Scholars' Mine
Professional Degree Theses Student Theses and Dissertations
1931
Design of a 2 HP Repulsion Start Induction motor
Joseph Worley
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Recommended Citation Worley, Joseph, "Design of a 2 HP Repulsion Start Induction motor" (1931). Professional Degree Theses. 113. https://scholarsmine.mst.edu/professional_theses/113
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Joseph ~Vorley
A
T Ii E SIS
submi tted to the f aculty of th e
SClI GOL OF ~.'TIlJE S .AlTD l:~fE TAI~LURGY
OF TIl]}; lJ1JIVERSITY O:B" IvTISSOURI in partial fuJ. fillmen t of the vlork require d fo~r the D E G R E E 0 F
ELECTRICAL EI:~GIIJ'EER
Rolla, 1~o. 1931
Approved by ~....."" _"_...... /1-..-.. "_...~__(Jl;~,'d4an...... ~".."""~""..-"';~~..../_"__"" "" -
P~otessor of Electrical Engineering. Table o~ Contents.
Introduction.••••••••••••••••••••••••••••••••l Required Data••••••••••••••••••••••••••••••••2
Stator Wlndlgg••••••••••••••••.•••••••••••• ~.3 Stator Magnetic Circuit••••••••••••••••••••••4 Rotor Winding••••••••••••••••••••••••••••••••6
Rotor Magnetic Circuit•••••••••••••••••••.•••? Required Ampere Turns •••••••••••••••••••••••• 7 Magnetizing Current••••••••••••••••••••••••••8
No Load Losses •••••••••••••••••••••••••••••••9-10-11
No Load Current•••••••••••••••••••••••••••••• ll~12 Reaotance•••••••••••••••••••••••••••••••••••:12 Blooked Current •••••••••••••••••••••••.••••••13 Blocked Power Factor•••••••••••••••••••••••••14
MaximlJIll rrr> •••••••••••••••••••••••••••••••••••14 Circle Diagram Discussion••••••••••••••••••••14-15
Per~ormance Data Compar1son•••••••••••••••••• 16 Final Tests on Motor•••••••••••••••••••••••••l?-18-19 INDEX
Ampere turns total ••••••••••••••••• 8
Air Gap w•••••••••••••••••••••••••• ? Rotor Teeth••••••••••••••.••• ... .. 8 Rotor yoke•••••••••••••••••• .. 8 Stator Teeth•••••...... ? stator yoke ••••••••••••••••••••••• 7
Armature Diagram of Connections••••. 28 Punching•••••••••••••••••••••••••• 26 'Reactanoe ••• ...... 13 Res i stance ••••• ...... 10 Teeth•••• ...... 7 Winding••••••••••••••••••••• • • • • 6 Yoke •••••••••••••••••••••••••••••• 7 Bearing Commutator Cover•••••••••••••••••• 29 Drawings •••••••••••••••••••••••••• 29-30 Friction•••••••••••••••••••••••••• 10 Loss•••••••••••••••••••••••••••••• 10 Pulley cover•••••••••••••••••••••• 30
Brake Test ••••• • • • • • • • • • • • • • ••• • •• • • 18... 19 Brush Drawing...... 32 Friction•••• ...... • •• • • • • •• • • • • • 11 Loss . 11 Circle Diagram•••••••••••••••••••••• 14-15 Commutator Drawing•••••••••••••••••• 31 Core Loss Curve ' 24 Current Blocked••••••••••••••••••••• 13 Full Load ••••••••••••••••••••••••• 3 No· Load ••••••••••••••••••••••••••• 12
Data••••••••••••••••••• ~ •••••••••••• 2 Distribution·Curve•.••••••••••••••••• 22 Erficiency - Full Load ••••••••.•••••• 2-3-17-18 Field Connections •.••••••••••••••••• 27 Punching•••,' •••••••••••••••••••• •• 25 Resistano.e•••••••••••••••••••••••• 10 Wind ing ••••••••••••••••••••••••• •• 4 Iron Losses Rotor Teeth • • • ...... 11 Rot or Yoke ••• ·.. 11 Stator Teeth •••.•••••• ·.. 9 stator Yoke •• ...... 9 t~agnet izat ion Current' ••• .... ·.. 8 Curve ••••••••••••••••••••••••••• 23 Perrormance Curve ...... 21 Power Factor Blocked ••••••••••••••• 14 Full Load •••••••••• .... ·.. 3 No Load ••••••• • •• •• • • • • • • 12
