US987044A - Dynamo-electric machine. - Google Patents

Description

J. BURKE.

DYNAMO ELECTRIC MACHINE. ABPLIGATION FILED MAY 1, 1907.

Patented Mar. 14, 191i 5 SHEETS-SHEET 1.

' INVENTOI? WITNESSES ATTORNEYS J. BURKE. DYNAMO ELEGTRIG'MACHINE. APPLICATION FILED MAY 1,1907.

987,044, 7 1 Patented Mar. 14, 1911.

, T) SHEETSSHEET 2.

j: ATTORNEYS.

W/T/VESSES Z INVENTOH J. BURKE.

DYNAMO ELECTRIC MACHINE. APPLICATIONIILED MAY1. 190T7.

Patented Mar. 14, 1911.

5 -SHEETS-SHEBT 3.

M INVENTOH W/TNESSES 5M 1/ 40km /4u.

A ATTORNEYS.

J. BURKE.v

DYNAMO ELECTRIC MACHINE- APPLIUATION FILED MAY 1, 1907.

Patented Mar. 14, 1911.

5 SHBETS-BHIIET 4' .S E w W A; ATTORNEYS;

I BURKE. DYNAMO ELECTRIC-MACHINE. I APPLIOATION 21min my 1, 1907.

. 4 Patented Mar.14,1911.

' BBHEETS-SHEET5.

Wu/25mm? v 1 4 ATTORNEYS.

' closed in said application.

UNITED STATES PATENT canton.

JAMES BURKE, or ERIE, PmmsYLvAN i-A, ASSIGNOR To sonar: ELECTRIC COMPANY, a A ocnromrron or PENNSYLVANIA.

DYNAMO-ELECTBIC MACHINE.

, To all whom it may concern:

Be it known that 1, JAMES BURKE, a citizen oi' the United States, residing at Erie, in the county of Erie and State of Pennsylvania, have invented certain new and useful Improvements in Dynamo-Electric Machines, of which the following is a 1111,

clear, and exact specification.

My invention relates to dynamo electric -machines and particularly to a method of In my pending application Serial No.

355,564, filed February 4, 1907, which has .matured into Patent No. 893,979, granted July 21, 1908, I have describermi'ethod and means for generating current for such a system and my present lnventionrelates toifurther improvements upon the invention dis My invention will be understood from the following description I and accompanying drawings, in which Figures 1 and 2 are diagrams for explaining my invention; Figs. 3 to '7 are diagrams showin various embodiments of my invention; ig. 8 is a diagram showing my invention applied to a multipolar ma-' chine having a'drum wound armature; Fig.

- 9. is a sectional view showingthe position of the conductors of Fig. 8 on the armature;

. vent-ion applied to another multipolar ma? chine having a drum wound armature.

' t-In explaining the theory of my invention,

and" in order to understand the practical fembodiments, I will first consider Fig. 1-, in

and Fig. 10 is a diagram showing my ini which the armature coils of a direct current machine are indicated at 1, and are connected to thecommutator bars 2. The machine isindicated asdii po'lar having the poles 3 midpositive and negative brushes 4. In

addition to the usual mainwinding, there are provided additional generating Wllld.-'

thearmature, which points in this example are 120 electrical degrees apart. 'The auxiliary windings or-coils are'shown as connected to the commutator segments, but they may, if desired, beconnected. to points Specification of Letters Patent.

' Application filed May 1, 1907. Serial No. 871,233.

iproaching Patented Mar. 14, 1911.

in the armature winding itself. The positlve' and negative mains of the three-wire system are-indicated at 7, 8 and the neutral wire at 9. The mains 7, 8 are connected to the positive and negative brushes 4: and the neutral wire is connectedto a brush l0 hearing on the collector ring 6.

In order to maintain the neutralwire at a fixed potential with reference to the potenti'als of'the positive and negative nialns and so secure a three-Wire distributing systern, the ends of the windings 5 5*, 5 being connected to ring 6 and thus to the neutral wire must also be maintained at fixedrpotential with reference to that of said .mains. In these windings there is generated an alternating electromotlve force, but the electroinotive force generated in each one at any instant, although diflerent from that generated inthe others, is always such in each winding' that the potential of ring 6 remains unchanged, whereas the potentialsv p ofthe 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 or" the neutral. of course, that the potential around the coinmutator or around thewinding .1, gradually falls from the positive to the negative brush and therefore the potential of a, which is shown midway between the positive and negative brushes, is approximately half-way between the potential of the positive and negative malns, or 1n other words is the same.

as that of the neutral, or the same as the desired potential of 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. oint 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 bis between that of the negative main and that of the neutralfand 1S apthe potential of the neutral assuming t indicated by the, arrow, As winding 5' is connected between point I) and theneutral,

It is understood p at the direction ofrot-at-ion is that then in order to malntain the neutral at the; I desired potential, the winding 5 must be so located as to clients an electromotiveforce I diflz'erence in potential between 1w 1 equal to the ti ve brush.

