US893979A - Dynamo-electric machine. - Google Patents

Description

PATBNTED JULY 21, 1 908 0 7 9 3 9 oo 0 N J. BURKE. DYNAMO ELECTRIC MACHINE.

APPLICATION FILED FEB. 4, 1907.

5 fiHEETS-SHEET 2.

PATENT'ED JULY 21, 1908.

J. BURKE. DYNAMO ELECTRIC MACHINE.

APPLICATION FILED IBB. 4.1907.

PATENTED JULY 21, 1908.

J. BURKE. DYNAMO ELECTRIC MACHINE. uruoumu FILED 1:34.1907. w

5 SHEETS-SHEET 4 Q a. w m E 1 H n B m MR Y n U m avy J D E T N H n A N. P IN m 1)): A4" 9 H J91) m J Tu Bm (LU J); JEN I!) D J mm A? 5 M 2min D H 6 u uED-sT-ATEsPATENT OFFICE.

JAMES BURKE, or ERIE, PENNSYLVANIA, ASSIGNOR TO BURKE ELECTRIC COMPANY, A CORPORATION OF PENNSYLVANIA.

DYNAMIC-ELECTRIC MACHINE. I V

. the county of Erie and State of Pennsylvania,

have invented certain new and useful Improvem'ents in Dynamo-Electric Machines, of which the-following is a full, clear, and exact specification.

' invention relates to dynamo electric mac ines and particularly to a method of I and means for generating current for suppl -tionable in practice,

ingLa three wire direct current system of distri ' ution. The advantages of three wire distribution 1 have been heretofore considerably offset by the large first cost of the generating apparatus, and this has involved a plurality .of generating machines or a single generating machine together with expensive auxiliary apparatus. he object of my invention is to reduce the generating apparatus toa simple and inexpensive construction, and to embody the same in a single generating machine.

In orderuto ad apt a direct current machine for a three wire system, it has been proposed to connect the neutral wire tobrushes which make contact with the commutator segments midway betwccn the segments which are in engagement with the. positive and negative brushes. This method is decidedly objec particularlvwhen the mains are unbalanced.

In the operation of a'dynamo of usual form, any one point in the armature winding changes adually from the potential of the positive rush to the potential of the negative brush approximately and vice'versa continually, and there is no point which remains constantly at a fixed potential. I f In carrying my invention into practice, I introduce means'for maintaining a oint at constant potential within practica limits, and I accomplish this directly b means of generating windings or coils adde to a direct current machine and without the use'of other upon the same core.

auxiliar a paratus, such as transformers or coils of ugh self-induction. The additional generating windings or coils are preferably in electrical connection with the armature oi the direct current machine and wound The additional gen- .erating'windings maintainon'e terminal of each of said windings at'a fixed potential;

and as the machine rotates, the other term-m Specification of Letters Patent.

Application filed February 4, 1907. Serial No. 355,564.

Patented July 21, 1908.

nals of said windings vary in potential and. the electromotive force generated by these" windings is just sufiicient in amount at each. instant to maintain the relation desired.

My invention will be understood by reference to the accompanying drawings and following description.

Figures 1 and 2 are diagrams for explainj mg my invention; Figs. 3 to 7 are diagrams showing varlous embodiments of my mven- 'tlon; Flg. 8 1s a diagram showm my mvention applied to a multipolar mac ine having a drum wound armature; Fi 9 is a sectional view showing the position 0 the conductors of Fig. 8 on the armature; and Figs. 10 and 11 are diagrams showing my invention applied to a five wire system of distribution and to the control of a variable speed motor.

In explaining the theory of my invention, and in order to understand the practical em-- bodiments, I will first consider Fig. 1, in which the armature coils of a direct current machine are indicated at 1 and are connected to the commutator bars 2..

positive and negative brus es 4. "In addition to the usual main winding, there are provided additional generating windings'or coils 5", 5*, 5 wound upon the same core as winding 1, one end of each of these three windings being connected to the collector ring '6. The remaining ends of the windings are connected to points a, I), c, in the armature, which points in this example are 120- electrical degrees a art. The auxiliary windings or coilsare s wn as connectedto the commutator segments, but they may, if desired,'be connected to points in the armature winding itself. The positive and negative mains of the threewire. system are' indicated at 7, 8 and the neutral wire at 9. The mains? 8 are connected to the positive and negative brushes 4 The machine is" indicated as bi-polar havin' .the poles 3 and andv the neutral wire is connected to a brush 10 bearing onithe collector ring 6. v

In order to maintain the neutral wire at a fixed potential with reference to the poten- ".natingelectromotive force, but the electromotive force gexieratedgin each one at any I tials of the positive and negative mains and ence to the ma ing a gradual y decreasin -neutral at t instant, although different from that generatod in the ot mm, is always such in each winding that the otential of ring 6 remains unchanged, w iereas the potentials of the ends of the windings connected to points in the armature are continually changing from positive to negative and from negative to positive with reference to the potential of the neutral.

