pump. can .be disassembled and Note: The numbers in parentheses in thistedtion refertd -entries'in the list of selected references that appear wiMin assembled ,to determine the principle of oper- this poblication irmediately after the text. ,/ ation, the flow of air, through the pump, and the function of each parrof the pump. (4), pp. 62, 150; (9), p. 98; (13), p. 223; (-2 pp. .2. Pump operatioh cah be demonstrated by 131, 582-86; (26), p. 157; (27), pp. 214-17; 6), attacl- in inflated balloon. onOle intake PP. 56-57;(37), p. 24;924), p." 207; (69), Chapter side ,.. Jeflated baloori on the outlet side., 6, p.I0, Chapter. 18, p 17-24; (75), Chapter 26, When the pump is pperated, the air will move pp. 1-3, Chapter 41, pp. 15-19, Chapter 51 , pp. from one balloon to the other. 6-9; (78), pp. 519-24.

100 -SELECTED REFERENCES

Note: The entries in this section are nuebered for the purpose of reference. The numbers listed here correspond to the numbers in parentheses located within the text of this publication in iections entitled "Selected References."

1. Above and Beyond: The Encyclopedia of AviatioW 18. ConstructionSafetyOrders. (Article27: and Space Sciences. Chicago: New Horizons Pub- "Powder-Actuated Tools.") Sacramento:' Division lishers, 1968. of Industrial Safety, California State Department 2. Ae, Spark Plug Service Manual.Flint, Mich.: of Industrial Relations, 1965. General Motors Corp., 1966. 19. Crouse, William H.. Automotive Electrical Equip- 3. Air Tools .(Catalog No. 166). Willowick, Ohio: ment (Sixth edition). Manchester, Mo.: Webster Stanley Air Tools, 30520 Lakeland Blvd., 1966. Division, McGraw-Hill Book Company, 1966. 4. Allen, Willard A. Know Your Car (Second edi- Crouse, William a_4utomotive Engines. New tion). Chicago: Ameiican Technical Society, 1967. York: McGraw-Hill BooWompany, 1959. 5. AlternatorTraining Handbook(Course 21Crouse, William H. Autdmolive Fuel, Lubricating, 10,000.2 10,001.2). .Dearborn,Mich.:Ford and Cooling Systems. , Nework: McGraw-Hill Motor Co., n.d. . Book Company ,4955. 6. Altland, George. Practical Hydraulics. Troy, Mich.: 22. Crouse, William H. Automotive Mechanics (Fifth 'Vickers, Inc., P. 0. Box 302, n. d. edition).Manchester,Mo.:WebsterDivision, 7. Atteberry, Pat H. Power Mechanics. Homewood, McGraw-Hill Book Company, 1965. Ill.: Goodheart-Willcox Co., 1961. , 23. Curtis, Francis D., and George .Greisen Mallinson. 8. Baker, Philip S., and Others. Chemistry and You. Science in Daily Life. Boston: Ginn & Company, Chicago: Lyons and Carnahan, 1966. 1953. 9. Barnard; J. Darrell, Celia Stendler, Ben Spock, and 24. Davis, Ira C., J. Burnett, and E. W. Gross. Science, Lon Edward. Science: A Key to the Future. New Discovery, and Prowess. New Yoilc: Holt, Rine- York: Macmillan Co., 1963. hart & Winston, Int, 1961, 10: Basic Automotive Electricity. Dearborn, Mich:; 25. Davis, Ira C., and Others. Science 3, Discovery and Ford Motor Co., 1959. Progress. New York: Holt, Rinehart & Winston, 11.Benrey, Ronald M. "Build a Skit Car Dynamom- eter," Popular Science,189 (December, 1966), Inc., 1965. 8-100. 26. Duffy, Joseph W. Power: Nime Mover of Tech- 12. B anchard, Harold F., and Rallih Ritchen. Auto nology. Bloomington, Ill.: McKnight & McKnight Engines and Electrical Systems (Third edition). Pub. Co., 1964. New York: Motor Book Department, 25Q W. 55th 27. Duir, Charles E., and Others. Modern Physics. New St.; 1963. Yoric: Holt, Rinehart & Winston, Inc., 1964. 13. Brandwein, Paul F., and Others. You and Science. 28., Dwiggins, Bgjce H. Automotive Air Conditioning. New York: Harcourt, Brace & World, Inc.; 1960. "Albany, N. : Delmar Publishers, Inc., 1967. 14. Branley, Franglyn M., Milton 0. Pella, and John 29. Evinrudes-Outbrd Motor 4ervice Manual (Fifth Urban.Intv)o volumes. New York: Ginn & edition). Milwaue, Wis.: Service Division, Evin- Company, 1965. (Vol. I: World of Life; Vol. II: rude Mo rs, 1 The Physical World.) . 30. Facts. Ab park Pluct Engines. Toledo, Ohio: 15. Briggs ct Stratton Repair Instructions IL-Milwau- Champion Spark Plug Co, kee Wis.: Briggs & Stratton Corp., n. d. , 31.,The Fundamentals of Copressed Air. Power. 16. Brinckerhoff Richard, and Others. The Physical Cleveland, Ohio: CompresieAir and Gas Insti- Woild (Sec nd edition): New York:- Harcourt, q>.Jute, 1966. Brace & W Id, Inc., 1963. 32.General Theories of Operatio MilwAukee, Wis,: 17, Buban, Peter, and Marshall L. Schmitt. Under- Briggs & Stratton Corp., n.d. standing Electricity and ENctronics. New YorIK: 33.Gerrish, Howard H. Electricity and Electronics. McGraw-Hill Book Company, 1962. Homewr, Goodheart-Willcox Co., 1964. 101

92 ( 93

34. Giachino, J. W William Weeks, and Elmer Brune. 55: Power Goes to Work. Detroit: General .Moiiirs Welding Skills and Practices. Chicago: American Corp., 1963. Technical Society, 1967. 56. A Power Primer. Detroit: Public Relations Staff,' 35. Gibbons,L.L., andL.L.Moody. Power General Mators Corp.,1955. Mechanics: A Textbook and Laboratory ManuaL 57. Purvis, Jud. All About Small Gas Engines. Home- Dubuque, Iowa: William C. Brown & Co., 1964. wood, Goodheart-Willcox Co., 1956. 36. Glenn, Ha old T. Exploring Power Mechanics 58. The Radio Amatear's Handbook. Newington, (Second e on). Peoria, 111.: Chas. A. Bennett Conn.: American Ra& Relay League, Inc., 1968. Co., Inc., 196 . 59. Sandfort, John F. Heat Engines. parden City, . 37. Hogg, John C., Judsr-B. Cross, and Kenneth E. N.Y.: Doubleday 8i Company, Inc., 1962.- Vordenberg. Physieigl Science: A Basic Course. 40. Semat, H., and it Katz. Physics. New york: Princeton, N. 1:: D. Van Nostrand Co., Inc., 1959. Harcourt, Brace ar.S.&1-951ir 38. Honda 250, 300 Maintenance Manual. Tolkyo, 61. Sharpe, Philip B. Complete Guide toHandloading. Japan: Honda Motor Co., Ltd. (American Honda New York: Fuhk & Wagnalls Co., 1941. Motor Co., Inc., Gardena, California,), 1960. 62. Sheoultz, Kenneth G. Basic Electricity: Theory and 39: How the Wheels Revolve. Detroit, Mich.: General Practice.Ontirio, Canada: Macmillan Co. of Motors Corp., 1952. Canada, Ltd., 1965. . 40. Introductory Physical ,Science. Physical Science 63. Smith, Victor C., and B.. B. Vance. Science-for Study Committee of Educational Services, Inc. Everyday Use (Third edition). Philadelphia: J. B. Englewood Cliffs, N. J.: Prentice-Hall, Inc., 1965. Lippincott Company, 1954. 41-.- Jones, F. D., and Erik Oberg. Machinery Hand- . 64.Space Resources for the High School, Industrial book (Sixteenth edition). New Yqpic: -The Indus- Art4 Resource Units. Washington, D. C.: National

trial Press, Inc., 1959. 1 Aeronautics andSpace Administration21967. 2. Jones,FranklinD.Engineering Encyclopedia 65. Steinberg, William F., and Walter B. Ford. Electric- (Sixth edition). New York: The Industrial Press, ity and Electronics, Basic (Third edition).Chicago*: Inc., 1954. American,Technical Society, 1964. 43. Leopold, Luna B., and Kenneth S. Davis. Water. 66. Stephenson, George D. Power Meahanics. Albany-, New York:Tinktife Books, 1966. N. Y.: Delmar Publishers, Inc., 1963. and Robert O'Brien. Ships. 44.. Lewis, Edward' ., 67. Stephenson, George D. Small Gasoline Engirws. New York: Time-Life Books, 1965. 45. Lindberg, Roy A. Processes and Materials of Albany, N.Y.: Delmar Publishers, Inc., 1964." " 68. Stever, Guyford H., and James J. Haggerty. Flight. Manufacturing.Boston: Allyn & Bacon, Inc., New York: Time-Life Books, 1965. 1964. MacCracken, Helen Dolman, and Others. Basic 69. Stockel, Martin W. Auto Mechanics Fundamentals. Physical Science. New York: The L. W. Singer Homewood, Ill.: Goodheart-Willcox Co., 1965. Company, Inc., 1964. 70. Stollberg,Robert, and Faith F.Hill. Physics 47. MarCus,'Abraham. Basic Electricity (Second edi- Fundamentals and Frontiers. Boston! Houghton tion). Englewood Cliffs, N. J.: Prentice-Hall, Inc., Mifflin Co., 1965. 1964. 71. Storage Batteries (DR-5133D). Anderson, Ind.: 48, Mark, Herman F. Giant Molecules. New Y Delco-Remy Div., General Motors Corp., 1966. Time-Life Books, 1966. 72. The Story of.Comirsotion. Detroit, Mich.: Educa- 49. McGraw-Hill Encyclopedia of Science and Tech- tional Services, Chrysler Corp., n. d. nology. New York: McGrawHill -Book Company, 73. The Story of Power. troit:, General Mo rs 1960. Corp., 1956. 50. O'Brien, Robert. Machines: New York: Time-Life ' 74. Swanson, Robert .S. P4stic Technology: Basic Books, 1966. s. Bloomington Ill.: 51. Original Electrical Equipment for Passenger Cars. Materialsand Procel Co., 1965. -- Anderson, Ind.: Delco-Remy Div., Gerieral Motors McKnight & McKnight Corp., 1961. 75. Toboldt, William K., and Jud Purvis. Motor Ser- 52. Owner's Manual. Lincoln, Neb.: Cushman Motors, vice's Automotive 'Encyclopedia. (Fourth edition). 1964. . Chicago: Goodheart-Willcox Co., 1962. 53. Palmer, D. B. The Lambretta Servicemdn's Book 76. Trudeau, Terence J. "Analyzing Piston Engle (Thirdedition).Croyden, England: Lambretta Performance in Power Mechanics Courses," Indus- Concessionairel, Ltd., Trojan Works, Purley Way trial Arts and Vocdtional EducationlTechnical- (31-17 38th Ave., Long Island City, N. Y.), n.d. Education, LV (January, 1966)?, 54. Pella, Milton 0., and Aubrey G. Wood. Physical 77. Van Houten, L. F., and PA Gilman.Gerte-r7--**': Science for Progress (Second edition). Englewocid Science Today. Chicago: Rand McNallr & Co., Cliffs, N.J. Prentice-Hall,lnc., 1964. 1954.

102 94

,,,, , ., . . . 78.,_Venk; Ernest A., and Walter E.Billiet.4utorhotive 81Wilso5, Mitchell. Energy, New York: Time-Life I - Fukdamentals (Third edition). Chicago: American- Books, 1963. . f Technical Society, 1967. . 84.Wisconsin Air-Cqoled Heavy Duty Engines (Model . Z9. Vespa 64: Parts qnd Accessories. Boston: Vescony, S-7D). Milwaukee, Wis.: Wisconsin MOtor Corp., n. d. Inc.; 949 Corfismonwealth Ave._ 1964. .' 85.Wisconsin Air-Cooled Heavy Duty Engines (models 80.AVa1ksr, John R. Mach Ming Fundamentals. Home-_ VH4, VH405..Milwaukee, Wis.: WPSconsin" Motor wood, Ill.: GoodhearMillcox Co., 1969: Corpn.'d. 81: Wetzel, Guy F. Automotive Diagnosis and Tune-- 86.Woodward, Robert L.,. and J. Lyman Goldsmith. A n Int rad u oA pplied -Up. Bloothington,111.: McKnight McKnight Pub, ion- Electricity, Electronics. Englewood Cliffs, N. J.: Prentice-Hall,' Co., 1965. , Inc., 1963. 82. White, Harvey El Modern.College Physics (Third . WoQdward, RobertL.Industrial Arts' Safety edition). Princeton, N. J.: D. Van Nostrand °Instruction: Sa6ramento: California State.Depaft- We., 1956. ment of Education, 1966.

