Characteristics of a Regulating Pole Synchronous Converter Citation Holmes, William Mowry (1915) Characteristics of a Regulating Pole Synchronous Converter. Bachelor's thesis, California Institute of Technology. doi:10.7907/r7dy-ym02. https://resolver.caltech.edu/CaltechTHESIS:12062024-225544309 Abstract Toward the latter part of the College Year of 1913-14, the Department of Electrical Engineering was augmented by the arrival of a General Electric Double Current Generator, or Regulating Pole Synchronous Converter. Because it was such a small machine, and also because it was designed for 50 cycle current instead of a standard frequency, the regular factory tests were omitted. It was therefore desirable to run such tests as would disclose its characteristics and action under various conditions. Item Type: Thesis (Bachelor's thesis) Subject Keywords: (Electrical Engineering) Degree Grantor: California Institute of Technology Division: Engineering and Applied Science Major Option: Electrical Engineering Thesis Availability: Public (worldwide access) Research Advisor(s): Unknown, Unknown Thesis Committee: Unknown, Unknown Defense Date: 1915 Record Number: CaltechTHESIS:12062024-225544309 Persistent URL: https://resolver.caltech.edu/CaltechTHESIS:12062024-225544309 DOI: 10.7907/r7dy-ym02 Default Usage Policy: No commercial reproduction, distribution, display or performance rights in this work are provided. ID Code: 16904 Collection: CaltechTHESIS Deposited By: Ben Maggio Deposited On: 10 Dec 2024 19:59 Last Modified: 10 Dec 2024 20:15 Thesis Files PDF - Final Version See Usage Policy. 31MB Repository Staff Only: item control page

THESIS Characteristics of a Regulating Pole Synchro nous Converter. by William M. Holmes. Cl ass of Nineteen Hundred and Fif·teen. Department of Electrical Engineering. THROOP COLLEf1E OF TECHNOLOGY Pasadena , Cal ifornia 1915 1 CHAI{ACTEF1.ISTICS OF A REGULATIUG POLE SYNCHRONOUS CONVERTER. Index. I. Introduction. II. Description of the Converter. 1 III. Theory of The Regulating Pole. IV. The Tests: 1. Measures Taken to Prevent Hunting. 2. Resistances. 3~, _•_Vol,tage ·.~Ratio (No Load and Full Load.) 4. Core Loss and Formula. 5. Short Circuit Saturation. 6. Friction and Windage. ?. Saturation (No Load and Full Load). 8. Synchronous Impedance. 9. Phase Characteristics (No Load and Full Load). 10. Running Light from D.C. Side. 11. Efficiency by Separate Losses. 12. Starting Tests. 13. Voltage Regulation with Regulating Field. 14. Normal Load Heat Run. 15. Polarity Reversal with Field Switch. 2 Index Continued. 16. Oscillograms of Voltage and Current. V. Concl U5ions. VI. Illustrations. Diagrams. Data Sheets. Curves. --G-- 3 REFERENCES. 1. Al~c.ernating Current Motors - Mc Allister. 2. Corrnnercial Electrical Testing - Collins. 3. Alternating Currents - Hay. 4. Westinghouse Bulletin "Factory Testing". 5. General Electric Bull etin No. 4723. 6. Electrical World, Vol.65 No.4. 4 CHARACTERISTICS OF A REGULATING POLE SYNClffiONOUS CONVERTER. I. Introduction. Toward the latter part of the College Year of 1913-14, the Department of Electrical Engineering was augmented by the arrival of a General Electric Double Current Generator, or Regulating Pole Synchronous Converter. Because it was such a small machine, and also because it was designed for 50 cycle current instead of a standard frequency, the regular factory tests were omitted. It was therefore desirable to run such tests as would disclil)~e its characteristics and action under various conditionsa 5 II. Description of the Converter. In general the construction of a synchronous converter is similar to that of a direct· current generator, with the addition of collector rings connected to the armature winding at equal distances a round the armature. There are, however, several important details in -,,hich the construction of a synchronous converter differs from that of a direct -current generator, notably in the arrangement of the armature winding, the shape of the pole tips, and, in the case of the regulating pole type, a complete auxilia17 set of poles, narrower than the ordinary shunt field poles, and set between them in the frame. Like all synchronous converters, it is equipped with a device for automatical l y opening the direct • current circuit i~ case the speed becomes too high. This safety device (or spe ed-limiting switch, as it is generally called) censists of a switch which is operated by a centrifugal governor. The centrifugal weight is mounted on the shaft and revolves with it, wli_ile the switch is stationary and i s mounted on the conunutator end bearingblock. The switch can be adjusted to operate at any pre- determined speed. Under normal operating conditions, the circuit of the emergency trip coil on the line circuitbreaker is open, but s h ould the speed of the converter increase to the predetermined setting, the switch will 6 close, thus tripping the line circui t-breake:r·. The m.achine is also su~pp lied with a four-pole, double-throw, field break-up switch for the shunt field. . Blue I,rint see Fig.III also :iiagram of field connections, Fig. in Lab. This swi t ch serves two purposes; it op ens the field in several pl ·aces to reduce the strain on the insulation, caused oy the high potential induced in the fields during al ternatin g· current starting, and it provides a means of obtaining the proper polarity. the "up" posi tio n. The switch is normally in The "down" position is used for re- ve rsi.r1g the 1) olari ty of the machine when it builds up wrong after alternating. current starting. Vv1len the switch is in the "downu position, the direction of the field. is opposite to that induced by the al ternating--current which causes the armature to u slip", thus reversing the polarity. When the polarity has been corrected, the switch is thrown to the operating position. The machine ha s six collector rings, and may therefore ·b e used on a line supplying six-phase al temating•·cur rent. The current most generally available, as in the present case, is three-phase which may be used with equal advantage. Conce ,r ning frequency, this machine is buil t for 50 cycle current, while the sta11dard form of syn chronous converter is for 25 cycle or 60 cycle current . The ratio of conversio n between the al tern atin g, and direct · current voltages is practically fixed, in ordin.a ,ry 7 synchronous converters ·by the design of the machine, except for a very slight mod.ification of the ratio of pole arc to pole pitch, and can.not be materially changed by al ter.in.g the shunt field strength. In the machine under test, however, the conversion rat io may be changed over a wide range by means of the Regulating Field , as wil l be explained later. The synchronous converter possesses the same char- acteristics regarding power-factor as a synchronous motor; that is, for each load there is a certain field strength necessary to give unity power-factor input, and any variation from this field strength produces wattless current, the wattless component lagging if the machine is u:ider-excited, and leading if over-excited. The best operating condition is obtained with unity power-factor input at the average load, because this condition gives the lowest heating in the armature and therefore the smallest loss. The r 2R loss in a sy:nchrono us converter due to the energy current is materially lei3S than in a direct current generator, owing tothe neutralizing effects of the motor and gen erator currents. The r 2 R loss due to the wat t less component of the current resul ti.ng from lagging or leading power-facto r is, however, the same as in an alternating curr.e~t generator. 