It is understood of co irse, that the potential around the commutator or around the winding 1, gradually falls from the positive to the negative brush and-,therefore the .potential of a, which is shownmidway between the positive and negative. brushes, is approximately half-way between the potential,

of the positive and negative mains, or in other words is the same as that of the neutral or' the same as the desired potentialof the neutral. Therefore since the winding 5 is connected to the neutral through the collector ring 6 at one end and to point a at the other, then in order that the neutral should be at the same potential as point a as desired, the winding 5" should be in such position at this instant that it will generate no electromotive force or no resultant electromotive force. The potential of point I) is between that of the negative main and that of the neutral and is approaching the potential of the neutral assuming that the direction of rotation is that indicated by the arrow. As Winding 5 is connected between point I) and the neutral, then in order to maintain the neutral at the desired otential, the winding 5 must be so locat as to generatean electromotive force equal to the difierenee in potential between that of point b and the desired potential of the neutral. Winding 5" is therefore indicated in a position to enerate an electromotive force equal to the ifference in potential between point b and the neutral; and as the potential of point b is approaching the potential of the e instant represented, winding 5'! is represented in such osition with referetic fiel that it is generatelectromotive force with reference to the irection of rotation indicated by the arrow. The otential of point a is above that of the neutra and between the neutral and positive brush, and is a proaching thatof the positive brushQ winding 5 is therefore diagrammaticallyindicated in such a position that it'is generating an electromotive force e ual to the differencebetween the potential 0 the neutral and that of point e and generating an electromotive force op osite in direction to that of winding 5*. t is also generating an increasing electromotive force so as to balance the increasing potential of point a. Conse-- uently, ,the instantaneous electromotive orce generated by each of the windings 5, 5", 5 18 equal to the potential difierenc'e between the neutral and the points in the armature to which the respective windings are connected. Moreover, as the armature rotates and the potential of oints a, b, a continuously changes with re rence to the desired constant potential of the neutral point, the electromotive force generated in each winding 5", 5", 5 changes in the same way and to the same degree; consequently the potential of collector ring 6 remains fixed and always mid-way between that of thepositive and negative brushes, and the de-' sired otential of the three-wire main is obtaine It. will be seen therefore that the windings 5', 5 5 act to generate alternating current electromotive forces which balance thechanging potentials of the points in the main windings towhich the; are connected and so maintain the potential of the neutral constant. When the load on'the system is unbalanced, current will flow either to or from ring 6 through the neutral-wire and will pass through the generating windings 5, 5 5 to or from the armature winding 1. The windings 5-, 5", 5" therefore not only serve as means for maintaining the neutral at fixed potential by their action as generating windings, but also serve as a path for the current due to an unbalanced load. It will be noted that the maximum electromotive force iglnerated by eachwinding'S, 5", 5 in one irection is equal to one-half the electromotive force between the positive and negative brushes under perfect conditions, and prefers ably is made as nearly so as possible in practice. This will be understood since the electro'motive force. generated by each winding must at some time equal the full electromotive force'between the neutral and any one'of the brushes, and this electromotive force is equal to one-half of the electromotive force between positive'and ne ative brushes. That is, the number of con uctors or turns per each alternating current winding or auxiliary windin 5, 5", 5, etc.', should be equal to, or equiva ent to, one-half of the number of conductors or turns per circuit from brush to brush of the main armature winding having the commutator.

may in some cases prov des. greater or less number of generating windings than potential between the position. Winding 5i is shown connected to a point which at the instant considered, is at the same potential as the "negative brush and should therefore generate its maximum elec- -tromotive force, and is shown diagrammatically in position for generating maximum electromotive force. As the armature rotates, the win dings 5 5 will'a't all times cooperate to maintain the neutral potential. Only one auxiliary generating wind1n as 5, may be used, but better results are-o tained by the use of more than one auxiliary winding, particularly where the system is likely to be very much unbalanced.

From the preceding, the general theory upon which my invention is based will be understood, and which theory is fundamentall based upon generating in one or more auxi iary windings by dynamic action variable electromotive forces for maintaining a fixed potentials of the outnow consider a few pracof this general theorv and side mains. I will tical embodiments of my invention.

Fig. 3, shows a bi- )olar machine having an armature windingof the Gramme type, the

- ring core being indicated at 11., and the main some of which are winding 12 is shown as having a total of 32 conductors or turns. As the machine is bipolar and has two brushes, there are two circuits from brush to brush, giving 16 conductors per circuit of the main winding. The winding is also shown as havingtwo conductors per coil between commutator segments, and these coils of two conductors each are indicated as displaced 22.5 electrical degrees from each other, and the two conductors of each coil are located in the same phase sub stantially, being shown in the same slot. It is apparent that the total electromotive force generated in each of the two circuits of the main winding is produced by the united ef feet of'the eight coils per circuit, and that some of these coils are generating a high electromotive force while others, being in different phase position with reference to the magnetic field, are generating less electromotive force. The total electromotive force is therefore made up of the united effect of eight coils, each in a different phase and subjected to a magnetic field very much different in strength from that of the others. Moreover, the irregu- -larity of the magnetic field causes corresponding variation in the electromotive forces generated by the different coils.