4

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. 103

4. t 1/ ---,v.. I ..

a. 0

f

. APPENDIX A ( POWER MECHANICS DCOU.RSE OUTLIkE

o: In the followings relatively,brief course outline for Lubricafion (Unit 7) . - industrial arts power mechanics*e topics, where aPPropri- .(Refer to Appendix B, Section 6,1-XV1.) ate, are keyed to the instructional units presented in this 1. Viscosity of oils publication for example, under "II. A. Muscle Power ' I Lubricatidg oil flinctions (Unit 1)"; and to the comprehensive" course outline ,for , 3. Dry, greasy, and viscous friction industrial arts autoibotive mechaniff in Appendix Bfor , C.Springs (Unit 8) example, under "I. A. Shop/Laboratory, Safety (Refer t (Refer to Appendix B,,SeCtion 16, V.) Appendix B. SectionI 1.)" This power mechanics cour 1. Classification of springs outline, when used fof a specific course/program, can 2.= Elasticity: Hooke's law expanded by. ineludin(1) additional points bavered in t D. Clutches,(Unit 9) designatedunits; (2) topics presented in the automoti e (Refer to Appendix B, Section 11, I2X.) mechanics outline; and/or (3) information from the publi- 1. Six classifications ofelutches cations listed under "Seleded References" at the end bf 2. Sliding friction bach unit. E. Vyaamometers (Unit.10) 1. Methods of providing load. I. Shop/Lbboratory Orientation 2. Horsepower A! ShOp/Laboratory Safety \ 7 . - (Refer tO Appendix B, Wtion I , I.) IV. Steam Engines 1.4,0eneral causes of accidents' A: Steain Engines and.Turbines "(Unit 11) 2. Personal causes of accidents B. Conversiop,of Hbat IntO Work 3. Safety instruction Tools and Equipment V. Thermal Power (Refer to Appendix-B,Section I ,il.) A. High-Energy Rate Forming (Unit 12)-. 1. Appreciation of tools 1. Fofar methods of faming : 2. Cario.of todts 2. Work, pcver, energy, force `s B. Powder-Actuated Topls (Unit 13) 3. Classification'of tools dee 4.. Precautions to be observed -11. Natural Power 't Expansidn of gases. A. Muscle Power (Unit 1) C. Jet and Rocket Engines (Unit 14)- :I. Introduction to simple machines 1,. Types of jet engines A 2. Work, power, energy, force P.". Newton's laws of interactiwis , B. Waterwheels (Unit 2) D. Gasagline Testing (Unit 15) . I. Types: undershot, overshot, breast * (Refer to Appen4 B, Section 8; IX.) 4 2. Water pressure a 1.Power tests C. Windmills (Unit 3) ' 2. Conversion of chemical energy toTheat energy to 1. Types: multivane, propeller, "S" rotor mechanical energy 2. Hdrsepower output of windmill E. Carburetion (Unit 16) D. Heat Collectors,(Unit 4), (Refer to Appendix, Section 8, VII.) k 1. Conversion of solar en to electricity 1. Carburetor ftinc qps .2. Nature of heat 2. Bernoulli's p ciple E. Solar Stills (Unit 5) -F. Two- alid Four-Cycle Engines (Unitt 17) (Refer toAppendi B, sections 3, 4; 5.) III. Mechanical tver .1. Four-stroke cyc f A.. Simple a Compound Machines (Unit 6) 2. Two-stroke cycle 1.;Mecha ical advantage 3, Expansion of gas s wheel and axle, inclined pl.ve,wedge, G. _Wankel Engines (Uit 18)' 'pulley, screw Is. Rotor-type gme "="6.."`- 3. CompourteMachines 2 Mojnent o inertia :, % , 95 a 96

H. Thermostats (Unit 14) G. Ignition Systems (Unit 27) '(Refer,to Appendix" B, Section 7, VIII) ,(Refer to APPendix'B,Section 9, IX.) Yyp,es and purposes I: ConVentiknal and transistorized systems .- 2 Thermaltexpansidn 2. Electromagngteenergy I.Welding Processes (Unit 20) H. Electric Motors"(Unit 28) Ges, are, and resistance welding (Refer td Appendix B, Section 9-; y.) Kinetic.mdledular theory P. Moctors:.Series and shunt wound 2.- Elec romagnetic induction . VI. Electrical Power 1.Fuel Celli (Unit 29) Dry Cells: Primary Cells (pnit 21) 1:, Use in spacecraa I. 4c-carbon-and mercurAe114, 2. Electrochemical etTect -4 "-2. Conversion of chemical, energy into _electrical J.Photoelectric Cells (Unit P) 'energy I. Types, and uses B. Storage-Batteries: Ser.Oadt-tyLelells (Unit 22) 2. Photoeleetric effect 4Refer to ApPendix B, Section .9,IV.), K. SemicondVor Power 'Real rs (Unit 3-1.)

1. Conversion of chemical energyinto, electrical 1 .-141pes of.rectifiers energy 2. Ps and N-type semiconductors 7" 2. Electrolysis VII. Hydranlic,Power 3. Hydrometer test A. Jacks andPresses (Unit 32) 4. Specific gravity 1. Hydraulic punip components 5. 'Battery installation anservicing 2. Pascal's princiMe 6. Corrosion and oxidatioOf metals 13. Machine Tools (Unit 33) ' 7. Battery testing . I. -Efficiency ofitydraulic systems, Capacityrating of- batte 2. Pressurekansmission by liquids 9. Battery charging ' C.BrakingSystems (Unit 34) .10. Chemical cfiange in lead-acid stora)e cell (Refer to Appendix p, Section 20, I-VH.) C. Generation of Electricit(Lnit 23) 14 Devices for retarding or stopOng motion I. Magnetos 2. Pascal's principle 2. Magnetimi a D. Fuel PuMps (Unit 35)- '3. Direet-current generators and alternators (Refer to Appendix B, Section 8, VI.) 4. \Electromagnetic induction- I. Positive displacement pump 5, Alternating-current rectifiers 2. 'Atmospheriorressure 6. Rectification of turrent E. Power Steering (Unit 36). 7. Generator regula0p (Refer/to Appendix B, Section 17, VII.) Electromagnetic sWitth I. Advaniage of power steering D: Transmission of Electric Power (Unit 24) ' 2. Pressure transmission by liquids (Refer to Appendix B, Section F. Air COnditioners (Unit 37) - 1. ElecOoniotive force 1. Types of air conditioners 2. Conductors and insulators 2. Heat transfer 3. Electron theory. . VIII. Pneumatic Power 4. Voltage, current, and Fesistapce A. Air-Powered Tools (Unit 38) 5. Ohm's law ,1. Piston and rotary-vane'motors 6.. Series and parallel circuits T2. Mechanical properties of gases 7.).Direct-ctirrent circuits B. Spray, Guns (*it 39) E. Transformers (Unit 25) , 1. OperStion and procedure for use I. Types: step-up, step-down 2. Bernoulli's prijitiple 2. Electromagnetic induct* C.,. Vacuum Pumps (Unit 40) F.- Spark Plugs (Unit 26) 1. Windshield wipers (Ref& to Appendix B, Seclion 9, IX.D.) 2. Powerbrakes I. Reat-range Classificatibn (Refer.to Appendix B, Section 20, IV.) 2: Ionization of gases- 3. Balancing effect of atmospheric pressonT . 105 .

a 4

'APOENDIX B AUTOMOTIVE MECHANICSCOURSE OUTLINE

Section 1.: Shop/Laboratory Practice C. Classification of Automotive Tools I. Chisels a. Cape I. Automotive Shop/Laboratory Safety rr A. General Causes of Accidents I). Cold I. lmaroper attitude c. Diamond-point -a. Disregard for rulei ofsifety d. Half-round b. Recklessness e. Roundnose c. Laziness 2. Drilling tOols d. Uncooperativeness a. Hand drill e. Fearfulness b. Electric drill f.Impatience , c. 'Twist drill g. Lack of consideration d. Reamers h.. 'Immaturity Files 2. Lack of knowledge or skill, a. Mill # a. Lack of understanding what is tobe done' J.Ta'per b. Lack of conviction of need Joi following c. Square, prescribed procfdures d. Round B. Personal Causes of Accidents e. Half-round 4 I. Operating equipment without permission-, f.Breaker-point 2. Neglecting to secure assistance When needed g. Vixen-cut (body) 3. Failing to warn other pegple about unsafe prac- 4. Hammeiing tools tices OF equipment a.Ball peen hammer J. Operating equipment atunsafe speeds b. Rawhide-faced mallet Working too fast _c.Plastic-tipped mallet 6. Neglecting to use safety devices d. Brass Mallet 7. 'Us' hands instead of equipment for holding e. Rubber mallet mat f. Sledgehammer 8. AsuiniItg an unsafc position oi posture . g. Dinging hammer 9. Working unsafe equipment 5. Measuring tools 10. Distracting, teasing, abusing, and startling others a. Feelergauges b. Micrdmeters . 11. Failing to use properclothing and protective gear C. (Refer to Industrial Arts Safetir Instruction, published 6 Steel rules by the California. State DePartment of Edudation, as 6. Pliers well as safety instructions issued by the offices of a.Slip-joint (combination) county superintendents of scho and by school b. Diagonal (cutting) . districts.) c. Lông7nose (needle-nose) .d- Round-nose II. Automotive Tools and Power Equipment type (chaniiel-lock) A. Affireciation of Dols f.S' .4-cu g (electrician's) 1. Development gnp , 2. Value to societ .'B rake -spring p, Care of Tools I.Hose-clamp 1. Storage Ofols,, o 7. Punt-hes 2.`Maintena a.Aligning a. Sharpening., b. Center '. b. Lubricating,. c: Pin , d. Starting Repairing. . ej...23t-tOols in need of repair.) 8. Hacksaw

97. 98

9. Screwdrivers' II. Engine, 4 a. Standard-tipped A. rurposê b. Phillips B. Types c. Clutch I. Internal combustion d. Offset 2. Externahcombustion e. Setscrew driver (Allen wrerA C. Sysfems 10. Shearing tools ' 1. Fuel system a. Straight shear's' -4 . a. Purpose b. Combination shears ,b. Components c. Duckbill shears (1) Fuel tank and lines , d. Multi leverage (aviation) shears ,.. (2) Fuel filter .,11. Soldering tools (3) Air cleaner (wet and dry) ,a. ,Soldering copper (4) Fuel pump (1) ,Standard (5) Carburetor (2) Electric.' (6) Fuel ikectOrs b. Fluxes (7) Intake*tanifold 12. threading tools (8) Fuel:level indicator. a. Taps 2. Ignition system (I) Taper a. rurpose * (2) Plug b. Components 43 (3) Bottoming , (1) Battery (6 or 12 volts) (4) Machine scow (2) Distributor b. Dies (3) Magneto .13. Wrenches and handles (4) Coil \----1.L\ Open-end wrench (5)'Spark plugs . Box-end wrench (6) Ignition switch c. Socket wrinch (7) Wiring (1) Standard 3. Lnbrication system (2) Deep a. Pdrpose (3) Universal b. Components 0. Torque wrench , (1) Oil pump . Adjustable-end Tench (2) Oil filter f.Monkey wrench (3) Oil galleries and passages g. 'Pipe wrench (4) Oil-pressure indicatol h. Handles , (5) Crankcase g (.1) Speed (spinner) (6) Crankcase ventilator (2) Ratchet 4. Cooling srstem (3) Flex (break-over) a. Purpose (4) Tee b. Types I. Extensions. (1) Liqyid-clied 14. Specialized tools (2) Air-cooled a. Pneumatic c. Components b. Hydraulic (1) Radiator c.Electrical testing (2) Fan blade d. Engine and accessories' testing (3) Water pump e. Body and fender (4) Water jackets and passages 15. Power equipment (5) Thermostat 16. Welding equipment (6) TehiRerature indicator 5. Electrical system a. Purpose Section 2: Automobile Components b. Components (1) Battery 'I. Automobile Comitnents (2) Regulator A. Engine (3) Generator/alternator B. Framework (4) Starting motor C. Power Train (5) Wiring D. Body (6) Switches E. Accessories (7) All activated components

a Ii 107 !,9

Fiaineworlc . " 1?- Types \ A.Purpose.. ' (I) Standard: nol.nual shift . B.Construction (2) A utoma tic I. Box type (3). OVerdrive 2. X-type." 3. Propeller shaft:Jurpose 3. unitized type 4, DefferentiaL Units Attached to Frarnew a. Purpose I. Engine . b. Gear ratio 2. .Slispension system j tid redr) 5. Rear axles a. Purpose a-.Springs . -11) Purpose b.. Types (2) 'Types (1). Live: rear .,(a) Coil Dead: front o . (b) LaminaW leaf V. Body (c) Single ICU A. Purpose (d) Torsion bar . B. Design (streaming) 4. . (e) Air suspension C. Construction b. iShock absorbers 1 .Pressed-stee) pane . lt IPurposk V.Reinforcing members (2) Type: direct-acting, telescoping 3. Attaching brackets c. Steering system: purpose 4. Attaching bolts (rubber-mounted)* d. Brakes D. Components (1) Purpose I. Firewall assembly I (2) Types ( 2. Instrument-panel assembly (a) Mechanical - 3. Floor assembly (b) Hydraulic 4. Roof assembly (c) Pneumatic .5. Doors- and center-pillar assembly "(d) Elect.tic 6. Rear-quarter assemblies (e) Rigid orIndependent 7. Rear-end assembly (3) Components 8. Front fenders, hood, andgri assembly (a) Brakepedal assembly 9. Windshield and glass assemblie (b) Muster-cylinder assembly 10. Seats (c) Brake lines II. Body-ventilating system Wheel-cylindei assemblies- 12. Headlining assembly (e) Wheel-brake assemblies 13. Exterior molding and trim (f) Hand brake E.Finishes (4) Principle ofoperation P. Body Styles (5) Power brakes Sports coupe and sedan Tires 2. Convertible (1) Purpose 3. Sedans (2) Types. 4. Station wagons (a) -Tube-tyPe , 5. Sports cars :-.(b) Tubeless 6. Compacts (3) Classification 7. Sports wagons (buses, others) (a) Size .8. Pick-up trucks, trucks (aSsorted sizes anduses) -(b) Plies (c) Material VI. AcCessories N (V. Power Train .A....Definition . I. Comfori/c nvenience A. Purpose belts...," - B. Components 2. Safety an safety I. Clutch B.., Examples a. Purpose I. Radio b. Types commonly. used 2. Heater, defroster/air condit)oner (1) Single dry disk 3. Windshield*iper (2) Fluid coupling 4. Clock 2. TrdhsmisSion 5. Back-up lights/ a. Purpose 6.,,Spotlight 4

.41 tj

4 ,7. Courtesy light G.Ideatiflcation 8. AptoMatic light-tlimmer 1. anufacturer's name e a. Real thartufacturek:Ford, "'enera I Motors, Section 3i4Types'orEngines. (Aires r , b. Applicatiomanufacturer: International Har- 1. *pose of Engine Clvsiflcatio t'N vester, did, others A. To Differentiatp..Between Engines for Cleai Commtp 2. Designer's name nication . Indiviabal designer: Diesel, Wankel, others B. To Categonzd Dienes by Cnmmon General Features' b. Multiple designer: Pratt and Whitney, others1 Describt Engines for Informition and Possible 3. Series mmber (390, F100, 300G, others). _ . , A , -Application * 11. Additional Types and Innovations H. , Criteria fbT Engirieglassifica non 1. Turbojet 2. Ramjet A. Types of Fuel 3. Gas turbine 1.. Gasoline (high andjow compression) -4. Free piston flipa. Fuel oil (diesel, Hesselman)' 5. NSU-Wankels----N. Liqueted petroleum gas (LPG) P. Rocket \ B. Cycling#,* , 7. Fuel cell .1. Four-stroke cycle 8. Solar 2. Two-stroke cycle 9. Electric C. Coolins 10. Steam 1. Liquid-cooled 2. An-cooled Section 4: Engine Operation and Measurement 3. Combined D. Valve Arrangement I. Physical Principles Related to Engine Operation 1. L-head (flat head) A. Definition of Physical Principles " 2. 1-head (overhead valve) B. Structure of Matter 3. F-head (combination L- and 1-head) 1. Atoms 4. a. Size E. Cylinders b. Structure 'Pa I. Numfkr of cylinders (1) Electrons 2. Arrangement of cylinders (2) Protons a. Inline (3) Neutrons (1) Vertical 2. Elements (2) Inverted 3. Molecules (3)Slant or tilt a. Structure b. Vee li. Chemical reaction (1) Vertical C. States of Matter (2) Inverted 1. 'Liquids 2. Solids (3) Variable angle 3. Gases c. Opposed (pancake) D. Combustion d. Radial 1. Definition bank (1 2. Products of combustion (2) Multibk e. Rotary Wan el a. Heat b. Light B. Use , c. By-products I. Passenger car E. Heat a 2. Truck or bus F. Change of State 3. Agricultural machinery 1. Definition 4. Construction equipment 2. Method of accomplishment 5. Aircraft a. Applica on of heat 6. Motorcycles b. Appp6tion of cold 7. Railroad engines G. Expansio of Matter 8. Marine 1. Liquids: thermometer 9. Stationary 2. Solids: thermostat 10. Specialized La`e 3. Gases: combustion chamber