that of point 6 and the desired potential of the neutral. Wmdmg 5 is therefore indi cated in a position to generate an electronictire force equal to the difference in .potcnthat it is generating an electromotive force equal to the dilference. between the potential of the neutral and that of point a and generating an electromotive force opposite in direction to that of winding 5 It, is also generating an increasing electroinotive force so as to balance the increasing potential of point 0. Consequently, the. instantaneous electromotive to'rce generated by each of the windings 5?, 5, 5 is equal to the potential difference between the neutral and the points in the armature towhich the respective windings are connected. Moreover, as the armature rotates and the potential of points a, Z), c continuously changes with reference to the desired constant potential of the neutral point, the electroniotive 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 midway between that of the positive-and negative brushes, and the desired potential of the three-wire mains is obtained. It will be seen therefore that the windings 5, 5 5 act to generate alternating current electromotive forces which. balance the changing potentials of the points'in the main windings to which they 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 neu tral wire and will pass through the generating windings 5 5 5 to or from the armature windin l.

The windingsfi 5 a therefore not only serve as means for maintaining the neutral at. fixed potentialby their action as gener ating windings, but also serve as a path for the current due to-an unbalanced load. It will be noted that the maximum electrometive force generated. by each winding 5. 5", 5 in one direction is equal toone-lialt the electroniotive force between the positive and negative brushesimder perfect conditions,- and preferably is made as nearly so aspossible inpract'ice. This will be understood since the electromotive force generated by each winding must at some time equal the ran electromotive force between theneutral und any one of the brushes, and this electroinotive force is equal to one-half of the elecvniotive force between positive and negative brushes. That is, the number of conductors or turns per each alternating current winda ing or auxiliary winding 5 5", 5, etc., should be equal to, or equivalent to, one-half of the number of conductors or turns per circuit from brush to brush of the main armaturewinding having the commutator.

I may in some cases provide a greater or lesser number of generating windings than three. If six windings should be used, the windings may be displaced approximately (30 electrical degrees fl'OlllGfiCh other and connected to points in the armature winding 1, at (30 electrical degrees apart.

Fig. 2 illustrates a form in which only two windings 5, 5 are used. These ,avindings are displaced approximately degrees electrically and are connected to points in the main armature winding approximately 90 electrical degrees apart. In the position shown and at that instant, winding 5" is connected to a pointin the main winding midway between the positive and negative brushes, which point is consequently of the same potential as the neutral and therefore winding- 5 should and does generate no electromotive force being shown in the neutral position. \Vinding 5 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 elect-romotive force, and is shown diagrammatically in position for generating maximum electromotive force. As the armature rotates, the windings 5, 5 will at all times cooperate to maintain the neutral potential. Only one auxiliary generating winding, as 5 may be used, but better-results are obtained 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 fundamentally based upon gene ntingiaroneQor mo auxiliary ,wmdmgs by dynamic action vari-' able elctromotive forces for maintaining a llU' fixed potential between the potentials of the The winding is also shown as having two -jected to a magnetic field very much different coils.