8 Therefore a synchronous converter s b.ould be operated as near unity power-factor as pos si ble. A compound wound converter, like the one under test, will operate at unity power-factor at only one load vaJ.ue for each adjustment of the shunt field. If the load varies, the field cur rent should be adjusted unity power-factor at the average load. III. Theory of The Regulating Pole. The extensive use of synchronoua converters, especially with electric lighting and power plants, frequen tly necessi ta.tes a variable ratio between the alternating current Md direct current voltages. Before the advent of the regulating pole converter the variation of conversion ratio from al te ,r nating current to direct current bus-bars had been obtained by means of auxiliary apparatus such as induction regulators, or voltage-varying dial switches connected to the taps of the transformer Yvindings. These devices, however, are expensive and require attention. To simplify the wiring arrangements and reduce the c cos t of auxiliary devices, the General Electric Company h as developed a regulating pole synchronous converter, the machine under test being the smallest commercial unit o .f thi s type built. In this machine, as in al l othe r;3 of modern design, the field structure is divided 9 into two parts - a main pole and a regulating pole. The ratio between voltages on the direct current and alter'nating current sides may be readily varied by varyi .1.g the excitation of the regulating poles,the only auxiliary apparatus .required being a field rheostat for controlling th~ exciting current in the regulatin g field. Consider a ma.chine wi U-1 shown in. Fi3. l ) resembli ncr. 8. :_1.. .field structure like that ~nachin.e with commutating poles, but wi t:h the bru.~}-, E:2 so set t11at one of the regulating poles adds its flux to that of one main pole,cutting t11e conductors between two direct currt:-nt- brushes. The regulatins pole is shown with a width 20 percent of that of the main pole. To obtain definite fig ures it will be asswried that the machine at normal speed,vl.'ith the main poles excited to normal,but no excitation on the regulating poles,gives 100 volts D. c. Then with each ree;ulat- ing pole excited to the same amount a.s the main poles and ~. with a corresponding po1s.rity,the D.C. voltage will rise to 120 vol ts, at the snme speed, since the total flux cutting the conductors in one d.ire c~tion between brushes has been increased 20 percent. If the excitation of the re r-1 ulating poles is reversed and increased to the same density as the main poles,the D. c. voltage will fall to 80 volts, since the regulatin ;.s poles arE; or·posing the main poles. If new the machine is a converter,this variation of D. c. vol ts may be accomplished without al terins the A. C. 10 vol tage,provided tl~"e rnain field excitation remains the same. Fig. 2 shows the A.C. voltage developed in :h€ armature winding by the two sets of poles. The horizon- te.l line OA represe.n ts the A. C. voltage generated by the main poles·, regulatir1g poles unexcited., when delivering 100 volts D.C. For a six-phase converter OA is about ?2 volts diarr:etrical. If the re 6,ulatin g poles ar e excited to full stren 6 th to bring the D.C. volts up to 120,the A.C. voltage generated by the regulating poles will be 90 degrees out of phase•with that generated by t h e main poles, since they are equally spaced between the main poles, and VI.rill be about 15 -volts as shcvvn by AB. This gives a resultant A.C. voltage OB equal to ?3.6 . If the regulat- ing poles are reversed to full strength to cut the D.C. voltage to 80,the A.C. voltage will again be 73.6. It is tt.erefore evide11.t that with constant field the D. c. vol tf~,ge ·£N W vary from 120 to 80 while tbe A. C. voltage varies from 72 to 73.6 volts. The A.C. volts can be kept constant through the full range of D. C. vo1 ts by changint~ the main field so as alvrn,ys to t ive an equal and 01 posh:.e flux change to tlrn,t of the regulati[lg filed. A constant total flux may thus be o b tain Ed. equal to the radius of the circle BAC, Fig. 2 ; OA, the rLain field strength,will equal OI:s when the re gula.tin 5 field is unexcited,and it is then that 100 volts only can be obtained. Tb~s method of operation ~ives unity po~.11J6r-fautor with con ,s tan t e.m.f. of 73. 6 vol ts A. C, and 8, 11 D.C. voltage range of 80 to 120 volts. In practice,machines are not built as indicated dia- gramatical l y; that is, wi tl1 re;_~ula ting poles mid,Nay between the rr~ain poles, because a better construct ion is obtained by placing tlJe regulatin ,:s pole closer to the correspond- ing rn2.in pol.e, see Fi~. 3, 7he effect on the D. c. Vol tRge remains 1..w.ch3,nged except for rriagn etic leakag e from the main pole to the regulating pole whsn th.e latter is opposed to the former. The effect on the A.C. voltage is somewhat altered. Fig4 shows the effect on the A.C. voltage of varying the regulating field strength of a machine similar to Fig. 3 , from a. density equal to that in the Lain roles to t:he sarne a1nou(.lt reve1~sed,main field excitation constant. The D. C. voltage in tbi;2 ease, varies from 30 percer.. t above t.r~t pr·od.uced. by t h ~ rEa.in field a.lone to 30 percent below, or fronJ. 130 to 70 vol ts, while the A.C. voltage varies from 80 to 70 volts. The A.C. voltage may be held constant ty strengthening the rr.ain field as the regulating field is reversed and vice versa. Thls range, however, is seldom required. Assume therefore that the range is 90 to 12[J volts, and that at the highest vo1 tage bot:h ma.in and regulating fields have the same density,thus giving practically a continuous pole face of 1.mifonn flux intensity. The dia 5 ram of A.C. com:1;;one.nt voltages to give constant A.C. resulta.nt voltage across the rings for this case is shown in Fig. 5. D.c. At 125 vol ts the main fielcl produces an. A.C. voltage OA,a.nd the 12 re gulati ng field a voltage AB, with a resultant OB equal to a b out ? 