In locating the auxiliary winding for maintaining the neutral otential, the irregularity of the magnetic fiel and of the electromotive forces generated in the main Winding, must be considered when such conditions exist, as is the casein all commercial types of machines at the present time; and for the purpose of balancing the main winding, the auxiliar winding mus; so related thereto, .thatjfpr 'i each phase of the main winding, there is a substantially corresponding location of part the auxiliary winding mustbe distributed so that its parts will be subjected toconditions similar or substantially similar to that of the parts of the main winding and so compensate or every variation in the magnetic field to which the parts of the main winding are subj ected. If the auxiliary winding be so located or distributed, then the same variations to which the main winding is subjected, and which thereby determine the electromotive force generated by the main winding Will correspondingly affect the auxiliary winding and a corresponding compensation will be secured. Thus, referring to Fig. 3, we may consider the circuit of the main winding from negative to ositive brush which is on the u per half of the corev and designated by the cl iaracter 12.- This consists of eight coils of two conductors per coil in phases marked 22.5 degrees, 45, to 180 degrees, respectively. The auxiliary winding 13 consists of one-half that number of conductors and comprises eight conductors in series having one conductor in each ofthe phases 22.5, 45, to 180 degrees, one conductor being in each of -the slots in which the two conductors of the main winding are located. One terminal of the auxiliary winding is connected at 14 to the lead of the main winding which is connected shown, and the other terminal of the auxiliary winding is connected to the c'ollector ring 6. At the position represented, it is apparent that the auxiliary winding must generate an electromotive force equal to one-half that beorder to obtain the desired potentialfontlre neutral, since one end of the auxiliary wind the positive brush. The electromotive force generated by the auxiliary winding must therefore be main winding, and this will be the maximum electromotive force winding.

coils of two conductors of the main winding 12,- there isone conductor in the auxiliary winding in the same phase. Consequently, in each of these phases the auxiliary windingforce generated by the main winding. The potential of the ring 6 and of the neutral tentials of .the positive and negative brushes. The desired potential of the neutral will also be maintained at other positions of the arma- -ture, since the changing phases and electro- .motive forces of the conductors of the main .winding are always balanced or corresponding is substantially at the same potential as one-half that generatedby theof the auxiliary winding. In other words,

directly to the positive brush at the position tween the positive and negative brushes in generated by the auxiliary It is apparent that for each phase of the will generate one-half of the electromotive must therefore be half way between the poreproduced in the conductors of the. auxiliary For .example, consider 25 neutral.

4 in which the armature is shown as havrotated '45 degrees fromthe position of" 3, As'the potential of the neutral is way between the positive and negative 5 brushes, thensince the otential of point 14 is reduced'in the positioniofFig. 4 by the amount of electromotive force generated by the two coils of-the main winding in the phases 202.5 and 225, and since the potenjo tial'of the opposite point'l5 is reduced a sirnilar amount, it follows that the potential of the'neutralmust also be half way between the potentials of points 14 and'15. As the difference of potential between points 14 and 5 15 is the resultant electro'motive force of coils of the main winding in phasesmarked- 67.5, 90, etc., to 225 degrees inclusive, and as the auxiliary winding generatesv one-half of the electromotive force generated in such 2 coils of the main winding, and is connected to point 14, it follows that the potential of ring 6 will be maintained at a potential half .way between the potentials of points 14 and the neutral by the amount of the electrometive force generated in coils of the main winding at 202.5 and 225. Consequently, the total electromotive in the auxiliary winding should be reduced by the amount of electro- 5 motive force generated in said two coils in order to maintain the neutralfat the same desired fixed potential. Referring to Fig. 4, it

' will be seen that the electromotive force is thus reduced because thetwo conductors of 40 the auxiliary winding now in positions 202.5"

and 225 degrees generate counterrelectromotive forces and the conductors of the auxiliary windinggenerating electromotive forces in the opposite direction are now reduced by' the two conductors of the auxiliary winding which in the position of Fig. 3, were at phases 22.5 and 45. This'=redueed electromotive force and the .counter-electromotive force produce aresultant decrease'in'the electromotive force of the auxiliary by an amount e%u'al to the electromotive orce generated mg at positions 202.5 and 225 above mentioned; The otential of-the neutral will therefore nemam fixed. .It will be apparent that for every other osition of the armature,

a proper balance wi be secured and the potential of the neutral remain fixed.

Instead of lacing the conductors of the so auxiliary win ing in the position shown in ite, 3 and 4, relatively to the main winding, the. auxiliary winding may be arranged' as in Fig. 5 fipon the principle that any conductor of an auxiliary winding may be shifted 180 as electrical degrees and so be'placed in acorrey the two cdils of the main wind 'ositione 1550,1575, 135 and 112.5 are the same as in Fig.3, but the remaining conduc-j" tors shifted 180 degrees from th'e position .of Fig. 3, the auxiliary conductor'at270degrees of v grees of, F1g. 3, thatat 247.5 corresponding to that at 67.5, that at 225 correspond' to that at 45, and that at 202.5 correspoii gng to that at 22.5. Also the direction of the four conductors trans osed in Fig. 5-is o 0- .site tothe corresponding conductors of ig. 3, in' order to preserve theglesired action. This transposition of conductors will be understood. to be correct fronfthe fact that the result is the same in thaf-iuxiliarywinding whetherthe conductor isinoving in one fiel at a certain ositionor in the opposite field of corresponding position with its direction reversed. The a plication of this'feature of my invention is im ortant in tending to secure equal electrica and mechanical effects,

. 5 corresponding to that at 90 dethat is, in tendin to avoidunequal distorthe winding will have t e general effect of that of Fig. 3 and on accgpnt of the more f.

symmetrical distribution; fthe auxiliary winding, the armature will\ be more nearly mechanically balanced and theelectrical conditions.become more uniform, a In this ure the eight conductors of he; auxiliary winding are notall-on one half f the "armature as in Fig. 3 and Fig. 5, but the conductors -of the auxiliary WindingAfFiE-K m phases marked 22.5, 6 7.5, 112.5, an 157,5 are trans osed to the other half of the corein Fig; 6, 1 0 degrees from the position in-Figg 3 and the direction is opposite as e Iained with reference to Fig. 5. The desire operaor xample, in Fig. 6,

,tion will consequently be secured, and at the same time secure a more symmetrical condition. Referring to Fig. 6, it willalso be seen that the sequence of connection of the conductors of the auxiliarg'winding is not the same. as in Fig. 3, an

that in Riga-'6,

the conductors are connected in succession tion of' electromotive forces generated are correct.