Punching Armature •••••••••• '26 Field ••••••••••••••••••••••••••• 25 Reactance Armature ·.... ·.., 13 FiaId ••••••••••••••• .. 12 Resistance Armature •••••••••••••••• 10 Field ••••••••••••• ·... ·.... 10 Rotor Copper Losses ••• ...... 10 Iron Losse s ••••••••••••• ·.... 11 Punching •• ...... 26 Reactance •••••••••••••••••••••••• 13 Resistance ••••••••• ..... ·.... 10 Teeth •• ...... ? Winding ••.•••••• ...... 6
Section and End View ... • • • • •• •• •• • 34-35 Shaft Drawing •••••••••••••••••••••• 33 Stator Copper Losses ••••••••••••••• 10 Iron Losses •••••••••••••••••••••• 9 Punching ••••••••••••••••••••••••• 26 Reactance ...... 12 Resistance ••••••••••••••••••••••• 10 Teeth • • • • ••• • •• • • • •• • • • • • • • • • • • 4-;-6 Winding •••••••••••••••••••••••••• 4
Yoke ...... ' . 4
Test B.rake ...... ~ ...... 18-19.• List of Illustrati ons. eircle diagram•••••••••••••••• ...... • ••20 Performance.Diagram•••••••••••••••••••••••••••21 Distribution Curve••••••••••••••••••••••••••••22
Magnetization Curve•••• • • • • • • • • • • • • • • • • • • • •••• 23 Core Loss Curve •••••••••••••••••••••••••••• ~ ••24 Field Punching ...... • ••••25 Armature Punching•••••••••••••••••••••••••••••26
Field Diagram of Connecti ens ••'•••••••••••••••• 27 Armature Diagram of Connectiont •••••••••••••••28
Commutator Cover •• • • • • • • • • • • •••••• 29 Bearing for Pulley cover••••••••••••••••••••••30
Comm.ut a tor•••••.••••.•••.•••..••.••••••.•...••31
·Bnlsh••••••••••••••••••••••••••••••••••••••••• 32
Shaft••••••••••••••••••••••••••••••••• .- •••••••33 Seotion•••••••••••••••••••••••••••••••••••••••34
End Views ••••••••••••••••••••••••••••••••••••• 35 -1-
The Repulsion start Induction motor comprises
a vJound fi eld or stator of lamina ted s true t11re and a wound armature or rotor whose coils are connected
to a commutator upon v.rhich brushes bear and function
during the starting period.
This motor opertites as a repulsion motor during
the starting period and at a 9redetermined speed the
short circuiting device actuates and short circuits
the commutator. The motor then op-erates as an induc
tion or squirrel cage type.
The starting -torque of this type motor is excei>t
ionally high, generally 300% to 400% of full load
torqueo Consequently this type of motor is regarded
as having a high efficien oy a t s tart. The starting
current is low which causes very little line distur
bance. Due -to this charaoteristic, this motor is rec
ommended :for general use by the -Central Stations. Due to the high starting torque oharaotistios,
thi s motor is well adapted forap-plieations suoh as
- air compressors, baker's maohinery, ooncrete mixers and refrigeration service. -2-
Design o'f a 2 HP Repulsion Start Induction Ivlotor.
Required -
Q,uiet Operati on
Efficiency 75% at rated load.
Power Factor ??% at rated load.
starting Torque not less than 350%.
~jaximum - 4 HP
40°C Rise by Thermometer on Armature.
~Jo tor Data•
110/220 volt, 60 cycle operation. 1725 R.P.M. Diameter of stator punchings 9.750"
stator slots based on s~acing of 32.
Connections, ,2 oircuits, 2 poles in·series . :I 4 poles series for 220 volt and series- parallel for 110 volt operation • .Numb.er of rotor slots - 48
~lumber of bars in commu tator - 48
Axial .vVid th 4.000" over end fibre.
