Experimental Study of the Regulation of Alternators Citation Ferguson, Robert Sindorf (1915) Experimental Study of the Regulation of Alternators. Bachelor's thesis, California Institute of Technology. doi:10.7907/d4ea-sa11. https://resolver.caltech.edu/CaltechTHESIS:07032024-160902874 Abstract No abstract. 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: 1 January 1915 Record Number: CaltechTHESIS:07032024-160902874 Persistent URL: https://resolver.caltech.edu/CaltechTHESIS:07032024-160902874 DOI: 10.7907/d4ea-sa11 Default Usage Policy: No commercial reproduction, distribution, display or performance rights in this work are provided. ID Code: 16532 Collection: CaltechTHESIS Deposited By: Benjamin Perez Deposited On: 08 Jul 2024 19:48 Last Modified: 08 Jul 2024 19:49 Thesis Files PDF - Final Version See Usage Policy. 27MB Repository Staff Only: item control page

1'1-&SIS An Experimental :5tua.y of the Regulation of Alt e rnators. by Robert S. Ferguson Class of .N ineteen Hundred and J!'ifteen Department of Electrical Engineering THROOP COLLEG:b: OlP TECHIWLOGY Pasadena, California 1915 1. A c a reful perus a l of the new Standa rdization Rul es of the P. • I. J::. B. ·,>'i ll reveal a no more r nd ic a l chm.ge than in th~t section devoted to the re gulation of alternators. '.L'hose who 2.re not famili r:: r with the VElrious articles which have been published on this subject of regulation will no doubt question the reason for changing a rule which has been so long in use, and perhaps will doubt the accuracy of the results obt ained by the new method. In cons i de ring thls snoject the writ e:r ha.cl a t vrn-fold lHlrpose in view, fir st , to cu ;:1:r:L·t i·e t .he :ces :1lts obt a ined JJ the ne'.N me thod ·,1ith those obt a ined by methods which have been advoc~ t c d in the pest, 2nd, second, to discover if possible an e ssy way of conducting the experimental psrt of the work ~v-:hich ·,vould enable the t est to 'i.J e i ncluded j_n the Junior Labor2.tory Course. Previously to this time there have be en t -.,rn e;eneral methods in use for obtaining the re gulation of an a-c, generator: by a load test, and by me ans of vectorial calculations from values obt f;. in ed on open cir onit an d ;:::L ort cj_ro ;,.:i t tests. The first has been included in the new rules (Rule 295) and stands fir s t in the order or preference. It is, however, npplic oble only to small mocL.ines, for, owing to the difficulty in di ss ipating the large quantity of energy generated, 2. it is ne xt to impos s i b:~. e t o a p pl:r it to l arge units. In the labora to ry and fact ory the t e st is usually conduct ed on small ma chines by driving from a d-c. shunt motor and loading b y means of a wat er resistance. Two errors a re inherent in this method of procedure. The first is due to the method of driving and the second to the method of loading. ~hen the e -c. circuit is opened and the load reduced, the d-c. motor will spe ed up. :rhis causes the alternator ·volt age to rise to a point ab ove that which it would reach i~ the speed had remained const s nt, by a value which is proportiona l to the difference in spe ed s. This is quite evident from a consideration of the fundamental generator equation B = y) - 8~ i'l The 10 . voltage E and E' generated at the speeds n and n' respectively nre in the proportion E: ~ ' N: lJ' and their difference is in the proportion E '-~ : = CT 1 -n: n. As sum- ing that the motor has a speed regulat i on of five pe r cent the generated volta ge b ' will be five :Jer cent gre a t er than the voltage E. Now the spe ed of the motor can be reduced to the speed n by an adjustment of field current but the voltage E' will not be reduced thereby to the volta ge R on account of the .hysteresis in the iron comprising the magnetic circuit of the alte rnat or. '.1.'he error introduced by this method of driving will depend upon the speed regul a tion of the motor and up on the quality and degree of saturation of the iron ma gnetic path of the alternator. Needless to s uy this error can be entirel y overcome by driving from a constant spe ed motor; on the other hand the error will be increas ed if the alternator is driven by an induction motor. A second error is introduced if the power-factor of the load departs even a slight amount from unity. In order to make it plain that even a very slight deviation from unity power-factor introduces a large error it is necessary to demonstrate that the quadrature component of the current has a greater influence on the re gulation than the active component. This may be shown by an analysis of the equation for finding the regulation of a transformer. The transformer equation is taken inste a d of a similar equation vvhich mi ght be developed for an alternator because it is much simpler, no modification being necessary to account for variations due to rotating parts, varying air-gap , etc. fhis equation is given in sect ion ~>02 st ~11clo.rdi zc.t ion rules as follmvs: Por induc- tive loads of power-factor m and reactive fact ~:r fl , (mq - nqr) :p r,r cent regulation = mq +- nq +- x r X 200 where q = per cent r e s istance drop r an d per cent reactance drop. (1 X - For our purpose the last term cnn be neglected for it is small compa red with the other t wo. drop q X Since the reactive is sever al times as great as the resistance drop gr' a variation in the ~uantity n will produce a much gr e ' t e r error in the result than a v:Jriation in the qus.nt it y m. Ta king t his into consi deration and referri ng to the following table, it is quite evident why a sma ll devi s tion of the power-factor from unity makes such a difference in the regulation. Power-Factor (m) Reactive-Factor (n) 0 . 995 0 .10 0. 9 ~) 0.1'1 0.9 8 G. 20 o. ~o 0 .20 0. 10 0 . 435 0. 