. Fi 7. shows the same form of machine and v (Eng! as in Fig. 3, but'in F g, 7 there is an I L w s min-w wimlin pism preferable to connect them to points in the effect of the number of conductors per cirthe eight phases marked 270, 247.5, 225,

the conductors of the main winding from point 17 will be generating the total electroelectromotive force.

If three auxiliary. windings are used, the

preferably substantially 120 electrical denuxiliary conductors are correspondingly the point i7 of the main winding 90 de rees I from point 14 to which the auxiliary Winding 12 is connected. Starting from point 17, the auxiliary winding 16 is similar in the first four turns to the winding. 13 but instead of continuing and overlapping winding 13, the remaining four conductors are transposed 1'80 degrees and connected as explained with reference to Fig. 5. WVith this construction, it will be seen that the conductors are symmetricall located throughout the armature giving t 10 desirable advantages of such an arrangement. Also with two windings, the balancing effect will be improved as already stated. With two auxiliary windings it'ls main winding substantia1ly'90 electrical degrees apart, but they may be connected to points widely different from 90 degrees displacement if desired. In each case however, the auxiliary winding should have its conductors so located and 't-onnected as to balance or correspond to the conductors per circuit of the main winding beginning at the oint of the main winding at which the auxiliary winding is connected. That is, in Fig. 7 for example, the auxiliary winding 16 isv connected to the main winding at point 17 and the eight conductors of the auxiliary winding must correspond in their effect to the cuit of the main winding and beginning at point 17; that is, must correspond to the 16 conductors per'circuit of the main winding in 202.5, 1230,1515, 135 and 112.5. This will be better understood perhaps by considering that when point 17 is at or nearest to the potential of either positive or negative brush,

motive force and the conductors of the corresponding auxiliary winding should therefore also be generatmg their highest or total points of connection in the main winding are grees apart; if six auxiliary windings are used theyare connected 'ireferably' to points substantially electrical degrees apart, but the points of connection may differ widely from these displacements and may be irregularly displaced if desired provided that the located as above. explained. Usually the stateddisplacements will be preferable, but very satisfactory results may be produced with other displacements. g

'lhc-connections of the auxiliary windingto the main. winding may be made to the commutator bars if desired, or to the end connec tionsof the conductors of the main winding. Althouglithe best results will be secured by the arrangement of auxiliary conductors withoutrenderihg the machine useless.

vided the divergence is not so great as to pro-- duce a commercially im ractical maclnne.

For example, instead of ocating the auxiliary conductors in the same phase positions as the corresponding main-conductors, they or some of them may be located inslightly different phase positions. However, the greater the displacement from proper position and provided this displacement is not properly compensated for, the more will be the eneration of unbalanced electromotiveorces and the greater the flow of useless and harmful local currents. Also, it is a parent that if the number of conductors in t e auxiliary windings is not made exactly the same as described with reference to Figs. 3 to 7, the number may beslightly difl'erent and still obtain operation which may be sufficiently satisfactory, although no t'so satisfactory as might be secured; with the best possible arrangement; For example, if the number of auxiliary conductors were very large, there might be-a slightly different number cmployedfrom that theoretically required, or the phase location might be slightly different all cases hi wever, the substantial requirements for good balancing effect must'be present in order to produce a commercially practical machine.

It will be understood that the auxiliary windin s may be considered as connected in parallefwith part of the main winding, and the auxiliary windings may therefore act to generate current in parallel therewith. By adding a lar e number of auxiliary windings and by mal ing their resistance low, they may be made to carry a considerable portion of. the current compared with that in the main winding. This will be so since the main winding, together with the auxiliary windings generate electromotive forces in parallel with each other and the current that will be caused to flow. in the influenced by their re ative resistances.

I have described my invention-as applied to a bipolar machine and to a Gramme winding as it is then in its simplest form and more easily understood. plied to multi-polar machines and to machines having the various forms of drum windings.

Fig. 8 illustrates as one example, a multipolar machine having a drum winding and aving my invention embodied therein. 1 The four poles of the machine are indicated in dotted lines and designated by the charac-' ters S within the poles is shown a development of the main winding and of the two auxiliary windings which are used in this instance. The commutator is indicated within the windings at 2, and the brushes 4 which parallel circuits will be inv It may likewise be apengage the commutater are shown as bearing;

upon the inner surface of the commutator for the sake of clearness.- The two I ositive brushes are shown connected toget er and the two ne ative brushes are joined together as is usua in multi-p'olarmulti le circuit windings. The collector ring is s own at '6 having one terminal of each of the auxiliary windings connected thereto. The brus 16 shown as engaging ring 6, will, of course, be connected to the neutral of the three-wire distributing mains, and the pairs of ositive and negative brushes bearing upon t e commutator will be connected to the outside mains of the three wiredistributing mains.