will be subjected to conditions similar or one-half the number of conductors per circonductors 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 substantially; being shownjn the same slot. It is apparent that the total electromotive force generated in each of the two circuits of the main windin is roduced by the united effect of the eightcoils per circuit, and that some'of theselcoils are generating a high electromotive force while others, being in different phase position with reference to the magneticfield, 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 some of which are subent i1 strength from.' that of the others. Moreover, the irregularity of the magnetic field causes corresponding, variation in the electromotive forces gen'eratedby the difier- In my said prior. application, -I described constructions based upon the principles that in locating the auxiliary winding for main taining the neutral potential, the irregularity of the magnetic field, and of the'elec- 'tromotive forces generated in the mainwinding,'must be considered when such conditions exist, as is the case in all commercial types of machines at the present time; and for the purpose of balancing the fnain winding, the auxiliary winding must be so related thereto .that for each phase of the main winding, there is a substantially corresponding location .of part of the auxiliary winding. In other words, the auxiliary winding must be distributed so thatits parts substantially similar to that of the parts of the main winding and so compensate for every mriation in the magnetic field to which the parts of the main windin are subjected. If the auxiliary winding ie so located. or distributed, then the same variations to which the main winding is subjected, and which thereby determine the e.ectroinotivtforce generated by the main winding will correspondingly affect the auxiliary winding and a corresponding compensation will be secured. In my said prior application, I disclosed constructions in which the auxiliary windings contained cult of the main winding. According to my 1 present invention, I am enabled to reduce the number of conductors in each auxiliary windingso that less than one-half the conductors per main circuit are required and I accomplish this without any practical disadvantage and of course obtaln further economy and simplicity in construction. My present invention may be understood conductor in of the phases 225,45, to 157-}, inclusive. One terminal of the auxiliary w1nding is connected to the collector ring 6 and the other terminal is connected to a point 14 in the mainwinding between the two turns inphase 180 degrees. Atthe position represented, it will be understood that the auxiliary winding must generate an electromotive force such that the potential of the ring (3, and therefore of the neutral will be midway between the potential of the positive and negative brushes. Since the auxiliary winding is connectcdto a point which is below the potential of the positive brush, it follows' that in this position, the electromotive force generated by the auxiliary winding should be less than one-half the potential difference between the positive and negative brushes, but at the same time should be sufficient to maintain the neutral at the desired potential. That this is so for the positioh of thearmature considered, will be understood from the following: As the potential of the neutral should evidently be half way between the potentialof the positive and negative brushes and since the electromotive force between these brushes is evidently generated by the conductors of the main winding on the upper half of the ring, the desired potential of the neutral willbe secured if the neutral is ata potential from the positive brush created byL-an electromotive force equal to 0ne-half that enerated by the main winding. Evidentfy the seven conductors of the winding'generate' an electromotive force equal toone-belf that generated by the coils of the main winding in phases marked 22.5, 45 to 157.5 inclusive, since there are onehalf the conductors in the auxiliary winding for each of these phases, and aszthe aux1liary windin is connected at point- 1'4 to the main winding between the two conductors ofthe main winding in .phase 180, the potential of point .70 22.5 degrees, 45, to 180 degrees, re- 5 spectively. The auxihary winding 13, com-; prises seven conductors in series having one 14 will be, by reason of this connection, at a potential from the positive brush equal to one-half the electromotive force generated by the two conductors of the main winding in phase marked 180.'- Consequently, the potential of the neutral will bebelowthat of the positive brush by the amount of half the electromotive --force generated by the main conductors in phase 180 degrees, givin; the potential of point 14, plus one-halfof the electromotive force generated by the' condu'ctors of the main winding in each-eff 13 the phases 157.5, to'22.5 d ag f fi.

. 112.5, 90, (37.5, 45 and 22.5 to the ring, making a sunnnation of one turn from all of the phases on the upper half of the arn'iature core and seven of which are auxiliary turns and one a turn of the main winding.

The potential ofthe neutral will be maintained substantially constant for every other position of the armature, since the changmg phases and electromotire forces of the conductors will always be such that the electroniotive forces generated by the auxiliary winding will correspondingly vary. For example, consider Fig. i in which the annature is shown as having rotated degrees fromthe position of Fig. 3. If in Fig. 1 we follow the circuit. from the positive bru h, it will be seen that the otential of ring 0 from the positive brush is that produced by the electroznotive force of two turns of the main winding in phase 202.5 and one t'urn of themain winding in phase 225, then through pointl l to the auxiliary winding in which there is one turn in hase 202.5 and one turn in each of the p ases 130, 157.5, 1235,1125, 90 and 67.5. It is evident that the one turn of the main winding in phase above mentioned, has the same value and electroinotive force as if it were one turn in phase 45. It is also evident that the one auxiliary turn in phase 202.5 caneels one of the two turns in phase 2.02.5 leaving the eil'ect of one turn in 202.5 which has the same valueas one turn in 22.5. Therefore we have the effectfrom the positive brush of one turn in each' of the pghases 22.5 15 to 180 inclusive, whichequa one-half the voltage from positive to negative brush.

nstead of placing the conductors of the auxiliary winding in the position shown in Figs. 3 and 4, relatively to the main winding. the auxiliary winding may be arranged as in Fig. 5 upon the principle that'any conductor of an auxiliary winding may .be shifted 1S0 electrical degrees and so be placed in a corresponding position under a pole of opposite polarity, provided the direction of. the conductor is changed so that the electroniotive force generate will have the sanreeii'ect in the auxiliary winding. For example,- in Fig. 5 the conductors of the auxiliary winding in positions 157.5, 135 and 112.5 are the same as in Fig. 3,

hut the remaining"conductors are shifted i 150 degrees from the position of Fig. 3, the' 5 auxiliary conductor at 270 degrees of Fig. corresponding to that at 90 degrees of i-ig. 3,'that at 2-17.13 corresponding to that at 07.5, that at 2:25 corresponding to that at 4:5, and that at corresponding to that at 22.5. Also the direction of the four con ductorstransposed in Fig.5 is opposite to the corresponding conductors of Fig. 3, in order to preserve the desiredaction. This transposition of conductors will be understood to becorrect from the fact that the result is the same in the auxiliary winding whether the conductor ismoving in one field at a certain position orin the opposite field of corresponding positionwith its direction reversed. The application of this feature of my invention is important in tending to secure equal electrical and meunequal distortion of magnetic field when current flows in the auxiliary winding and in tending to maintain a mechanically sym metrical and balanced armature. For example, in Fig. (3, the winding will have the general efi'ect of that of Fig. 3 and on account of the more symmetrical distribution of the auxiliary winding, the armature will be more nearly mechanically balanced and the electrical. conditions become more uniform. In this figure the'seven conductors of the auxiliary \vindingare not all on one half of the armature as in Fig. 3 and Fi 5, out the conductors of theanxiliary winding of Fig. 3 in phases marked 22.5, 67.5, 112.5, and 107.5 are transposed 'to the other half of the core in Fig. 6, 180 degrees from the position in Fig. 3 and the direction is opposite as explained with reference to Fig. 5. lhe desired operation will consequently be secured, and at the same time secure a more symmetrical condition.- Referring to Fig. (i, it will also be seen that the sequence of connection ofthe conductors of the aimiliauy winding is not the same as 'in Fig. 3, and that .in- Fig. 6, the conductors are connected'in succession around the ring' which allows the connections to be simplified over what would otherwise be necessary. The same resultant electromotive force will be secured however, regardless of the sequence tive forces generated are correct.-