98 0 . ~9 ~ On the other hand a considera ble deviation from zero ma kes practically no diffe Tence. re f erred to l ater. This point will be It is usua l to a irnurne that the cur- rent t a ken by a water-ba rrel is in phase with the voltage but this is not strictly t he ca se. The water barrel has a slight electrostatic capacity which causes it to draw a le a ding current. Since a piece of electrical app a ratus will have a better r egulation on a le ad ing current than on one which is in phas e, as a rule the wa t erba rrel-load test of an a lternator will give a re s ult which is optimi s tic. It may be a r gued that the er r or in volt afoe which is caused by a deviation from r at ed s pe ed or unity powe rf a ctor is quite ins ignific ant. It is true that t he abs o- lute Vf: lue of the er ro r is general ly s ma ll but it mus t be reme mber ,d thnt in r egulation we e re dealing with a difference bet ween two numbers which is small in compa rison with the numbers themselves. This being the case the percent age error in the difference due to a sli ght error in one or both the volta ges will be large. .J.: ortnn:itely the tvrn erTors just cited a re to some extent compensating. J.·he former tends to give a poorer regulation while the latter tends to give a better regulation than the correct value. l have gone to considerable length to point out some of the difficulties and errors encountered in the experimental determination of regulation by a loa d test at unity povver-factor. ,,e shall now consider sorne other methods for determining regulation.· These necessitate the running of two curves; na mely, the no-load saturation curve and the short-circuit curve, or instead of tho la't -c er t.ne syncnronous imped ance cnrve. _rj ~r means of vector quantities which may be obtained from these curves the regulation may be calculated in two different wa ys. :i:hese two methods have received the names e.m.f. (pessimistic) method and m.m.f. (optimistic) method. With the type of alternator in use at the time it v1as introduced, the pessimistic method ga ve a very good result; but with the modern machine it gives a regulation usually far in excess of the true value . .t1ence its name. ·.!.'he m.m.f. method is the one which ·was adopted by the A . I. b. E. in 1902 and has been recommended by it until the a doption of the 1915 rules. ~his method while with most modern machines giving results quite close to the tr~e value, is only on approximation. it wa s pointed out by n. ~:. • .r,ehrend in a paper v. published in vol. 21 Transaction s of A. I. ~ . E. that the m.m.f. method ne glect e d the self-inductive effe ct of the local armature fields. In order to take this ef f ect int o account by a test method it becomes necessary to obtain a full-load saturation curve at a power-fac tor approa ching closely to zero. J.'his solution was the one advocat- ed by hlr. behrend at that time and is the one which has been adopted by the lnsti tute Standurdi z;::ti .on Cammi ttee. It is contained in section 296 of the Standardization Rules as follows: "This consists in computing the regulation from experimental data of the open-circuit saturation curve and the zero power-factor saturation curve. The latter curve, or one approximating very closely to it, can be obtained by running the generator with over excited field on a load of idle-running underexcited_synchronous motors. The power-factor under these conditions is very low and the load-saturation curve approximates ve r y closely the zero power-fa ctor s aturation curve. J!'rom this curve and the open-circ t;..i t curve, point::.: for the load saturation curve for an y power factor c an be obta i ned by means of vector diagrams." '.l.' his method sets aside all theories a s to the effect of the re a ctance drop and substitutes in their place experimentally ascei'fe ined d~: :. ta from vrhich the r egul ation at any pow e r-factor can be ac curately calculated by means of "'le ct or 6. 7. ~y t his me thod of load ing reco mmended it is l) OSsi ble on small ma chines to obt tdn a powor-fact or of from 20 to rlemembering that it is the rea0tive-f2ct or which h 30~ . has the greater effect upon regulation and a gain referring to the table of power-fa ctors and reactive-fact ors, one will re a dil y see why a lo a d-sat uration curve at a po·l'v er-fact or ar ound 2070 is a ver;/ close approximation to the zero power-factor curve. I shall later p oint out a method whereby it is quite possible to obt a in a powerfactor much lower than is possible by this method of loading. Having considered thus briefly the four methods of determining regulation let us turn our attention to the experimental side of the question. '.L'he machines available in the laboratory ~re four in number; two of these are revolving field alt er m, t or s , the others are synchronous converters. The make, rating, and method of driving these machines can be re a dily ascertained by reference to the accompanying table. name Centra l L:J borato r y Alternator " 11 hesting house Converter Rating or Number Connect ed Vo lts and Cycles 1.~ot or Drive 7.5 Kw 3-phase y 194 Et -C, shunt 7 .5 Kw 3-phase A 110 a-c. 60 IV shunt 7.5 Kw 629991 armature 125 d-c. 60 N shunt 110 a-c. 50 ,v sh1mt HoltzerCabot S~rnch. Motor 7.5 Kw 1 30298 General 1Uectr:i.c splitpole Converter 695707 6,- IV d-c. y 6. -75 Kw d-c. armature 90-125 d-c. 50 ,v induction '.l.1he Central Laboratory .Alternator has its leads brought out to a terminal bo a rd so that it can be connected either Y or delta. '.i.1his makes it possible to run five series of tests on the four machines available. The tests run on each machine are as follows: 1. Regulation tests by direct loading nt unity power-factor. 2. No-load saturation test. 3. Short-circuit test. 4. Full-load saturation test at power-factor less than 2010. The data obtained from these tests were plotted on coordinate paper and smooth curves drawn through the points thus averaging errors in reading the instruments. From the no-load saturation curves and the short-circuit curves the regulation nt unity power-factor for various loads was calculated by both the e.m.f. and m.m.f. methods. These values were plotted for the various machines·, and curves dravm through the points in order to average small errors in calculation. The full-load saturetion and no-load saturation curves for each machine were plotted on the same sheet and from these two curves the saturation curve at unity power-factor was calculated by means of vector quantities. Prom this latt er curve the regulation at full load and unity power-factor was obtained. The armf: ture !- -i ! ! 1-- - · -'-·-i -· • •••• 1 -··r l . I. -: - -- ··· ·· • - r- - - -' 1 ; I • ; l : -+- I - - - i .. :__ + ----~-·- -- ! ~ I .. :_.,_ .~. • ! : ; . ' _ , ,J . --;-- __j • - ·· ' ' • ·- -:-.. i '·- I 1 - _ · __ __ ' . . I i ! ; ! I - -·r - - -.. 