The conductors of the main winding are numbered consecutively from 1 to 32 inclusive. The phase ositions of the conductors are designated or the purpose of reference by 10 designation of the number of electrical degrees beginning with zero degrees for conductors 1, 32. Passing from this position towards the right and coming to the lower conductors 16, 17 the number of electrical degrees passed has been 360, and similarly there are 360 degrees in passing from the lower conductors back to the upper conductors. It will, of course, be understood that conductors in a certain phase position with reference 910 to a field pole of one polarity arain the same phase position as conductors located under another pole of the samepolarity and in corresponding osition with reference thereto. For examp e, conductors 4, same phase as conductors 20, 21. Although in Fig. 8, there are shown two conductors of the main winding displaced by a small amount from-each other, it will be understood that they are'intended to be in the 40 same slot of the armature coreian'd in substantially the same phase-position. As there are-32 conductors in the main windin and as there are four multiple circuits, eing a four-pole machine, there are eight conductors pier circuit from brush to brush bearing on t e commutator. Each of the auxiliary windings consists of four condoctors. One of the auxiliary windings is shown as havingone terminal connected to the commutator bar to which conductor 1 of the main winding is connected and com-i prises conductors 18, 18', I8 and 18, be connected to the collectorring -6 at the other terminal. As there are points of equi-- potential in multi p'olar machines every 360 electrical d ees apart, 'theauxiliary wind-,- ing should be connected at one terminal to each-of the points of the same tentiall in order to improve the balancing e ect. Con- I sequently -m this figure there is a cross con- I from the beginning of'the auxil: or from the commutator bar tonection 19 iary winding,

which it is connected, to the commutator bar- 3B0 electrical degrees therefrom. The other 7 e5 auxiliary winding is connected at one termi 5 are in the veated in either of the 0 degree nal bar to which condmw tor 5 is also cross connected by: connection 2l to the commutator 'bar 360 degrees therefrom, andcomprises four connoted that the points in themain Winding to which the two auxiliary are connected, are displaced electrical degrees.

It will alsobe noted that the conductors of are so located as to sethe auxiliary cure a balanced armature, there being a con- It will be ductor of an windingdiametrically opposite another in every case. It will be understood from the diagram thatthe auxil iary' conductors are intended to be located in the sanie slot of the core asthe two adjacent conductors of the main winding. It Wlll also be noted that in each circuit of the main winding there is only one conductor per slot insteadof two as was the case in Figs. 3 to-7. Bearin in mind .the principles already explaine with reference to Figs. 3 to 7, we may now understand the arrangement of the windings in Fig. 8.

Since the auxiliary winding 18 is connected to the commutator bar to which conductors 1 and 6, of the main windi are con nected, the auxiliary winding must ave conductors located an connected to correspond with the circuits of the main winding beginning with conductors 1 and 6.; The circuit ofthe main windingl be 'nning with conductor Icomprises t e to ductors:'-l, s, 3, 10, 5,12, 7, and 14. this circuit, conductors 1 and 8 are displaced 180 de *rees, and as conductor 1 passes out from t 1e commutator end of the armature and conductor 8 returns-to the 'commuta end, the resultant effect of each as far as generation of electromotive force is con-- These two conductors .may therefore have a single auxiliary con gener-', :ate a corresponding one-half electromotive cerned, is the same.

ductor corresponding thereto and. so

force provided the auxiliary conductor is 10- v positions or 180 degree positions, and if m'the 0 position it must be an outgoingconductor from the commutator end andif in the '180, degree position must be an inco conductor towards the commutator end. eferring. to the wind' it is found Ithat'conduetor 18 of the a 'ary is located in one of the 180 gsgree positions and is so connected 111 the a 'ary windiphg as to be an incoming conductor towards e commutator en Conductors 1 and 8 of the main will therefore be roplerly compematedifor 'by conductor 1 the eendaa rse and 10 of this circui'tof the-main winding m the same way, it will be seenthat conductors being displaced 180 degrees balanced either-by an outgoing conductor in either of the 45 degree "one, or by an incoming conductorm ei her lowing eight con;

of-the225 degreelci 7 circuit, these may be compensated forby an coming conductor, and therefore properlyof the auxiliary sated for by a conductor of outgoing conductor in either of the 90 degree positions, or by an incoming conductor n either of the 270 degreepositions. The conductor 18 of the auxiliary winding is in one of the 270 degree positions and is an incorresponds in phase and direction to the conductors 5 and 12 ofthe main winding.

he remaining conductors 7 and 14 of thls circuit of the main winding may be com enthe auxi iary winding which may be outgoingin either of the 135 degree positions or incomm in either of the 315 degree positions. Con uctor 18 winding is an outgoing conductor in one of the 135 degree posltions and is therefore suitable. It is therefore apparent that the auxiliary winding 18 com rises the proper number of conductors, an that they are located in phase ositions corres" onding to the phase positions of the conwhich is to be balanced, and it is ent that the conductors of the auxiliary wind-- uctors of the circuit. ofthe main winding also ap aring are connected in such relation as to be correct in direction with reference :to the phase in which they are located. The other circuit of the main winding which begins at the commutator segments 'to which the auxiliary winding 18 is connected, comprises the eight conductors 6, 31, 4, 29, 2, 27, 32 and 25. If we should consider/in detail the phase locations of these conductors and the conductors of the auxiliary winding 18, it would nected by be found thatthe conductors of this auxiliary .winding would correspond in phase location and in direction to such conductors of the main winding. Since the auxiliary winding 18 is cross conconnection 19 to the segment of the commutator to which conductors 22 and degrees.