Rotor Twis ted 1-1/2 slots.
ft Single Air Gap .020 • rz -t,)-
E LEe T RIC ~ L
ElTATOR Vv'IJ. The a pproximate flux per "901e for a 2 lIP motor wh,ich is to have a 4 HP maxirnum is 390,000 line.s, · Then the number of turns required per .795 =Dist. Faotor pole is" .95 • Voltage Drop Factor ..) N:;: 55 x 108 x .95 4.44 x 60 x .795 x 390,000 63 turns per pole. Since the efficiency desi red is 75% the total watts input will be, 746 x 2 1990 watts• • 75 The power factor required is 77% which make s it po ssib le to find the full load ell rrent , which is, 1990 11.72 anperes 220 x .77 In order to keep the heating at a minimum an allowance of 550 circular mils per ampere should be made. The proper size of wire for the stator 1s 550 x 11.72 = 6460 Cir. Mils. This is ap~proximately #1'2 Enamel and 't, cotton wire. -4- The stator winding is 63 #12 E&C per pole, or distributed' properly and using 2 #15 E&C which can be handled wi th greater ease, the vlinding becomes - tor the inside, middle. and outside coils It is necessarjr at this point to consider the calculation of the stator magnetic circuit. MAG NET ICC IRe U I TeA Leu L A T ION STATOR YOKE. Assume a working density of· 68,500 lines per square inch. Then the thickness of the s tator yoke will be, STATOR TEETH Assume a density of 78,500 lines per square inch and since the teeth are to have a taper the minimum thioknessof the teeth will be - 390,000 x 1.57 .95 == .260" 8 x 78,500 x 3.93?HX A oheck should: be made at this time to determine if' there. is space available in stator.' punehirtg. for ·the?Jinding. However, we find· it nec- . essc.;ry to determine the d1~me ter Qf the rotor or bore' ·of the s .tat6:r_. Should an' under ·size annature be -5- chosen excessive heatirlg will result. In some design~; tlle D2L or a. ctive TrE. terial of the rotor iE~ the determining factor. I-Iov;ever , it is possible to determine directl~r the proper eize by calculating the flux density in the air gap. By setting a limit to this value, it is possible to quickly determine the bore of the stator. In most designs i t is good ':)ractice to allovi 30,000 lines "!jer square inch as density in the air gap. Conse(J.llently, "h'e get the pole -nitC.h in this case 390 z000 x 1.57 x •95 = 4.94" 3.93?"x 30,000 From this we get the bore of the stator it D = 4.94 x 4 =: 6.30tt '~'3 .1416 Rather than to use an odd size such as this, we select 6 .250 ft as the b ore • Ache ck sho uld be made a t this time to determine if there is available space irl the field for the winding. 2 2 x 24 x .651 .368 Square inch area 55 required. In order to keep the tooth tip vibration at a minimum, a thickness of .075" .is alIa_do The thiokness of the tooth tip at the side of the slot is .-125". The slot depth is 9.750'" - (2 x .760")::: 8.230". ft tt 6.250" + (.2 x .125 )::: 6.500 1.7~Oft -6- 1.730" 2 = .865" slot depth .3680: .427" average width of slot .86511 4271'1 :t .050'· .050#is allowed as slot taper. The maximum tooth width is 8.230" x 3.1416 n 32 ....477" = .329 The minimum tooth width is - 6.500" :x 3.1416 - .377" .260" 32 = The above value of .260" agrees with the value as previously caloulated. Consequently we have ample slot capacity. ROTOR\VINDING. In designing rour pole 60 cycle Repulsion Induction Motors., the writer has always tried to use in the rotor approximately the same slot~turns as in the field and at the same time keeping in mind t,he cross secti on of' the copper. In this case we will use #16 E&C wire in the rotor. The number of turns per slot in the rotor are - 21 x 6 x4 x ~260 x2 .= 26.6 48 x 2580 Since we are using a 48 slot rotor with a 48 bar commutator the rotor winding is 13-26 116 E&C. -7- 1.'1' .d. G· 1>T IE TIC C' IRe 1J IT C .,:',~ 1.1 C 1J L J.::" TI 0 J>J S ---_..