109 H. PressureIn/ase (3) POwer 1: Cause (4) Exha 2. Results " 3. Two-stroke cy a. Temperaturein'creas'e .-4. Diesel engines b: Compression G. Flywheel I.Gravity I. Desci-iption I. Defmition 2. Purpose 2. Measurement: weighi J.AtmosphericPressure III. Forces I. Defmition A.1 Work 2. We :Sof air.A. Dermition 3. Pr fxeited 2. Illustrations K. Vacuum 3. Meastut in,terms of distaisce and farce 1. Definition 4 rmula: Work f Xd 2c "Partial vacuum" Energy *, 1. Defmition Engine Operation 2. Potential A. Cylinder Design, es' 3. Kinetic . I. Description 2. Sealing C. Power a. Head 1. Definition b. Valves 2. High-powered machine B. Piston 3. Low-powered machine I. .DesCription 4. 1-lorsepower a. Deftnition . 2. Piston fit . b. Formulc Hprforce X distance 3. Material used 33,000 -X time 4. Piston action D. Inertia , a.Combustion I. Definition b. Heat 2. Evidenciz. of inertia at 'work c. Presiure increase E. Torque' C. Piston Rings t, 1. DefmItion. I. Purpose 2. Method of measure (foot-pounds) 2. Location 3. Forniula: Torque = force X distan-ce (lever arm) 3. Types F. Friction D. Valves I. befmition I. Type .2. Type,s 2. Purpose a.- Dry 3. Ports b. Visedus a. Intake c. Greasy b. Exhaust 4. ValveoperatinOpechanisim. Engine.MeasuremenIs a. Camshaft A.. Bore b. Cam follower; or lifters I. Definition ° c. Pushrods . 2. Method of determination d. Valve spring ,- B. Stroke e. Rocker arm 1. DefinitiOn E. Crankshaft 2. Method of determination I. Purpose C.Piston Displacement 2. Description 1. Definition 3. Rotary motion 2. Formula: Displacement =ffD2 L F. Action in Cylinder 4 I. Definition of "stroke" 3. Multicylinder" total displacement X number of 'o TDC cylindkrs

. TDC BDC D. Compression Ratio 2 our-strotce cycle -1. Definition Th aankshaft revolutions 2. Clearance volume b. Four strokes 3. Formula; Cylinder volume @ BDC clearance (1) Intake volume (2) Compression 4. Problem related to higher compression ratios

% 110 102

a. Power increase 3. Location b. 4'redetonation more aclite (knockini) 4. Manifold heat-Control valve V. Engine Power Output D. Manifold Inspecifon A. BrakelfOrsopower (bhp) I. Check for warpage II. Defmitiod 4 Check for Cracks ' 2. Pro* brake test 3. Check surface B. Indicate 11 Hprsepower Op) 4. Check heat-controtvalve' for freeniss - 1. Definition 11. Cylinder Head 2. Oscilloscope test' itthods of Manufacture t C. L., Friction Horsepower (fhp) 17, Materialsusq 1 1. Defmition 2. TSesign , ethod of.determination B. TYpes D. SAEHorsepower 4 1. Valve-in- ead/ I I. Definition 2. Flat head.. ,2. *urpose G. Purpose - , E. Engine Torque i. Combustion chamber 1. Definition' 2. Water jackets ' 2. Method of determination 3. IMake and exhaust ports and passad1s VI. Engine Efficiency D. Rocker-Arm Cover A. Mechanical Efficiency III. Oil'Pan .i I. Relationship between bhp and ihp A. ,Methods of Manufacture 2. Formula: ME ihp (answer in peri:ent) 1. Materials used B: Thermal Efficiency /2. Design 1. Relationship between power output and energy in 2 B. Purpose fuel burned I. Baffles 2. Heat losses 2. Oil troughs a. Cooling by water and oil (35 percent) asirs3. Nozzles i b. Lost in exhaust gases (35 percent) 4. Drain plug 3. Limitations to thermal efficieacy_ 5. Seals a. Excessive heat C. Oil Pump b. Breakdown in lubrication system 1. Purpose C. Voluntetric Efficiency 2. Types I. Relationship between amount of fuel-air Mixture a. Gear actually entering cylinder and amount that could b. Dual rotor over 3. Location 2. Factors affecting volumetric efficiency 4. Oil intake a. Engine rpm 5. Screen b., Temperature of fuel-air mixture IV. Valve Train VII. Overall Efficiency . A. Camshaft A. Rolling ResistaInce 1. Methods of manufacture B.Air Resistance'. 2. Purpose C. Acceleratioh (overcoming of inertia)- 3. Types a. Stock b. Other grinds Section 5: Engine Construction 4. Location 5. Components I. Manifolds a. Cam lobes A. Methods of Manufacture b. Fuel pump eccentric 1. Materials used c. Distributortirive gear 2. Design d. Bearing jo als B. Intake Manifold e. Thrust plate 1. Purpose . 6. Camshaft timing gear or sprock 2. Types 7. Timing chain 3. Location B. Valve Lifters (Tappets) C. Exhaust Manifolds 1. Purpose - 1. Purpose 2. Location 2. Types > a. I-head b. L-held G. Valve Springs c. F-head 1. Purpose -r 3. Types 2. ypes a. Solid 7 a. Single b, Double b. Adju'stable 1. c. Hydraulic 3. Reiainers a. Stationary C.Push Rod 1. Purpose b. Free type 2. Location c. Positife type 3. Types 4. Retainer locks (keepeirs) a. Tubu ar a. ConiCal 'b. Solid, b. Piri " ; c. Horseshoe RockerAmf and Shaft H. Relationship of Parts in L-Head Engine 1. Purpose I. Relationship of Parts 4I-Head Engine 2. Rocker-arm types J. Relationship of Parts'ineF-Head En "a. Cast At t b. Forged w14,17.is61 and Connecting Rod Assembly

ag, Stamped stltel , A.istoi -)A 341Rockeliartn shaft 1 . Methods of manufacture a. Location 2. Purpose b. Purpose 3. Parts of piston Valye Guides a. Flea d 1. kurpose b. Ring grooves 2. .hocation c. Ring lands 3. fypes d. Pin boss and bushing a. Pressed in e.' Skirt b. Slip in (1) Major thrust face c. Integral (2) Minor thrust face 4. pfteirguides 4. Expansion control F. Valvei 'a.Steel ri 1..Methods of manufacture b; Struts 2:' Purpose ots a. Intake w dj1am groun pistons b. Exhaust, 134 Piston Rings 3. Types (past and present) 1. Methods of manufacture a. Rotary 2111Furpose b. Sliding-sleeve a. Seal compression c. Poppet or mushroom b. Control oil 4. Parts of poppet valve 3. Types a. Head a. Compression b. Margin st (1)_ Plain c. Face A (2) Tapered d. Neck (3) Grooved e. Stem b. op control f.Spring-retainer lock groOve 4. Ring joints g. Tip a. Types 5. Valve ccio41: (1) Butt a. Purpose (2) 6ngle b. Method (3) rap (1) Water jackets b. Ring gap (2) Water-distributing tube 5. Ring expanders c. Sodium valves a. Purpose 6. Valve seat b. Location a. Purpose 6. Coated rings b. Types 7. Chrome-plated rings .(1) Direct C. Piston Pin (2) Inserts 1. Purpose 112. 215P Types 3. Counterbalances a. Center-lock 4. Oil passages b. End-lock 4 5. Oil slinger/thrust pad c. Slotted Flywheel 'd. Press-fit 1. Purpose e. Floating a. Supplies inertia tocrankshaft \QS.Connecting Rod b, Engages witlr starter mot& 1. Purpose . c. Driving member, of clutch 2. Method of manufacture oo 2. Location 37Parts !; - D. Crankshaft Timing-Gear or Sprocket a. ,Rod E. Vibration Damper

. b. Little end (bushing) 1. Purpose c. Big end fr 2. Construction Rod cap 3. Location e. Oil holes ra. Cylinder Block 0' f.Rod nuts Methodi of Manufactkie (1) Safe wire 1. Materials used (2) Self-locking 2. &sign (3) Cotter pin 11. Purposes (4) Palnut' 1. Cylinders g. Tonglie and groove 2. Water jackets , 4.Rod stretch and reconditioning 3. Welch plugs (soh plugs) 5. Alignment of oil holes 4. Intake and exhaust ports and passages VI. Bearings 5. Valve-lifter chamber A. Methods of Manufacture' 6. Oil galleries B. Purpose 7. Pressure relief valve C. Types Engine Serial Number Location . 1 Bushings IX. Gaskets 2. Sleeve A. Materials Used 3. End thrust , 1. Soft metal 4. Poured 2. Fiber 5. Semi-fitted 3. Rubber 6. Precision insert: types of metal overlays 4. -Ndorprene 7. Roller 5. COrk 8..Ball 6. Leather D. Location.0 B. Purpose 1. Main bearings C. Types and Location onnecting-rod bearings 1. Cylinder head 3. Camshaft bushings 2. .0i1 pan 4. Piston pin bushings 3. Push-rod cover 5." Clutch pilot-bushing or -bearing 4. Valve cover 6: Camshaft ihrust plate. 5. Manifolds E. Oil Clearance 6. Timing-gear cover and seal F. Requirements . 7. Main bearing seal I. Load-carryinecapacity 2:Fatigue resistance X. Miscellaneous Components 3. Embeddability A. Beli Housing 4. Conformability 1. Purpose 5. Corrosion 'resistance 2. Dust cover 6. Low wear rate B. Engine Mounts

VII. Crankshaft ISection 6: Engine Lubrication:System A, Methods of Manufacture A 1. Materials used I. Purpose of Lubrication S9Mem 2. Design A. Lubricate Moving Parts to Prevent Wear \- B. Purpose B.Lubricate Moving Parts to Reduce PooVer Loss from .Connecting rod throws Friction 2. Main bearing journals C. Act as CoolingcAgent

113: ., D. Absorb Shock BetWeenBearin--\gs and Other, Moving B.Ilil Change Interval Parts 0.. 1. Factory recommendations' E. Form Seal Between Piston Rings andCylindeiWalls ro a, For engine with oil filter F. Act as Cleaning Agent , b. For engine without oil filter II. Theory of Lubricat* 2. Other recommendations A. Friction Bearings VIII. Oil Consumption' B: AntiNction Bearings A. Causei C. Oil Passages 1. Engine condition 7 1. Circulation 2. Driving conditions 2. Location 3. Mixture of oit'types a.Inte'rnal B. Corrections b. External pIX. Types of Lubrication Systems III. Source of Oil A. Splash A History and Development 'B.Pressure Feeil Discovery C. CoMbination of Splash and Pressuil Feed 2. Early uses X. Oil Pumps 3. Oil ankautomobile A. Purpose: Circulation B. ModertePrOresses ,B. Location 1. Modern oil fields 1. Internal 1. Refining 2. External .z? ,IV. Properties of Oil TYpes A. Viscosity' a, 1. Gear 1. Body 2. Dual rotor 2. Fluidity 3. Vane B. Viscosity Ratings 4. Plunger 1. Viscosimete,r D. Theory of Operation

- 2. Tempeithure 1. Capacity 1 C. Viscosity Index 2. Priming D. Resistance to Carbon Formation . Method of Drive- E. Additives - 1. Distributor V I.Oxidation inhibitors 2. Cam gear 2. Antifoam agents 3. Crankshaft geor 3. Detergents 'F.Parts 4. Antiweai*ditives 1. Camshaft gear 5. Acid inhibitors 2. Shaft 6. Varnish inhibitors 3.. Body. 7. Sludge inhibitors 4. Drive gear V. Water Sludge Formation 5. Idler gear A. Process of Formation 6. Cover 7. Inta : B. Prevention of Sludge' 1. Types of car operation g. Outl 2. TemPeratde 9. Screen 3. Crankease ventilating syitem XL 'Relief Valve§ VI. Service Ratings of Oil (API). A. Purpose, A. MS B. Types ,B. MM , 1. Plunger C. MC 2. Ball D. DS C. Location E. DG r- 1. 'Block a.Internal, VII. Qithariges b. External, 2. Pump I. Rep ce contaminated oil D. Operation 2. Keep çngine clean 3. Drain XII. Oil Filters a. From below A. -Purpose b. From aboVe B. Location,

114 106

C. Types II. ,Xypes of Cooling Systems a I. By-pass ,A:NAir-Cooled 2. FUll-flow 1. Cooling fins D. Theory of Operation 2. Circulation of aiir E. Choge Interval B. Liquid-Cooled 1. Thermosyphon XIII. tOil Coolers a. GravitY A. Nirpose B. Types b. Natural laws of w r circulation (convection)- 2 Forced circulation ) C. Locati (15 a. Me*od of ciircuion D. 0 on -ze er preisure \.../ E. Trans erence of Heat p. Circulation u my. Oil-Prure Indidators Essolitials of Calthng System A. Pairpose AL Absorption B. Location B. Circulation I. [Sash unit I C. Radiation 2. Engine sender imit D. Control C. Types IV. Water Jackets I. Bourdon tube A. Cylinder Block 2. Electric B. Cylinder-Head a. Balancing coil C. Water-Distribution Tubes b. Bimetal D. Water Nozzles _ c. Warning light E. Soft Plugs (Welch Plugs) XV: Crankcase Ventilation A. Pprpose V. Water Punipc_ B. Types A. Purpose I. Standard B. Type Used 2. Tositiv C. Location C. Operation ---.*D. Pares; D. Smog Contro 1. Housing 2. Water inlet , . ators 3. Water oukt Purpose 4. 'Impeller lif . Location 5. Shaft . 6. Seals 7. Pulley Section 7: Engine Cooling System 8. Bearings E. Thecky of Operation I. PtirpOse of Engine Cooling System F. Method, of bole A. Maintain Efficient Engine Operating Temperature 'VI. Engine F.,an . B. Regulate Engine Operating Temperature tdA Driving A. Purpose C oan;titons B. Location Temperature Limits C. Method of Drive ReAults of overheating a. lareakdown of lubrication oil -VII. Radiator b. Damage, to bearing and moving parts A. Purpose c. Warpage and cracking of cylinder head B. Compartments d. Loss of coolant 1. Air passagek, . . e. Stoppage of water ciiculation 2. Water passages f.Changes in clearance C. Radiator Types 2. Results of overcooling J- 1. 'Ribbon cellular . a. Loss of engine thermalefficiency 2. Tube and fin b. Excessive consumption of fuel D. Radiator Parts . lar - c., Dilution of engine oil 1. Radiator shell d. Fiirmation of sludge 2. adiator core (1) Lubrication failure a. Top header (2) Corrosive acids b. 'Water tubes e. Changes in clearance c. Air fins ri r ( 107