1 ! - -1 - - · · I . .. , - - - --: -- - - , · 1 -- . I ·-- I i • : I - -i ! ' •. j , i -- - 1 l ~rv ·- • 7J:±Lw:~:; ;•' ' •'; ' ' 1" ~ - ,• -; ;; :· : ' i ;+.· s-m~; :~:r .:· -'-'.:; ·:· :1.;s [ ,;r::1!mr • ~ ,-,.I : ... ' j .! C resist cm ce of ea ch ma ch i ne was measured at r ooo te mp·e rat u re by means of a l)0 rt ab le 1,'hentstone brid ge. The resistance 0 culculs.ted for a te mpe r atv.re of 75 C is the one used in a l l ca lculations. Since in obtaining the regulation by the direct method of loa ding the armature conductors 0 did not attain a tempernture of 75 C, this te s t will be slightly optimistic as compared with the others. The regulation at full load and 1mity powe r-fa ctor obtained by means of these va rious methods are tabula ted in the accompanying table. Manufacturer:Connection:Direct Load:m.m.f • . tlule 296:e.m. f .: . ... Central La borator;f y • delta Tl IT ~Jestinghouse:: .. .. Holtzer-: Cabot . Gene1·a.l Electric .. .. . .. ... 38 . 40 .7 40 : 41.7 8.95 .. 7 . 80 41. 2 .. 43, : E2 ..: 53 8. 50: 8; 70 :13.30 7.30: 7; 30 :13.95 9. 2 l U;O . ... . : 20 . 6 in the cases of the t wo machines with low reactance, the Holtzer-Cabot motor and the Westinghouse converter, attention is called to the close a greement of the res ults obtained by the m.m.f. method and by rule 296. In this connection we may point to section 297 of the standardizat i on in which a method is given for obtaining the zero power-factor s nturAtion curve from the open circuit and short circuit cha rac te ristics of the ma chine in question by refe rence to tests at zero power-factor on other ma chines .. ,; ·;:: ...1··-- ---· .. . : , .: :-: --2:( ; ~., ··- . --,-.. --;: : : , ., --. - •r:~ ~ ~t : -=-,=::::_ ,__;__~ -+-~ '-+~,-1 ·--'-1...-='--4+ '.._!_:,· _:.;0 . ; 1JJ .J_j ' \: • I, •" ( .• ~ :f ,: :i:: . I · ···- ;+£ , ; ~ ~, r ,' ~ l ; :~ - ~ • ,_• ; . I 1 0, of s i mil 2. r ma gnetic circ uit. 'l'his is done by shift : :_ ng the open-circ uit satur ation curve to the right by an amount equal to the number of ampere turns necessary to send rated current through the armature at short circuit. In high speed machines having low reactance and a low degree of saturation in the magnetic circuit the zero power-factor curve will be quite close to this curve. 'l'his is the theory upon which the m.m.f. method is be sed and in the case of the t wo alternators just cited the experimental results are in agreement with this theory. J ith machines ha ving high react ance, high saturations and .high magnetic le akage , the zero poY;e r-j:" o.ctor curve will fall below this curve. r his is evidenced by the ca s e of the Central La boratory .Alt ernator in which the regulation as calculated by rule 296 is considerably greater than that obtained by t he m. m.f. method. In running the te :::ts on the vs. rious machines so me difficulty was at first encountered in obtaining the zero powe r-factor saturat ion curve. In the cas e of the machines first experimented on, the 'iJestinghouse converter vvas used a s a loa d. It was synchronized from the d-c.si de, af t e r which the d-c. circuit was 01)ened. ,v ith a v e ry much under-excited field on the motor it wa s difficult to obtain a p owe r-fa ctor of le ss than 30; :;: . :L' rouble wus a lso encountered in keeping the 11 . mnc hi ncs in ste p . Several expe dients were tried to lower the power-factor. '.l.1 he fir s t vm s to suppl y energy to the converter fro m the d-c. side. This method was un- s ntisfactory because a chBnf e in the convert er field not only changed the torque but also the a-c. volta ge. 1i. load of idle-runn ing induction motors ·wa s next tried. This method of loading wa s successful in tha t a low power-factor vm s procured, but the number of induction motors necessary to obt a in full ampere load was an undesirable feature. The synchronous convert er was aga in resorted to for a load but inste a d of a ttempting to s11pply energy from the d-c.side of the converter it was driven by a shunt motor. By a ca reful adjustment of the shunt motor field it was made to s upply the energy losses in the converter, thus reducing the p o~er-fac t or to a value very nearly zero. The published papers do not a pply the vector solution outlined in section 296 to the solution of the regul ation of an alternator drawing a leading current. In order to check this method a test was run on the G. E. Double Current Generator to obtain the saturation curve at rhe results thus obt 2 ined zero power-factor le~ding. are compared with the calculated re s ults in the following t Gole and the curve s obt a ined by these t wo methods ~ are shown on curve sheet D. 7...... &'..., ') . :b' IELD C l.ITE·i llJ T i.\EGULA'.L1ION by exp. by cnlc. by exp. by c&lc. 2 27.8 31.6 ,.:,3. 5 2 .5 3.45 4. 24.6 20.6 19.0 36.4 30.0 21.9 20 .1 20.0 21.6 19.3 2 :-: . 7 20.2 The curve obtained by experiment falls a little below the CBlcnlated curve, thus making the regulation obtained from the experimental determination at leading powerfactor of zero a little less than that calculated from the saturation curve at a lagging power-factor of ze ro. However, no very definite conclusions can be drawn for this condition until tests have been made on more machines. This consideration of regulation on a high condensive load ha s l ed to a study of so ~e of the conditions at first encountered in the operation of the Big Creek Transmission Line of the Pacific Light and Power Corporation. 1iower is supplied to this line at 150 Kilovolts from two generating st ations. One of the stations con- tains two 17500 Kva. Westinghouse alternators; the other two General Electric alternators of the same r oting. The line is 241 miles long and has a capacity of 3.413 micrafarads, an inductance of 528 millihenrys and a resistance of J6 .l ohms. ~ith a volt age of 150 ,0GO at the generator end the charging current is 98.38 amperes. The cor:iplex expressioi, of this current is .6584 + 98. 