" phase 315 F 17 are connected, this auxiliary winding should also correspond to the two circuits of the main ductor 22 or 17. If we take for illustration the circuit beginning with conductor 22, it will be seen' that this circuit comprises the eight conductors 22, 15, 20, 13, 18, 11, 16;and 9. Of these conductors, 22 and 15 aredisplaced 180 degrees, 22 being an outgoing conductor and in phase 135 degrees, and 15 being an incoming conductor and in phase 315 The effect is consequently the same as two outgoing conductors in phase 135 degrees, or two incoming conductors in degrees, and consequently these conductors may be compensated for by winding beginning with either con-- v of the 45 'degree positions or by conductor 20' either an outgoing conductor inphase135 degrees, or an'incomin conductor in phase 315 degrees. The con uctor 18 of winding 18 is an outgoing conductor in phase 135degrees and therefore compensates for the said two conductors of the main winding. Similarly, condu'ctorsZO and 13 may becompensated for by an outgoing conductor in either of the 90 degree v coming conductor in either of the 2.70 degree positions, and this requirement is fulfilled by conductor 18 which is an incoming conduc-. tor in one of the 270 degree positions. -In the same way conductors 18 and 11 of the main armature circuit may be compensated for either by an outgoing conductor in'one by an incoming conductor in one ofthe225 degree positions,

' and this requirement is answered byconductor 18" which is an outgoing conductor in-one of the 45 degree positions. Also conductors 16 and 9 of the main circuit sated for by an outgoing conductor in one of v the 0 degree positions, or by an incoming conductor in one of the 180 degree ositions. Conductor 18 of the auxiliary wining is'an incoming conductor in a 180 degree position and therefore properly corresponds to the location of conductors. 16 and 9. The auxiliary winding '18 therefore is correct in location and connections for balancing the maincircuit just referred to as well as the main circuits beginningwith conductors 1 and 6, as above explained. I r

We may now consider the auxiliary winding 20 which is made up'of conductors 20*, 20 20 and 20. One of the main circuits compensated for by this winding will be considered in detail as an example and from the foregoing it will be understood that'other circuits will be similarly compensated. One of phase positions, or by an in-- v may be compenthese circuits beginning at the commutator bar through which winding 20 is connected,

is the circuit comprising the conductors 5 12, 7, 14, 9, 16, 11 and 18. Conductor 5 is an outgoing conductor in phase 90 degrees and conductor -12 is an incoming conductor in base 270 degrees, andthcse conductors wil be compensated for by an outgoing conductor in one of the 90 degree positions, or by an incoming conductor in one of the 270 degree positions. This requirement is fulfilled which is an incoming conductor in one of the 270 base positions. Conductors 7 and 14 should have in the auxiliary winding either an outgoing conductor in one of the'135 degree positions, or an incoming conductor in-one of the 315 degree positions. Conductor 20 is an outgoing conductor in one of the 135 degree positions, and therefore answers the purpose. Conductors 9 and 16 should be compensated for by an outgoing conductor in one of the '180 degree positions or an incoming conductor in one of the 0 degree positions. Conductor sitions.

.20-answers this r quirement, beirtigian outgoing conductor in gene of the 1.80 ee po- Conductorskll and 18 of 't e winding may be com ensated for by an outgoing conductor of tlie auxiliary winding in either of the 225.degree positions or by an incoming conductor in either of the 45 degree positions. Conductor 20 is an incommg conductor in one of the 45. degree positions and therefore fulfils ,the 'equirement. Consequently, the circuit of. .themain winding beginnin with conductor 5will be proper y balance by the conductors in the auxiliary winding, since they are inproper corresponding phase ositions and so connected asto be correct in direction, c From the above it will be understood that I any desired number of additional auxiliary windings ma 'be added to the structure represented in ig. 8, andconnected at any desired point in the main winding provided the are suitabl locatediand connected, It wil also be un erstood that the conductors of .the auxiliary winding 18, or of the winding 20,,may be otherwise arranged si e each conductor of such windings may be placed in any one of four positions. The arrangement shown is a desirable one however, since the armature is well balanced and quite symtion.

metrical. Of the two auxiliary windings represented in Fig. 8, it will be noted that the winding 18 has one conductor located under the influence of each of the four poles, whereas winding 20 has all of its conductors located within the range of 405 electrical degrees and nearly confined within the influence of two of the field poles. This illustrates how differently the conductors of the auxilia winding may be located.

rom the foregoing it will be understood that my invention may be applied .to machines having a larger number of poles and to various other forms of armature windings. It will also be understood that m invention may be applied to machines having stationary armatures and revolving fields instead of machines having rotating armatures as above described. v

Fig. 9 is a diagram which shows the location of-the conductors of Fig. 8 on the armature. The' poles N, S are indicated in full lines, and the armature core is designated by the character 22 and is re resented in sec- The core is indicate as being a slotted core, and the conductors of the main and auxilia 'windings are designated by 'the same 0 aracters as in Fig. 8. It will be noted that the conductors of the auxiliary windin are shown aslocatcd in the vbottom of the s ots and this location is preferable.

