US990647A - Alternating-current motor. - Google Patents

Description

W. E. GOLDSBOROUGH.

ALTEBNTING CURRENT MOTOR.

APPLICATION FILED MAY 1 Y 990,647, 'ma' Patented Apr.25,1911.

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W. E. GOLDSBOROUGH.

LTZBNTING mlm KOTOR. APPLI'oA'rIoN FILED HAY 1.1903.i

Patented: Apr. 25, 1911.

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W. E. GLDSBORUGH.

ALTERNATING CURRENT MOTOR.

APPLIUATIUN FILED MAY 1,1903.

990,647, Patented Apr.25,19171.

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W. E. GOLDSBOROUGH. ALTBNATING CURRENT MOTOR.

APPLIOATION FILED nu 1.1903.

990,647, Patented Apr. 25, 1911.

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APPLIGATION FILED un 1,1903.

990,647, Patented Apr. 25, 1911.

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INVENTOR,

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wlNDEn E. eoLDsBonoUGn, or LA FAYETTE, INDIANA.

ALTEnNnTmG-CURRENT Moron.

Specication of Letters Patent. Patented Apr, 2.5, 19.11,

Application l'ed May 1,1903. Serial No. 155,172.

To 'all whom it may concern:

Be it known that I, WrNDEn E. GoLosBoR- orrori, a citizen of the United States, residing :1t La Fayette, in the county of Tippecanoe and State of Indiana, have invented certain new and useful Improvements in Alternating-Current Motors; and I do hereby declar the following to be a full, clear, and exact description of the invention, such as `vill enable others skilled in the art to which it appertains to maire and use the same.

The object of the invention is to produce an improved form of alternating current motor, in which there is no electrical connection between the primary or lield circuit of the said motor and the secondary or armature circuit of the said motor, and having characteristics which do not differ greatly from those of a direct current series motor. The motor may run at, below,or above, synchronous speed', when fully or partially loaded, or the motor may be run as van induction motor upon attaining synchronous speed.

In a pending application, Serial No. 136,171, I have shown and described the arrangement in common t pes of armatures of electric machines, of in uctance neutralizing electro-magnets and commutatin impedance coils. In this application, I set orth special applications of the said inductance neutralizing electro-magnets and commutating irnpedance coils lin combination with new and useful improvements in alternating current motors. V

In the drawings, forming a part of this specification, and in which like letters of reference indicate corresponding parts, I

-alternatin have illustrated several way of carrylng my invention into effect, it I that the forms of appara-tus herein shown may be departed from and still be within the scope of my invention, and in thes'e drawin' Figure 1 is a diagrammatic view, exhibitmg one formof my single-phase alternatin current motor, showing the field coils an pole-face coils of the primary ele ment and their connections, and also the coils, commutator, and connections of the secondary element, occupyingthe cen-ter of the figure, and also the brushes resting on ment that are short-circuited upon one another; Fig. 2 is a diagrammatic view, ex-

hibiting another form of the single-phase current motor, the primal" element forming the outer portion of the gure,

ing understood.

and the secondary element the central portion of the igure.- The magnetic circuit of the primary element is here given the form common to induction motors, and connections are shown whereby the direction of ro` tation of the secondary element can be re-l versed, or be made to run as a single-phase induction motor. Fig. 3 is a view exhibiting diaoframmatically the arrangement of parts of: a device whereby the commutator of the secondary element shown in Fig. 2 may be short-clrcuited; Fig. 4.- shows another form of my invention, the primary element forming the outer portion `of the figure, and the secondary element the central portion of the figure. Commutatino' impedance coils are here shown inserted 1n the commutator leads ofthe secondary element, and inductance neutralizing electro-maonets are shown superposed over certain o? the commutating lmpedance coils; Fig. 5 is a view showing diagrammatically the arrangement of my commutating impedance coils with reference to my inductance neutralizing electro-magnets placed over the said commutating impedance coils at the points of commutation; Fig. 6' shows diagrammatically another arran ement o f commutating impedance coils, wit superposed inductance neutralizing electro-ma ets; Fig. 7 shows diagrammatically my smgiephase alternating' current motor, in which two ndu'ctance neutralizing electro-magnets are used at each point of commutation, one of these inductance neutralizing electro-magnets being placed over the armature or secondary element in inductive relation to the armature coils between the pole-tips in the plane of commutation, and the other inductance neutralizing electro-magnet being placed in inductive relation at the points of commutation to the commutating impedance coils shown connected in the commutator leads o f the coils of the armature of the secondary element, which coils are Wound about a common core; Fig. 8 is a diagrammatic view of a part of a single-phase alternating current motor similar to that shown in Fig. 7, except that every slot of the secondary element contains the conductors of .the secondary or armature coils, as 'well as the conductors of the commutatin impedance coils, While 'above the teeth o the core ofthe said arma.-

ture or secondary-element, over the point of commutation, is placed aninductanc'e neutralizing electro-magnet; Fig. 9 is a diagrams matic view of a part' of an armature or secondary element that is provided with a doublewinding. By this arrangement, each slot contains the conductors of an armature or secondary coil, as Well as the conductors of one of my commutating impedance coils.