3 8 j. As is seen by this expression the re uctive com1, cnent is very l 2r ge. In consequence the volt nge of tb.e generator supplying this current will be boosted very high. In practise this is the case. Oii th one generator charging the line it is necessary to excite the field in a reverse direction in order to keep the voltage within safe limits. With one General Electric alternator charging the line and with no exciting current in the field windings and with the line open circuited at the receiver end, the voltage at the generator rises to a value of 7,000; with one Westinghouse alternator the voltage rises to a value of 9,000 volts at the generator which corresponds to 205,000 volts between lines. normal generator voltage is 6600. The The writ er is ,I indebted to Mr. Woodbury's paper entitled 150,000-Volt \l Transmission System, published in the Sept. 1914 Proceedings of the A. I.E. E. for these values. The operation of an alternator supplying charging current to a long transmission line is similar in many respects to the regular operation of a series generator. On curve sheet Hare plotted the external characteristic curve of a 7.5 Kw. series generator, and the voltagecurrent curves corresponding to a total resistance of 1,1. 5 ,2, 3 ,4,5, and 6 ohms respectively. :i..'hese curves s how t hat, while with a line resistance of 3 ohms the voltage builds up to a value of 60, with 4 ohms resistance the limiting volt ~ge is 17. In other words the ·ji-:7TSfF!:8 -~k !_-lJr- ' ' ' ~ ' i ___ ' •• ' :__ i ' I 'I : .:_ _ _ L- --j- , , ·I : I ------t . _ __ • '__ ; _· , '; . , ' .• - :-:~ : :r: ~~i,_: :;r ~ '.._j-'--+---'->-'-· ·:.(;·:::; •..-c/: 2 I I -- • -1 · c- ~ j- ~ :;/t-g): ~-----1' _;__:I --,- ~± --~ :h~•:_:.. ; .:-:=1:: _-. -~f-'-._--.c.;-,f E. - h----'----l-'--,-'-c+.c.._4----'-'-;.J i. !" curves s how that there is a certain critic a l line resistance above which the generator volt age will not build up , but that if this resistance is decreased the volta ge will build up and, if it were not for the saturation of the iron, it would continue to build up indefinitely. i'he same method of reasoning may be applied to an alternator operating without field excitation and supplying charging current to a long transmission line. On curve sheet His also shown a characteristic curve of an 6.75 Kw1 alternator operating without any direct current excitation, and the voltage-current characteristics of a number of circuits he. ving capacities of 2, 000 mf., 4,OOC mf., etc. res pectively. 1·he curve shovm is thnt of the General Electric Double Current Generator /f 695,7O1 and was obtained by approximation after a cs re- ful study of the four characteristic curves of this machine already procured. the conditions pictured in this figure are in all respects analogous to those previously set forth for the series generator and the conclusions drawn are the same for both cases. He:ferring to these curves v✓ e may now explain some of the conditions encountered on the .dig Creek J,ine. It is found that with half the length of line connected, the volta ge vvill not buLLo. up without field excitation. From the curves on curve she et ii we see that with a line c&pacit y of 12, GOO ~f ., t h e volta ge will atta in a val ue of 90 whi le with ha lf this capa cit y the pressure rise stops at a value of 20 volts a nd in order to build it up higher some field excitation will oe neces m:. ry. Then , ag&in, .with two alternators charging the line the volt age does not rise to the excessive value which it reaches when one alternator charges the line. This is for the reason that, since the line current flows through the two machine s in pa rallel, the flux which is formed by this current is divided between the two machines, and consequently the voltage will not rise to a value as high as it did with but one machine charg ing the line. What has gone before shows that the Rxternal Characteristic is of great importance in the case of alternators built to sup .fl ly energy to be transmitted through long lines with consid erable electrost atic capacity. A careful consideration of this working characteristic by the manufacturer would prevent an occnrence li ke the one encountered in the Big Creek development in which, in spite of guarantees, a volta ge of 9,000 is re a ched when the alternators of one manufacturer charge the line unless a provision is made for reversing the excitation. An attempt was made in the laboratory to make a further study of the External Characteristic. This curve was obtained for the Central Laboratory Alternator. The l.b • Holtzer-Cabot mot or r-,:uming ·;dth strongly over-excited field suppli ed the lo nd. the alt ernator. No field excitation was used on Under these conditions the excitation is supplied entirely by the motor. '.l.1his condition- approximates closely the one obt ained when a generator supplies charging current to a transmission line. '..i:he field of the Holtzer-Cabot motor was varied, and readings taken of generator voltage and line current. I shows the results. Curve sheet A saturation point has not been reached at the highest point on the curve but it was impossible to carry the current any higher for fear of overheating. It has been the desire of the writer to make a test on the generators at Big Creek, but this has not been done as yet. nowever, through the courtesy of Professor Sorensen the short-circuit and open-circuit chara cteristics of both the Westinghouse and ~eneral Electric alternators huve been procured and from these approximations of the external characteristic curves without field excitation for the alternators of both manufacturers have been made. '.J.'his was done by as::nuning that for a leading power-factor of zero the load saturation curve corresponding to any given current is formed by shifting the no-load saturation curve to the left by an amount equal to the number of ampere turns necess&ry to send :iJ-0: ., . • • • ' ~ I ;,?:"F~ ~; i • .' ., • ! :_ - ,' .l~ ·· -.;. . j-r' ! ......,..-+-.;-.-+--~ J: -.-~L { I ~ 1 :_·, -·~ :'.: ! ,,_; 't, }~J f -f l :' ftl+ I,> 17. r o. t 8d cur r ent through the a rmo.t ure at short circnit. A number of currents were taken and the saturation curves at zero power-factor corresponding to these currents were laid off . The values of voltage where these curves crossed the vertical axis we r e plotted as ordinates a gainst the corresponding line currents as abscissas and curves drawn through these points. 