Fan shroud 2. -Prevention of freezing hell att bOlts C. Requirements for/Good Antifreeze Solution ter inle I. Mixes readily vith water ater outl 2. C cates free 5,- 7. Upper tank 3. ust not damae sYstem by

8. Lower tank I 4.ust, not freez 9. Connecting lloses D. Ina equate Antif olutions 10. Drain cock \ 1. t solutions EDraining Radiator 3- 2. Sugaolutio 1. With pressure caP\ 3. Oil-pructs 2. Without pressure aap 4. Kerosen VIII. Thermostats 5. Glycerin Terhporary Antifreeze Solutibns A. Purpose i.....,, Ts...\--. B. Location , L. Alcohol 1. Water-co6lid/- 2. Alcohol base, nAerials 2. Air-cooled a. Low boiling- pOint C. TyRes.; Evaporation F. Pgrmainent Antifieeze Solutions *1. Bellows 2. Bimetallic 1. Ethylene glycol materials: perc rjtages 3. Solid expansion . 42. Methanol materials: percentag s Thermostat Parts . XII. Radiator Additives

1. Case 0 A. Cooling System Cle 2. Bellows ot spring B. Sealer

3. By-pass valye , C. Acid and .4. Air-bleed hole XIII. SPecial Pew E.1)inciples of Operation A..:Surge, ;'! .Temperature ranges 4 B. Radiator tekieriV 2. Water circulation: cold > C. Radiator Sci4e.4., 3. Water circulation: hot /4- .. -5civ. 'Hot-Water Car Heater IX. Radiator Pressure Cap A. Purpose A. Purpose B. P r ; 1. Improve cooling efficiency. 1.Ieaterrad4or 2. Preveut evaporation ,.. 2. Fah motpi 3. Prevent surge losses. 3. Fan blades B. Physical Piiiiciples 4 4. Connecfi g hoses 1. Pressure increase , C. Theoo ration 2. .Boiling-point effects--! C. Pressure Cap Parts 4. Vacuum valve ,S;ion 8: Engine Fuel System 2. Blowoff vagre 1.4:Purposaof Engine Fuel System 3. Overflow pipe A. Store Fuel. D. Pressure Cap Capacities- B:. Deliver Fuel to Engine X. Temperature Indicators C. Mix Fuel and Air to Proper proportions A. Purpose ' IL History and System Types B. Location A. Gravity4Feed System 1. Dash unit ., 1. Tank located higher than carburetor 2. Engine unit ' 2. System used about 1900 to 1931 C. Indicator Types B. Vacuum System ? 1. Vapor pressure 1. Vacuum lank located higher than carburetor 2. Electrical 2. Intake-manifold vacuum applied to vacuirm tank -a. Balancing coilv 3. Gravity from vacuum tank to carburetor b. Bimetal thermoutat 4. System invented bout 1920 XI. Antifreeze Solutions C. Pressure SyAem A. Purpose I. Fuel tank unde2- to 4 pounds higher pressure

B. Physical Principlu ' than atmospheric 7 1. Freezing: expAding force Z. Hanthpump on dash for starting 116 3. Engine pump usea aft r running 3. Ifiweller, .4. System used in some higher-priceTkars about 4. Combination 1915 D. Operation -.D.-Propane and ButaneSy4Nems 1. Creates own pressure Carburetion 2. Sto d s a liquid A. CarburetorFundamentals . 3. Releiseas a vapor 1. Purpose of carburetor .4.jUsed in 1alities where redily available 2. Physical principles 5.1 Usernown sore installi 'Na. Atmospheric pressure E. Pump Syste b. Vacuum c. Evaporation a 1. Draws from tank by vacuum 2. Forces to carbureto by pressure d. Atomization 3. Now standard typeof installation B. Carburetor Basic Parts 1. Air horn la III. Fuel Tanks 2. Venturi A. Purpose 3. Fuel nozzle B. Location 4.....Throttle valve C. Structure C. Fuel Mixtures 1. metal: spark proof 2. Corroation ' a. Ratio 3. Baffres b. Conditions when needed 4. Filler 'pipe 7 2. Lean 5. Filler cap a. Ratio 6. Vent c b. Congitions when needed 7. Oauge sending-unit location a Float Circuit; a 8.. Fuel line' . 1 . 9. Filter screen 2. Ope ation _a 1.0. Drain. plug 3. Pu -pump conirol a. leverage IV. Nei-Level Indicators b. Hydraulicv rface areas A. Purpose `4: Con4Rttric 4 B. Types a. Horseshoe float 1. Stick b. Dual-float assembly Hydrostatic 5. Dual-float circuits \2.3. Mechanical 6. Float-bowl vent 4. Electric / e a. Balanced a.aBimetaFtype b. Unbalanced b. Balancingril type 7. Air bleed: purpose Adjustment . , V. Fuel Lines a. Fuel level too low A. Purpose b. Fuel lefie too high B. Types- E.Idle- and Low peed-Circuit !. Steel 1. Purpose Copper .2. Operation .Flexible --41.Air-horn c nditions C.Fittings b. Idle circuit 1. Comptess on c. Low-speed circuit 2. Flared d. Air bleeds D. Location 3. Adjustment 1. Vibration a.Idle speed 2. Sharp edges b. Idle mixture 3. Heat F. High-Speed Part-Loadircuit VI. Fuel Pumps 1. Purpose A. Purpose 2. Operation B. Location a. Mechanical (met g rod) C. Diaphragm Types- b. Vacuum (power e) 1. Bellows G. High-Speed Full-Rowei Circuit 2. Plunger 1. Purpose

117 109 A

2. Operation I. Operation a. Mechanical '(metering rod) 2. Service b. Vacuum(powei yalve)- IX Fuels ° c. Combination mhariical and vacuum A. Fuels in Generil Use - Ii .Accelerator-limb Circuit I. Gasoline . I. Purpose r / 2. Benzene 2. Operation 3. Benzgl a. Plunger .... . A 4. 'AIcolRil b. Diaphragm" 5. 'Natural gas. 3. Adjustment 6. Fuel,oil 1. Choke Circuit e. 7. Propane and butane I. PurOose B. Physicsof Carburetionand Comb1stion cGasoline 2.- Manual operation I..Combustion 3. Vacuum opeirion -2. Compression 4. Electric 3. Fuel knoc(deton4tion and preignition) 5. Adjustment . a.kfeat onregular surfaces J.Other Carburetor Features .1 b.. Co sion ratio f. Throttle cracker c.Ignition timing . 2. Fast idle . d. Rapid 'burning 3. Antipercolator ....Niz. (1) Antiknock v"lue 4. Throttle4etum ches (2) Measurement 6f antiknock.value a. Dashpot (3) -Chemical c6ntrol . b. Dia.phrignf (4) Weight of air. '4 . Distributor4acuum crff cuit (5) Vaporization 6. 'Starter switches (a) Spraying 7.. Kick-down switches (b) Heat 8. Governors (c) 'facuum K.., Carburetor Types - (6) Vol tility I. Fuel entry to m (a) tafting a. Downdraft (b) Vapor lock b. 1..1p.ctraft (c) Warm-up c. Side draft (d) .Acceleration 2. Barrels (e) Economy a. Single barrel (f), Cragirose dilution b. Two barrel (gl:EvaMation during noneration c. Four barrel. Th) Atmospheric conditions (I). Primaries (i)Blend (2) Secondaries (7) Harmful chemicals.and gum (3) Progressive linkage.z..., .. 4 (4) CircuitvariationS' 'fr hisingle.and two Section 9 ilectrieal System barrel .. I. Purpose-of Electrical System ( 3. Multi le carburetors A. Cranks Engine for Starting a. io two-barrels ' B. Helps Create.High-Voltage Surge for Ignition b. Three two-barrels C. Provides E4ectrical Current for Electrically Operated c. Two fourinirrels Device's' ( I) Unison linkage (2) Progressive linkage II. Copponents of Electrical §_ystem (3) Vacuum-controlled linkage A. StOrage Battery B. Cranking Motor 4{- . 4. Fuel injection a. Combustion chamber C. Geneptor/Alternator b. Intake manifold D. Regulators ip....Jgnition Distributor ( I imp) VIII. Air Cleaners. F.`...Magnetp) A. Purpose , G. Coil .!..° B. Oil-Bath T5;pe H. Spark Plugs I .Operation.- I.6Witing 2. Service J. Switches C. Dry Type K. Accessory Units

118 110 417*. .,- 8 HI. Fundamentals of Electricity. . h. IV. Storage Battery

A. itharacteri;tics , .... ,_. A. Purpose 1. Atoms I . B. ConstructiOn a. Electrons: negative () I. Cpntainer b. Protons: positive (+) sksag 2. Plates. 2.AttractOn of opposite charges is a. Positive: lead peroxide J. Repulsion of like charges . b. Negative: sponge lead 4. Accumulation of electrOns: elqictric cfiarge/ 3. Separators 5. Accumulation of electrons hyeneratOrs and 4;6-Post straps , batteries " 5.' Terminal pos& . . B. Principles-of Electricfiurrent 6. Cell covers 7. Cell connectors (internal ahd extehial) C. --Conductors 8. Vent plugs . I .Example:.copper . 2. Free movement of electrons-- 9. Sealing compound , Principles of ChemiCal Activity D.- Insulators 1..Example: rubber - D. Battery Ratings 2. Few freselectrons s Defmition da. -Total afea ` 3. Prevention of loss of electronkfrpm conductors L. * .b. Volume of active plate material' E. Electrical Terms ount of electrblyte 1. Voltage d. ength of elecfrolyte a. Electric pressure . . . b. Pressure measured in volts 2: Methoof rating a.. Ampere-hour capacity 2. Amperage a. Current flow b. Cold rating_ b. Flow measuga in amperes V. Cranking Motor 3.`ResigtanCe . A. Purpose esistanct to electrical piessure B. Principles of Motor Operationrt. .:, .,,,,i, b. esistrce measure51, in Ohms I. -Magnetic field around conductoi F. Ohm's Law j 2. Conductor in magnetic field V-. ..- G. Circuits 3. Lines of force action

1:- Series . 4::''Current flow . .4,. , a. .0ent flow samein an parts of circuit C.Construction of Cranking Motor alristance equal to sum.pf individual 1. Basic elements stance a. Uthaped Condiictor . o tage e ual- to ..$qm..4 pot,Aid differences b. Contacts across eac of in.'.. .114;411942ces' r .: ' c. Brushes 1. Parallel ;A ; d. Magnets a. Voltagrsanie ices ran6es e. Battery :...... 13'..;TOtal current equ f Currents througkh a.. 2. Components of cranking motor branches -,.., - a: Armature v. c. Total'resistance.equallto voltage across rcsist- ,-/ b. Field-frame assembly ances divided by total circuit current c. Cornpiutator end-head assembly 3. Series-parallel .,. d. Brushes a.. Certain components in series . e. tDrive housing , b. Certain components in parallel k.Drive mechanism H. Magnetism g. Solenoid assembly . I. Magnets: charactetistics h. Shift-lever assembly 2. Lines of fotce a D. Cranking-Motor Drives a. Stretch .hetween magnetic pores .. , , I. Purpose b. Tend to be parallet(do not cross) 2./Types . Electromagnetism a. Overrunning clutch Lines of force produced by current flow , b. Inertia 2. Electromagnets: combined magnetic field (I) Bendix dirke 3. Permeability (2) Dyer drive a. Iron core in coil (3) F.flo-thrU drive

, b. Increased magnetic field c. Principles of operation 119 .E. Cratiking-Motar Controls ..4 (2) Magnetic fields reversal-weakened 1. Purpose (3) Contat pos separate 2. Manual operon 'ss, (4) Circuit ope 3: AutomItic control: solenoid C. VOttno-ResulatOr 4. Methods CO operation, I. Purpose

F. Simple Wiring fiagram a. Prevents excessive voltage A VI. irect-Current Generator b. Maintains constant voltage A. Purpose . 2. Operation a 4! EN Principles of Oenerator Operation D. Current Regulator I. Conductor mqving through magnetic field I. Purpose .2. Currentflow a. Refulates current to battery 3. Magnetic lines of force b., Protects battery A 4. Rate of cutting lines of force 2. Operkion C. Construction of Generator VIII. Afiernating-CurrentC*Generator System (All ernator) 1: li--.Shaped conductot N4. A. Wiring Diagrain of Alternator Circuit Contacts. B. Function of Alternating-Currtnt Generator ter- 3. Bru nator) 4. Fiild coils ' Constructifin and Descriptyon of Parts , 5. Drivenit D. Principles of Alternator Operation D. Components of Generator IX. Ignition System (Conventional ana Transistorized 1. Frame aSsemblY A. Purpose a. Frame B. Components b. Field coil I. Battery c. Pole shoes 2. SWitch d. Terminals 3, Resistor 2. Armature 4. Coil 3. Commutator end frame 5. Distributor 4. BrAshes 6. Spark plugs 5. Drive end frame 7. Wiring 6. Fan 8. Switch 7. Pulley 9. Timer E. Outppt control H C. Distributor 'F.Wiiing diagram 11 Purpose VILGenerator Regulator's (Conventional ihd Transistor- a. Closes and opens circuit between battery and ized) - coil A,*Purpose b. Distributes high-voltage surge to spark plugs B. Cutout Relay (Circuit Breaker) 2. Location I. Purpose 3. Construction 2. Construction a. kousing a., Two wMdings b. Drive shaft (1) Current (1) Breaker cam (2) Voltage (2) Advarice-niechanism b. Core c. Breaker plate c. Armature d. Contact points d. Contacts e. Rotor e. Spring f. Cap 3. Operation 4. Qperation a. Voltage buildup 5.\Spark advance mechanisms b. Magnetic fieldproduced a. Purpose c. Spring tension overcome b. Types and operation), d. Armature closes (1) Centrifugal e. Generator current flowing (2) Vacuum 0 -Current flows-torbattery -from generator (3) Combinafion (2) Magnetic field buildup (4) Full vacuum (3) Points hela closed by current D. Spark Plugs f. Generator current -flowing I. Purpose (1) Current flows frorn battery to generator, 2. Location *`' 12,0 112

. Construction Section104gine-Troub1eDiagnosis a. Shell I. Engine Failure b. Insulator A. Compression Loss c. Elearodes B.Failure Of Engine to Turn.Over