When it is desired to secure a multiple voltage distributing system having more than three wires, I may combine two of my three wire machines and secure a five wire system of distribution- Such a distributing g smm is illustrated Two of my .machines are indicated-,at 23'and 24, machine 23 having its positive and-n 'tive brushes, and brush bearin on the co actor m. 5 connected to the t ree distributing mains 25, 26, 27 as shown. Machine 24 is connected in series with machine 23 through the'commutator brushes, and from the 001+ lector ring'of this machine 24 connection is made to the intermediate main 28 and the other brush bearing on the commutatorof 29 of the five wire distributin system. If machine 24 is designed for a di erent voltage from that of machine 23 it will be seen that the voltages between mains 27, 28 and-29 will be different fromthat between mains 25, 26 and 27.v Such an arrangement will be desirable where a lar e number of different voltages are require or desirable, as in motor control for securing various speeds. For example, in Fi 11, machine 23 is indicated as having a v0 tage of 100, and machine 24 as having avoltage of 150, thus givingadifl'erence of 50 volts between mains 25 and 26 and between mains 26 and 27, and a difference of volts between mains 27 and 28 and between 28 and 29. An electric motor is indicated at 30 with the fieldsconnected across the outside mains and therefore, having a substantially, constant'strength. The armature terminals are shown as adapted to connect one terminal of the armature as desired to any one of the upper four mains, and the switch 32 beingada ted to connect the other armature terminal to any one of the lower four mains. The field strength being constant, the speed of the motor will depend u on the voltage ap lied to the armature. T e lowest speed tained by a Iplying 50 volts to the armature which may e accom 26 or between mains 26 and 27. The voltage may be increased and consequently increase [machine 24 is connected to the outside main 'rovided with switches 31 and 32, the switch 31 being.

boob-.-

lished by connecting the armature, either etween mains 25 an the speed by connecting the armature by means of switches 31, 32 either between mains 27 and 28 or between 28 and 29, when a voltage of 75 volts will be applied to the armature.

applied to the. armature. Connection .between mains 26 and 28 will cause volts to be applied to the armature. By connecting between mains 27 and 29, volts may be applied to the armature. Connection be- 15 Next connection may be made tween mains 25 and 27 when 100 volts will tween mains 25 and 28 will secure an appli- I cation of volts to the armature terminals. If "the armature terminals are connected between mains 26 and 29, 200 volts willbe apfi lied to the armature. Finally by connectmg between the outside mains, the full voltage of 250 will 'be ap lied to the armature. It willthus be seen t at a'large number of iar r tial, said winding being connected at one terdifferent steps or running positions are obtained which inc ease gradually to the maximum.

It will be understood that my invention may be embodied in various forms of construction, and. that I am not limited in the scope thereof to the particular forms shown and described.

Having thus described my invention, I declare that what I claim. as new and desire to secure by Letters Patent, is,-

l. The combination of a winding having a comn'iutator, a n1ulti-polar field magnet having consecutive poles of alternate polarity, and a dynamo electric generating winding connected to a mint of varying potential in said first named winding, said second winding having substantial] one-half the conduc ors per circuit of said first named wind in 5. The combination of a winding having a commutator, a multi-polar field magnet havingconsccutive oles of alternate polarity, and a plurality of d namo-electric generating windings connectec to points of different and varying potentials of said first named winding, each. of said plurality of windings having substantially one-half the number of 0011- ductors per circuit of said first named winding.

I brushes, and adplurality of dynamo electric generating win ings connected to points of difierent and varying potential s of said first named winding and sub'ected to the same magnetic field, said plurality of windings being also connected to'a common point, each of said plurality of windings havin substantially one-half the number of conductors per circuit of said first named winding.

4. The combination with a multi-polar direct current generator having. consecutive field poles of alternate polarity, of an auxilwinding for maintaining a fixed potenminal to a point in the main armature winding and having its parts located in the magnetic field to corres 0nd substantially with the base location oi the circuit of the main win ing beginning at said point of the main windin ,said auxiliary winding. having substantiafiy one-halfthe conductors per circuit of the main-winding.

5. The combination with a direct current generator, of a plurality of lugs for maintaining a fixed otential, said windings having one termina of each connected to a point in the main armature winding of varying potential and each of said windings being located in the magnetic field to correspond substantially to the phase 19- 3. The combination of a multi-polar field.

auxiliary wind-' cation of the circuit of the main winding ginning at the which it is connected, each of said auxiliary windings having substantially one-half the conductors per circuit of the main winding and a terminal of each of said auxiliary windin s bein connected to a common oint.

6. The com ination' with a multi-po ar direct current generator having consecutive field varying electromot-ive forces for maintaining a point of fixed potential, said auxilia winding hav-- ing its conductors located in. s ots of the arms. ture core which also containconductors of the main armature winding and the said conductors of the auxiliary winding beinglocated at the bottom of said slots.

7. The combination with a multi-polar di rect current generator having consecutive field oles of alternate polarity, win ing adapted .to generate varying electrornotive forces for maintaining a point of fixed potential, said winding being connected at one terminal to a point in the main armature winding and having its parts located in the magnetic field to correspond substantially with the phase location of the circuit of the main winding beginning at said point of the main windin and having its conductors located in the siots of the armature core which also contain conductors of the main armature winding and the said conductors of the auxiliary winding being located at the bottom. of said slots.

8. In a thre-wiriesystem of electrical distribution, the combination with two main wires and a neutral wire,,of a dynamo having its armature rovided with a main winding connected wit said main wires and an auxiliary winding having one-half as many turns as are in series between brushes in the main winding, said auxiliary winding having its ends connected with the main winding and the neutral wire.