1'hese curves to- gc th:; r with the Big Creek Line Characteristic are to be found on Curve sheet J. While these curves neglect the boosting effect of the transformers and the magnetic leakage in the alternators themselves, they show with a fair degree of accuracy the comparative values of the limiting voltages which the machines will generate when connected to the Big Cre ek line. The boosting eff ect of the transformers and , the magnetic leakage, however, will cause the voltage to rise much higher than the values shown by these curves. By a ca reful consideration of the method just outlined it will be quite evident that the load saturation curve of that machine h:.:"ving the higher reactance will be shifted further to the left than the saturation curve of the other machine, and in consequence the voltage which corresponds to zero field excitation will be higher in this machine than in the other. It is for this re ason that, for line currents within the range of values plotted on curve sheet J. the volta ges of the J estinghouse alternator are higher than the voltages of ~ -t'--'-i--i:::1..,...."?4,'rr+-+S..+"""'~~:.-l-t-~P-'--'-t--,""'-'--H--,..,.:, .:_; O· <:1' !"" "' ;;- .;...c.:-1,-,-,-+-+-,-+~'+,--f-t-'-f-;-~'-i-j..:.;.""'"'1--.,""'J-!-;..;..c-bj,"""'f-'-'--'-'+--~+;-+,-+~+'"'-'-+'-4--'+-'-f"-"'-i-l'-,--~P..::;cl-"'c;:.:.+;:::.q ~ :,t' f..: f-'-'+'-l+-"-'-l~ P-4:-'bt'---H:7.±ci:::--'-:±-"-'..!.f--'-H~+'+n'"TT"7±-'-:+r--i-t~+~'-;-ti~~':'-i-i-:+c+~-H-:--rl-.,.;:,-+;'i-'-j'-'-'--f-'-t-'..;.:..cf-'-,--,-,+:'--,--+:-,,-,-,,-+.+,+i-;:;::.::+=;.;~Lr;J?, :.:· -~ -~ !,~~ •r: :~,. :,~h-1- 1 . ·~· • .:J i.,he u-cneral L.lP-ctr :i c alt errn:t or. ~t will be noticed, how3ver, tha t the ,: estinghouse alternator is re2.ching a sa , ;;i.rat ion point more rapidly th,:.n the G-enero.l ,.le ct ric Alternator and, had the transmission line been a little longer, conditions might have be en reversed; that is, the voltage might ha ve risen higher with the G-eneral .t.lectric alternator charging the line than vvi th the 1iestinghouse alternator charging it. After saturation is once reached, however, a conslderable increase in the length of line will cause the voltage to rise only a trifle higher. ln conclusion, the rise in voltage inherent in the two alternators under consideration when separately charging the big Ureek Line might have be en entirely prevented by designing them with lowe r reactance, or the rise in voltage might have been arrested at a lower vnlne either by designing with lower reactance or by designing the magnetic circuit to have a higher saturation. 1.:egnlation of .Alternators 1. A. I. B. E. vol . .A.Al page L..i:07 '.J.:he .L.xp crimental De.sis for the 'l'heory of the negulation of Alternators • .ti. A• .0ehrend 2 • .:l.. . l.. L. L . vol .1.:...1...l ll page 291 A contribution to the theory of the ::egulation of Alternators. H.. M. ho bart o.: .lf . runga 0pecial attention to discussion by bradley i. Mc~ormick page 330 3. A. i. • .t.:. E. vol • .,.J,.1d l page 7 83 i'he .c.xperimental Determination of the .::,egulation of Alternators. A. 15. .;:-'ield .... egulation of Definite £>ole Alternators. Soren H. kortensen Discussion page 846 4. 1;, . I. B . .t<.;:. .troceedings 1914, page 1259 ~tandcrdization of the A. 1. B. E. ?0 , :a chine Central Labo r nt or y A7tc rna tor Holtzer Cabot Synch. Liot or J est i ng house Rot a r y Convert er Genera l El ec t r i c Splj_ t po l e Conv e r t e r Comrnct c d 5 q ,1/\4. I 8 .2 e r rninal ~:es i s t &nce ~ 1 8 H}"'l'i \t =-e 'c)c (.' tJ t ,-, . I ;_J r) e r I 1-8 4-9 5-1}: .164 .l o4 . 165 1-2 1-3 2-3 .05 9 . 059 1-5 1- 6 5-6 . 058 . 058 . 058 1-3 1-5 . 049 . 049 . 049 2 4 _,-, 24 " 24 C ~plia ce .1 97 . 059 24 C . 035'.l: 24 C . 104 22 C . 088 3A~ I 66S I sD3 J -5 21 . 7 . 5 t .w . Cent ra l J..,abo r at ory 1..rcne r a t or 3 phas e-- delta connec ted -- 60 c ycle s No-Loa d Sa t u r a tion If i,_; .45 42 curve f 60 II .50 47 II .55 51 IT .60 55.5 IT .65 60.5 11 .70 64.7 • 75 70. .so 74.2 • 85 79.1 " " n lt .90 84.2 .95 89. " II 1.00 93.8 II 1.11 103. II 1.20 110.5 il 1.31 119.5 II 1.42 128. 22 . 7. 5 Kw . i.; entral J.Jabo r a t ory t;i-enerat or 3 pha se--d e lt a connect ed--6 0 c ycles ~ o-Loau Satura tion Uurve lf f 1.50 134 . 8 1.63 142.2 1.70 148 1.82 154 " 1.92 159 II 2.00 163 IT 2.10 164 .5 II 2.20 167.5 11 2.30 170.5 II 2.40 173.5 2.50 177 2.60 179. 5 11 2.70 1 81 " 2.80 1 83.5 II 60 7. 5 L\'l • ve ntra l ~a boratory Alt erna tor 3 plms e--delta e; on:nect ed --6 0 cycles '.l:hree-J:has e 0hort c;ircuit c;urrent If 1 .33 9.80 a £ f 30.0 60 40.0 .43 12.85 .48 1 4 .20 .60 17.90 Ii 45.0 ,., 56.3 II 65.5 .70 .so 20.1 11 75.5 23.5 II 85.0 .90 27.0 1.0 29.7 1.1 32.3 1.2 35 .0 1.3 37.8 1.4 40.8 1.5 44.0 1.6 47.0 If 94.0 II 102 .0 II 11 0 . 5 II 118 II 127 11 136 II 141 Centra l 3 .La :) OrD.t or ;y _,;.1 t e rnat or pha. so--de lt a c onnect e d.-- 60 c y ul es .l!' ull-.Loa d 0atura tion liurve at t ero .t'O\ver-.L' act or p • .b'. .r.; . 1. lf f 19 54 3 9. 4 1.95 60 15 53 .5 " 1.94 11 20 60. 2 .03 fl 21 65.5 2.10 11 0 57 " " " 1.98 11 22 70 11 2.15 IT 17 68 II 2 .13 II 25 73 11 2 .20 II 22 109.5 " 2.62 11 22 118 II 2.76 n 23 102 n 2.50 II .b'Ull-J.Joad uat ur a tion li urve at LJ ero .t' ower•b·act or Lead i ng 110 volts--------7.5 Kw I If f 159 o'J . 4 .6 60 108 39 . 4 0 59.5 137 39 .4 .3 60 124 II .18 59.5 .4 60 ii B 144 ,, 120 II .11 130 II . 25 148 94 ,, . 46 -.11 n 11 ,, Gi) Gentral .:11 :)o r a tory _,lt e rnator 3 p has e--delt a c onnected--60 c :rcles 110 v olts------7 .5 i,:w. ~ractional -~oad ~aturation Gurv es .i::. I I ,,,_-· f 132 30 .59 60 128 .5 II .52 [f 1 23 " .48 119.5 . 40 .30 80 " " " " " " 0 " 100 20 .5 60 93 II .43 n " .31 II 88 II .38 II 66 " .18 " 84 II .35 7:;z-.5 " .23 " " 65 II .17 II 5 6.5 If .12 II 110 81 Cent rn l L2. r)or!':.t or;y .lt c r nnto r 7 . 5 =~w --110 v ul t--6 0 c y cle s -- de lt a c onn ect ed 3 l) h e.SG :::. egnl ati on: f Dir e c t Met h od ,.· f u ll loa d If I 60 1.1 9 o.o o. oo 110 IT 1. 28 10.0 25.4 111 116 5 4.5 " 1.:54 17.1 43.5 109 121 12 11.0 11 1. 42 24 .2 61.5 1 08 128 20 1 8 .5 II 1.57 30 .3 77.0 11 0 140 30 27 . 3' " 1. 62 33 . 2 84 .4 1 09 1 42 ~?3 3 0. 3 Tl 1. 77 40 .0 1 01.0 1 09 153 44 40 .4 1. 90 45 .3 114.0 109 159 50 45 . 8 2 .1 0 51.8 13 2 110 166 56 51. () II " ( i' I - °R.w ~• 0 E , -E 0 ' 1,0 xlOO , Externa l Cha r a ct e ri s tic Curve 2 unning as a generator t aki n g leadi ng c u rre nt wit h Th is c urve is si mila r to t h e no field ex cit a tion. E.xt e r na l Cha r 2c t oristic of a Series Dynamo. P. 22 II " II II II II 11 7",") ~ . f I E. 60 62 1 68 " 60.5 1 65 II 5 8.5 161 " 58 160 " 5 7.5 15 8 " 55 .5 1 53 " 53 1 44 Centra l ?.5 La 1)01~r1.t 0 1 y 1 .!:'~W- -11 0 3 Alternc t or v olt--60 c~1clos pha s c s--cle l t a c 0nnect 0d External Charact e ristic Curve ·~ P. 22 22 .... I ..:::.. 