-..-...-.-,...-..- ~--~ ...... ~_-..-...-- ...... --~--. .. _------ ROTOli TEETII Assuming a density in the rotor teeth of 83,500 lines per square inch, we find the ~idtr of the rotor teeth to be 390,000 x 1.57 x .95 1/ .155 83,500 X 3.937#x .95 x 12 The flux density in the yoke of the rotor is 390,000 x .95 34 200 1- - 2~1.45}'x 3.937/1x .95 == ., lnes "'1er sq. In. O.h.Le l1IJATI O~l OF IJill?ERE TtJIiIJS RECiU'IRJBD. ST.li~eOR YOKE. From the magnetization curve 68,500 lines per sq. in.::: 4 amp. turns/inch. f1 ft (9.?50 - .760 ) x 3.1416 - 4 ::: ? .82'" length of path 11 ? .82 X 4 = 31.28 ampere turns. ST.i:..TOR TEETH. FroTa tb.e magne ti za ti on curve 78,500 lines per 5(1. in. ~ 6.25 amp. turns/'inch• • 989 tf X 2 = 1.978" length of path I.978ft X 6.25" =12.32 ampere turns AIR GAP. el.6 x ~O,OOO x .020Hx 2.54 x 1.210 . 6.45 ::: 459.00 ampere turns. -8- ROTOR TEETH From the magneti zati011 curve 83,500 lines/sq. in. :::= 8.75 amp. turns/in• 11 • 945 X 2 = 1.89on length of -pa th 8.75 X 1.890ft~ 16.53 ampere turns From the magnetization curve 34,300 lines/sq.• in. ~- 1.25 arap turns/in. 1.560n + 2.150'" ~: 3.710tt length of path. . II. 1.25 x 3.710 :::: 4.63 ampere turns. The total ampere turns reql1ired for the various parts of the magnetic circuit are: Stator Yoke 31.28 stator Teeth 12.32 Air Gap ~ 459 .00 Rotor Teeth =- 16.53 Rotor Yoke ~ 4.63 523.16 ~il~ it G lJ E .T I Z I N G C IT RRE 1~ T· ~--_.-~--....-,-- --_ ..... __ .-...... ~ I 'T · 2 (523• ? 6 ) - 2. 92 amperes h 1.8 x .79 x 252 allowing 95% for ero 55 flux current. The magnetizing current is - 2.92 x 1.95= 5.70 amperes Mag. Current. -9- CALCULATIOl\T OF NO Ii..QAD LOSSES STATOR IRON LOSSES STATOR YOKE. The volume of the yoke expressed in kg is 4.87~- 4.1142 x 3.1416 x 3.93?"x .95 x 16.4 x 7.9 000 10.43 kilo grams. The density of the yoke expressed in lines per sq. em is - 68,500 = 10620 lines/sq. em. 6.45 From the core loss curve we find the corresponding loss to be 3.25 watts per kg. The loss in the yoke 1s 10.43 x 3.25 = 33.9 watts. STATOR TEETH The volume of the stator teeth expressed in kilograms is - 'I l 4 x 6 x .284 X 3.937 X 16.4 x 7.9 x • 98g/ x .95 1000 + 3.1416 (4.1142 3.1252 x 3._ 9371'X' 16.4 x 7.9 x .95 - I: 4 X 000 6 • 00 kilograms., , The density of the teeth expressed in lines per sq. em 1s - 78500 =12180:. lines/sq. em.. 6.45 From the core loss curve 'we find the corresponding loss to be 4.68 watts per kilogram. The loss in the te$th is - 4.68 x 6 = 28.08 watts. -10- COPPER LOSSES STATOR VlINDIT,JG RESISTANCE. R ~ 1.20 x 1.16 x 8.00'/X 2.54 X 2 x 252. F 5700 x 3.304 = .753 Ohms at 40° c. ROTOR '~lI:r-IDING RFSISTM{CE. 17J/x R = 48 x 4.48 x 13 3.97 Ohms. A 12· x 1000 = 1 R 3.~7 .X 2522 :A = .908 • 8452 x 6242 = Ohms • The copper 10s5 in the stator is 2 5.70 x .753 = ~ Watts. The copper loss in the rotor is - 2 ~5270~2 x .90S = 14.7 watts. LOSSES ---. - ...... -. - ~ BEARING LOSSES. The commutator cover bearing loss in watts ts 1.20 {.S75"x 2.125~ (1750 x 3.1416 X.S75'1 3/ 2 .. ( 12 x 1000 ) 17.9 watts. The pulley cover bearing loss in watts is - 3 1.20 (1,,062"x 2.125'~ (1750 ;3.1416 x 1.062'1 /; 28.7 ( 12x 1000 ) The total bearing loss ·in watts is 46.6•. As it is difficult to determine the windage losses, 10% 1s added to the bearing loss which makes total frio,.... tional and windage 1085.51.2 watts. -11- The brush friction loss may be expressed in the following:- 1.2:5 eX 4 (1 X .281j X 3.1416 :x: 4.062":x: 17~O 100 X 12 = 26.2 Watts. SUMrYtARY OF LOSSES AT NO LOAD. Since the rotor runs a practically synchron- ous speed it is assumed that the rotor iron losses are negligible. There are add!tional losses which occur at the surface of the stator teeth and further losses due to eddy currents. It is generally assumed that these are· approximately 75% of the stator iron losses. Losses in Stator Yoke 33.90 Losses in Stator Teeth 28.08 75% Additional 46.30 Stator Copper Losses 24.50 Rotor Copper losses 14.70 Friction and Windage 51.20 Friction due to Brushes 26.20 Total No Load Watts224.88 NO LOAD CURRENT. The component of the current due to the losses is .... 