8e5 vol ts A.C. At 10?.5 volts D. C. the main field prod u ces a n A. C. voltage OA1 and a re gulatin :E f ield voltage A1B1 giving a resultant A.C. voltage OB 1 equal to ?8.5 volts. Similarly at 90 :volts D.C. the main ~ield produces an A •.c. voltage OA2, and tt._ e re gulatin g f ield, now reversed ,produces the vol tc,,ge A2B2 giving ;..he result- ant oB 2 again equ a l to ?8 .5 volts. I t will be no t ed that theoretic al ly the .rn.ain field s t rength must b e increased abou t 15 percent above its value at 125 volts D.C. in order to keep the D.C. voltage at 90 volts. IV. The Tests. 1. Measures tak en to prevent hunting . When the machine was set up a;1d tried ou t it was fou nd i rr.possible t o load it with mor e than 25 amperes, and even at this load it i.voul d sometimes fall out of s tep. Knovd ng the rated l oad to be 75 runperes, there was ob vious ly somet bing wro n,g. The fi rst step taken to get :rid of the h unting wa :_' to subst itut e heavy cor..ducto rs ( 0000 stranded catle) from the secondaries of the t ransform ers t o the co nver ter. This he lped a great deal. -The next step was to allow more trans former cap acity, and ac c ordingly two ban k s of transformers were paralleled. co nnect ed ~ Y , the Each bank. was Y being connected to t h e mac hine . Then the Ind uct io n Re gulat or was placed in the circuit 13 between the transfonrier secondaries and the machine to maintain constant voltage. This also reduced the hunt- Separate excitat ion was then adopted as a further ing. aid in tbe desired d.irec t ion,and was used throughout the tests. Self excitation may,however,be employed. As a result of these additions and considerable running under load the mac bine was made to carry 112. 5 amperes or 150 percent of rated load vdthout falling out of step. It may be noted that during the heat run,as well as a.t other times after continued running under load, all hunting ceased;the meter needles holding a set deflection, and the machine operating without the characteristic pulses. ::Before proceedinr:; with the testing of t:he synchronous converter it was necessary to detennine the A.C. voltage for best operation. Tr.i.is was limited to some extent by the available taps on the transformers used. Three corr- plete tests were run a,t 70, 80, and 90 volts respectively, between the incoming three-phas e lines;and it was deter- mined that the best oreration was approximately 80 volts. Other t .e sts showed the correct voltage for best operation to be ?8.5 volts. See page 55. 14 2. Resistances. The resistances of the various windings were measured , several readings being taken with each method at the "cold" and "hot" temperatures. The followin g is a. list of measurements and method enployed: Wheatstone Bridge (Leeds & Northrup Potentiometer No. 9678.) Vm. - - Am. Synchronous) Converter ) ) Armature Cold Hot Cold 0.050 0.063 0.055 Shunt Field 13.255 14. 905 13.280 Series Field 0.016 0.018 0.01? Reg. Field 18.50? 19.805 18.520 Hot 14. 650 19,400 3. The Voltage Ratios. In order to determine whether the va.rious taps had been brought out correctly, and were connected to their proper rings , readings of voltages between each ring were trJ..ken. The voltage betwe en phases balanced up exactly as shovm below. As will qe seen from the data. and diagram, the machine is connected "double del ta"on the circular D. C. winding, so tbat three phase current may be applied. One delta is betwe en rings 1-3-5, and the other is between 2-4- 6 With tbe line voltage held at ?8.5 volts applied, with 1.0 power factor, regulat ing field neutral,and 10?.5 volts on the direct current side,carrying no load,the following voltages were obtained: 15 Between Rings 1 1 l l 1 2 2 2 Voltag e 2 between Rings 48 80 93 80 - 3 - 45 - 36 - 54 2 80 6 -4 3 - 5 ,,. 3 4 - 5 4 - 6 5 - 6 3 48 80 93 0 48 48 80 - Voltage 93 48 80 48 With the A.C.line voltage held at ?8.5 volts applied, 73.0 amperes A.C. with 1.0 power factor,and regulating field neutral,and 9?.5 volts on the direct current side, carrying full load of ?5 amperes D. c., the following voltages were obtained: Voltage between Rings 1 1 1 1 1 - 2 - 3 - 4 Between Rings 48 2 91.5 79 48 48 2 - 5 - 78 91. 5 Meters see pag€ 54. 78.5 v. 97. 5 v. 73.0 a. 75.0 a. Line 1'he ra.tio of A. No Load. 3 Phase A.C. 83. 5 78.5 ?9.0 c. 73 ?8.0 48.0 79.0 91. 5 48 78 48 Cap. A. C. D.C. A. C. Weston 11583 It 6427 D.C. G. E. ?9?0 tt 252432 150 v. 150 v. 150 a. 150 a. c. volts to D. c. volts is: Full Load. D.C. 123.0 115.0 113.4 The ratio of A. A. - 6 - 45 -6 4 - 5 4 - 6 5 6 3 3 3 79 - 56 2 - 3 4 2 Vol ta.ge Ratio f.,7. 9 68.0 69.0 A.C. 83. 5 75.0 78.5 D.C. 114.0 103.0 107.5 c. to D. c. currents is: D. c. Ratio. ?5 9'7. 5 Ratio ?3.2 73.0 73.0 16 4. Core Loss ~est --- Open Circuit. The method emp loyed for these tests was the "belted core loss rr.ethod, 11 which separates the core loss frorr. the bearing friction, brush friction and windage. A small direct current motor was used to drive the machine under test, as a generator, at its rated speed. a,s follows: '.C he rating was General Electric Continuo us C1.,;.rrent Motor, Shunt Wound , No. 340?59, Speed 1650, Volts 115, H.P. 3, amperes 2~3. 9; operated with a 4" and a 9 1/2" pulley onto a ? 11 pulley on the converter. The motor was operated with good comrrrn.tation and a. fixed setting of the brushes through the ran ge of lo ad re qui reel for the core 1 o s s test. The m.otor was operated above and below its rated speed in order to get a check on the test and on the motor losses. The belt tension was maintained just sufficient to overcome slipping, in order not to increase the bearing friction unnecesse_rily. The driv i ng motor was wired so that read ings could be taken of armature vol ts and amperes, and speed. A reading was ta.Jr.en on the motor corresponding to normal spe Bd o:f the machine under test. The synchronous converter was wired with its field separately excited and provision made for reading armature volts, (and current in the Short Circuit Cure Loss Test) a.lso field vol ts and amperes. Several n sadings were taken of t h e arrr:ature resistance, both cold and hot, so a.s to determine the motor. r 2 R loss in the l? The test was then carried on as follows: the field of the driving motor v,ras adjusted to about normal value, and excited from a source of constant voltage, so that it could be held constant througho'Ll.t the test. The speE;d. o-+-:> the driving motor was regulated by varyin g the voltage applied to the armature. The motor ·was allowed to run the convert er for a sufficient time to tring the friction to a constant value as determ.ined by constant motor input, and no field on the converter. Readings were then taken of the input to the 11lotor with the converter unexcited and all brush es doYm on the com.mutator of the converter. The dif- ference between these two sets of readings gave the brush friction. Starting with zero field on the converter, ob- servations of the input to the motor were made at various values of the field current up to that giving 125 percent mean normal load voltage. Correcting the motor input at these various field st:cengths by subtracting the r2R loss of the armature of the driving motor, and the