60 49 135 44 122 34 92 40 108 36 gg 32 86 30 .5 80 29.5 '75 29 73 28 70.5 27 68 26.5 66 25.5 61 ci r:; 59 n 22 22 ,, .p .J:! • " II 22 II 22 II 23 II 23 II 23 II 24 II 24 II 24 II 24 II 24 ,,. ,c:.,D • u 7. 5 Zw. Centra l La borotory Alt ernator. 3 pha s e s --Y connected--60 cycles No-Load Saturation f 40 60 65 82 .50 II 99 .60 II Curve 3 phase - - Y c onr, ect e c1-- GO c y cles NO-Lo ud Sa tura tion Curve l~ If f 116 .70 60 132 .80 II 149 .90 164 1.00 " " 202 1.26 " 236 1.50 " 266 1.75 II 285 2.0 . II 290 2.06 Tl 3 00 2.28 II 306 2.40 n ;311 2.50 II 314 2.60 II 319 2.7 0 " Three-Phas e Short...;Circui t Current '\ h f 4 .2 40 60 .50 8.6 82 .60 10.1 98 n .76 12. 85 1 22 n _- 90 l .,_, . J7 148 n 1.00 17. 2 165 l.f I :: Ia .25 i;: "C 7. f Kw. Co n~; :2:1.11 Laboratory Al t errn1tor 3 phase ·--Y comiect ed--60 c;:,rcles '.L'hree -.2hase Short Gircuit Gurrent If Ia B f 1.15 19.5 185 60 1.25 21.1 201 TT 1.40 23.8 220 II 1.50 25.0 234 11 1.59 26.5 246 " 7.5 1.w.--60 cycles--191 volts 3 phase--.1. connected 1\'.egula.tion: - Direct Method full load .r~o o.o o.o 192 9.0 39.8 192 206 14 7.3 11 1.30 10.1 t:i:4. 8 191 209 18 9.4 II l.95 12.1 53.3 191 215 24 12.5 11 1.40 13.8 60.7 192 224 32 16.7 ii 1.50 16.4 72.5 191 235 44 23.0 11 1.55 18.3 80.5 11 242 51 26.6 II 1.61 20.3 89.3 II 254 63 33.0 II 1.71 22.6 100 II 264 73 38.2 ti 1.82 24.9 110 11 274 83 43.5 f lf I 60 1.20 II 1.25 70 B• r;,-~o E 1 -.Go x_ 100 Lo 0v 7. 5 i).V7 • ventrul .La1Jora to r y Alt ernat or 3 phase -- r c onne ct e d.-·00 c y-c 1 e s - - ~;2 . 4 amperes Jc·ul1-.Load Saturation c;urve at .6 0rO .r:ower-.:c act or :Uagging P . -Ii' . E I f If 18 160 22:,l: 60 2 .3 19 153 " 11 2.25 21 145 " 2 .2 22 135 " " 2.1 17.5 172 " " " Fl 183 II II 2.5 16 200 II II 2.6 22 140 " II 2.16 20 150 " " 2.24 18 171 11 ti 2.39 l? 185 II " 2.5 l6 2') 1 II tt· 2 .6 LS, 118 " ti 2.05 _t7 122 II " 2.08 ing points L5 , 125 II II 2.11 obtained wit h L2. L 132 f;V II 2.15 a load of ) 140 II II 2.21 ind uct i on 16 115 II II 2 . 01 motors r un- 17 109 II II 2 . 00 ning light. 2.4 :rhe follow- 1 7 . f, J.~vv Gent ral J.Jallora tor;/ .~lte rna to r 3 -ph~1s e--.1 c orm ectod--60 cycle s --22.4 amperes 1.· ull-1,o ad ::iaturat j on vurve at Zero rowe r-.., act or 1.1ag , ·ing j_ f If 19 1 08 22.4 60 1.99 25 98 II 11 1.93 30 90 It " 1.88 " 11 1. 83 54 63 " " 1.68 47 69 " " 1.73 38 76 " " 1.79 Holtzer-Cabot .L'ype u .t' ;::5 i z e .ti -1.;. h-iot or 20 @ 10 110 volts--48 amperes--50 cycles 1000 ri . P. k .--3 phase--b o. 130,298 ri o-1,oad Saturation uurve If f 30 1.17 50 40 1. 5 1l " 46 1.80 n 50 1.99 II 54 2 .1 8 " 62 2 .49 " 65 .5 2.6.8 Tl 71 2.96 II 76 3 .15 I •' .J..:, " 1,oltze :t~ Cab ot ·.1:ype O P :~,i ze 20 iP l0 110 volts-- 118 a:uperes--50 c y cles 100 0 ~. P. M.--3 phase--~ o. 130 ,2 98 D0-~oad ~a turation ~urve B If f 81 3.38 50 8G 3.64 IT 90 3.84 II 95.5 4.15 II 101 4.44 " 105 4.72 Tl 109 5.02 Tl 117.5 5.61 " 120.5 5. 8 9 " 125 6.5 " 12 8 . 7.0 " J 32.5 7.6 II 135 8.01 " 13? 8.46 II r1 ol t ze r- c i b ot _\ . 1..ot or G. ·.L·yp e O l? :.::,i ze 20 .tP 1 0 11 0 vo l ts- - 48 a ,np e r es- -50 c :10les 1 000 H . l:'. H.--3 phase lf ·- - 110. Ia 130, 2 98 f :. \ .L, 1.07 3 30 1.57 40 II 50 1.91 43 43 43 50 " 2 .11 46 46 46 5 4 .5 II 2.31 51 51 51 60 " 2 .71 60 60 60 68 " 3.01 66 . 5 67 66 .5 76 " 3. 20 71 71 71 80 II 3 .76 83 83 83 92 II 4.26 93 93 93 100 " 4 . 90 1 08 1 08 1 08 110 " c. • ·ull-Loo. ;J 3atura tion 8urve at t ero Povve r-.!!'a ct or E. I lf f 10 48 48 4 .07 50 22 62 II 4.64 II 15 71.5 II 5.07 II 19 81 II 5.54 II 18 87.5 II 5.90 II 0 91.7 II 6 . 08 II 22 92. 2 II 6.15 " P. .b' • A■ no ltzer-G abot 'J.'ype u I' Size 20 G ■ ~ otor i-:? 10 110 volts--4 8 amperes--50 cycles 100 u . ~ . M.--3 phase--~ . 130, 298 ~·. L. 1 r~I f 0 102.5 48 6.86 50 0 104.5 II 7.1 2 II 0 105.5 " 7. 22 " 0 1 06 .5 II 7.29 II 0 108 11 7.4 9 II .t' . Direct i.lethod Hegulation:f If i /0 full load ho J.:.i 1 L1 - L 0 V .. .i.;,-; -.r, , E X. 100 o • .1. .3 6 50 b .O 20 41.7 110 111.5 1.5 II ~. : :s 31.3 65.2 II 114. 'I • -~: • J 4.19 II 5.4 38 '79.2 II 115.5 5.5 5. 01 11 5.6 47 98 . 0 n 117.5 7.5 G.82 at u r at i on Curve ~:o - L o tid l,l o. 629991 ,1est i nghous e,, Rot a r y Convert e r 7 .5 Zw. 1 25 d-c.v olts 1 800 :a . P . Ivi . 60 c yc les E GO d-c. amper e s . T f 30 . 57 60 37 .74 60 43 .5 . 87 " 48 1. 01 " 50 .5 1.04 II 54 1.14 II 57.5 1.24 II 68 .2 1. 54 II 75.5 1.74 II 81.5 1. 95 II 87 2 .16 II 95 .5 2 .57 II 101 2 . 89 II 107 3.30 II : .!.f Three-Phas e Sh ort-Circuit Current Jf I c..."' 3·._. f .62 53.5 ;)l; 60 . 84 72 40 60 1. 04 90 50 60 p Jes tinghouse ilotary Conv ert e r No 62 99 91 7.5 l<::w 1 25 d-c. volts 60 cycles 60 d-c. amp. lt300 .::, . r . LI • . :! Ull-Load ~aturation Curve at ~ero Power-.b'a ctor E I If f 0 73.5 56.5 56.5 2.44 60 0 79 " 2.64 0 82.5 Tl 2.84 " " 0 87 II 3.04 Tl 20 89.5 3.18 II 0 97 " " 3.49 Tl 20 99.5 55.7 3.74 Tl 00 101 56.8 3.84 Tl 0 105 56.5 4.19 11 p. JJ'. Hegulation:f I If o/o full load Direct Method E0 EI E,-B 0 :& , - E Q "/.. 1 00 60 11.7 10.0 18.0 76.6 77.5 .9 Eal.18 " 1.7 15.0 27.0 " 77.8 1.2 1.57 II 1.72 20.0 36.1 II 78.6 2.0 2.Gl " 1.80 31.1 56.3 II 80.0 3.4 4.44 II 1. 8 9 37 66.7 II 81.3 4.7 6.14 II 1.90 48 86.6 " 82.3 5.7 7.45 " " 1. 95 57.5 103.6 II 83.5 6.9 9.02 2.00 66 119 " 85.2 8.6 11.20 37 '..reneral .t:.lectric D'.) Uble current l., e): e rator ;f695701 '.l.'ype 'i. C Class 4--61 --1500 Speed 1500 Continuous Current Amperes 75 Volts 90/125 Alternating Current Cycles 50 No-Load Saturation Curve E If . f 15.5 0.27 51 17.5 0.37 " 20 0.46 " 25 1.66 n 30.5 0.86 n 35.5 1.06 43 1.36 55 1.99 60 2.28 " " " " 65 2.66 70.5 3.11 75 3.53 II 80 4.01 " 90 5.46 II 93 5.99 II " " "'.-enerul ~:lectri c Double Current Ge nerator // 695701 Cla ss 4 -- 6 : --1 500 .L Speed 1500 orm l' Continuo us Current Ampe re s 75 Volts 90/1 25 Alternating Current cycles 50 Thre e-Pha s e Short Circuit Cur ve E If f II 15 .28 50.5 22 21 . 46 29 25.5 .70 41 30 . 86 37 1.14 45 1.46 50 .5 l.7Sc f,O . 5 22 52 .5 51 20 50 62.5 50 .5 80 .5 80 79 91 Ji1 ull-Loa d Saturation Curve at 2e ro Power-Factor La gg i rn· ~- F . B 27 .;, .l. I If 64.7 70.7 4.66 50 lU 67 " 4.86 50 05 69 5 . 06 50 .5 10 71 " " 5.:34 50 10 63 II 4.36 50.5 10 5J .5 If 3 . 