(1) Center ç.Ignition,Troubles . (2) Ground 17.). carburetion Troubles' d. Terminal e. Sealing methods II. Comillessitr,.,Loss f.Threads A. Causes 4. Heat ranges 1. Cylinder bore wear a. Heat path 2. Improper valve timing , b. Hot 3. Improper valve seating c. Cold 4. Cylinder-head gasket 5. Spark gap 5. Cracks 6. Oper. B. Trouble Checklist E.Ign ti Coil -1. Crank engine; diagnose ccinfression noises., I.urrtfge__ 2. Make comprdssiorrtest 2 Location 3. Observe valve action , Corlgtruction 4. Check valve adjustment . ais Case HI. Failure of Engine to Turn Over b. Coils (wire) A. Causes (11 Primary I. Piston and ringfir'f: (2) Secondary 2. Bearing clearances c. Iron core 3. Valve action d. Insulatino materials 4. Lubridation system e. TerminaIs 5. Cooling system (1) Prim 6. Starting system (2) Seco B. Trouble Checklist 4. Operation .1. Check lubricating oil a. Creating magnetic field 2. CheCk water b. Collapsing magnetic,field: primary Turn crankshaft by hand, if possible c. Collapsing magnetic field: secondary 4. Observe valve action d. Capacitor (condenser) effect 5Diagnose abnormal knocks and noises F.Ignition Switch 14% IV: Carburetion Troubles 1 Purpose , -Ai, Causes 2. Operation 1. Carburetor circuits G. Wiring Diagram '\a. Float 1. Primary circuit b. Idle . 2. Secondary circuit c. Part throttle ft .Ignition Timing Marks d. High speed 1. Purpose I e. Accelerator pulp 2. Location f.Choke X. Electrical Circuits 2. Fuel pump A. Horn - 3. Fuel tank

.B.Lights (Internal) 4. Fuel lines C. Running Lights 5. Manifold find exhaust system 1. Headlights B. Trouble Checklist 2. Tailfights '1. Theck fuel level in tank 3. Stop lights 2. Check accelerator action 4. Back-up li s 3.1 Remove carburetor fuel line; crank engine D. Directional Signals 4. Check fuel pump E.Accessories 5. Test fuel lines XI. Relays A. Purpose V. Ignition Troubles B. Uses A. Causes 1. Lighting 1. Primary system 2. Horn a. Battery 113

b. Switch . E. Flywheel and 'PressurePlatePermittedto Turn c. Primary winding UndependentlY of Friction Disk d. Connections III. Types of Clutches e. Voltage-drokra resistor A. AllSimilar in Construction and Operation f.Coil primary-winding I. Expanding clutches g. Distributor points 2. Contracting clutches h. Capacitor (condenser)" 3. Cone clutch i.Ground return to battery 4. ,Dry-disk tlutches 2. Secondary system ,ta. Coil pressure-spring type , a. Coil secondary-winding b. Diaphragm-spring type b. _Distributor, rotor Crown pressure-spring.type c. Distributor cap_ UltiOe thy-disk 'clutches (1) Broken ' il-bath disk clutches (2) MAture Multiple disk High-tension wiring gingle disk e. Spark plugs Mo*commonly Used Clutch: Single Dry-Disk 1. Ground return' through Part of primary system . .3y. FrictiOn Disk-. B. Trouble Checklist (Use of Juepper Wire andAreti(- A. Hub Assembly CI meter) .1. Splined hdb I. Remove coil wire from distributor a. Splined to clutch shaft < a. Crank engine , b. iAllows mt;yement lengthwise b. Check'spark f. ;Forcealigt to turn with clutch shaft 2. Check battery side of coil d. :Must fiesringly yet without drag or bind h -* :Torsional springs a b. Inspect wi,tirtg battery connections a.Adced between drive*ashers 3. Check distribUtor side o b. c4bøfbs torsional vibration from en! Clink points .!TAbsorbs some engaging shock b.. Inspectleviring and convaions c.Sheck-5ipacitor (condenser) Vane' Ve.ivasherS, 4. Check ignition timing 5. Moldid friction,,vasher a. Licated bet'eenhub'\41ange and drive wasker Section 11: Clutches b. Prevents oscillation betveen hub flange ands, drive washer I. Purpose of Clutch 4 6. Movement of hub flange limited,by stop pin A. Used with Standard 'Transmissions B.Disk Assembly B. Couples or Uncouples Engineiand Transmission 1., Friction rings or clutch facings I. Coupled vosition (normal running) a. Made of frictional material a. Power to transmission (1) Asbestos main part of composition b. In gear: power to rear wheels. (2) Heat-resistant materials .Uncoupled position .. b.Providas proper dmount of slipping wh'en start- W r a. Allows gears to be shifted easily ing , b. lo,wkii4 to ryn with transmission in gear c. Providespositive-nonslippingdrivewhen C. ProvidGraffifil;thut Positive Application. of Engine elaged. Power to Peer tain , d. Usually riveted tocughionint SPrings 1 .MineniZes shoal 2. Cushioning springs a 2. Provides comfortable starts a. Provide cushioning effect as clutch is engaged II, Principles of Operation b. Produce smoother engagement A. Frictional antact Made Between Two Smooth Metal- c. Consist of waved cushion springs lic Driving Surfaces °kid Facings -Riveted to Driven d. Waves compress when engaged Disk V. Pressure-Plate Assemlily 1. F eel and pressure plate: driving surfaces A. Pressure Plate arid Flywheel 2. F disk? driven plate .,. . 1. Both driying_surfaces B.FIy PressurePlate,- and Fittion 14sk Held 2. -Surfaces1 smooth, parallel Toge Pressure Springs .!'" .:i-- a 3. Friction disk between driving surfaces C. Hub of ction Disk Splined to Clutch Shaft r B. Clutch Cover D. Clutch Uncoupled 15y Release 9f Spring Pressure on 1. Bolted to flywheel z- -- Pressure Plate by Operation of Clutch Pedal a. Becomes part of flywheel a

122 ' 114 so

b. Rotates with flywheel- 2. Mounted on throw-out collar c. All parts of pressure-plate assembly attached to 3. Moved forward,against release levers

clutch cover ( 4. Turns with the relear levers 2: Houses pressure spring arrangement 5. Depresses releaselevers, disengaging clutch . eA 3. Houses clutch release Mechanism VII. Cluteh Pedal and L4inkage - C. Pressure Springs A. Effects of Depressing Clutch Pedal .Coil 1. ClutcA pedal arm depressed a_ Contains three to nine' springs 2. kotation of clutch pedal shaft b. Spring loads frictitudisk between pressure 3. AdjUsting link pushed or pulled plate and flywheel when coupled 4. Rotation of cross shaft (if included) c. Clutch released by compression of springs S. Forward movement of throw-out fork 2. Diaphragm (tapering-finger type) a. Forward movement of throw-out bearing a. Provides spting prestuft-to pressure plate b. Release levers depressed b. Acts as release levers c. Pressure plate pulled awky from friction disk c. Reacts similarly to bottom of oil can when B. Effects of Rgleasing Clutth Pedal depressed 1. Return of clutch pedal arm (assisted by return (1) Tapered fingers depressed spring) (2) Diaphragm pivots on pivot ring 2. Clutch fork pulled back by linkage (3) Outer edge raises Throw-out.bearing pulled away from release levers (4) Works against retracting spring to pressure 4.' Return of release levers plate 5. Pressure plate, friction disk, and flywheel com- (5) Pressure plate pulled away from friction preSsed by pressure springs 'disk 'C. Hydraulically Clutch Operated d. Clutch engaged by built-in spring tension of diaphragm VIII. Clutch Shaft Suppqrt 3. Crown A: Crankshaft End of Clutch Shaft Supported in End of a. Variation of diaphragm type Crankshaft or Center of Flywheel by Bushing, Roller, b. Diaphragm formed of single corrugated plate of or Ball Bearing spring metal B.Shaft to Be in Perfect Alignment (Will not "Whip") c. Action (same as in V.C.2.c.) IX. Semicentrifugal Clutch D. Release Levers A. Clutchimilar in Construction to Coil-Pressure-Spring- 1. Purpose: to disengage clutch by relieving spring Clutch pressure to pressure plate B. WeightsRlaced on Outer Ends of Release Levers a. Coil-spring type C. Added Pressure on pressure Plate Exerted by Release (1) Usually three levers Levers Becauge of Increased Speed (2) Adjustable D. Genaifugal Action When Clutch Begins fo Revolve (a) Adjustment screws X. Clutch Trimble Diagnosis (b) Uniform pressure -A. Slipping b. Diaphragm-spring type B. Chattering or Grabbing ...... (1) Tapered fingers C. Spintiinlor Dragging (2) Nonadjustable D. Noises (When Engaged, Disengaged) c. Crown-spring type E. Pedal Pulsation (1) Corrugated edge release F. Friction-Dnsk Facing Wear (2) Nonadjustable 2. Release levers depressed by throw-out bearing Section 12: Standard Transmissions and Overdrives

VI. Throw-Out Mechanism e I. Purpose of Transmission A. Clutch-Shaft Bearing Retainer and Sleeve A. Provides Means of Varying Gear Ratios Between 1. Front transmission bearing retained Engine and Rear Wheels 2. Clutch shaft covered by sleeve 1. Ratios between engine andgrear wheels (approxi- B. Throw-Out Collar matel) 1. Slides on clutch shaft sleeve a. Low gear 12 to 1 , b. Second gear/ 8 to 1 2. Holds throw-out bearing \ C. Clutch-Release Fork c. High gear 4 to l 1. Pivots on flywheel housing: ball stud d. Reverse gear 12 to 1 2. Moves throw-out bearing and collar forward 2. Ratios between clutch shaft and transmission main D. Throw-Out Bearing shaft 1. Sealed ball bearing a. Low gear 3 to 1 123. 115

b. Second gear 2 to 1 4. Main-shaft second and high sliding gear c. High gear I to I 5. Reverse idlergear d. Reverse gear 3 to I B.Shafts B. Provides Reverse Gear for Backing Car I. Clutch or pilot shaft 2. Countershaft, II. Transmission Gears 3. Transmission main shaft A. Relative Speed of Rotation (Gear Ratio) 1. Speed determined by number of teeth 4. Reverse idler gear shaft a. Same number of teeth C.Thrust Washers (1) Tum at same speed 1. Countershaft (2) Gear ratio: 1 to I 2. Main shaft 3. Reverse idler shaft b. Different number of teeth Bearings (1) Smaller gear turns faster D. 1. Clutch gear bearing (2) Large gear 24, smaller gear 12; gear ratio: 2 2. Main-shaft rear bearing to 1 3. Front pilot bearing 2. Number of teeth of driven gear divided by number 4. Countershaft bearings of teeth of drivinglear to determine ratio 5. Reverse idler bearing B. Direction of Rotation E.Bearing Retainers 1. Turn in opposite directions (wlien two gears Mesh) 1. Clutch gear bearing retainer and throw-out bearing 2. Idler gears sleeve a. Change direction of rotation 2. Main-shaft bearing retainer b. Do not change gear ratio between driving gear F.Transmission Case and driven gear G.Shifting Mechanism C. Types of Gears 1. Shifting forks 1. Spur gear 2. Shifting levers (side mount) 2. Helical gear 3. Cover 3. Bevel gear 4. Skew-bevel gear V. Operation of Basic Standard Transmission 5. Worm gear A. Neutral 6. Rack gear B. Low Gear 7. Pinion gear C. Second Gear 8. Planetary gears D. High Gear . a.Internal or ring E.Reverse Gear b. Planetary c. Sun VI. Gearshift Lever (Transmis d. Spider or planet carrier A. H-Pattern B. Two Separate Motions III. Torque (Transmission) 1. Selection of gear assembly A. Change of Torque According to Gear Ratio 2. Movement of gear assembly B. Torque in Any Turning Shaft or Gear I. Torque applied to crankshaft Transmission Synchronizing Device (Synchromesh) 2. Torque supplied by crankshaft to gears in trans- Gears About to Mesh Made to Rotate at Same Spied mission so that gears turn 1. Mesh without clashing of gears 3. Torque carried through power train to rear wheels, 2. Easier shifting 3. Less wear on,transmission parts causing rear wheels to turn C. Torque on Gears Measured as Straight-Line Force at Synchromesh Types 1. Cone-clutch type (Ford) Distance from Center of Gears 'D. Torque Ratio Opposite to Gear Ratio 2. Pin type ('Doscl_ge) E. Torque Increase Caused by Reduction of pear Speed Constant-Mesh Transmission Main-Shaft and Countershaft Second Gears Always in IV. Basic Standard Transmission Mesh A. Gears Constant Mesh- Used in Conjunction with Synchro- 1. Clutdilbr main drive gear mesh 2. Cluster gear or countershaft gears Principles of Operation a. Countershaft drive gear b. Countershaft second gear IX. Selector and Shifter (Transmission) c. Countershaft low gear A. Types of Selector and Shifter Devices d. Countershaft reverse gear B. Steering-Column Gearshift Mechanism 3.. Main-shaft low and reverse sliding gear C. Floor-Shift Mechanism 116

X. Transaxle Units: Similar in construction and operation c. Sun gear rotating faster than cage to other standard transmissions d. Driven member turning fastef than driving4 member XL Purpose of Overdrive 3. Speed reduction (ring gear turning) sk` A. Establish More Favorable Gear Ratio a. Ring gear turnchg_ B. Reduce Engine Speed at High Car Speed b. Sun gear stationary C. Provide More Economical Operation c. Planet-pinion cage turning slWer than ring gear D. Lessert.Entdue and Accessory Wear Pei Car Mile d. Driven membes -turning slower than driving E. Drop Engine Speed About 30 Percent member XII. Method of Operation f Overdrive) 4. Speed reduction (ring gear stationary) A. Automatic a. Ring gear stationary 1. Operation automatic at about 30 miles per hour b. Sun gear turning 2. Selective c. Planet pinions 4 a. Direct drive (1)Turn on shafts b. Into overdrive: foot to be raised from acceler- (2) "Walk around" ring gear ator '(3) Planet-pinion cage rotates c. Out of ove0ive d. Cage rotating slower than sun gear (1) Accelerator to be_ depressed "wide open" e. Driven member turning slower than driving (2) Throttle switcfr actuated member B. Two Separate Controls 5. Reverse (planet-pinion cage stationary) I. Centrifugal device (governor) a. Planet-pkion cage stationary 2. Electrical control (solenoid) b. Ring geii turning Freewheeling Mgithanism (Overdrive) c. Planet pinion Coupling Between Two Shafts in Line with Each (1).'Acts as reverse idlers Other (Overrunning Clutch) (3) Causes sun gear to turn in reverse direction 1. Inner shell to ring gear 2. Outer shell d. Sun gear turning faster than ring gear 3. Rollers'between 6. Reverse (planet-pinion cage stationary) Solid Drive When Power Delivered to Input Shaft a. Planet-pinion cage stationary Output Shaft Ovefrun Because of SloWdown of Input b. Sun gear turrimg Shaft c. Ring gear turning opposite ,to and slower than 1. Uncoupling of clutch sun gear 2. Free turning of output shaft 7. Direct drive .a. Any two members locked together: then entire 3. Input shaft on transmission planetary-gear system locked, and input and 4. Output shaft on propeller shaft Mechanical Principles of Operation output shafts turn at same speeds bNo member held stationary and no two mem- XIV. Planetary-Gear System (Overdrive) bers locked together: system will not transmit A. Components power at all 1. Outer ring gear (internal gears) C. Appliggion to Overdrive 2. Three planet pinfions 1. Riggear attached to output shaft 3. Planet-pinion cage 2. Planet-pinion cage splined to transmission main 4. Planet-pinion shafts ( shaft 5. Sun gear 3. Sun gear 6. Sun-gear shaft a. May be permitted to turn free 7. Ring-gear shaft b. May be locked in stationary position B. Principles of Operation (1) Ring gear (output shaft) forced to turn 1. Speed increase (sun gear stationary) faster than transmission main shaft a. Planet-pinion cage turning (2) Transmission main shaft "overdriven" by b. Sun gear stationary output shaft c. Planet-pinion shafts carried aroundwith cage d Planet pinions XV. Nomenclature (Overdrive) ( I) Rotate on shafts A. Clutch Cam (2) "Walk around" stationary sun gear B. Transmissidn Main Shaft (3) Cause ring gear to rotate C. Sun Gear 2. Speed increase (ring gear stationary)' D. Pinion-Cage Assembly a. Ring gear stationary E. Ring Gear b. Planet-pinion cage turning F. Pinions 125 117