power input to the driving motor for zero field on the converter, the core loss at the various field strengths is found. In order to insure constancy of' friction losses during the test, readings of motor input for zero field were repeated during and after the test. Headings were also tal<:en at the end of the test with normal voltage field current and with brushes raised from the commutator, for comparison wit h t h e reading in which the same field current 18 was used with the brushes on the cow.mutator, and with the set of readings giving the brush friction. The speed vi.ras held constant throughout the test by means of a Schuchardt und Schutte Tachometer, and a Hartmann and Kempf Frequencymeter. The brush tension was 0.8 lb. per brush. The correct ions for losses wei-·e made a-s indicated above, and the corresponding values of watts loss in the See pages34-5 for data obtained, and core were obtained. also page 5? for curve. It will be observed that the motor was run at two different speeds, one above rating, viz. 2625 R.P.M., and one below, at 1115 R.P.M. The former was merely a. check on the latter, as at the former speed bE::lt slipping could not be avoided. As seen fron: the curves, the differ- ence of the losses is constant throughout the test. The converter was run at i tr., ra.ted speed (1500 R.P.M.), the two mot:or speeds being caused by tl;.e ratios of pulleys used. The tests are inter~sting as they show the effect on tl:t€. results of the speed of the driving motor. and the slip of the belt. Curve "A" shows the relation between the direct current volts and the core loss at the check speed. Curve "B" shows the relation between the same two quantities a.t the test speed. Curve "A" is consistent ,,vi th this, since at the check speed the losses are greater. In order to obtain definite inforrr1-ation concerning the core lose in the synchronous converter, use is made of mathematics and a formula is :leduced. page 5? is parabolic in form. The curve "B" of It therefore follows some 19 definite parabolic law, aad it only remai ns to d i scover a. formula. expressing the corr ec t relation betweE:n core loss and direct current vol ts. If 'th e vol ts are ~:3QVB. red~ and a curve plo.tt ed with these as ordinc.1. tes, and watt s loss as a bs ci s sae, we obt ain a straight li n e, see page 56. Now usin g th€ equation of the parabola X == a~by 2 and using any two points on tLe st raight line, a formula may be obtained expr ess iri g tr1e desired relation. Takin g points (5 0 45, 275) and (16190, 991) and subst i t uting 275 =a+5 0 45b 9 91 == a+l6190b 716 = '. 111456 therefore b := O. 06424 a= -49.0 Therefore X = 0.0 6424y2 - 49 . 0 where X == cor e, los s of synchronous conve rter in watts. y =- direct current vo1 -:~s gene rated. Tbe 2.bove formul& was tested th rou~out the r-an e;e plot ted, and the maximiu.n erro r- ,11,~~-~~ 0.3 perc ent, an error almost entirely personal, a s an o ther trial was 0.09 percent of the exp erirr:.c::n ta.l value obtained. I t wi ll be seen t hat the core loss of the converter may be readily calculated for any value of t h e direct current volts generated. 20 5. Short Circuit Core Loss. Synchronous al terna,tin g machines generally ha.ve loss measure:m ents ta.ken, not only on open circuit, b ut also on In the latter case, the increase in power short circuit. supplied by the drivin g motor over U J.at required by the friction. loss is plotte:l as onl.inates agaiflst the armature amperes as abs c is s ae. The curve obtained is similar in character t o t he op-:n circuited core loss curve. Oos e1-v a- tion s ·w€re ir ad.e with the short circuited armat ure current up to 260 percent of its nonrial full load current. See pages 36 and 5?. 6. Friction and Windag e. The friction and windaf~ e losses in t h e synchronous conver t er were found when driven by the srn.all direct current motor use r1 ir-1 tlle core lozs test. The brush friction is d.eterm.ined by f indin g the difference in drivin t~ motor amperes wi th brvshes d ovvn and brushes up, and. multiplying by "the vol tae;e. The friction and windage loss equals the d ifference in driving motor current with all brushes on the cormLutator up and with the belt off. See page 36. 21 ?• Saturation - No Load - - Full Load. \ The saturation test was made in order to ascertain the characteristics of the magnetic circuit. saturation" met.bod was used. The "motor The ma.chine was operated as a motor with no load and then with full load. The energy was supplied. frorr1 the City, stepped dovm through the two banks of transformers, previo1J.sly me11tioned and led tbroug,h the regulator to the converter. After the machine had at- tained synchronous speed, the field, already weak, was increased in s1riall steps; but as tlle speed was independent of the motor field, the ff ac:bine was regulated for minimwn in1 put current at ea.ch voltage. Readings were taken of am1a,- ture volts a.mi. amperes, and also field vol ts and amperes. The curves, see page 58, show the saturation or magnet : ization of the converter. As this magneto0.oti ve force, which is caused by the ampere-turns of the field windings, acts over the reluctance of the magnetic pathe, it produces a magnetic flux. by varyin ~.£ tb.is flux. Th e electromotive force is generated The M. M. F. =~lAt, but 4--flt is a constant for the machine. therefore the field current is a measure of the M.M.F. Also the E.M.:b..,. 2:enerated = .2.pNHp GOXJcP)C and as all but 4' are constant at synchronnus speed, the E.M.F. is a measure of the flux. Fnr t h is reason the sat- uration curve may be drawn, taki.n E the field current and the armature vol ts as coordina,tes. 22 8. Synchronous Impedance. Syt1chrot1ous Impedance was taken to determine the field current necessary to produce a given a.rmature current when the machine is r ·c.nn ins sr.:.o rt-circuited. The armature was first short-circuited tl1:rough an ammeter, and then, with the machine running at synchronous speed and a weak field current, the current in each phase was read. The field current was gradually increased until 200 percEnt normal armature current was reac~ned. Readings were also to.ken of armature volts and field volts, also current and speed. The armature current in a polyphase machine produces a M.M.F. which remains constant for a ::siv s n current,its angular position dependi:lt: upon the power factor. It also produces a C.E.M.F. of self-induction, due to its stray field excitatiom~ These two forces change the voltage directly as the current, that is, the change produced is directly proportional to the current. L1 as much as the resistance drop is also directly proportional to the current, the total change due to these forces may be expressed as a consta11t multiplied by the c urrent. This constant is called the "Synchronous Irrp edance" of the mac hlne; and as the line E.M.F. equals the induced E.M.F. minus the impedance E.M.F. IZ, we have E1==Em-IZ. When the machine is short circuited, the terminal volts are zero, therefore E1= E..