Above'the teeth of the armature or secl rinner side of a circular core, and the poleface coils being placed in smaller slots cutl into the faces -of the teeth due to the presence ofthe dee slots. This field or primary core is shown tted with inductance neutralizing electro-magnets magnetically insulated from the said core, the armature or sec ondary element being provided with a double Winding. By this arrangement, every other slot contains the conductors of an amature coil, while the intermediate slots contain the conductors, of one of my commutating impedance coils. A device for short-circuiting the commutator leads of the coils of thev armature or secondary element between the amature coils and the commutating impedance coils is shown diagrammatically, as is also a connection whereby the circuit through the pole-face coils can be ct out of the prlmary circuit; Fig. 10b is a detail View, showing the arrangement of the .parts for securin andscontrollin the position of the circu ar core referre to in the description of Fig. 10. Fig. 11 is a diagrammatic view of a singlehase alternating current motor, eve -ot er slot oi the amature or secondary o which contains the conductors of the amature or secondary coilsfwyhile the intermediate slots contain the conductors of my commutating im- 4 pedance coils connected -to commutator bars and short circuited u on one anotherthrough brushes and brush eads, while above the teeth of the said amature or secondary element over the points of commutation are placed my inductance neutralizing electromagnets, which .are in this case made a part of, but separated from the field-ring of the priming element of the said motor; Fig. 12 is a iagrammatic view of a primary element of a single-phase alternating current motor similar to that shown in Fig. 11, and rovided with connections whereby the lclrcuits of the neutralizing electromagnets may be opened, and a connection whereby the circuits of the field or primary element can be rearranged so as to make them eiective as the primary circuit of single-phase induction motor; Fig. 13 isla diagrammatic view of a primary element of extendin my single-phase induction motor, similar to the primary element shown in Fig. 10, except that special connections are provided whereby the neutral plane may be shifted relatively to the position occupied by the inductance neutralizing electro-magnets and having the cores of the neutralizing electromagnets made a part of the field ring of the primaryelement, which field ringis of the internal slotted'type common in induction motor construction; Fig. 14 shows diagrammatically an arrangement of my invention whereby the primary element is made to consist of two cores placed side by side, one of these being Wound with the primary field coils, and the other being-.wound with what I have termed the primary pole-face coils. The armature or secondary element is lengthcned so as to present a continuous surface in front of' both the primary cores; Fig. 14 is a transverse sectiontaken through Fig. 14; Fig. 15 is a diagrammatic view of an adaptation of my invention whereby two field rings with polar projec tions placed side by side and similar to those shown in Fig. l, are used in combination with a secondary element which is so elongated as to bring its coils into inductive relation with the polar projection of both field i rings. The polar projections of 'the two rings are so placed that the polar projections of one are at the side of, but between, the pole corners of the polar projections of the other field rings; 15 is a transverse section-taken through Fig. 15.

Inthe consideration of the above figures,

it must be borne in mind that the principles i of the machines shown in Figs. 14 and 15,

the pole-face coils in this case being eliminated from the field-ring of Fig. l.

In m several devices, laminated metal should preferably be .used in the const-ruction of primary and secondary magnetic circuits. Further than this, either the pri. mary or secondary can, in any case, be made either the rotating or stationary element, and the design of the cores modified accordingly.

Referring to the drawin s and toFig. 1' thereof, R designates the eld ring, an N. the north and S the south cles o the primary element of a single-p ase alternating current motor. J desi nates the field-windings, and K the poleace coils of the primary element. The conductors Kzof the pole-face coils K are so placedrelative to the pole-.faces as to be brought into inductive relation with the conductors A of the coils A of the armature or secondary element.y As here shown, thev secondary element is provided with a Gramme ringwinding, the coils of which are connected to the commutator segments E by non-inductive commutator leads M. The brushes F, F are placed in conta-ctwith the commutator segments, and are interconnected through the medium of the brush leads G, and the short-circuiting ring' H. The brushes are so located as to bear upon the commutator segments which are connected with the armature-coils which are in such positions, relatively to the space between the pole tips, as to admit of their most success ul commutation. By the connections shown, the field coils'J are all connected in series, and the pole-face coils K are also all connected in series; and, further, the field coils' J are connected in series with t-he pole` face coils K, thereby causing the alternating currents which are drawn from the source ot'supply to traverse all of the primary windings connected inv series. The function of the field coils J is to Vproduce a magnetic field varying in its intensity with the pulsations of the alternatin currents from the source 'of suppl The -unction of the poleface coils K is, by virtue of ltheir position, to inducevelectric currents in the armature coils 'A, which by reaction with the magnetic fields ofthe poles N and S, roduce relative motion of the surfaces of t e 'rimary and secondary elements. The pole-iiice coils are so arranged and connected as to tend to promote the same polarity at the Vpole tips N2' and an opposite polarity at the pole tips S2.