Figr'l shows the same form of machine there is an additional auxiliary winding 16 connected to the point l'l of themain wlnding 00 degrees from point Mt'o which the i auxiliary winding 12 isconnected. S ta-rtfrom point 17, the auxiliary wind ng 16 winding 13 but instead-ofcontinuing and overlapping wlndmg l3, the remaining four chanical effects, thatis, in tending to avoidof'connection so long as the locationof the conductors andthe direction of=electromo-.

and windings as in Fig. 3, but in Fig. 7'

IS similarlinthe first three turns to -thc -arrangement. Also with two 'windin s,.the

balancin effect will be improved as already stated. l vith two auxiliary windings it is preferable to connect them to points in 'the m'ain. w-i.idingsubstantially 9O electrical degrees'apart, but they may be connected to 2 points widely different from 90 degrees displacement if desired. In each case however, the auxiliary winding should have its conductors so located and connected as to balance or'correspond to the conductors per circuit of the main winding beginning at the point of the main winding at which the auxiliary winding is connected, although without any auxiliary conductor or conductorsto correspond to the conductors of 'the main winding in the phase of the point to which the auxiliary winding is-connectcd. That is, in Fig. 7, for example. the auxiliary winding 16 is connected to the main winding at point l7 and the sevenconductors of theauxiliary winding must correspond in their effect to the effect of the remaining number of conductors per circuit of the main winding and oinittin he'condncto'rs in phase 270 which is the, Ease of point 17 that is, must corres )ondf'o the It conductors of the main winding in the seven phases marked 2am, 202,5, 180, 1.37.5, 135 and 112.5. In general it may be stated that the algebraic sum of theelectromotive forces in the auxiliarywindin plusthe eleetromotive force iii the main winding from the point where the auxiliary winding is joined to the main winding to either brush will be equal to one-half the electromotive force between brushes.

A rule which is applicable to the form of my invention above described is that the number of turns in each auxiliar winding is equal to one-half the number 0 turns per circuit of the main winding minus one-half the turns per slot of the main winding.

Thus, the number of turns per circuit of the main winding is .16 and there are 2 turns per slot and therefore according to the rule there should be -1. 16-=} 2=7 turns in the circuit of the auxiliary winding. It will be understood that instead of using the num-' ber called for by this rule, an intermediate number of turns may be used which might be between the numbergiven by the rule and the full numberof half the turns per circuit as described in my said prior application.

vidin an additional turn orturns in an additlonal phase position and still obtain the resultant effect desired. The use of Also a greater number than half; the turns per circuit might be used by pro- "machine useless b ta nal requirements for good balanc ng effect mustbe present in order to produce more conductors than necessary will however, generally be undesirable although, of course. within the scope of my invention.

If three auxiliary win..ings are used. the points of connection in the main winding are preferably substantially 120 electrical degrees apart? if six auxiliary windings are used they are connected preferably to points substantiallytlO electrical degrees apart. or with 5 windings they may be 72 electrical degrees apart, but the points of connection may dill'er widely from these displacements and may be irresmlarly displaced if desired provided that the auxiliary conductors are corrcspmidiiugly located as above explained. Usually the stated displacements will be preferable, but very satisfactory results may be produced with other displacements.

The connections of the auxiliary winding to the main winding may be made to the commutator bars if desired in those windings where intermediate points of the main conductors per slotare connected to comnutator bars, or may be made to the end connections of the conductors of the main winding.

Although the best results will be secured by the arrangement of auxiliary conductors as described generally with reference to Figs. 3 to 7, it will be understood that such an arrangement is not absolutely required provided the di\-'erg ;ence is not so great as to produce a commercially impractical machine. For evantple. instead of locating the auxiliary conductors in the same phase positions as the corresponding main conductors, they or some of them may be located in slightly 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 generation of unbalanced electronictive forces and the greater the flow of useless and harmful local currents. Also, it is apparent that if the number of conductors in the auxiliary windings is not made exactlythe same as described with reference to Figs. 3 to 7, the number may be slightly different and still obtain operation which may be sufiiciently satisfactory. although not so satisfactory as might be secured with thebest possible arrangement. For example, if the number of auxi iary conductors were \ery large, there might-boa slightly dilferent number employed from that theoretically r'equired, or the phase location might be slightly different without rendering the In all cases however. the

a commercially practical machine.