-,-IZ=O t::> or Ei:,= IZ. 0 T:b.e current values obtained. on short cirtuit and the voltage were plotted with the corres- 23 ponding field excitation. Values of I & E for correspond- ing field excitation were th.us obtained from which values of Z were tal-~en; these were a.vera.g ed, and as a result the value of 0.4258 ohm for "Synchronous Impedance" resulted. However, Eay, in his "Alternating Currents" page 152 voltmeter readin~ circuit =the 1.·m. . ., in open ammeter reading in short circuit pedance of the apparatus, which rr~ay be assumed constant says: "The un,ier all conditions er load". T11.is gives the value 2* 5 =0.43 olrru Synchronous Impedance. 0 9. Phase Characteristics. In takin~ the phase characteristic curves to determine the field current for minimum input at a given load, the synchronous converter was operated as a motor from the re ~-sular source of alternating current, having a frequency and voltage desired at the poir1~ of minimurr.;. input. Start- ing -with a weak field the armature volts and amperes, and. the field vol ts and amperes were read. The field •.'Vas in- creased by small sters up to and beyond the point of mini mum input armature current. 0!1 a no-load phase character- istic curve, the watts input at the lowest point should check very closely with the sum of the core loss, friction and windage losses, since the power factor is unity on synchronous motors at tt.i:3 p oint. the case. This was found to be The first value being obtained as follows: ?3.O><. 9 .SXL?J:=1.238 kw. and the se0ond value, see page 24 35, 8 5 . 4 x 14 . 8 == 1 . 2 6 3 kw. is lagging, With a weak field the current and with a strong field. it is lead.in;_?'. Two no-lo ~~d a.c1i. two full -load phase characteristics ·were taken; Curve 1 was taken with the desire~ voltage at see page the poin t of :minimuJn input. If this had been held cor.- stant through:>ut the run the left half of the curve would have been drawn at a less oblique angle, while that to the right would have tended more to the vertical - in no way affecting the minirrn.un curre~ '1 t input, however. curve 4 shows the effect of holding 70 volts impressed on the machine. Curve 2 was taken holding A.C. volts constant and varying the ma.in field only. Curve 3 wn,s taken at t h e lowest limit of direct current volts, holding the A. C. and D. C. volts constant and adjusting the D. C. line current to that value whicr1 gives the rated o u.tput for the mid-voltage wi tr1 zero B.UxilL:i.ry field. 10. Running Light T est . The ruiu.i.i ng light t -e st was .made to determine the shunt field exciL=ttion at the impressed D.C. voltage, and is taken on the synchronous converter with the machine n .rnnin 6 f:com the D.C. side. The D.C. voltage is held con- stant, while the shunt field is varied until rated speed is obtained. The input to the field and armature is then 25 taken. See I pa~e41 also page60. Another test was made runni.n 5 li ght fr om the D. c. side, holding speed a nd shunt field current obt a ined from test. See II page 41 also p a ge 60. Another test wB.s :m ade holding speed consta.n t an.:1 varying the s h unt field. S -Sc III page42 also page60. The curves show the relation of D· C. and A.C~voltages to fi6ld curre :1t; and i t may be seen th::1,t the A.C. volta,ge correspondi~~ t o D.C. mid-voltage of 10?.5 is 77.5 volts. It was fou;id in operat in g from the A. c. side that ?8. 5 vol ta Ln1Jressed were ne c essary to hold the D. C. mid-voltage at 10?. 5 vol t :3 . This difference is probably due to experi- mental. error, and the field curret1t corresponding to ?8.5 volts A.C. may be tak ,:_; n as correct. 11. Efficiency by Separate Losses. Th e efficiency of the synch rono us converter was cal- cul ate.J. by the "separate loss" metl-x>d at unity power factor. The losses were calculated. at no-load and at eacr1 quarter load up to 50 percent over-load. The core loss, brush friction, friction ani winda3e, resistance and tenwerature were previo 'J.sly obtain ei, and with thes e and the constance of the machine, the efficiencies were calculated. The recorded values include the loss due to the re g ulatins field and the shunt field, which are separately 26 excited . However, the energy should be charged up a gainst the converter as auxiliary to its operation. ijee pages 43 and 61. 12. Starting Tests. Synchronous converters are designed to b e started by one of the following methods: 1. Small induction motor. 2. From the alternating current side as an induction motor. 3. From the direct current side a,s a shunt motor. 4. From an auto-starte r . 5. From normal-voltage tap of transformer by throwing the converter on the line through reactance coils. The first thre e of these methods were used, as the others were not available. 1. In order to observe tne volts and amperes necessary to start the machine, using the General Electric 10 H.P. Induct.ion Motor mounted with i t ( see illustrations), it was necessary to use 3 phase energy from the Westing- house Rotary Converter No. 629991. The volts and amperes necessary to start the machine were observed, but readings at synchronous speed could not be obtained because of 60 cycle supply. 2. The starting of the converter from the A.C. side ?:I is similar to the starting of any synchronous motor, except that the field is left open-circuited, otherwise there would be destructive flashing at the commutator. In this condition there is generated in the field a very high voltage which would be liable to break down the insulation. To avoid this the field is "sectionalized", each section being connected independently to a double-throw break-up switch mounted on the fra.ne of the converter as described in Sect ion II. The switch is left open on starting and as soon a.s the machine has reached synchronous speed it is cJ.osed_. If the direct ion of the D. C. voltage is wron 6 , the swi tc}1 is closed in the "down" posit ion until the right polari -cy ob ta.ins, when it is put in the II up" po si- t ion, 3. The test as a shunt .motor allowed the energy used a.t synchronous speed to be observed. The energy required to start by the three metho •i s is as follows: 1. By induction motor 4.85 kw. 2. From. A.C. side 5.77 kw. 3. From D.C. side 0.091 kw. 13. Voltage regulation with Fegulating Field. Having considered the principle of the regulating field(Sec. III) its operation is of interest and according- ly two tests were made taki.n ~~ the nine posit ions o .f the rheostat arm as indiGated on the data sheet, under the 28 follow·in 6 four condi t. ions: No .Load Unity Pov,er Factor. Full Load }To Load 11 II Constant Shunt Field. Full Load II II It The results of these tests agreed very closely as shewn on page 62. As will be seen from the curves, ex- tremes of the voltage ra11 g e for no load a_.re 133 vol ts and 55 volts, or a difference of 78 volts produced entirely by the recsulating field; while those for full load., of 75 amperes, are 125 and 54 respectively. The regulation, or range obtained. by the regulating poles, of the synchronous converter is,therefore: No Load 133 55 ---m volts Full Load 125 54 ---r;rvolts The regulation of the synchronous converter from the A.I.E.E. standardization Rules 1914 - Sec. 285, is found from the data and curv e s to be Terminal vol ta.,:re no load " " --ful 1 11 Regulation Or 14. Regulation 107.5 95.5 12.0 vol ts 12. 