9. In'a dynamo electric machine, the combination of a multi-polar field frame having consecutive poles'o alternate polarity, an armature of the direct current type, and an auxiliary winding distributed on said armature for d namically maintaining a fixed otential lietween the potentials of the rushes bearin armature, sairf winding having approximately half the conductors per circuit of the main winding, and a collector ring to which said auxiliary winding is connected.

-10. In a dynamo electric machine, the combination of a multi-polarfield frame having consecutive poles of alternate polarity,-

an armature of the direct current type, a.

plurality of auxiliary windings distributed on said armature for dynamically maintaining a fixed lpotential, said windings having one termina -Varying potential in the main armature poles of alternate polarity, of an auxiliary .windmg adapted to generate of an auxiliary on the commutator of the of each connected to a point of 1 point of said main winding to ductors winding, a collector ring to which one terminal of each of said auxiliary windings is connected, and each of said auxiliary windings having approximately one-half the coner circuit of the main winding.

11. Tie combination with a direct current generator, of a plurality of auxiliary windin s within the influence of the magnetic field for dynamically maintaininga fixed potential, said auxiliary windings being connected'to points of varying potentials in the main winding, said point-s of connection being displaced less than 180 degrees electrically, and each of said auxiliary windings having approximately one-half the conductors per circuit of themain armature windi l n a dynamo electric machine, the

.' combination of a multi-polar field frame having consecutive poles of alternate polarity,

. an armature of-the direct current type, a

. plurality of auxiliary -ture for d namica potential ly maintaining a fixed etween the potentials of the rushes bearing on the commutator of the armature, said auxiliary windings being connected to pints of varying otentials 1n the main Win in said points 0 connection bee in displace less than 180 degrees electric a1 y, a collector ring to which one terminal of each of said auxiliary windingsis connected, and each of said auxiliary windings having approximately one-half the conductors of the main armature winding.

13. The combination with a; mat-pas direct current generator having consecutive,

, poles of alternate polarity, of an auxiliary lector ring winding distributed on the armature for dynamically maintaining an intermediate fixed potential, one terminal of said'lauxiliary winding. being connected .to a plurality of points in theniain winding having the same potential approximately, and a colto which the other terminal of said winding is connected,

14. The combination of a multi-polar direct. current generator'having consecutive poles of alternate polarity, of a plurality of ing of said windings being connected to a auxiliary windings distributed on the ar ture for dynamically maintaining an int rmediate fixed potential, one terminal of each lurality of points in the main armature wiiidmately the points of connection of one'auxiliary windingbeing displace-d less than 180 degrees electrically from the points of connection to the main armature windi of another of said auxiliary windings, ea th din dings is connected.

windings on said arma" having the same potential approxi-'- of said auxiliary windings having ap'proxie mately one-half the conductors per circuit 1 of the main winding, and a collector direct current generator having consecutive poles of alternate polarity, of an auxiliary winding having'app'roximately one-half the turns per circuit of the =main winding for maintaining a fixed intermediate otential, said auxiliary winding being distri uted on the armature under polar areas of the same polarity and olar areas of different polarity at the time t e auxiliary winding is generate is connector 16. The combination with a direct current to a point of varying potential in theniain winding for maintaining a fixed potential, the auxiliary winding having its conductors located on the 'armature to correspond sub stantiall with the phase location of conductors of t e main armature winding beginning the auxiliary windingis connected, certain uns mmetrically located with reference to eac 7, other, and a collector ringto which said auxiliar winding is connected.

17. T e combinatiomwith'adirect current generator, of a plurality of auxiliary wind- ,ings for maintaining a fixed potential con- 'nected to points in the main winding, said points of connection being displaced less than located on the armature'in phase ositions to correspond substantiall witht e phase winding beginning with the point in the main connected, certain conductors of atleast one located with reference to other conductors of said auxiliary winding, and .a collector ring to Y which said auxiliary windings are con nected i 18.: In a dynamo electric machine, the combination of a multipolarfield framehaving consecutive pole of alternate polarity, an armature of the dii-ectfcurrent t p'e, a pin: rality of auxiliary windings on sai armaturefor maintaining a fixed potential between the potentials of the brushes bearingon the comeach of said auxiliary windings ,beingcon winding'hayin the same potential; approximately, the points of connection of one auxfiliarywindi'n'g being displaced less than 180, degrees electrically from the points of conmotion to the mam armature windin of another of said auxiliary windings, the p D tors 'ofsaid "auxiliary windin beingidistnbuted so as to substantially Ba ance earmarture mechanically, the conductors ofat least 15 The combination with a multi-polar in its maximum electromotive force, and a co lector ring to which said auxlhary winding with the point in the main winding 'to which.

180 degrees electrically; from each otherythe' conductors of each? auxiliary wind ng belng auxiliary winding being unsymmetrically generator, of an auxiliary winding connected conductorsof the auxiliary winding being locationof conductors oft e main armature I windingto which the auxil ary winding is mutator of the armature, one ,terminalof 'nected to a plurality of points in the main one auxiliary winding being distributed on and a collector ring to whieh said auxiliary the armature under polar areas of the same windings are connected. 10 polarity andpolar areas of different polarity In testimony whereofl affix my signature, at the time the auxiliary Winding is generatin presence of two Witnesses. 5 ing its maximum eleetromotive force and cer- JAMES BURKE.

tain of the conductors of said auxiliary wind- Witnesses: ing being unsymmetrically located with ref- L. K. SAGER,

erenoe to other conductors of said winding, 1 M. STRICKLAND.

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