4 It' will be understood that theauxiliarywindings may be considered as connected in parallel with part of the main winding, and the auxiliary windings may therefore actthe auxiliary windin lleT to gcucrate current in parallel therewith.

By adding a large number of auxiliary windings and by making 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 generate electromo tive forces in para with each other and the current that will be caused to flow in the parallel circuits will be influenced by their relative resistances.

I have described my invent-ion as applied to a bipolar machine and to a Gramme winding, as itis then in its simplest form and more easily understood. It may likewise be applied 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 having my intention embodied therein. The four poles of the. machine are indicated in dotted lines and designated by the characters N, Sfwithiu the poles is shown a deve op ment of the main winding and of the two auxiliary windings which are used in .tljis instance. The commutator is indicated within the windings at 2, and the brushes 4 which engage the commutatorare shown as bearing upon the inner surface of the'com-. mutator for the sake of clearness. The two positive brushes are shown connected t9- gcther and the two negative brushes are joined together as is usual in multi-polar multiple circuit windings. The collector ring is shown at 6 having one terminal of each of the auxiliary windings connected thereto. T he brush shown as engaging ring 6. will ..of course, be. connected to the neutral of the three-viiredistributing mains, and the pairs of positive and negative brushes hearing upon the connnutator will be connected to the outside .mainsof the three-wire distributing mains. The conductors of the main winding are numbered consecutively from 1 to inclusive. The phase positions of the conductors are designated for the purpose of reference by designation of the number of electrical degrees beginning with zero degrees for conductors 1, 32. Passing from this position toward the right and coming to the lower conductors 16, 17 the number of electrical degrees passed has been-360,

and similarly there are 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 to a field pole of one polarity are in the same'phase positionas conductors located under another pole of the same polarity and 'in corresponding posit-ion with reference thereto. For example, conductors 4, 5 are-in the same phase as condu tors 20, 21; Although in Fig. 8, there are shown two conductors of the main winding displaced by a smallamount from each other, it'will be understood that they are in tended to be in the same slot of the armature core and in substantially .the same phase position.

As there are 32 conductors in the main winding, and thereare fourmultiple circuits, being .a four pole machine, there are eight conductors per circuit from brush to brush bearing on the commutator or four turns per circ'juit and one turn per slot. Applying the rule above 'giy'en that the number of turns per auxiliary winding shall be onehalf the tu ns per circuit minus one-half the turns per s t, we find that this is equal to l ;=1 tuuns .for each auxiliary winding, or 3 conducttlrs for each auxiliary winding. The point of connection of the beginnin of the auxiliary winding to the main wind should be the middle point of theturn or turns per slot selected. Thus,'in Fig. 8, the turn selected for starting is turn 1, 8, the middle point being point- 33, from which one of the auxiliary windings is started, which it will be observed is at the rear end of the armature. The three conductors ,of the auxiliary winding should now be located to correspond to the remaining conductors per circuit of the main winding; that is, assuming that the turn comprising conductors 1, 8 is taken care of, then the'conductors 3, 10, 5, 12 and 7, 14, should be considered in locating the three conductors'of the auxil ing.

iary winding. -The auxiliary conductor of the main winding there should be either an outgoing conductor in phase 90 degrees, or an incoming conductor in phase 270 degrees, 'andin Fig; 8, an incoming conductor 31 of the auxillary winding'is located in phase 270. Similarly, for the turn 7, 14, of the main winding, the corres onding auxiliary conductor should either he an outgoing conductor in phase degrees, or an incoming conductor in phase 315 d ees. In Fig. 8, the conductor 3ethofrthe auxiliary winding is located in pha'sel35 degrees and is an outgoing conductor. The auxiliary winding comprising the conductors 34, 3d and 3-L will therefore act to maintaingthecollector ring 6, to which it isi'connected, ata constant potential mid-way between the'potent-ials of the positive and negative brushes of the ma; chine. As the point offthe main winding which is located 360 electrical'degrees therefrom should be at the same potential 'asthat 1 of point 33. these two points are shown windings shown may beotherwisearranged, 65 cross connected by the conductor and if since each conductor of such winding mar desired this auxiliary winding may be coube placed in any one of four positions: It is sidered as starting from the point 36 which evident that the general principles of these is cross connected to the point 33. windings applv to any number of slots. and

In Fig. 8 another auxiliary winding is any number of conductors per slot. It will 70 Shown which Starts from point 37 of the also be clear that in some instances better main winding, 90 degrees fi-ompoint 33, and mechanical and electrical arrangements of which is the middle point of the turn 12. conductors will occur with some numbers of 10 We may therefore assume that the turn 5, auxiliary windings than with ill-lltl'm, and