0 100 _ 11.15% -Io?.5 - Normal Load Heat Run. O.ne of the most importan.t tests of a converter is the heat run. It is made to determine the performance of the 29 machine under operatin~ conditions, the temperature rise of the various parts, and the location of any hot spots that might develope with continued runn ing. The normal load of ?5 an~eres was put on the machine, runn ing as a straight rotary, for sBve n hours before the temperatures became constant. After four and one half hours the converter showed fewer signs of hunting, and at five hours no hunting was observed. This condition lasted until the end of the run. 15. Polarity Reversal In Synchronous converters. In the Electrical world, Vol. 65, page 210 there is an article by E.R.Shepherd, which sets forth some experiments made on the rever 3ing switch in the field circuit. The purpose of the study is to determine just what takes place in the converter whe.n the field switch is changed frorn "up" to "down" position. As the present machine was equipped with such a switch, it was desired to duplicate the exper- iment as far as possible. Accordir1gly the machine was syn- chronized by mear1s of the induct ion motor, The stroboscop- ic disc showed that it came up to speed and locked in step. With the field switch op en the volt meter read 97 vol ts, and the compass showed the poles alternately N and S. On closing the field switc?-1 in the "up" position the E.M.F. increased to 112. s}:wvm by the disc. There was no shift of the armature as On closing the switch "down" (reversing 30 the main field),the D.C. armature voltage reversed to 10, arid did disc showed a slip of half a pole in the direct ion or,rJ•osite to armature rotation. Or1 opening the switch the armature slipped another half pole and the voltage came up to 110 volts with poles reversed.. With the switch in the "down" posit ion the brushes were shifted along the commu- tator causing violent sparkinr.s, but it was r1ot shifted enough to cause it to fall out of step. As a result of the test it was deterrnined that the "up" position was that designed for running. The "dovm" posit ion is ma.de use of when in starting up from the A.. C.. side as an induct ion motor and phasing in, the wrong pola.r- i ty is given the D.C. voltage. 16. 0scillograph Curves. The 0scillograph was used to show the character of the voltage and current wa:ves in the line feeding the synchronous converter. A series of curves were traced showing the waves at the extreme posit ions of the regulating field rheostat, and under three concli t ions, viz: No load., constant shunt field; 1?ull load, constant shunt field; and No load unity power factor. They were taken on the load side of the transfonners, ·which were connected b Y The curves obtained shov.r ed plainly the ha,rmonics ir1 the line and distortion of the current, caused by the tendency of the converter to hunt. 31 V. Conclusions. ·rhe foregoing experiments have brought out the characteristics of the regulating pole synchronous converter under ~est, and of this type of machine in general. The disadvantages of the machine are: its tendency to hunt, and its large losses. Its advantages are: its wide range of application, eg. as a synchronous converter, as a double-current generator, as an A.C. or D.C. generator, and as an A.C. or D.C. motor; and its voltage regulation - by means of the regulati.ng poles. With the tendency to hunt entirely elLminated by proper connections to the energy supply, it should prove a useful piece of laboratory apparatus. 32 VI. Data Sheets, Illustrations, Diagrams and Curves. Operation of Synchronous Converter. Reg. field neutral. Shunt field separately excited. A.C. Obs. Obs. Field D.C. Vol ts Amps. K.W. P.F. Vol ts Amps. Amps. 90 13.5 1.9 1.00 12?. 0 0 4.95 90 23.0 3.2 .93 126.5 10 4.95 90 33. 5 4.6 .90 125. 5 20 4.95 90 42.5 5.? .88 124.5 30 4.95 90 54.0 ?.l .8? 123.0 40 4 .95 90 66.0 8.3 .87 122.0 50 4.95 90 76.5 9.4 . 87 121.5 60 4.95 90 87. 0 10.6 . 8? 120.0 70 4.95 90 98.0 11.7 .s? 119.0 80 4.95 90 109.0 13.0 .88 118.0 90 4.95 80 21.0 1.8 1.00 109,0 0 3.9 80 28.0 2.9 .99 107. 5 10 3.9 80 34.0 4.3 .98 106.0 20 3.9 80 41.0 5.3 .97 105.0 30 3.9 80 49.0 6.2 .96 103.0 40 3,9 80 60.0 7.6 .95 101.0 50 3.9 80 62. 5 8.3 .95 100.5 60 3.9 80 78.0 10.5 .96 99.0 ?O 3.9 33 Operation of Sync11ronous Converter con. A.C. Obs. Obs. D.C. Field Volts Arrg;) s. x.w. P.F. Volts Amps. 80 83.0 11,2 . 98 98.0 75 3.9 80 89.0 12.0 .99 97. 5 80 3.9 80 97.0 13.2 .99 96.5 90 3.9 ?0 14.0 l.? 1.00 92. 7 0 2.8 70 23. 0 2.7 . 98 92.0 10 2.8 70 30.0 3.6 .97 91.0 20 2.8 70 37.5 4.4 . 97 89,5 30 2.8 70 45.0 5.4 .97 88.3 40 2.8 70 54.0 6.4 .95 87.3 50 2.8 70 61.0 7.3 .96 85.0 60 2.8 70 69.0 8.3 . 97 84.0 70 2.8 70 77.0 9.3 .96 82.2 80 2.8 '70 83.0 10.0 • 97 81.0 90 2.8 Amps •. 34 Core Loss Tests. Reg. field unexcited. current 0.32 amp. 4 11 motor .pulley. Motor field Spe ed 1 500 R.P.M. Motor Volts Conv erter D.C. Volts. .Anps. Vol ts Amps. F·ield Vol t:3 . 147.0 ?.6 ?2.0 37.0 51.0 1.07 14?.0 8.1 ? 2. 0 46.0 63.0 1.50 14?.0 8.9 ?2.0 54.6 ?6.0 2.00 14?.5 9.7 ? 2. 0 63.0 87.4 2.50 147 . 5 10.5 ? 1.9 69.0 96,0 3.00 147.5 11.2 74.0 103.8 3.10 148.0 11.8 ?1.9 79.3 110.6 4.00 148. 0 12 ..J 71.9 83.0 11 6.0 4.50 148.o 12.a ?1.8 87.3 122.9 5.00 149.0 13,5 71.8 91.0 127.9 5.50 149.0 14.3 71.8 94.7 134.0 6.50 10498 Meters. 37604 5374 11583 6427 2844 A.C. Fi eld With no fie l d excitation on converter 147.0 6.2 Loss 147.0 x (?.6-6.2) == 205.5 watts. D.C. 51.0 Volts. 2600 Volt s 2 149.0 ~ (8.1 -6.2 )=1208~0 wat t s. 134,0 Volts. 1?960 Vol ts2 35 . Core Loss Tests. Reg. field u.nexci ted. field current 0~50 amp. 9 1/2" motor .Pulley. Motor Speed 1500 R.P.M. Mot~r Converter A.C. Volts D.C. Field Volts .Ang;,s.• Volts Amps. Field Volts 81.9 9.1 122.0 30.0 38.0 1.0 84.3 11.3 122.0 53 .1 ?1.0 2.0 85.1 13.9 122.2 6?. 5 91. 8 3.0 85.4 14.8 ?1.9 98.1 3.4 86.2 16.0 122.6 ??.O 106.4 4.0 87.0 18.0 121. 9 84.5 118.0 5.0 8?. 5 19.8 121.4 90.8 12?. 2 6.0 89.5 22.0 121.0 9?.C 13?.4 ?.35 10498 Meters. 37604 53?4 11583 642? 2844 With no field excitation on converter 81.9 8.0 Loss 81.9 ><. (9.1-8.0) =89.8 watts. n.c. 38.0 Volts 1442 Volts 2 89.5 x(22.0-8.0)=1197 watts. 13?.4 Volts 18890 Volts 2 36 Short Circuit Core Loss. Reg. g 1/2" motor pulley. field unexcited. field current 0.50 amp. Motor Motor Speed 1500 R.P.M. Converter D.C. A.C. Volts Amps. Volts Field Amps. Loss K.W. Volts Amps. Field Volts 83.0 9.3 115.0 2.4 15.0 0 0.10?9 84.9 14.3 114.8 10.0 61. 