51 50 .5 c: O 5b .5 II ,) . 71 5u .5 15 57 II 6 .81 50.5 12 60 II 4.09 50 .5 General .:.:lectric Dou1ile Cu:cre nt Gen e r:_t tor j G9570 1 Cla .s ~ -- 6J- -1 5 0G Porm P Continuous Current Amperes 75 Volts 90/125 ~lternat ing Current Cycles 50 Pull-Load Saturation Curve :.: . t Zero Povver-Fa:c:tor Lagging ,., r: I If f 15 61.7 70.7 4.26 50.5 32 ;39 " 2. 71 50 . 5 05 49.5 " 3.29 51 15 40 II 2.71 51 15 44 Tl 2 .96 5 () . 5 ..t • :B., • Full-Lo ad Saturation Curve at Z·: ro Powe r-F a ctor Leading Leading P . F. ,, I If f 10 74.5 70.7 1. 44 50 10 71 II 1.29 II 10 67 . 5 " 1. 06 Tl l CJ 66 II 0.90 II 10 62.5 " 0. 70 II 0 58.5 " 0. 62 " 0 56.7 Tl 0 . 51 II 0 54 II 0 .40 0 bO II 0.32 .L II " 40 GenGral ::1,::-, c tric Dou"ble Cur~·ent Generator } 695701 '.rype Y C Class 4--6¾--1500 1!1 orm P :3pe e d 15 u0 Continuous Current ,1.mperes 75 Alternating Current Cycles Volts 90/125 50 Full-Load Saturation Curve at Zero Power-Factor Leadinf leading P.F E I If f 10 80 70.7 1.78 50 10 81.5 11 1.94 11 84 11 2.12 " 10 96.3 11 3.GO n 10 98.5 4.00 " 10 101 4.45 II i--, ._, " " Central Laboratory Alt e rnator 110 volts 7.5 Kw GO cycles .S9.4 amperes 3- pha se delta connected Calculation of Regulation at Unity Power-}Pactor e.m.f. method XI RI EtRI I l ,.)i:· 47 J.. 70. J. 11~5 :i:_; I E, E ·o reg ,u load Et-RI E• 2209 l f43 0 14640 121.0 11. 0 1 . 3 8. 1 20 63 i.27 112.5 .J6JO 126.30 25 78 2 .84 113.0 ur~OO 12770 189?0 137.8 27.8 2C.22 63.5 30 ~5 i5. 41 113.5 ~025 12900. 21 925 148.0 38.0 34.60 76.2 2 TI 2 2 6 16620 127.9 17.9 16. ;:;[) ;_;O . d j5 110 3.~8 114.0 12100 l J OOO 25100 158.f 48.5 44.1 09.0 40 124 4.55 114.5 1562~ 13150 20775 170.0 60.0 54.5 1 01.G 45 137 5.12 115 18800 13225 32025 179 69 G2.7 114 1 11 Cent r a l Labo r nto r y .\lt .·r nn t or '7 . 5 110 volt s }~VJ de lt a connect e d 3 - phus e GO C? Cl es o Sl . 4 ampe r es Ca lculat ion of Re gul a tion 8' ,-v ~Jnit y l?or: e r-:i:'a ct or m. m.f. method ,~ ,, ":: i i re g % l oa d I i 15 l;:.;l . 50 1.4 G . 2b0 1. 71 1. 31 11 9 . 5 20 12 2 .6 8 1.4 9 .462 1. 95 1.40 126.6 16. 5 15 50 . 8 25 1 23 . 84 1.51 .706 2.22 1. 49 1 33. 5 23 . 5 21. 4 63 . 5 r jx i i r X z 1;, z ..., I E • - E ';o ~. 5 8.65 38 .1 30 1 24 1. 0 2 1. 54 1. 04 2 . 58 1. 61 142 J2 29 .1 76. 2 :55 1 24 1.19 1. 54 1.42 2 . 96 1.72 14 9 39 35 . 5 89 . 0 40 1 25 1.37 l. L6 l. U8 3 . 44 1. 8 6 156.7 4 6 .7 42 . 5 101 . 6 45 1 26 1. 5 4: 1.5 9 2. ~;7 3 . 96 1. 99 1 62 . n 5 2 .8 4 8 .1 114 Calc ul a t ed Hegula tion at Unity ? ower-:J'actor 1 94 volts m. m. f . me tho d ix I ir 2 22 . 4 amperes Y conne ct e d 2 2 5 . 28 1. 21 E, B •~E % reg ~ l oad iz .078 1. 4 6 1. 54 1.24 200 u ;5 .1 :,2 . 4 10 . 58 1. 2 2 . 32 6 1. 49 1. 83 1. 3 5 215 21 10. 8 44 . 8 15 . 88 1.24 .773 l. fi 4 2 .31 1. 52 238 44 22.7 67. 2 i r i X i z 20 1.18 1.26 1. 39 l. h 8 2 . 97 1.7 2 2Gr.'. 68 35 25 1.50 1. 2 7 2 . 25 1. 61 3 . d6 1. 97 283 89 <1:5 . 8 11 2 89 . 5 Cnlcul nt Pd ~.egulution a t Unity .P o·:: ,;; r - ~1::ctor Centrul ~a bo r ~tory ~lternat or 7. 5 Kvv . GO c yc l e s 3 - ph~e e Y connec te d e.m.f. method 2 XI I RI B+RI XI 2 :2t-HI 2 E, 0 194 5 45 1.71 196 20 25 38416 40441 202.1 8.1 4.17 %2 . 4 10 96 3.42 1 J 7.5 9216 39000 48216 219.6 25.6 13 .20 44.8 15 146 5.13 201. 21316 40400 61716 248.4 54.4 28 . 00 67 . 2 2C l Jl 6.34 202.5 36481 41000 77481 278.4 84.4 43.50 89.5 25 236 8. 55 204 .5 55696 41800 97496 312.2 118.2 61.00 11 2 Holtzer-Cabot 110 volts a-c. Motor 48 ampere s 50 cycles 3-pha se Calculation of Regula ti on at Unity Pov.rer-:r<act or e.m.f. method I XI RI :i::tRI 2 EI 2 ;uload 121 1 2200 12300 111 1 .91 20 . 8 506 12400 1 290 0 11~.7 3.7 3.36 41.7 1.8111.81 220 12500 13700 117.0 7.0 6.36 62 .6 40 45.5 2.5 112. 5 2060 12600 14600 120.9 10. 9 9.UO 83.5 10 11 .6 110 .6 2 XI KHU 20 22.5 1.2 111.2 30 35 50 58 3.1 113. 1 3360 12800 16100 127.0 17.0 15~45 1 04 Holtzer- cs bot 110 volts a -c. :.:ot or 1302913 50 c ycl e s 3-phase 48 amp e res . m. m.f. method i 2 2 .2 i i i E I - E 1/0 reg. >,; load I i r 10 5 .1 .45 26.0 .2 26 .2 5.13 J Ll .91 2 0 .8 20 5.15 .90 26.5 .8 27.3 5.23 112.2 2.2 2. 00 41.7 30 5.20 1.40 26.9 2.0 28.9 5.38 114 4.0 3. 64 62.G 40 5.25 1.80 27.5 3.2 30.7 5.55 116 6. 0 5.45 83.5 50 5.30 2.30 28.0 5.3 33.3 5.78 118.5 8.5 '7.82 104 l X :c X z }~ I ~'.'.'. 1.0 1ie st inghouse Rotary Converter '7. 5 Kw. volts 125 d-c. 629991 60 d-c. ampe res 3 phase 60 cycles a-c. amperes 56. 5 a -c. volts 76.6 e. m.f. method I XI HI Et ::U XI 2 2 E-t-RI 2 p .w I E ' I~ I f'"". - .11.J ';o reg. %l oad 10 6 .6 77.2 36 5950 5986 7 '7. 4 .8 1.04 1717 20 12 1.2 77.8 144 6050 61 94 78.6 2.0 2 . 62 35 . 4 30 18 1.8 78.4 323 6140 6460 80.4 3.8 4.96 53 .l 40 24 2 .4 79.0 573 6230 6800 82.4 5.8 7.5 8 70.0 50 30 . 5 3. 0 179.6 . 930 6020 7250 85.1 8.5 11.1 88 .6 60 35.5 3.6 80.2 1260 6420 7680 87.7 11.1 14. 5 106 44 Ca lculs. ti on of i-{ eg tll e t :\ on a t -:Jni t y Pov: er-l:'a ct or G2Sl991 60 cycles 3-phase a-c. volts 76.6 a -c a mp o res 5 6 • 5 m.m.f. method i i 2 2 2 i i r x r x z z 10 1.80 .12 3.23 .01 3.24 1.80 77.2 I i i .6 .78 17.7 20 1.83 .24 3 .34 .06 3.40 1.85 78.4 1.8 2.35 35.4 30 1.85 .36 3.41 .13 3.54 1.88 79.5 2.9 3.78 53.1 40 1.87 .47 3.49 .22 3.71 1.93 80.6 4.0 5. 2 2 70.9 50 1.89 .59 3.56 .35 3.91 1.98 82.1 5.5 7.18 88.6 60 1.91 .70 3.64 .49 4.13 2.04 83.8 7.29.14 106. Calculation of Regulation at Unity Power-Factor ] 695701 General Electric Double Current Generator 67.8 volts 70.7 amperes. 50 cycles 3-phase XI 10 10 .50 68.3 100 4660 4760 69 1.2 1.77 14.13 20 16 1.00 68.8 256 4730 4986 70.G 2.8 4.13 28. 2 6 30 21 1.49 69.29 441 4790 5231 72.4 4.6 6.78 42.40 40 26.5 1.99 69.79 700 4860 5560 74.6 6.8 10.0 56.50 50 31 2.48 70.28 960 4940 5900 76.9 9.1 13.4 70. 70 60 35 2.98 70.88 1220 5010 623079.011.2 16.5 84. 80 ?O 40 3.48 71.28 1600 5080 6680 81.7 13.9 20.5 99.00 8U 44 3.97 71.77 1930 5150 708084.116.3 24 113. 0 0 2 2 e.m.f. method I XI RI ErRI 2 Et-}U E, .i~ , B, -E 1u reg. 1o load 'l:U Ca lcul a t j_ on of ~:e gul 2tj_on C!t Unj_ ty J! owe:r-:Jfact or Genera l Electric Doub le Cur :c ent Genera tor ) 695'701 70.7 amperes 6'7.8 volts 3-phase 50 cycles m.m.f. method 1 i r 10 2.87 i i 8 2 2 i i z iz E E, -E }J reg. /.J load X r .10 8.21 . 01 8.22 2.87 68.3 .5 .74 14.13 20 2.90 .30 8.40 .09 8.49 2.92 69 1.2 1.77 28 .26 30 2.95 .44 8.60 .24 8.84 2.98 69.7 1.9 2.80 42.40 40 2.99 . 