224 •.88 = 1.02 Amperes. 220 -12- This current should be added ~vecto~ally" to the magnetizing current in order to determine the no load current. I == V 5,.70~ + i.02! = 5.78 Amperes, No Load Po.wer,'Factor=225 x 100 = 17.68% 220 x 5.78 CAL CUL it T 1. 0 N' ·0 F REA eTA N Q E. STATOR The permeance, of the path of the stator slot leakage flux per em. of the slot is - P 1 25 .818¥ ..... 047 ,~ ,.. 2 x .05'0'J.+ .0751 1, = 2.095 ems. S = • ~ 3 x •'410 ' .377" • 377" + .110" :rIO The leakage flux per em,. length of end wire is - 1/ P = .46 x 3 ~lOg 1.5 x 4.50 ) x 2 x 1.30 a .825 Oms. w 3.97/~ ) Expressed in terms of motor width 1 t 1s .825 :x: 4.5011 .945 3.937" = ems. The pe~eaaoe' due to the slot opening is - .= 2.245 ems. The total pe~.aD8.: 1s 5.285 ems for the stator. The reaotance 'for the stator expressed in ohms is 2 h 12.5 x 60 x 252 X 3.937 x 2.54 x 5.285 = 2 :x: 6 x lOB 2.125 Ohms. ROTOR The pennea.c. of the path of the rotor slot leakage flux per Qm of the slot 1s- -13- ~ .714'/ + .064// - .04?" .060 1/x 2 .060 2 ~ 3 X .155H 3 X .096"T .235#+ .235t.o9cf .090 = '7.44 Cms. The permeance due to the end wire of an~·armature is generally .8 em for this case we get - P .8 x 4.50II E = 3.93711 = .92 ems. The permeance due to connections at the conmutator is so small too t it can be neglected. The leakage flux due to the slot opening in the rotor expressed in ems is - plo = 1.25 (.504" - .o9d1 :::: 3.45 Oms. ( 6 x .025") The total permeanCe for the rotor is 11.81 ems The reactanoe of the rotor expressed in terms of the stator is - 2 2 12.56 x 60 x 252 X 3.93?HX 2.54 x. 8.09 x .792 X.95 . 2 x 12 x 108 x .8452 = 1.84 Ohms. The total reactance is 2.125 + 1.84 = 3.965 Ohms The total impedance when the commutator is short cirellited and the rotor is at a stand-still 1s - The bloekedeurrent for the above condi tiona will be - 220 = 51.2 Amper.es 4.30 -14- The power factor blocked will be - 1. 661 100 _ 38 8(/r 4.30 x -. 70 TIle v.ora ttE~ input to the rna tor for t:he locked and, shorted COmTIllltator c()ndition are = 4320 ,VEt tts. IIavin;;.~ determinod the n.o loa dcurrent and power factor and the blocked current and ~o~er factor, it is ~;ossible to construct the circle diagram arld check the mEtximum liP vlhich tIle motoT* ,rill develop. From tl.1is diagrarnit is possible to'deterr:lil1e tb,e power f8.ctor and efficiency for full load. T11ewriter Ilas found tb.at it is possible to approximate the nlaximum HI' vlhich the motor t8 capable of developing by usin.e~ the va.lues heretofore calculated in tI:Le folloVJing ma11Iler. ~vIax. :HP = 220 (51.2 - 5.78) .85 =: 4.11 HP 2 (1 + .388) ?46 The circle diagrCTIl is constructed in the 11sual manner., Using the angJ_e whose cosine is the no load po\ver factor, the an'g]_eAOC is laid off and the no load curren t· .A.O is measured. according 'to a suitable scale. The angle COB oorrespondsto thepovJer factor angle 'for blooked condition. The blocked current is measured on the lineOB. -15- Through point A and parallel to the horizontal, the line AD is drawn. The line AE represents the no load watts. Through points A and B and using a point on the line AD, the circle is drawn. Since we