2 0.82 0.535 86.2 19.6 114.2 11.5 89.0 17. 5 1.22 1.000 86.0 26.8 106.0 13.0 112.0 21.0 1.48 1.618 85.8 2?. 3 113.a 15.0 112.5 22.0 1.60 1.655 85.J 33.5 113.4 18.0 130.0 84. 5 1.80 2.1'75 Friction and Wind age. Motor Field Pulley in. Field Volts Volts Amps. Amps. 147.0 6.20 0.32 4 ?2.0 148.0 3.80 0.32 4 ?2. 0 No field on converter. All brushes up. 142.5 2.60 0.32 4 ?2.0 Motor only. 81.9 8.00 0.50 9 1/2 122.0 No field. 81.0 5.40 0.50 9 1/2 121.4 D.C. brushes up. 80.0 3.80 0.50 9 1/2 121. 6 All brushes up. 81.0 1.60 0.50 9 1/2 121.? Motor only. Remarks 37 Saturation (lfo Load and Full Load). Constant speed. Impressed voltage varied. Fiel d. current adjusted for minir1um current demand per voltage. A.C. No Load Full Load Volts D.C. Volts 23.4 D.C. Field. Volts Field 37. 5 11.0 0.8 41.9 62.2 20. 5 1.5 53. 2 ?6.0 2? .o 2.0 62.2 89.2 34.0 2.5 68.1 9?. b 41.1 :3.0 74.:3 106.6 48.2 3.5 79.2 11:3.4 55.? 4.0 83.9 119.? 63.0 4.5 87. 3 125.0 ?0.5 5.0 91.2 131.3 81.2 5.5 94.0 134.0 88.0 6.0 89.0 12?. 2 ?4.0 5.0 82.2 11? . .8 60.0 4.0 ?2.1 103.2 44.8 3.0 58.1 83.1 30.0 2.0 31.6 52.2 15.0 1.0 33.0 44.0 ?5.0 33.8 2.35 4?. 2 68.5 ?5.0 43.4 3.0 55.9 82.2 ?5.0 51.0 3.5 62.0 91.8 ?5.0 58.1 4.0 Amps. A.mps. 38 Saturation (No Load and Full Load). D.C. D.C. Full Load Vol t:s Volts ~s. Field Volts Amps. 6? .8 102.0 ?5.0 66.3 4.50 ?3.0 109.6 ?5.0 ?5.0 5.00 60.0 88.8 ?5.0 55.2 3.65 51.0 75.8 ?5.0 46.3 3.10 42.5 56.0 ?5.0 3?.0 2.45 34.0 46.0 ?5.0 33.0 2.20 26.0 34. 0 ?5.0 30.0 2.00 A.C. Field Synchronous Impedance. Speed 1500 R.P.M. Short A. c. Open Circuit Circuit Field. Field Amps. Volts A.mps. Volts 45 19.0 0.593 8.0 50 21.5 0.671 9.0 55 24.0 o. 750 10.0 60 26.0 0.82 11.0 65 28.0 0.90 12.0 ?O 30.0 o. 97 13.0 ?5 32.0 1.04 14.0 80 34.0 1.12 15.0 85 35.8 1. 20 16.0 90 3?.5 1. 27 17 .o 95 40.0 1.34 18.0 100 10942 42.5 1.42 456 19.0 2?904 6427 39 Phase Characteristics. No Load. A.C. Volts Amps. I. Obs. Obs. P.F. K.W. Field Volts Amps • Volts D.C. 65.0 52.0 . 63 3.7 14.5 1.00 93.5 69.8 2~.o .90 3.0 29.0 2.00 98.0 73.0 9.8 1.00 1.3 43. 5 3.00 102.0 74.8 11.5 e 9 .::, 1.45 49.0 3.39 102. 6 76.9 21. 5 . 84 2.4 59.0 4.00 104.9 79.0 39.5 . 67 3.6 72.5 5.00 107.9 81.0 58.0 . 60 5.0 88. 5 6.00 110.0 1557 10942 114058 65139 5374 456 V 6427 D.C. Meters. VoltsA-mps II. 68.? 89.0 .93 9.8 14.5 1.00 84.0 75.0 73.0 79.0 .95 9.5 28.0 2.00 88.0 75.0 75.0 69.5 1.00 9.0 44.0 3.00 89.5 75.0 75.0 74.0 .88 8.4 59.0 4.00 87 .o 75.0 75.0 85.0 .7 9 ..., 8.0 73.3 5.00 87.5 '75.0 III. 70. 0 71.8 .99 8.6 30.0 2.05 83.0 75.0 70.0 69.5 .96 8.1 44.0 3.00 81.5 75.0 70.0 70.0 1.00 8.0 34.5 3.40 80.6 75.0 70.0 81.5 .77 7.6 59.5 4.05 80.0 75.0 70.0 9~.o .36 4.3 0 40 Phase Characteristics. A.C. Field Volts Amps. D.C. Obs. Obs. A:rll) s. P.F. K.W. IV. 70 98.0 . 70 8.3 6.0 0.50 90 62.5 70 73.3 .82 7.2 14.0 1.00 90 44.8 70 42.5 .85 4.4 28.0 2.00 90 30.0 ?O 2? .o .96 3.1 43.0 :3.00 90 19.0 70 44.0 •3D ~ 1.8 58.0 4.00 90 12. 0 70 60.0 .10 0.7 67.0 4.60 90 4.0 70 73.0 .05 4.5 ?3.0 5.10 90.0 0 70 41.5 .45 2.3 58.5 4.00 91.3 0 ?O 15.0 .88 1.6 44.0 3.00 92.5 0 70 13.0 1.00 1.6 41.0 2.80 92.8 0 70 31.3 .60 2.3 29.5 2.00 94.8 0 70 67. 5 .39 3. -~ 14.5 1.00 98.0 0 Volts v. Vol ts Amps. 41 Runnin g L ight Test. Im.pressed volts 100.0 Shunt Arm. H .P . M. F ield Amps. Speed 8.0 9.5 1015 7.5 9.5 1 0 40 7.0 9.5 10?0 6.5 9.5 1100 6. 0 9.5 1140 5.5 9.5 1150 5. 0 9.5 1200 4.5 10 .2 1 275 4.0 10 . 5 1330 3. 5 1 0 .6 1415 3.0 10 . 8 1500 ? 11.3 1650 I• - ·---• 0 A.C. D.C. II. F ield Volts Amps. Volts Amps. Amps. Speed 98.4 11.0 69.2 0 3 .39 1400 10 2. 0 11.3 71 . 9 0 3.39 1450 1 0 7.0 11.0 75 .0 0 3 .3 9 1500 110 .3 12 . 0 77.3 0 3. 39 1550 113.0 1 2. 3 79.5 0 3.39 1 600 42 R unning Light 'l'est. D.C. III. A.C. Field Volts Amps. Volts Amps. .Amps. Speed 92.3 12.5 66.8 0 2. 75 1500 97. 2 12.9 70.0 0 3.00 1500 103.5 13.0 ?4.3 0 3.50 1500 108.0 13.1 77.5 0 3.?5 1500 111.9 13.2 ?9.9 0 4.00 1500 114.0 13.4 80.9 0 4.30 1500 122. 4 13.9 87 .o 0 5.05 1500 130.9 14.0 92.3 0 6.00 1500 13?.0 14.1 96.? 0 7.00 1500 141.0 14.2 98.9 0 ?.60 1500 43 Calculations of Efficiency. Percent of Rated Load 25 50 75 100 125 150 Line Amperes 18.75 37.50 56.30 75.00 93.'75 112. 5 Shunt Fiel d. Amp eres 3.8 3.8 3.8 3.8 3.8 Armat ur e .Arrrp ere ~3 22.55 41.3 60.1 78.8 97. 55 116.3 Terminal Volts 90.0 90.0 90.0 90.0 90.0 90.0 Armature Drop 0.725 1.45 2.18 2.90 3.63 4.35 Series F'i elcl Drop 0.235 0.47 0.705 0.94 1.1?5 1.41 Brush Drop 1.85 1.55 1. ?4 1.925 2.11 Total Induced Volts 92.81 93. 29 94.44 95.58 96.73 97. 97 Core Loss 0.535 0.540 0.550 0.560 0.580 0.595 Annature I 2B. Loss 0.019 0.063 0.134 0.228 0.352 0.501 Series Field Loss 0.006 0.020 0.043 0.0'74 0.114 0.162 Shunt Field Loss o.342 o.342 0.342 0.342 0.342 0.342 Regulating Field Loss 0.076 0.076 0.076 0.0?6 0.076 0.076 Brush Loss 0.053 0.112 0.187 o. 272 0.375 o.490 Brush Friction 0.251 0.251 0.251 0.251 0.251 0.251 Friction and Windage o. 275 o. 275 0.275 o. 275 o. 2?5 o. 275 Total Losses 1. [)57 1. 6? 5 1.858 2.0'78 2.365 2.692 Kilowatt Output 1.69 3.38 5.06 6. '7 5 8.44 10.12 Kilowatt Input 3. 24 5.05 6. 92 8.82 10.80 12.81 Efficiency in Percent53. O 1.37 67. 0 73.0 77. 0 78.0 3.8 79.0 44 Starting Tests. I• With Small A.C. Volts .Arr;) s. Induction II. A.C. p. F • Side 31.0 92.5 Volts Ar.np s. 23.0 140.0 23.5 140.0 23. 0 1'15.0 23.0 146.0 .98 Motor. as 30.0 93. 0 .9? Ind. 31.0 92.0 .98 Motor. 31.0 III. D.C. Side 92.0 .98 D.C. as Shunt 6.0 18.0 Motor. 5.0 20.0 Sh. F. 1. 5a,, 5.0 19.0 4.0 12.0 3-. 5 14.0 Sh. F. 3. Ba. 3 .e>r.; 15.0 At synchronous speed: v. A. 4.5 14.0 114.2 12.0 Sh. F. 3. 9a, 4.0 16.0 114.0 12.0 ~ Voltage Regulation with Regulating Poles. Sh.Field Rel, Field Osc. A.C. Reg. D.C. Vol ts .Amps. Volts .Amps. Field No. Amps. P.F. Volts 9.0 1.00 54.5 122.0 0.42 10?.5 0 i 2. 11.0 . 83 54. 5 121. 5 0.52 112.0 0 ~ 3. 18.5 .50 55.5 121. 2 0.91 11 6 .8 0 -+ 4. 43.0 . 24 55. 2 120.8 2.14 125.0 0 ,,7' 5. 83.0 .02 55.0 120.0 5.85 133.0 0 t g. 4- .93 55.6 121_. 0 0.53 102.1 0 ?. 11.3 • ?5 55.6 120.9 0.88 96.8 0 ~ 8. 16.? .58 55.5 120.3 2.12 ?7.8 0 ...."' 1. 6. ✓ 45 Voltage Regulation with .' Regulating Poles . and Oscil l og:nipb Data. Osc. A.C. Sh .Field Reg . Field D.C. Reg . No . .Amps. P. F. Vol ts Vol ts .Arr.q.)s. Vol ts ~ s. Field 9 . l3.4 .77 55.2 119.5 5.95 55.0 0 Above d.ato, taken at No Load, constant shunt field; A.C .. volts 78.5; sl1.unt field amperes 3.8 Data below taken at Full Load co n s~cant shunt field; A.C. volts 78.5; shunt field amperes 3.8 10. 60.0 .99 55.5 129.3 0.45 94. 0 - 75 11. 69.0 1.00 55. 2 129.0 0.58 99.5 75 12. 75.5 .94. 55.1 128.8 0.98 113.0 75 13. 96.0 1.00 55.l 128. 0 2. 28 114.0 75 r 14. Too much load for transformers. 15. 63 .o 1.00 55.2 128.8 0.59 90.0 75 16. 63. 0 .99 55.2 128.3 0.93 85.0 75 .. 95 57.0 128. 0 2. 26 70.0 75 .85 56.8 126. 9 6.18 52.0 75 18. 54.0 Data below taken at No Load 1. 0 power factor; A. C. Sh.Field Vol ts Amps. volts 78.5; 9.0 22.3 1.52 127.5 6.10 128.0 0 20. 10. 5 32. 3 2.25 128.0 2.22 126.0 0 21. 9. 5 45.0 3.12 12?.8 0.98 118.5 0 22. 9. 0 49.0 3. 