68 8.91 .46 9.37 3.06 70.4 2.6 3.84 56.60 50 3.04 .88 9.21 .77 9.98 3.16 71.7 3.9 5.75 70.70 60 o.09 1.07 9.53 1.14 10.67 3.27 72.9 5.1 7.52 84.80 70 3.13 1.25 9.78 1.58 11.36 3.37 74 9.15 99.00 X 80 3.17 1.45 10. 0 0 2.10 12.10 3.48 75 6.2 7.2 1 0 .60 113 . GU APPENDIX Since writing the above thesis a test has been made on the alternators at Big Creek and in order to make the thesis more complete the results of this test will now be added. The following tests were run on the alternators at Power House No. land Power House No. 2 of the Big Creek development. Running one alternator with no field current, but supplying exoitation by means or the other alternator operating as a synchronous motor with over-excited field, readirgawere taken of armature current and terminal voltage. These quantities were made to vary by controlling the field current of the alternator which was operating as a synchronous motor or condenser. The results of these tests have been plotted on Curve Sheet A· .An atterppt was made to run the zero Power Factor Saturation Curves of the alternator at both power houses. To do this one machine should be operated as a generator and the other as a motor with under-excited field. By this method of loading the alternator under test a power faotor of approximately zero can be obtained. Readings are ta'.J.9n of exciting current and voltage. A series of readings may be obtained by varying the field of the motor or synchronous reactor. Due to the fact, however, that the stations are each equipped with but one exciter buss, it was impossible to obtain the necessary high excitation of the alternator and at the same time a low excitation of the synchronous reactor. Points were obtained, however, by running the motor without excitation. By this means one point was oltained for the G. E. alternator and two - '1·•' ' ·' J· l.. , .r l ,. -~~:l(hl1··· · 11..i ~-~ , -·· ·1 1·- - i •• ··'~-,-;-,- . ·: ··Itltr :~ .. [-,,7.: '~1P~::": ; f J~~ ~ +'L: "-' ""• 7j~,i ' f;+ ,, : :r 'l' -,: u · • 1· . .. --,-- - - - ~. ~ :. d l"Lr . ,.1 '· •• , ,--TTT.0T-,:~ 1·' !· 1- ~r : ::·!-11 - ;.: J ; , __ l ... ;77""·: .: ::;:;:iT=-t--;: ,y:-:,·rr:177-:-:::: :::::-: .;l-~J T. : :•. :. ~t ·'.-- , •. • 1; ~ -' •~~}~ ." ~ :..:;..:_:_;::;+::..:...:...:.:j:=.,;..:.:j.l.L'.:.;..j..1..;j~-'!ll;J;,+.,_µ'..L!'.Jf.'L~a;,.+..:::J~•~;-':.;'~1"L"iJif'>-!:;1~~,ij<:--C:..~ii.Jql:~¥-:i-:..j i :; -_f. ~ "j_ '5.: . 11; ".L .!" z --1-'-,--i-'-!::;..:......::.i.= :!:.l,;2 :;i.::_.:..!..;.j.c:~ :-:. : t;-< for the Westinghouse alternator. In the oase of the Westinghouse alternator one point was obtained with the motor operating as an induction motor and the other as a synchronous machine. The points thus obtained were su.ffioient to give a fairly accurate location of the zero power factor curve. These curves and the No-Load Sat- uration l:lnd Short Cirauit Curves are plotted on Curve Sheets Band c. The method of Article 296 of the Standardi:ation Rules was used to calculate the regulation. The results are shown;.in the accompanying table. Make of Alternator Westinghouse Regulation at Unity Power Factor 14.4 % At o. 80 Power Factor, lagging 24.2 % General Electrio No great degree of aoouraoy oan be claimed for the value of regulation of the Westinghouse machine at 803& power factor since not enough points in the upper portion of the no-load saturation curve have been obtained to locate it with precision. On Curve Sheet A, the External Characteristic Curves with No Field excitation for both the G. E. and Westinghouse alternators have been plotted alohg with the current-voltage relation of the Big Creek Transmission Line. It was impossible to run the curve of the Westinghouse machine to a point where it intersects the Transmission Line Characteristic, because to do so would necessitate over-exciting the synchronous condenser to a very high degree. However, this test shows conclusively that the Westinghouse machine will build up the voltage of the line on charging to a muoh higher degree than the G. E. machine. It is also possible from these results to detennine a length of line upon which the Westinghouse generator would operate without exceeding rated voltage when charging. It will be interesting to compare the results obtained from test and plotted on curve sheet A of the appendix with corresponding values found by approximation and plotted on Curve Sheet J of the thesis. Line Voltage Kilovolts Armature currents KilO-am;Eeres Westinghouse General Electric Test results Test results Approx. Approx. 2. 0.54 0.53 0.10 o.sa 3. 0.77 0.'75 0.97 0.87 4. 1.02 1.04 1.26 1.20 5. 1.30 1.38 1.60 1.60 6. 1.62 1.76 2.00 2.06 '7. 2.02 2.25 2.60 By means of the acoom;panying table these values may readily be compared. The accuracy with which the test values were approximated demonstrates beyond a doubt the applicability of Seotion No. 297 of the Standardization Rules to the approximation of the current-voltage relation of alternators supplying long transmiasion lines. General Electric A. c. Generator No. 559520 - 16 ~ 17,500 M. - 395 - 14000 Kw. A.T.B. P.F. o.e Volts 6600 No-Load Saturation Field I 1000 3000 3200 3750 88 4250 4600 5200 5925 100 110 125 150 6600 7000 7500 8000 176 195 220 260 35 68 73 Three-Phase Short Cirouit Arm. Field 1. I. 500 760 35 56 1015 73 1200 1350 1520 88 100 1720 2000 125 150 110 .Amperes 1530. 5' Westine-houso A. c. Generator No. 1100596 17500 :Kv.-A. 6600 volts 1530 amp. 3-phaae 50 cycles 375 r.p.m. No-Load Saturation Field E. I 1750 50 2450 63 3950 100 5050 130 5600 150 6600 195 7000 215 7300 250 8000 300 Three-ahase Short Circuit Am. I. Field 1. 600 1030 50 65 100 1380 1530 1735 132 150 170 1935 185 400 Westinghouse A. c. Generator 17500 Ev.-A. 6600 volts 1530 amp. 3-phase 50 cycles 375 r.p.m. External Characteristic with No Field Excitation. Full-Load Arm. I. E. Leading P.F. 600 2300 .05 1000 3850 .05 1400 5350 .05 1530 5750 .05 1700 6275 .05 1760 6425 .05 Saturation at zero P.F. lagging. Arm. E. I. Field P.F. I. lagging 1550 2800 220 .20 1500 5800 380 .oo General Electric A.C. Genera.tor - 16 - 17500 M. - 375 - 14000 Kw. A.T.:S. Volts 6600, amperes 1530, - 375 r.p.m. External Charaoter1st1o with No Field Excitation. E. P.F. 775 2300 0 leading 950 3000 0 1100 3400 0 1250 3950 0 " 1500 4750 0 " 2000 6100 0 tt 2300 6300 0 " Arm. I Full-Load " " Saturation at Zero P.F. lagging. E. Field 1. lagging 240 .075 Arm. I. 1530 4800 P.F.