know the resistance of the rotor and stator it is possible to separate the losses for blocked condition. The losses corresponding to any load can then be determined for the stator and rotor. The max- imum HP which the motor will develop occurs where a line parallel t·o AB is tangent to the circle. The maximum power factor which the motor will have can be found by , drawing a tangent to the circle through point O. By locat Ingthe point corresponding to the rated load, it 1s possible to determine the effi 01 ency and power factor. It was found that the circle diagram varies with the frame co'nstruction and the amount of twist either in the rotor or stator • Consequently, for th·e larger frames such as has been used in the design of recent motors, an approximate calculation has been used. Since the results are within 2% of actual t es t value, the writer chooses to use the following: - Max. Hi? = 16.3 (1 ~ '.1992) 225 3.950 HP , 146 = It 1s realized that this 1s not ~hsolutely oorrect and further work and tests are continuing to determine if it is possible to const~uet the el'rcle diag 'ram so that the results will agree wi th the test data. -16- The writar has designed during recent years, Repulsion Start Induotion and Polyphase motors ranging from 1/8 HI? to 2 HP., for frequencies ranging from 25 to 60 cycles. In the design of single-phase induction motors rated from 1/30 liT' to 1/2 HI? , the problem of sound condi tion has resulted in extensive noise tests. The writer remembers particularly an instance where it was round that 32 slots in the stator and 41 slots in the rotor result ed in an exoellent sound condi tion. Thi 8 combinat,lon was tried in a smaller and a larger motor in an effort to improve the noise condition. It was foundtha. t noisy operation resulted. There:rore sound not only is dependent upon the combine. tion but also upon the size and shape of the frame. or course in making the aboTe ,statement, it is assumed that the various portions of the magnetic 01 rcui t are approximately the proper 51 ze and shape. -10.... Performanoe Data Comparison Predetermined - Actual Brake Test I:~o Load Current 5.78 5.75 Watts 225 a36 Power ]'aotor % 17.68 18.65 Full Load 2.00 2.025 Amperes 11.60 11.20 Watts 1965 aooo Efficiency % ?6.0 'l5.5 Power Factor % 77.0 81.1 Maximum Pf. % 81.9 62.7 Maximum H.P. 3,.95 & 4.11 4.00 Locked Rotor With Commutator Shorted Watts 4320 4120 Amperes 51.20 49~6 Power Factor % 38.80 3?7 The starting torque of the final motor 1s 409~ ot the full load torque whioh should be ample starting torque for almost any eondi.tion. -18- B,rake. Test Type IR9 AB-130-?440 H.P•. 2 Date 8... 5-30. Volts 110/220 Phase 1 Cyol.es 60 Field 'tVinding 18-21..23 (2 # l5) E&C Field Iron 9724 A Field Bore 6.252" Arm. Winding 13 - 26 #16 E&C Arm. Iron 6248-A Diameter 6.,.21l!' Arm. Twist 1-1/2 Slots Uomnlutator 48 Bars. INDUCTION TEST Watts Volts Amps. RI?M· wt. Arm. H.P. Eff.% Pf.% 4700 220 29.5 1625 10 15i 3,.99 63.5 72.4 4100 220 24.0 1675 10 14i 3.85 70.0 77.8 3275 220 18.0 1730 8 l5 3.30 '75.1 sa.7 2000 220 11.2 1760 5 14i 2.03 75.5 SI.! 1560 220 g.45 17'15 4 14 1.58 75.5 75.0 1100 22,,0 7.65 1785 4 9 1.04 69.0 66.0 660 220 6.45 1790 2 9 .512 57.7 46.6 236 220 5.75 1795 No· Load 18.65 3400: 220 32.8 Lift 16 18t BRUP 10 12 -19- REPULSION' TEST Watts Vo~ts Amp. liPM l-vt. Arm., H.P. 2680 220 14.6 1030 10 16 2.61 3040 220 16.? 955 10 lsi 2.81 3280 220 18.0 900 10 20 2.86 3680 22-0 19.8 850 12 19 3.0? I\4AGNETIZATION TEST watts Volts Amp. 400: 300 9.19 320 260 7.10 240 220' 5,.78 20Q ~80 4.57 155 140 3.51 120 100 2.68 110 70 2.30 BEAT RUN Rise 0 c. Frame 2·7.5 Field Iron 31.5 Arm. Iron 40.0 Joseph Worley/Louise Beiser~