37 1 27.8 0.58 114.3 0 23. 10.0 54.0 3.?0 127.5 0.45 109.5 0 24. 10.0 58.4 3.95 127.2 0.58 100.0 0 25. 61. 0 4.10 126.0 0.97 93. 0 0 19. 9. 0 ·i i 46 Voltage Regulation with Regulating Poles, and Oscillograph Data. Osc. A. C. Shunt Field No. A..rnps. Volts .Amps. Volts Reg. Field Arr4) s . Volts Amps. D.C. 26. 9.0 63.5 4.38 125.4 2.22 77.5 0 27. 10.5 60.5 4.05 124. 2 6.24 56.0 0 Data below taken at Full Load 1.0 power factor; Reg_. Field ""' ,. A.C. volts 78.5 69.0 51.0 3.55 129.1 0.53 96.5 75 * 7 2.0 43.5 3.00 128.0 0.65 102.0 75 ~ 73.5 38.0 2.65 128.1 1.15 106.0 75 ~ 79.0 20.0 1.40 128.2 1.80 116.0 75 83.0 13.0 0.95 1 ~~8. 5 3.10 119.0 75 66.5 54.0 3.80 128.8 0.60 91.0 75 ~ 64.5 56.8 4.00 128.7 0.92 86.5 75 ~ 57.5 66.0 4.60 128.0 2.00 75.0 ?5 ~ 49.0 ? 2. 5 4.80 12?. 8 6.65 57.0 75 ' 7' f 47 Normal Load Heat Run. Power Factor 1.0 A.C. Volts 78.5 Shunt Field Cal. D.C. A. C. Time Amps. K.W. Volts Volts .Afn.P s. D.C. Axr4)s. 75.0 Tel14) eratures 1. ] ... 12:10 2. c. 3. c. 4. F. 70.9 24.0 23.0 73.3 12:40 15.6 2.12 109.5 62.0 3.90 77.0 44.0 29.0 94.5 1:00 ?3.0 9.91 98.0 62.0 3.90 77.6 49.0 31.BlOl.5 1:30 7 2. 5 9.85 99.0 62 .. 0 3.90 '78. 0 53.0 35.1107.1 2:00 7 2. 5 9.85 99.0 62.0 3.90 78.3 55.0 37.8111.3 2:30 74.0 10.00 99.0 62.0 3.90 77. 0 58.0 39.9 46.3 3:00 73.0 9.91 99.0 62,0 3.90 80.1 60.0 42.0 50.4 3:30 ?3.0 9.91 99.0 62.0 3.90 ?8.0 61.0 42.6 51.? 4:00 ?3.0 9.91 99.0 62.0 3.95 75.8 63.0 43.0 52.8 4:30 73.0 9.91 99.0 62.0 3.95 76.5 63.7 44.0 52.9 5:00 72. 5 9.50 98.0 62.0 3.95 76.5 64.9 46.0 53.4 5:30 73.0 9, 91 99.0 62.5 3.95 77. 6 65.0 47.1 54.0 6:00 71.5 9. 70 98.0 62.0 3.95 77,3 65.8 47.0 54.3 6:30 71.5 9.70 99.0 62.5 3.95 76.1 66.0 47,0 54.8 ?:00 71.5 9.70 99.0 62.5 3.95 76.0 66.1 47. 1 55.0 7:30 71. :5 9.?0 99.0 62.5 3.95 75.9 66.l 47.0 55.1 8:00 ?1.5 9.70 99,0 62,5 3.95 76.0 66.1 4? .o 55.2 C 48 Normal Load Heat Run. 'I' emp er at ur es. Time 5. 6. 7. 8. C C C C 2:30 38.8 25.0 33.0 3:00 40.7 25.0 35.2 3:30 41.9 24.9 35. 5 4:00 42.8 24.8 37.5 4:30 43.3 24.6 38.5 5:00 43.8 24 .? 39.5 5:30 44.2 24.6 39.8 6:00 44.7 24.3 40.0 50.0 6:30 45.0 24. 2 40.2 52.4 7:00 45.2 24.0 40.4 52. 5 7:30 45.2 24.0 40.5 52.5 T ernp er at ur es : 1. Room. 2. ShW1t Field Pole Face. 3. Regulatin g Pole. 4. Shunt Field. 5. Bearing. 6 . Room. 7. Frame. 8. Transformers. 49 VI. Illustratio ns, Diagrams, and Curves. Ill us trations. 1. Shows Eegulating Field Rheostat. 2. General Layout. 3. Shows Tenninal Board with Four-Pol e F ield Break-up Swi tch. 4 . ShoV1.rs Sp eed Limit Device , Regulati n g and Shunt Field Poles , and Induction Volt age Regulator. 50 Fig . I. Fig . II. 51 Fig. III. Fig. IV. : ~ R e.9 u IQti t1_s Field I 234.S-6 .,,,,. .S>,u11trield. ~ + - + - - - - - - - - - - .::s .31'hQ~e • I I I I I I ~, I 4 3"Ph4Se 2 '- 'd "' ~ I ]J.C. I I I PhC1.se A. C. Vo/t-.s:: 70.7''?0 Il.C. Volf-.s. 6 ,, Thesi.s. " == Gl,2.%1].c. ,, ::: JS.J% JJ.C. " ~ t, ~ J A. 2. \0 I J 0 IliQ_,5Jram of Cot1 nec+ior1.s. G.E'. 'Re_g1,,1la+i".:3 Pole s.!:JHch,-.oHOJ.J,S CoHVf!!!,,..,..et-. No.6s.s♦ 701. W. MJ•4oJme.s. 01 l\) 53 W.M.HolmeB. 54 IliQ_:JrqM-1 of Volt-a.9e.s OH A .c. .Si,:ie No /oQc:/ . ..... Fi_g. 7. .Diq3ra.m of V0Jta.9e..s o"' ff.C . .Side rull/oQd , 7-oR. The.sis. W.MHolme..s. ◄ -- ---· ..-n -. . . . •• . • • • .... • I • ' • 55 t• t ♦ l j .-1-- f:~-t-:+---B---+---+--+--'--+,-..;.--+---'-'---+--~--1-Q__ • --•-· 'I - .'t0 f· t9 . -~ ... L::.J ' =·1· •• ' 1~;~1 1- :: - 1~-;{ : "Jl:1 ;l~f ' .--J~-.-- ·+-- L.:-L----'-- ~-' -~~__._ 'QJ ~ ~... '.;: :•! : :. " 1:: ,,; :-: ;-:- ..1.. . ,... I ' - ..1....:.:..;,:.J. --. ,•••• 1. - ' ·.1...L ,.. '. . . .. ' ~ ~ ' ~- ' I 56 - --·--- , -- '., .. .. L:I.: , . - - -- --· I ~ i---t-:---r----r------1 r;:c c.. ?. - ' ' ... ~ ,---+---+---+----1-----i ~ I;~ .. I'. -+---+---+-l.2-1-'--+--+--+--+--~--+-- ·' 2 ~ ~~~\-k ~·~r .. _::-_!_:~~ ~~- - _ ... . . :-. . . . ~ ' l e ·eF- . ; ,• ~=-~:-1~::~t ~:~i~~c 1- -;;, ~-:~ IT1~~~:1 ~] ~,~~~( -~ ,.: ,!~.1~~[~~[ ~:-~-. L ~ _ _ _ _ _ . . _ .~ ~ - ' - - ' - - ' - J - . - !" 58 -• • • ~ ,... .- I • ! • 4 o-- • .J, ' t---c-----, ..... ~1 T. ;:::: ---+- -+- - - + - - - + ~ - ~ - - - - , (~ --+'---+--+-=d- - + - - +--+-r---+--+--+- :: ,-'.- .· 1 1 ' : '-.-< •- I >1_~ • ~· :,.,: --+---+~ : _-c-"1 ;._ ~ 11: ! - - ~ - - s ~ ..:.,---~1---+---+--I - • I (i :++-'-+----++-'--'--:-'-+-:-i-f..,..-:-~-,-;-,-'-l--'--'-'--:-t-,--t-'-H~....;...+-.....:.,.-,-c--,-+..,-'--f-~-'--,-rrl...,.---J--:--;-i--f"7".'"7"1r-:-7T-1h--H-:--;--i ~, ;! '+ ,--,----+----+--~-,-,----~-rl-- ·-c+--.,-+------:-'7'"C-'7'"C-,-,-Tt---'7'"C-"H---,·-r•-,---r-;·-,-r-:-71 ~ • - ----··-- ·•--. --, -1•-, _• . •• , ·-~ -- , -· ,., 59 · l-:--t-t--.-t---!-f-J...!-f-:..-1-_.µ........:...;..;,...~-1-,--...,...,..+-,-'-+---c-+-r-........+--,-,-+--,-,-t-'-i,..:-+--'-'c..:...;.+-..;_+--+---'-+--+.-:--+.--+,--+-,-+,---+----:--+---+---:--1 =I:: ~ ---f...........'+t...........~ - - - - - - - t -- ---t-·'---1-·--!~ 0 ;=+-r--'-+-~+-'-'+--+-e-+--+-----.-,---+---,-+-'-t-+:-~+--:-.+-~+-;-;...-+-'--+-'-'--~--+---+--'-'+-+-+--+---'-+-.1..C-......._-'-I-J-+--:+-+---1 :, ::,:, a: l-'-'-J...h-'-+-,-,-+-,-'-'-+---;-+--+--r.-i-ri-;~t-t""-'7rr,.--i--,--,-+i--'--+--c--++--.-+,~c....,.-1-,-----1-+- -'-+---+--+--+-"--+r'--+'-"----ta~ _o z l--1h.w..1---;.-ir-"-l--,-~~~.....:...i--:~j.;-.~+:-::..i..l..+-=~+---µ..,.:..µC-'-+-,,--~-,-+~+!-+-H-,-H~+---+++.-~--+- _.;.+J-~+l----l-,:--+---+---+-2-+----h-:..L.;.+:-~':--< . 1' l <> i-;...;.~+.-'-'-'--'.µ;:~a.._;7-+--,--:.-~~~~+..!..,--I--L__,_~'--e--l--__.:.+-c......:.+-,-,-.:...µ.4-,-+-,-.:.+--+-;..__..i...:...,-.:...µ.~-l----l--~"---l----l----l-__.!..j......_-,..l .--+---'-+-·....--'c-l--_;__--l---_;__...L__!...,...-l ::, ;i:, 61 -:--. -,1' ' ; - . ·----:- ;- - : I - -T- - £ -~ ,~-~ ,_ I I .'I,.. -.• I ll~ ;---f----+------1 ~,,...± _...~ r: ■t.:---+H---+---+---+--+---+--c ~--+- -t---t-----11---'--t----t--+ - - - - t - - + - - + - - - - - s - - - + -- l - " - + - - + - + -- - + - -+---+--1----'-·-'I ~ ____: L - !. . : :!_'.~-~_J __ _ I i. ~~ I I I I - L_ --+,i; . ' --~r- ____ !_ -- -- . --+----+- - I ~ .:1_ - - r- I '. - --~-:>t .I - ! i-· -l - 1 .I - -- ·f--- -1-- 1 1 ,. -1 i ._ - - -: J -.---- + -. -~ _ ' - - , l" i >---+-~ - t -~r• :-' I •• - 2.0 .I - i - -t-- ·-+------lf---~.- --+----+-·.-+-·--'---+---+--+------+--'---+----+-- - -, +-"-, ·_,~~ I.'. ' 1 I .I.-. ' -- . e I 1- _- l •_ I : r --~- I • ~ -- , - . - :-1 ~ -, - '' ~- - + - - -~ - ~--I ----- -I I I:- - - - ' - -- 1-- _ _L_ .i ; ,. - 1- -- I 0. I 1-: I -+ --~- fi ';_·~ ·:~-::I :_ - '~ 1 ·" - ' ' ,-- -; --r--:--➔~_:__:'._LL. •'. _:_ ,- ·_L - . :~ _L __ r - +·--- )_11-t--ff+-HW--:.--L_L I l. I. I -~-± +~t - 1 - - ·,- i --1----I-JJ_- ' ! I J.r - 63 .,,. _... ~ ir ~-~'--'----4'---'--4 ~ • - - -"-'- 1 - - - . · - . -... - • ~-:~~Ii~-•~±~=--+~~ c::_· _:...J . :..; ... :~-· :.i ~- ~~, ~:.~~-- 64 -lf. • r .•, .. _. • t I ~ . • • -- - ~ - -- ~ -- ~ ~ . ,::, - .:; H h i~; - :~_- ,J-: i_ . . ~: ._,. ~~~ [:_~_:_~;_.__~-~---~-~ 65 9. . Fi_g. e. 0.sci/10=1,-.QpJ., Curves. W.M.Hol'"Me.s.