G. Output Shaft XVII. Overdrive Electrical Components , ' H. Output-Shaft Bearing A. Battery 4.3 I.Clutch-Cam Rollers B. Ignition Switch J.Control Shaft and Lever C. Relay K. Shift Fork D. Kick-down Switch L. Solenoid Assembly E. Governor Switch M. Control Rod F. Ignition Coil and Distributor N. Sun-Gear Pawl G. Solenoid 0. Blocker Ring 1. Ground-out contact P. Sun-Gear Plate 2. Pull-in and hold-in winding Q. Governoi H. Wiring

XVI. Overa,rive Operation Section 13: Automatic Transmissions A. Going into Overdrive 1. Car speed approaching 18 to 20 miles per hour I. Main Sections of Automatic Transmission 2. Sun-gear pawl retracted A. Clutch Coupling or Torque Converter 3. Governor closing electrical contact B. Planetary Gear Box 4. Solenoid energized H. Fluid Coupling (Torus) a. Spring loading solenoid pawl A. Fluid Coupling Theory b. Pawl held away bY blocker ring 1. Two fans facing each other 5. Accelerator pedal momentarily released by driver 2. Oil coupling driving and driven torus (straight a. Engine speea dropping vanes in both torus units) b. Freewheeling mechanism 140tg into action B. Engine Flywheel to Torus Cover Drive c. Output - shaft , overrunning transmission main C. Torus Cover to Driving Torus shaft D. Driven Torus and Input Shaft (1) Sun gear slowing and reversing direction E. Acts as Clutch (2) Moving blocker ring III. Torque Converter (3) Pawl moving inward A. Torque Converter Theory (a) Registers with notch on sun-gear con- 1. Two fans facing each other trol plate 2. Stator redirecting oil at different angle to turbine (b) Locks control plate: stationary 3. Torque multiplied (c) Locks sun gear: stationary B. Engine Flywheel to Torque Converter Cover 6. Driver accelerating and engine .speed ihcreasing: C. Pump (impeller) to Stator to Turbine car going into overdrive (See XIV.B.1.) D. Turbine to Stator, Where Oil Is Returned to Pump B. Coming Out of Overdrive: Accelerator Pedal De- 1. Turbine driving input shaft pressed 2. Spiral vanes on turbine 1. Operates kick-down switch E. Three Jobs of Stator 2. Produces two actions I. As stationary member for oil to push against a. Opens solenoid circuit 2. Redirects oil to pump (1) Attempts to withdraw pawl 3. Overruns (like a bicycle coaster brake) when car (2) Considerable pressure against pawl reaches cruising speed b. Grounds out ignition circuit F. Torque Conversion Ended at Ccuising Speed, with (1) Prevents engine from delivering power Coupling Taking Place (2) Relieves driving thrust on sun gear (3) Pawl pulled backsby solenoid IV. Pfanetary Geats (4) Ignition circuit reopened by solenoid (Review Section 12 of this outline.) C. Locking Out of Overdrive: Control Knob Pulled V. Automatic Transmission Operation 1. Actuates control rod A. Oil Pump (to Supply Pressure) 2. Moves shift fork B. Pressure Regulator Maintaining Constant Pressure a. Sun gear meshingwith ring gear C. Shift Valve Directing Oil to Band-Seryo or Clutch- b. Sun gear and ring gear locking Piston Action 3. Locks sun-gear pawl D. Manual Valve Turning Oil Pressure On or Off D. Reversing E. Governor I. Overdrive to be locked out (shaft mechanism 1. Operated by centrifugal force to make shifts occur reversed by transmission) automatically 2. Overdrive control rod moved to lockout position,. 2. Attached to transmission output shaft and thus when reverse shift is made sensitive to car speed 126 118

-F.Throttle Valve I. Construction 1. Operated by accelerator pedal position to time a. Propeller,shaft enclosed shifts - b. Universal joints 2. Wqrks in opposition to governor pressure and thus (1) Type-used sensitive to engine speed (2),Number i,( VI. Automatjc Transmission Maintenance c.Universal ball jOint A. Checking Oil Level , d. Slipijoints - B. Changing Oil e. Support members 2. Rear-end torqUe 'absorption Section 14: Drive Lines 3. Push delivered to front section of chassis B. HotEhkiss Drive I. Purpose of Drive-Line Assembly d I. Construction ..." A. Trinsfers Power from Transmission to Differential a. Propeller shaft exposed CI. Change in angle b. Universal joints 2. Change in length , (I) Type used B. Absorbs Rear-End Torque (2) Number II. Components of Drive Line c.Slip joints A. Universal Joints d. Support members B.Slip Joints- )2. Reat-end torque absorption CPropeller Shaft 3. Push &livered to rear section of chassis . Torque Tube C. Curved Flexible Shaft . Universal Ball Joint I. Construction F. Supporting Members a. Three-inch bow III. Universal Joints b. Ball-bearing pillow blocks A. Purpose c. No slip joints B. Types . d. No universal joints I. Cross and Yoke 2. Rear-end torque absorption a. Yoke 3. Push delivered to rear section of chassis b. Spider c. Trunnions Section 15: Rear Axles and Differentials d. Needle,bearings I. Purpose of Differential 2. Ball and trunnion A. Transmits Rotaiy Power Through Right Angle a. Propeller shaft b. Pin B. Allows Different Rear-Axle Speed /. Prevents skidding in turns c. Body 2. Improves steering control d. Ball. e. Needle bearings II. Types of Differentials f.Centering button A. Conventional g. Grease cover B. Nonslip (Limited Slip) 3. Constant velocity. C. Transaxle a. Reasons for III. Differential Components (Major) - b. Construction A. Differential-Side Gears (1) Body B. Differential-Pinion Gears (2) Balls C.Differential-Pinion Shaft C. Operation D.Differential Case I. Cross and yoke . E.Ring Gear 2. Ball and Trunnion F.Drive Pinion 3. Constant velocity G.Drive-Pinion Carrier and Caps a. Bendix Differential-Bearing Adjusters b. Double cross and yoke Differential Bearing (Cone and Rollers) IV. Slip Joints J.Axles (Axle Drive Shafts) A. Purpose IV. Differential Power Flow B. Types A. Drive Pinion Driven by Propeller Shaft I. Splines B. Drive Pinion Meshed with Ring Gear 2. Built-in (ball and trunnion) C. Ring Gear Bolted to Differential Case, Causing Case V. Types ot Drive to Turn (Rotate) A. ,Torque-Tube Drive D. Differential-Pinion Shaft Mounted in Case

127 119 . E. Differential-Pinion Gears Mounted on Shaft IX. Differential Trouble Diagnosis F.Differential-Pinion Gears Meshed with Side. Geari A. Noises Mistaken for Gear-Axle Noises G. Differential-Side Gears Sp lined to Axles I . Road noise 2. Tire noise V. Differential Gear Action . 3. Front-wheel bearing noises A. Stfaight Ahead 4. Engine and transmission noises , 1. Differential-pinion gears noflotating B. Rear-Axle Bearing r 2. Equal pressure exerted on side gears I ...Wheel bearing a. Bothwheels turning at same speedL 2. Side gear and pinion B. Turning 3. Pinion bearing 1. Two pinion gears rotating on shaft 4. Ring and pinion noise 2. -More tnnung movement exerted" to outer side gear a. Drive with same amount of torque b. Coast 3. Outside wheel turning more rapidly c. Float d. Drive, coast, 'and float VI. /;ionslip Differential 5. Nonslip differential chatter A. Similar in Constructibn to Conventional Type B. Incorporates Two' Sets of Clutch Plates (or Cones) Between Side Gears and Caw Section 16: Suspension Systems C. More Power Instead of Less Applied to Drive Wheel I. Purpose Hdid to Turn A. Support Weight of Front End of Car VII. Differential Gearing B. Permit Steering Of Car: Provide Safer Steering Control A. Manner of Gear Reduction C. Absorb Shock Through Springs B. Variance of Ratios According to Make, and Appli- D. Provide Ride Control cation II. Types of Front Suspensiov---N

, 1. Passenger cars (3.36: I to 5:1) A. Rigid Axle 2; Heavy-- duty applications (9:1 by double reduc- B. Independent Front Suspensio tion) III. Rigid Axle C. Calculation of Gear Ratio ls A. Applications D. Types of Gears I .Heavy-duty trucks and buses .Spur (obsolete) 2. Industrial vehicles 2. Spiral bevel (nearly obsolete) 0.606,1/ Early model autos a. More geag. tooth contact . onstruction b. Even wear I Beam c.- Quieter operation 2.\ Steering knuckle 3. Hypoid 3. \Kingpin a. Similar to spiral bevel 4. Leaf spring b. Drive pinion lowered C. Characteristics c. Wiping action I .Both front wheels affected by 'any surface change d. Needs special lubricant 2. Gyroscopic effect of tilted wheels E. Nomenclature of Gears I . Toe IV. Independent Front Suspension 2. Heel A. Construction 3. Flank I . Upper control arm 4. Face 2. Lower control arm 5. Pitch line 3. Steering-knuckle support F. .Gear Measurements 4. Steering knuckle I .Clearance 5. Spring 24Backlash 6. Stabilizer shaft or sway bar 7. Shock absorber VIII. Rear Axles B. Operating Characteristics A. Purpose I .Wheels completely independent of each other B. Types 2. Better ride control I . Dead 3. Smoother ride 2. Live C. Variations in Design of Independent Front Suspen- a. Semifloating sion b. Three-quarter floating I .Coil spring c.Full-floating 2. Transverse leaf spring

128 120

3. Torsion-bar spring VI. Shock Absorbers 4. Ball-joint front suspension A. -Purpose a. Replaces steering knuckle and support I . Dampen spring osc lations b. Uses spherical joints 2. Keep wheels on pa ement c. Uses fewer moving parts 3. Provide better con rol 4. Provide smooth ride V. Springs B. Types A. Purpose I .Hydraulic -2"°'10.'Sperating Characteristics a. Direct-acting 1. Rate b. Opposed-cylinder 2. Frequency c. Parallel-cylinder C. Types d. Rotating-vane I .Leaf 2. Friction 2. Coil' C. Theory of Operation 3. Torsion bar 1. Hydraulic principles 4. Air suspension ( 2. Forcing liquid through orifThe D. Leaf Spring Testing I . Common types VII. Front-End Geometry a.Serhielliptic A. Definition, b. Quarter elliptic B. purpose 2. Installation 1. Provide steering ease a. Transverse 2. Provide steering stability `4 b. Longitudinal 3. Provide maximum tire life 3. Construction 4. Provide ride quality a. One or more leaves C. Classifications b. Master leaf 1. Camber c. Spring seat a. Positive d. Cvter bolt b. Negative e. U-bolt 2. KingPin inclination f.Rebound clips 3. Caster g. Spring eye . a. Positive, h. Spring hanger b. Negative i.Spring shackle 4. Toe-in j.Bushings 5. Include angles E.Coil Spring 6. Toe-out on turns 1. Operating characteristics D. Methods of Adjustment a. Free of friction b. Requires efficient shock absorber 2. Installation Section 17: SteeringeSystems a. .Requiresjinbge to support,v,ehicle.thrust, I. Purposepf.Steering5ystern b. Used priniarily in front suspension A. Guide Car F. Torsion-Bar Spring B. Provide Easy Steering I. Operation II. Early Steering Systems a. Twisting action A. Tiller b. Free of friction B.Fifth-Wheel Steering c. Provision for adjustment III. Ackerman Steering System d. Lightweight A. Front Wheels Supported on Pivots 2. Constructip B. Front Wheels Linked to Steering Wheel by Gears and a. Spring-steel round shaft' Levers b. Linkage c. Adjustable anchor IV. Classification of Steering Systems G. Air Suspension anual 1. peration e r 2. Construction 1. Integral or hYdraulic . 2. Linkage or mgchanical a.Air-bag or air-spring aSsembly b. Air compressor V. Manual Steering Gears

. c. Leveling valves A. Recirculating Ball and Nut

129 121 ,

B. Worm and R011er / III. ftypes of Tires C. Cain and Lever - 'Sad B. Pneumatic VI. Steering Linkage I. Tube A. Steering Wheel 2. Tubeless 11. B. Steering Shaft 3. Puncture-sealing C. Steering Gear C. Materialg D. Pitman Arm I. Natural rubber 4 E. ,Drag Link or Steering Connecting Rod .. 2. Synthetic rubber F: Tie Rod(s) . G. R,dlay Rod IV. Tire Sizes A. Rim Size H.- Steering Arms B. 'Thickness at Sidewalls Steering Knuckles I. I. Inflated 1. Knuckle support 2. No load 2. jKingpin J.Ball Joints V. Inner Tubes K. Spindle A. Materials L. .Wheel Bearings I. Rubber. 2. Synthetic VII. Power-Steering Opeiation B. Air Valve A. Hydraulic I. Stem I. Power-steering pumps a. Construction 2. _Core 3. Cap b. Operation c. Location - C. Special Tubes 1. Puncture-sealing 2. Power-operating mechanism 2. Safety tube a. Valve operation b. Power cylinders VI. Tire Inflation B. Mechanical A: Proper Inflation L Construction B. Low Pressure a 2. Operation I. Hard steering 34. Location 2. Front-wheel shimmy. 3. Steering kickback 4. Side of tread worn /Section18: Tires and Tubes Excessive flexing I. Purpose of Tires a. Heat b. Ply separation A. Provides Cushion I. Absorbs shock 6. Rim bruises 2. Tire flexes 6 C. Excessive Pressure NovidesFrictional-Contact \ genterof tread,worn I. Minimizes skidding on films Hara ride-ZS 2. Provides for quick stops Fabric ruptw D. Uneven Pressuie (Pulls to Side) II. Ca§ing Construction VII. Tire Rotation A. Plies (Variable Number) A. Purpose B. Beid B. Procedure C. Sidewall I. Bladk 4 VIII. Causes of Tire Wear 2. White A. Excessive Speed . 3. Colored B. Improper Inflation "%.- D. Curb Bead C. Improper Front-Wheel Alignment E. Sh9ulder I .EAcessive camber F. Tread 2. Excessive toe-in or toe-out I. Design D. ImproPerly Adjusted Brakes 2. Purpose E. Unbalanced Wheels a.PrOlide traction F. Incorrect Steering-Linkage Adjustment b. Reduce surface area IX. Recapping and Regrooving Tires . & Cool tire 122