12 is taken care of, and we should locate the he des gn rm y ele t s ch number a to 75 three conductors of this second auxiliary give the dcsiredcondition. winding so as to correspond with the turns Fr m the foregoing it will be understood 7, 14, 9, 16 and 11.18. Taking the turn 7, that my invention. may be applied to ma- 14 of-the main winding. this may be taken chines having a larger number of poles. and

care of by an Outgoing conductor in phase to various other forms of armature windings. 80 135 or an incomingconductor in phase 315. It will also be understood that m ini'eh- The conductor 38" of this second auxiliary tion may be applied to machines having stawifiding an Outgoing conductor in phase tionary-armatures and revolving fields. in-

20 135 which answers the requirement. The tead of machines having rotating armaauxiliary conductor for turn 9. 16 should be tures as above described. 85 either an outgoing conductor in phase 180. Fig. 9 is a diagram which shows the locaor an incoming conductor in phase 360. and t-1on of the conductors of Fig. 8 on the armathe conductor 38 of the second a xilia y ture. The poles N. S are indicated in full winding is an incoming conductor in phase' l neand the armature core is designated by 360 The auxiliary conductor for turn the character 40. and l'PPlLStlllLtl in St('- 90 18 should be either an outgoing conductor in phase 225, or an mcomm conductor in phase 45; the conductor 38 o tlllS'flllXlllttl of the additional windings are suitably located andconnected. It will also be undertion: The core is indicated as heir-1! a slotted core. and the conductors of the main and auxiliary windings are designated by starting one auxiliary winding are made'up winding is an incoming conductor in phas the same characters as in Fig. it will he 45, which answers the requirement. This. noted that the. conductors of the auxiliary 95 second auxiliary windi will the f l o windings are shown as located in the bottom serve to maintain th i tr l t th d i d of the slots. and this location is preferable. potential. Point 37, from which th s o d Fig-l0 illustrates my invention as applied auxiliary winding starts. is cross connected to -a machine having a larger number of to point 39, which oint i 360 le t i -a] (l conduetors than that represented in Fig. 100 grees from oint 37, and therefore of the and having more than one turn pcr slot. same potential. It will therefore b seen The mat-him aeprcsenlcd in Fig. l) is the that in Fig. 8. there are two auxiliary wind- Same as that of Fig. except that there are h1g5 which begin at points in the mai windtwo turns per slot per circuit instead of one.

ing electrical degrees apart. and that each and each turn is provided with its correof the auxiliary windingscomprises nly spending commutator segment. There are three conductors. and each of these three, therefore twice as many conductors or turns windings serve to maintain the desired poand twice as many commutator segments in 45 tentia'l of the collector ring G-and of the new Fig. 10 as there are in Fig. with the M {1-31 wire, {twill al b t d th t th conductors in the main winding of Fig. 10. ductors of the auxiliarv windings are so 10- and four multiple circuits. there are 10 con- 'cated as to secure a Sub tantially bala d ductors per circuit from brush to brush armature. It will be understood from the hearing on the commutator, or eight turns 50 diagram that the auxiliary conductors are per circuit and two turns per slot. .-\pplyintended to be located in the same slot of the ing the rule above giveii =that the number of core as the two adjacent conductors of the turns per auxiliar winding shall he one main winding. It will also be noted that half the turns per circuit minus one-half the arrangement is such as to bring the colthe turns per slot. we find that this is equal 55 lector ring 6 on the same side or end of the to 3 =3 turns for each auxiliary winding armature as the commutator. or six conductors'for each auxiliary wind- It will be understood that any desired ing. As already stated. the point of conneca nurnber of additional auxiliary windings tion of the begin'uingof the auxiliary windmay be added to the structure represented in ing to the main winding should be the mid- 60 Fig. 8 and connected at any desired point in tile point of the turn or turns .per slot sethe main winding provided the conductor i lected. In Fig. 10, theturns selected for of the conductors 5, 19, 6, 20. The middle} stood that the conductors of the auxiliary l pointof these two turns is therefore point;

41, from which the auxiliary winding. 42"

to42starts. Assuming that these two turns are taken care of, the six conductors of the auxiliary winding should be located to cor respond to the remaining conductors of this circuit of the main winding; that is, should correspond to the turns made up of con- -ductor's -9; 2a, 10, 24, 1a, 21, 14, 28, 17, 31,

18, 32. Taking the turns made up ofconductors 9, 23,10 and -2a, the-. correspondi ng -'conductors of the balancing windingmay beeither an outgoing-conductor in phase 90 and an incoming conductor in phase 270;"01' two outgoing conductors in phase 90, or if desired two incoming conductors in phase 270. In the auxiliary winding 42 to 12,

, ,t.he conductor 42 is an-outgoinq conductor n phase 90, and the conductor i2 is an inomrng conductor in phase 270, which anvers the requirement. Now taking the turns made up of conductors 13, 27, 14 and ,28, the corresponding auxiliary conductors conductor in phase 180, and an incoming conductor in phase 360, or two outgoing conductors in phase 180, or two incoming conductors in phase 360. The conductor -12 is an outgoing conductor in phase 180 and- .r2 is an incoming conductor in phase 360.