Section 19: Wheel Balance 2. Greasy I. Purpose of Wheit Balance 3, Viscous A. Provide Easeig Steering B.Factors Affecting Friction B. ProvideiContfortable Ride 1. Pressure applied or load C. Provide Maxiinum Tire Milea e 2. Roughness of surface 3. Type of materials H. Problems of Balancing Wheel C. Types - A. Centrifugal Forte 1. Static friction (at re B. Making Wheel Rtitt True (Mt Be Round) 2. Kinetic friction (in mon) C. Flexing of Tire on Wheel D. Cause: Surface Irregularities D. Wheel Tramp (Bowice and Wob e E. Application III. Types of Wheel Iiribalance (Out of Balance) 1. Brake shoe and brake drum friction A. Static a. Slows wheel rotation \, 1. Lies in plane of wheel rotation b. Stops wheel rotation 2. Causes front and rear wheels to bounce 2. Tires to road surface friction B. Dynamic , a. Sliding stop (kinetic) 1..Lia- in zone oneither or both sides of planeof b.. Rolling stop (static) rotation 3. Front brakes larger than rear 2. Causes front wheels to wobble as well as bounce II. Hydraulics IV. Types of Balance A. Definition A. Static B.- Physical Principles of Liquids I. Balancedwheelassembly, when onspindle, 1. Not coinpressible remains in fixed position regardless of how placed 2. Transmit motion on the spindle a. Act as solids under pressure WV, 2. Weight added or subtracted for equal distribution b. Action and reaction of wheel weight around its axis of rotation 4,3. Transmit pressure B.Dynamic a. Pressure equal throughout system 1. Wheel rotation true, wifhout wobble or shake b. Pressure equal in all directions 2. Diitribution of corrective weights on both sides of c. Output force equals pressure times area wheel ,d. System pressure equal to input force divided by V. Tire Balance Marks piston area, A. Symbols Used for Marking Tires 6 --j III. Hydraulic Brake Fluid B. Markings tiaine Up with Valve Stem Hole in Rim # C. Less Accurately Balanced -Assembly Marked by Red A. Chemically Inert (Must Not Affect Metal and Rubber Dot Parts) B. Must Not Vaporize at High Temperature VI. Types of Wheel Run-Out C. Must Remain Fluid at Low Temperature ; A. Lateral D. Must Act as Lubricant 0: 1. Wheel alternately movesin and obt from center of E. Must Mix Readify With Other Hydraulic Fluids . _vehicle while-rgtating- on itsspind1e - - - -re ... .. K RV, .4".r .ar nr,,er ve.et rt .r ...... 2. Causes dynamic imbalance (out of balance) IV. Types of Brakes 3. Checked by pointer neat: side wall A. Mechanical 4. Rnn-out not to exceed 1/8 inch B. Hydraulic (Four-Wheel) 5. Corrected by remounting tire on wheel or straight- 1. Shoe ening wheel 2. Disk B. Eccentric or Radial 3. Caliper or spot I. Amount of spindle deviation fromits center Electric during vheel rotation Air 2. Causes static and dynamic imbalance (out of . Vacuum balance) 3. Checked by poiNer near tire tread V. Components of Brake System 4. Corrected by shaving tread A. Master-Cylinder Assemb y I. Brake pedal 2. Brake-pedal linkage Section 20: Automotive Brakes 3. Master cylinder I. Friction a. Body A. Definition (1) Reservoir 1. Dry (2) Cylinder

131 b. Piston B.Release (1) Primary cup I. Release brake pedal (2) Secondary cup 2. Master-cylinder piston returns c. Piston return spring 3. Brake-shoe return spring activated d. Head nut 4. Brake shoes pulled from.drums e. Check-valve assembly ,5. Wheel cylindel pistons forced inward f.Push rOd 6. Liquid returning to master cylinder g. a. Pressure dropping 4. Dual er Cylinder b. Check valyegclosing B. Wheel Bra echanism (1) Maintains some pressure in system 1. Wheel cylinder (2), Keeps fluid in. a. Cylinder body (3) Keeps air out b. Pistons (1) Piston cup- VII. Accessories (2) Piston spring A. Hand Brake c. Boots I. Drive shaft d. Activating spring 2. Rear wheel e. Bleeder valve B. Power Brakes 1. Purpose 2: Brake-shoe assembly 2. Basic principles of operation a. Backing plate b. Brake shoes C. Self-Adjusting Mechanism 1. Purpose (1) Friction material 2. Method of operation (2) Primary shoe D. Hill Holder (3) Secondary shoe 1. Purpose c. Anchor pin 2. Method of operation d. Hold-down spring E.Stoplight Switch e. .Brake-shoe return spring 1. Mechanically operated f.Adjusting mechanism 2. Hydraulically opergied Hydraulic Brake Lines I. ial type 2: Stee pipe Section 21: Purchaging Automotive Parts 3. Fittiigs 4. Fle1ible hose I. Make of Automobile a. Front.wheel connection A. Model . r ax1e connectibn B. Year . . ,) VI...Hydraulic Brake OppratiOn. 11. Engine Type A. Application A. Number of Cylinders I. Brake pedal depressed B. Cylinder Arrangement Aaster,cy.1 inder.piston. Erwin& Nalve-Arrangement . a. Compensating port covered D. Cubic-Inch Piston Displacement b. Hydraulic fluid trapped in system E. Horsepower Rating (1) Fluid moving in system (2) Fluid under pressure Exact Part to Be Purchased 3. Wheel cylinder pist9ns moved outward A. Location -; a. Activating pin moved outward B. Casting Number (if available) b. Brake shoes forced against drums C. Part Number (if available) .c.Frictional contact D. Design (1) Heat I. Type (2) Dragging.reffect 2. Size 1 d. Slows wheel rotation 3. Description t, ft APPENDIX C BATTERY TERMINOLOGY

Amperage The rate of flow of electric current (movement of electrons) in aised circuit measuied in amperes

Battery A unit (two or more cells connected together) that consumes chemical energy to produce electric energy when needed

Electrolyt\k A solution of sail's, bases, or acids in water in which the negative and positive plates are immersed

. Gfid A framework-made of an alloy of lead and antimony that holds an active material

Hydrometer An instrument used to measure the specific gravity Of a liquid

Lead-acid cell secondary cell that can be recharged

Negative plate A grid filled with sponge lead (Pb)

Overcharging Passing a direct current through a battery that has already been charged to maximum

Positive plate A grid filled with lead peroxide (Pb02 )

Primary cell A cell that cannot be recharged

. 0. Secondary' cell A cell that can 1:+charged

;.- . . . Separa tor .An insulating mat6ria1 made of wood, glass,1or rubber that serrates ihe positive and negative plates

Specific gravityThe weight of any volume Of a liquid divided by the weight pf an equal volume of water or the ratio of the density of a substance to the density of a standard.

Siilfation A process in which lead sulfate'coats the plates of a lead-acid battery that has been allowed to remain partially charged

Sulphuric acia The electrolyte of a lead-acid battery and water . Voltage Electric pressure', electromotive forceemf) that causes current flow (movement of electronswhen the external circuit is closed

133

.10 124 APPENDIX D

ASSIGNMENT 'SHEETS -1

Unit 17: Four-Cycle Engines Eiplain briefly what takes place during the following strokes: lntake '

CompressiOn:

Intake ; -

Compression Power.

fIr- '

7 Exhaust.

Exhaust

134,

125 4 .126 4--4

Unit 22: Storage Battery

1. Whgris the purpose of a storage battery'

2. What is the major difference between a stotage batte"and a cell'

3. What is meant by the capacity cif a battery'

4. What dete,rmMes the capacity of a battery" 5. What are the chemical§ used in'a conventional atlilbmobile battery?

A. C 6. What is a plate grid'

7. What is the e(omposition of a plate grid' 8. What imeaiit by the overcharge of a battery'

9. What is.a plate group9 10. The two types of plates used'in a lead-acid ce11..are:

A. B 11. How are the plates held apart' 12. What would happen if the plates touched" 13. Why are the separators made of wood, glass, or rubber'

14. What is the electrolyte of a storage battery' 15. Describe first aid procedures when an electrolyte is spilled on a person'

"". 16. Explain what happens when the electrolyte is added to a dry-charged storage battery:

17. What is the maximum voltage of a storage battery cell' 18. What will-occur when the two terminals of a battery are connected through.an external circuit" .19. From which direction-does internal.current flow in a battery' 20. Describe what occurs when a continuous supply-of curient has been used from a battery

135 127

21. Describe the chemical activity involved in recharging a battery

22. How many.tells are there in a 6-volt battery? In a 12-volt battery? How are the cells connected? 23. What two things determine the battery rating?

A B. 24. Of what material is the automobile battery case made? 25'. What type of water should be added to a battery if the electrolyte becomes low?

26. How is the specific gravity of the electrolyte in a battery determined?

27. What is meant by a dry-charge battery? ,

.13

40,

136 128

Unit -23:11agneto and Generator

1: What iS a permanent magnet?

2. How is a magnet identified? 3. What makes up the external magnetic field between the two poles of 4 magnet?

4. In what direction do magnetic lines of force move? 5. What are two characteristics of lines of force?

A

B. 6. What will happen when unlike poles of a magnet are brought together?

7. What is magnetic repulsion? 8. What is formed around a wire when current is flowing through it?

9. How can the magnetic lines of force around a wire be demonstrated?

10. State the left-hand rule-

11. What is an electromagnet? 12. Ex Plain briefly- What hapPeni to the- maknetic, lines bf Otte aroUnd tWo parallel wites that- have electric current -flowing- through them:

13. What is the purpose of a magneto? °

14. How is a magneto driven?

15. What is the purpose of a generator?

16. How is a generator driven.?

137 129

17, Describe a simple magneto

.18. What is the meaning of a "load" in a generator circuit9

19. Explain the major difference between a simple direct-current generator and an alternator

20. How is current generated in the windings of an armature9

21. What is the source of the current that flows through the field windings9

22. What effect does the current flow hikve on the field of an electromagnet7

23. What kind of current is produced in the armature of a direct-currentgenerator9

24. How is the generator made to produce more current when its load is increased9

25. The three basic parts of a generator are

26. What are slip rings9 27. What is a commutator9i 28. What is the function of brushes in a generator? 29. Where are the generator brushes located? 30. Why must the output of the generator be controlled9

31. What two devices must be used in controlling the output of the generator?

A.

138 130

Unit 23: Rectification and Regulation I. What is rectification qcurrent? z

2. Describe a silicon diode rectifier

3. What is half-wave rectification?

4. What is full-wave rectification?

5. Describe pulsating current 6. What is another name for a cutout relay? 7. What device made it possible to adapt alternators for use in automobiles?

8. Where is the cutout relay located in the electrical system?

9. What are two functions of the cutout relay?

A

10. Describe a cutout relay-

L 11. When the direct-cu,rrent generator is in operation, what allows current to flow to the storage battery?

12. When the alternator is not operating, what prevents current from flowing from the battery through the generator?

13. Vhat causes the contact points of the regulators to close?

14. What causes the contact points of the regulators to open?

15. Give two rewlts that will cause damage if the generator output is not regulated:

A

B. 16. What is the purpose of the voltage regulator?

1 3 9 131

17. Does the generator always charge the battery at the same rate?

. Explain

18. To which generator circuit is the voltage regulator connected?

19.4As the battery approaches a charged condition, what happens to the voltage applied to the field coils?

20. What is the effect on the magnetic field around the armature as the voltage applied to the field coilchanges?

21. What happens when a predetermined voltage is reached at the output terminalsof a generator circuit?

22. Describe what happens in the voltage regulator when the outputvoltage of the generator drops below a predetermined voltage.

23. Why is a voltage regulator referred to as a vibrating voltage regulator?

24. Are current regulators similar to voltage regulators? What is the basic difference?

25. Why isacurrent regulator described as a vibrating current regulator?

26. Where are the diodes installed ih an automobile alternator?

27. Is a cutout relay needed in a transistorized regulator system?

140 132

Unit 24: Electricity/Electronics

1. What is the nucleus of an atom9 2. A proton in the nucleus of an atom has a charge, and the electron atside the nucleus has a charge. 3. When free electrons collect in one place, a is formed. 4. When these free electrons move from one,place to another, it is called

5. What two devices in the automotive electric system provide emf? A. 6. What terminals are found on an automobile baRery or alternator9

7. What substances allow electrons to move freely9 8. How is the negative (-) terminal determined9 Positive (+) terminal? 9. Why is copper wire a good conductor9

10. Why is rubber a good insulator?

11. What normally covers a conductor9 12. Defme voltage 13. If the voltage is increased, what will be the results on the electron movement?