Consequently, the auxiliary winding 42 to ,4

-'-:.tions which answer the requirements and '2 contains six conductors located in posit-he winding will therefore serve 'to maintain ring 6 at the desired neutral potential. Point 41 where the auxiliary winding starts, is shown cross connected to point 43', located 360 electrical degreestherefrom, and which connection assists to improve the balancing efi'ect. p

Another auxiliary winding comprising the conductors 451, 4:1, 4 1, 44", 44c and 4-1 is shown in Fig. 10,.which is connected to point-t5 of the main winding, degrees from the beginning of the auxiliary wind ing already described. It will be seen' by; comparing the location of theconductors 44 to 4 1, that they correspond to the proper conductors of the main winding and that they will serve to maintain'the desired neutral potential of ring 6 constant. Po nt -15 is cross connected to point-'16, which. is the c Qrrespondi ng,- point of the same potential.

It wil b understood that the various conductors which are grouped together in Fig.

10, occupy the same slot as explained in 'connection with Fig. 8, and that the other general statements made 'in conri'ection with Fi 8 also apply to Fig. 10.

n the diagram Fig. 10, although I have shown the main winding with full pitch, it will be evident that, with fractional pitch windings, the same general principles apply, the main feature to be observed being-that in each auxiliary circuit, the algebraic sum of the electromotive forces from the collector ring to each brush shall be equal to half the electromotive forces between the ositive and negative brushes, and also that t ie algebraic sum of the electromotive forces from the collector ring through any one auxiliary winding to its connection with the main winding and through any part of the main winding to the connection of any other auxiliary winding, and then through said winding back to the collector ring, shall be zero.

T hediagrams shown herein refer to multiple windings, but the invention is equally applicable to series or two-path windings. For example, with a six pole machine having 59 slots and 2 turns per slot in the main winding, making the total number of turns equal to 118 and the turns per circuit equal to .59, we would have for the auxiliary winding 28%, for each auxiliary winding.

Although in modern machines, the numher of conductors in themain armature winding is usually very. much larger than the number represented in these figures, it

art how the conductors of the auxiliary will be understood by those skilledin the winding or windings should be located in such machines, and also how they should be located for various other types of main windings. It will also 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 form shown and described.

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

1. The combination with a direct current generator, of a plurality of auxiliary dynamo electric generating windings wound on the armature core of said generator and electrically connected to points of different potential in the armature of said. generator and also electrically connected to a common point, each of said-auxiliary'windings having less than one-half. the conductors per cir cuit of the mam winding,- and certam conductors of said auxiliary windings being located unsymme'trically.with reference to each other.

The combination of a winding havinga commutator, a field magnet, and a dynamo electric generating. winding connected to a point of. varying potential lin said first named winding, said second wmdmghavmg less than one-half theconductors'per circuit of saidfirst named winding, and located in core slots also containmg conductors of said .lirs named winding.

. 3. The combination of a winding commutator.

having a a field magnet, and a plurality of dynamo electric generating windings con- 1 nected to points of different and varying potentials of said firstnanied winding. each of said plurality of windings having less than one-half the number of conductors per circuit of said first named winding and located in core slots also containing conductors of said first named winding.

4-. The combination of a field magnet. a main windingsubjected to the magnetic field thereof and having a commutator and brushes. and a )lurality of dynamo electric enerating win ings connected to points of c ifl'crent and varying potentials of said first named winding'and subjected to the same magnetic field for generatin a maximum electromotive force equal to less than onehalf the electromotive force generated by said main winding, said plurality of windings beingalso connected to a common point, each of said plurality of windings having less than one-half the number of conductors per circuit of said'first named winding and I located in the same. phase positions as cer- .tain conductors of said first named winding.

54 The combination of a winding having a commutator, a field magnet, and a dynamo electric generating winding connected to a point of varying potential in said first named winding. said second winding ha ing'a different number of conductors than one-half the conductors per circuit of said first named winding 'and located in core slots also containing conductors of said first named windin 6; The combination of a winding having a commutator, a field magnet. and a dynamo electric generating winding, onnected to apointof varying potential lns 'id first-named winding, said second winding having a number of conductors differentfrom onehalf the conductors per circuit of said first named winding and less than the number of conductors per circuit of said first named winding and located in core slots also containing conductors of said first named winding.

7. The combination of a winding haying a commutator, a field magnet, and .a plurality tentials 'o said plurality of windings, having a number nected to of conductors different from one-half the.

number of condi1cto'. per circuitof said .first. named winding-and located" in core slots also containing conductors of said'jfirst' named winding."

8, The combinationwith" a direct current generator, of an auxiliary winding for main- I iainiug a lixed potential, suid winding liari ing its parts located under the influence of 1 the magnetic field to correspond substain l tially with the phase location of'thc parts of a circuit of the main winding cxceiting the portion of the main winding to which the auxiliary winding is connected.