14. How is voltage measured9 15. What is amperage9 16. How is amperage measured9 17. What is meant by resistance?

18. Why is there more resistance in a small wire than in a lar6 wire9

19. Why is the resistance less in a short wire than in a long wire2,

20. How is resistance measured?

21.* State Ohm's law (in words)

141 133

22. What is the basic formula for Ohm's law9 23. In the formula, what instruments are used to measure each of the follm-ving9

E =

24. Using Ohm's law, how much voltage is required to force 8 amperes of current through a resistance of 4 ohms9

25. Describe a series circuit. if

26. Describe a parallel circuit.

27. What is the advantage of a parallel circuit when a number of units are involved9

28. How are switches wired into a circuit9 29. What happens to the voltage as it travels through a circuit9

142 ACKNOWLEDGMENTS . . The Bureau of Elementary and Secondary Education gratefully acknowledges the assistance of the Central Califotnia Automotive Technical Committee in the preparation of Industrial Arts Power Mechanics. It was this committee that authored Industrial Arts Automotive Mechanics, published by 'the California State Department of Education in 1964. The Bureau also gratefully acknowledges the assistance of the Statewide Industrial Arts-Science Study Committee, which appraiseda set of proposed power mechaniCs activities involving the application of scientific principles; and the National Power Mechanics Review Committee, which evaluated, the' experimental edition of Industrial Arts Power Mechanics. The teachers, supervisors, or teacher educators who served as members of one or more of these committees are as follows: Californii Committee Membets Richard S. Acuna, James A. Garfield THigh School, Los'Angeles; Leslie L.ldrich, Fresno State College; Cornel Amnasan, California High School, Whittier; Glenn F. Amsberry, San Ramon Valley Hi chool, Danville; Howard Chest& Anderson, Orange Coast College, Costa Mesa; LMley A. Anderson, Sylmar High School;orman Avedian, Clovis High School; Fred A. Baer, Los Angeles Unified School District; William F. Bain, McLane High.School, Fresno; Stan C. Barrett, Taft High School; Robert C. Behzner, Rancho Cotate High School, Petaluma; William H. Bernard, Robert A. Millikan High School, Long Beach; Thomas W. Birch, Luther Burbank High School,, SaCramento; Dean A. Bishop, Culver City High School; Ralph C. Bohn, San Jose State College; Clifford J. Boyd, Coronado High School; Gaylord B. Boyer, Modesto City Elementary and High School districts; Joseph J. Bradbury, James Lick High School, San Jose; Orval Breckheimer, Leuzinger High School, Lawndale; Benjamin D. Briscoelçhatsworth High School; W. Harvey Bronsert, Washington High School, Fresno; B. Wesley Brown, Chico State College; John i. Brown III, Sweetwater High School, National City; Bustir L. Burris, San Bernardino High School; Burl J. Bushman, Hueneme High School, Oxnard. ' Laurence A. Card, Inglewood High SChool; Eugene, A. Carlson, Wheatland High School; Carl W. Cavallo, Cordova High School, Rancho Cordova; John L. Cesareo, Western High School, Anaheim; Jesse Z. Chandler, Live Oak High School; Wallace M. Chaney, Sr., Ravenswood High School, East Palo Alto; Eugene A. Clarke, Pleasant Valley High School, Chico; Donold L. Cleland,ELCapitan. HighSchool, Lakeside ; Charles M. Coffman,Fresno City_ College; Robert A. Compton, James Logan-High----- School, Union City; John M. Conway,, Benicia High School; Dell 0. Cooper, Terra Nova High School, Pacifrta,4,.,\QLloyd G. Corliss, Santa Barbara High School; Albert L. Cox, Helix High School, La Mesa; Walter D. Cox, Pacific Unionollege, Angwin; Eugene P. Crawford, Glendale. High,School; James A. Cresta, El CamMo High School, South San Francisco; Lionel E. Cross, San Jose Unified School. District; Robert A. Curtis, Bishop High School; Willie W. Dancer, RanchoAlamitos High School, Garden Grove; David 64,13aniih, Ravenswood High School, East Palo Alto; Glenn E. Dargatz, Jordan High School, Long Beach; Henry E. DaVis, Analy High School, Sebastopol; John C. Davis (retired), Fresno City Unified School District;C. Thomas Dean, California State College at Long Beach. Renso Del Carlo, La Sierra High School, Carmichael; Jack D. Diss, McFarland High School; Dale L. Dougherty, La Puente High School; Bruce R. Dunham, Doi Pueblos High School, Goleta; Eddie Nelson Dupee, Anderson High School; RussellJ. Duval, San Luis. Obispo High School; William W. Dyer, Oakdale High School; D. Dale Easter, Office of the Kern County Superintendent of Schools, Bakersfielk John D. Ehrenborg, Monte Vista Elementary School, Santa Barbara; Ralph B. Erb, Atascadero High School; Robert A. Escobar, Modesto High School; Larry E. Fanucchi, South High School, Bakersfield; Raymond E. Faugel, California Stati College at Los Angeles; Robert E. Finn, Richmond. High School; George M.Fowler, California High School, Whittier; Milton J. Freitas, Fortuna High School; Herbert H. Gadbury, Rosamond High School;David M. Gallegos, Oceana High School, Pacifica; Keith E. Gittins, Foothill High School, North Highlands; Richard J. Glaff, William N. Neff High SchoOl, La Mirada; Lester M. Gosa, Thomas Downey High School, Modesto; Ruben C. Granados, EdisonHigh School, Fresno; Edward J. Guffin, Point Loma High School, San Diego; Harley T. Haas, Narbonne High School, Los Angeles; Lee W. Haeberlein, Sierra Vista High School, Baldwin Park. Jaciab M. Hamann, Atascadero High School; Robert P. Hansler (retired), Fresno City Unified SchoolDistrict; John D. Herrell, Monache High School, Porterville; Marvin E. Hess, Pomona High School; Donald F. Hills, Gridley High School;Ivan D. Hinerman, Yucaipa High School; Jack R.,Hodgman, Alhambra High School, Martinez; Walter E. Hoover, Bell GardensHigh School; Paul W. Howard, Thomas Downey High School, Modesto; Fred P. Howe, Cordova High School, RanchoCordova; J. 143 135

Brady Howell (retired), Santa Barbara City Elementary and High School districts; Douglas Hudiburg, Dos Palos High School; Robert J. Hughes, Albany High School; Frank J. Irgang, San Diego State Co Beg; Donald E. Jeisy, San Clemente High School; De Iton Lee Johnson, E.O. Green School, Oxnard; Thomas Arnold Johnson, Santa Monica High School; Frank H. Jolly, Humboldt State allege, Arcata; Mark Jones, Tustin High School District; John Z. Kell, Mirarnote High School, Orinda; Stanley Kemper, Willow Glen Iligh School; San Jose; James Ken ley, Reed ley College; Frank 0. Kennedy, Tulare High School; David R. Kernberger, Napa High School; Billy H. Knoles, Apple Valley High School. . Donald S. Kyle, University High SchoOl, Los Angeles; Jatfes H. Laflin, Fontana High School; George C. Langley, San Jose Regional Vocational Center; William 13. LaPorte, Whittier High. School District; George B. Law, Jr., Sierra High School, Whittier; Alfred L. laig,Fresno High School; Stephen V. Ledbetter, Manoni Technical Center, Sacramento; Peter A. Lefevre ; Sunset High SchoollirSyward; Val T. Lepovitz, Mar Vista High School, Imperial Beach; Richard H. Levy, DeAnza High School, Richmond; Thomas Dan Love, Ramona High School, Riverside; Sterling C. Lowe, Encina High School, Sacramento; James H. Luckinbill, Nevada Union High School, Grass Walley; Angus J. MacDonald, San Jose State College; Richard S. MacPherson, John W. North High School, Riverside; Ernest P. MacRostie, Grossmont High School; Robert W. Magginetti, Capuchino High School, San Bruno; Stanley Mamulski, Polytechnic High School, Riveiside; Harold L. Marsters, San Diego State College; Charles H. May, John Swett High School, Crockett; Ted A. McCoy, Hanford High School; Harry J. McDevitt, Oceana High School, Pacifica; Paul D. McLaren, Lower Lake High School; Ben H. McLeod, Brea-Olinda High School Area ; J. M. Mc Robbie, California State Polytechnic College, San Luis Obispo. Robert L. Meeks, Arcata High School; Robert D. Meran, formerly at Chico State College; James N. Milligan, Rio Linda High School; James ?Mum, Western High School, Anaheim; Oro D. Mitchell, Palo Alto High School; Lynne C. Monroe, University of California, Los Angeles; Prince. Ell Moore, Gladstone High School, Azusa; A. D. Morehead, Selma High School; Robert E. Mullaney, San Marcos High School, Santa Barbara; Larry M. Munz, Cope Junior High School, Redlands; James E. Musick, formerly at Fresno State College; William Naman, Bullard High School, Fresno; Carl L. Nelson, Las Plumas High School, Oroville; Nicholas J. Neuburger, Chico State College; James L. No lt, Turlock High School; Albert I. Odsen, La Serna High School, Whittier; Vern L. Osborne, Montgomery High School, Santa Rosa; Roy Louis Osella, Roseville High School; John I. Owens, Santana High School, Santee; Orville Page, Reed ley College; William G. Palmtag, Ana ly High School, Sebastopol; Waldron H. Parker, Sonoma Valley High School; John E. Pierson, Vacaville High School; Thomas J. Powersi Fremont High School, Sunnyvale; Craig K. Preisendorf, Washington High School, Fremont. Kenneth Proctor, Wasco High School; Robert B. Rankin, Redwood High School, Visalia; Albert L. Ratliff, Office of the Monterey County Superintende ools; Ernest J. Rawson, California State College at Long Beach; Barra% W. Ray, McCloud High School; Frededdin, Arvin High School; Jack E. Reynolds, Sacramento City Unified School District; Earl S. Rice, Live Oak High School, Morgan Hill; James E. Rice, California State Polytechnic, College, San LuilObispo; Steven J. Richardson, Shafter High School; Larry W. Roberts, Enterprise High School, Redding; Dwight E. Rob Edson, North High --School,- Bakersfield; Earl A. Robertson, -De Anza High- School; .Richmond; Adolphus G.-Rogers; Centennial High School Compton; John E. Rude, Lemoore High School; Ivan W. Ruhga, Patterson High School; John C. Ruppert, Ganesha Hi School, Pomona; William M:Savage, Mt. Whitney High School, Visalia; Frederick T. Schalesky, Rio Linda High School; Ar en E. Schifer, Hamilton High School, Los Angeles; E. Blaine Schoolcraft, Santa Fe High School, Santa Fe Springs; 1ame H. Sells, Summerville High School, Tuolumne; George E. Shelden, Sr., El Cerrito High School, Richmond; Floyd R. Sheppard, Alhambra High School, Martinez; Howard D. Simpson, Calexico High School. Albert J. Sindlinger, College of the Sequoias, Visalia; James L. Smartt, Cubberley High School, Palo Alto; Sampson J. Smith, Jr., Ventura High School; Delbert L. Solomon, Atascadero High School; Sigurd M. Sonnevil, Modoc High School, Alturas; Richard R. Sonnie, Los Angeles High School; Norman R. Stanger, Office of the Orange County Superintendent of Schools, Santa An ; Vernon R. Starr, Hanford Highchool; John H. Stead, Ventura Unified School District; Rohert (Jack) Stinson, MonterePeninsula Unified School Distr.; Lester J. Swartz, San Juan Unified School District, Carmichael; Ernest M. Swenson, Sunt High School, Hayward; Da 'cl 0. Taxis, Office of Los Angeles County Superintendent of Schools; James I. Taylor, Hemet High School; James T. Taylor, Paic High School, San Bernardino; Robert R. Telmos, Monte Vista High School, Whittier; Delbert C. Towell, Eagle Mountain High School; George F. Trasky, Paramount High School; Roy Tuttle, Delano High School; John L. Van Zant, Office of the Ventura County Superintendent of Schools; Robert J. Vargo, San Clemente High School,. William Lee Vassar, Hiram W. Johnson High School, Sacramento; David F. Viera, Pittsburg High School, South Campus; Robert T. Vogel, Placer High School, Aubum; Dale G. Wagner, Merced High School. James A. Walker, Clovis High School; Wayne E. Wallace, Wasco High School; John B. Walsh, Sequoia High School, Redwood City; Glenn D. Warrick, Long Beach Unified School District; Jay LeWebster, California State College at Long Beach; James L. Wellington, Lincoln High School, San Jose; Barton W. Welsh, Cerritos College, Norwalk; Norman D. Willems, Dinuba High School; Robert Willhoite, Coalinga High. School; Clifford R. Williams, Willits High School; J. Howard Williams, Leuzinger High School, Lawndale; Frank T. WilsonNiest Covina High School; Richard S. Winslow, Fairfield High School; Jack S. Yamabe, David Starr Jordan High School, Los Angeles.

144 136

Committee Members from OtIttr44tes and Countries ) Robert C. Anderson, Warwick Veterans Memorial High School, Rhode Island; Herbert. Y. Bell, Washington State Department of Education, Olympia; Richard D. Berg, Wheaton Community High Schools, Illinois; T. Gardner Boyd, Kansas City School District, Missouri; Carl G. Bruner, Wichita City School District, Kansas; Carl W. Butler, Maine State Department of Education, Augusta; William Cady, Homewood1Flossmoor High School, Flossmoor, Illinois; Richard P. Callan, New Jersey State-Department of Education, Trent n; Lee D. tarter, Idaho State Department of Education, Boise; Harlan Clouse, South Fligh 01, Pueblo, Colorado; H an G. Collins, Northwest Missouri State College, Maryville, Missouri; Marvin A. Curtis, , dei.lunior" High School, *te Plains, New York; Howard,13. Davenport, Pu*ski High School, Milwaukee, Wisconsin; Ronard 13Disch, Bay, View. Hi School, Milwaukee, Wisconsin; Patrick R. Doherty, Jr., New Jersey State Department of . Education, Trenton; hck T. Duvall, Detroit City School District, Michigan; William R. Eister, Virginia State Department& Education, Richmond; Wade 0. Fredrickson, New Mexico State Department of Education, Santa Fe; Nathan L. Friedman, New 'York City School District, Brooklyn; Leo B. Gardner, Mesa High School, Arizona; John J. Geil, Florida State Department of Education, Tallahassee; Tea Gould, Oregon State Department of Education, Salem; James L. Heller, Delaware _ State Department of Education, Dover; Thomas W. Hodgson, Seattle City School District, Washington; Marshall Hurst, Office of the Dade County Superikendent of Schools, Miami, Florida. Joseph P. Indresano, tt: S. Dependents Schools European Area, APO New YorkGermany; George C. Jackson, City School District No. 1, Wesf Allis, Wisconsin; Richard V. Johnson, Waukesha High School, South Campus, Wisconsin; Willey P. Klingensmith (retiresl), Chicago City School District, Illinois; Harry Krane, New York City School District, Brooklyn; Deno G.. Lepas, Central High School, Cheyenne, Wyoming; John Lucas, Ridgewood High School, New Jersey; Myles Marcovitch, Elizabeth D. Gillespie Juntpr tligh School, Philadelphia, Pennyslvania; W. A. Mayfield, Texas State Department of Eflucation, Austin; Thomas C: McCoriile,Dobyns-Bennett High School, Kingsport, Tennessee; Leo Millea, Jr., Lunenbarg Junlor-Senior High School; Massachuset ; seph Murri, John Baitram High School, Philadelphia, Pennsylvania; Edward H. Palonty, Gary City School District, Indina r; Anthony J. Palumbo, Bowling Green State University, Ohio; Forest L. Penny, Kansas State College, Pittsburg, Kansas*, Thseph A. Prioli, 13rockton High School, Massachusetts; Kenneth L. Schank, Unified School District No:1, Racine, Wisconsin; Dmitri Slobodian, Garden City High School, Michigan; Kende!! C. Smith, Dimond High --School, Anchorage, Alaska; Bragg-Stockton, Dallas City School District, Texas; Thomas J. Straka, Kent City School District, Washington; Charles J. Teryek, Montclair State College, Upper Montclair, New Jersey; William A. Whitehouse, Board of _ Education, Toronto, Ontario, Canada.

145 In 8-115 (1717 & 1535) 78957 & 80202-300 8-70 10M