H. The coml'iination with a direct current generator. of means for maintaining a fixed intermediate potential comprising an auxiliary winding on the armature core for dymnnieally generating a nuixinnnu electronu-ti c force equal to less than one-half the clectrnnuuiye force of said generator. and a collector ring to which said auxiliary winding is connected.

10. The combination with a direct current generator. of an auxiliary winding connected to a point of varying potential in the main winding for maintaining a fixed intermediate potential. said auxiliary winding haringits conductorslocated 0n theartnat-ure 1o ccrrespond substantially with the phase location of a part only of the conductors of a circuit of the main armature winding, certain conductorsof the auxiliary winding being unsymmetrically located with reference to each-other, and a collector ring to which said auxiliary winding is connected.

11. The combination with a direct current generator, of means formaintaii'iing a fixed potential. said means comprising a winding having its partslocated in the magnetic field. and in armature core slots also containing conductors of tlu main armature winding to correspond substantially with the location of parts of the main armature winding and having a number of conductors equal to less than one-half the conductors per circuit of the main winding, and a collector ring to which said auxiliary winding is connected.

12. The combination with a direct current generator, of means for maintaining a fixed potential. said means comprising a winding for generating a maximum elcctromoti e force equal to less than one-half of the electroinotiye forc of said generator and having its parts located in the magnetic field to correspond substantially with the phase location of only parts of a circuit of the 5 main armature winding. and a collector ring to which said auxiliary winding is connected. v

13. The combination with a direct current generator, of an auxiliary winding formain- 2 taining a fixed intermediate potential, said winding beingconnected 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 2 phase location of only a partbf a circuit-of the main winding for generating a maximum electromot-iveforce equal to less than on'ehalf the electromoti e force of the generator, and a collector ring to which the winding.

other terminal of said auxiliary winding is connected.

14 The combination with a direct current generator, of'an auxiliary winding adapted to generate varying electromotive forces for maintaining a point of fixed potential, said auxiliary winding having less than one-half the conductors per circuit of the main winding and located in slots of the armature core which also contain conductors of the main armature winding;

15. The combination with a direct current generator, of an auxiliary winding adapted to generate varyin electromotive forces formaintaining a poiih; of fixed potential, said auxiliary winding having less than one-half the conductors per circuit of the main wind in g and located in slots 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.

16. The combination with a direct current generator, of an auxiliary winding adapted to generate varying electromotive 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 a circuit of the main winding excepting that portion to which the auxiliary winding is connected and having its conductors located in the slots of the armature core which also contain conductors of the main armature 17. The combination with a direct current generator, of an auxiliary winding adapted to generate varying elect-romotive forces for maintaining a point of fixed otential said winding having its parts istributed with relation to the magnetic field to correspond substantially with the phase location of only :1 art of a circuit of the main armature win ing and also to substantially balance the armature mechanically.

18. The method ofderiving an additional point offixedpotential from a direct currentmachine, which consists in generatin dynamically a resultant alternating electromotive force which continually equals and 5 corresponds to the change in potential of i point in the armature from the potential of 1 the said fixed point, said resultant. electromotive force being attained by generatin a plurality of electromotive forces in di fercnt phase relationship and in phases corresponding to the phase distribution of only a part of a circuit of the main armature winding.

19; The combination with a Inultipolar direct current generator, of an auxiliary winding distributed on the armature 'for dynamically maintaining an intermediate fixed potential, one terminal of said auxiliary winding being connected to a plurality of points in" the main winding having the same potential approximately, said auxiliary winding having less than one-half the turns per circuit ofthe main armature winding, and a collector ring to which the other terminal of said" winding is connected.

20. The combination of a multipolar direct current generator; of a plurality of auxiliary windin s distributed on the armature for dynamically maintaining an intermediate fixed potential,- oneterminal of each of said windings being connected to a plurality of points in the main armature winding having the same potential approximately, the points of connection of one auxiliary winding being displaced less than ,180 degrees electrically from the points of connection of the main armature winding of another of said auxiliary windings-each of said auxiliary windings having lss than ong-half the conductors per circuit of the mam winding, and a collector ring to which one terminal of each of said auxiliary windings is connected.

21-. The combination with a direct current generator, of an auxiliary winding for maintaining an intermediate potential, a collector ring to which one terminal of said winding is connected, the other terminal of said winding being connected to the main armature winding, and the number of turns of the auxiliary winding being one-half the numberof turns per circuit of the main winding minus one-half the turns per slot of the main winding.

In testimony whereof I a-fiix my signa' ture. iii-presence of two witnesses.

1 J UMES BURKE. 'itnesses; I

- L. K. Sacra,

Gno. X. KERR.

Copies of this patent may be obtained for five cents each, by addressing the 'Washing'ton, D. C."

Commissioner of Patents.

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