It is to be understood that Fig. l is merely diagrammatical. The armature, pole face, and field windings may be given the form of wave or lap windings, or Such other common forms as. may, in special cases, be deemed most effective.

The inductive action of the primary pole face coils K upon the secondary or armature coils A is such as to cause currents to pulsate through the armature windings in s'uch manner as to produce natural points of commutation at or near the neutral planes between the pole tips, as in other forms of commutating electric machines.

It is to be understood that the field and pole face coils maybe connected in avariety-of ways. The .field coils may all be connected inparallel, andV this parallel sys tem connecte in series with a series arrangement of the ole face coils; or the field coils, all connecte in parallel, may be connected -in series with the pole-face coils also connected in arallel; or other arrangements' maybe use as may b e found in special cases most effective.

.In Fig. l, the single-phase alternatin current motor there 'shown is equipped wit four poles. It must be understood, however, that any even number of poles may be used successfully in this motor, other de-y number of turns in the pole-face coils need not be the same as the number of turns in a field coil in any one slot, these factors dependin u on the desi of a specific motor. The e ec of the com ination of field coils and pole-face coils, ashere shown, is, how-l ever, such that the field-coils J create magnetic fields which have greatest intensityV at N, N and S, S, the magnetic fields at N being opposite in polarit fields at S. The fringe o the two fields combine to make neutral magnetic planes at or near N2 and S2. The tendency of the Ipoleface coils K is to promote magnetic elds permeating the air-gap between the primar and secondary elements at and a out 2 and S2, the magnetic fields at N2 being of opposite polarity to those at S2. The coils,

4A of the secondary element are, however,

brought into such close inductive Yr'elation'to the pole-face coils K as largely to neutralize their effect in producing the magnetic fields mentioned. In this motor, the secondary element is of the slotted core type, and is shown equipped with a (hammering-wind! p ing. Under ordinary circumstances, formed coils would be used in arranging both the primary. and the secondary windings. In the'construction here shown, the ole-face coils are preferably placed on top o ,the field coils, thereby bringing the former nearer 4the tops of the teeth of the primary core.

In this motor, as in the one shown in Fig. 1, the function of the field-coils J is to create magnetic poles or fields. The function of the pole-'face coils K is to induce electric currents in the armature coils A, which currents, by reacting magnetically upon the magnetic flux set up by the field coils J produce relative motion between the primary and secondary elements. Attention 1s called to the method of connecting up' the field' and pole-face coils of the primary winding. The switch X is the main switch connecting the motor leads X, X2- with the source of electric energy. The switch Y is a double throw switch, by means of which the direc' tion of rotation of the seconda element is'- reversed. Throwin the switc from the position shown in ig. 2 to its other position reverses'the currents through the polefaceV coils K, and thereby reverses the reaction between the currents induced in the secondary element and the magnetic flux to the magnetic set up by the fieldcoils of the primary element. The switch Z is used td\ reverse the direction of the flow of current'- in a portion of the field coils when it is desired to make the motor operate as an induction motor after the secondary element has approximated to synchronous speed. The short-circuiting ring U shown inside of the commutator E is an auxiliary in producing the induction motor effect. Under ordinary circumstances, when not running as an induction motor, theshort-circuiting ring U would occupy the position shown at U3 in Fig. 3. When, however, it is desired to make the motor .act as an induction motor,

4the switch Z must be thrown into its other position, and the short-circuiting rino' U advanced from its posit-ion at Ua in Flg. 3 to the position U in Fig. A3. The eifect of the short-circuitingring U is to short-circuit the commutator bars of the commutator E, and thereby 'short-circuitvthe armature coils one upon another. It is understood that the operation of this motor as'an induction motor is not essential tosuccessfull carrying all loads from no load to full loa Its characteristics, however, as regards torqueand speed, etc., are immediately changed when the transition is made by the operation of the switch Z and the short-circuiting ring U.A In Fig. 2, a second set' .of brushes F2, F2 is shown. These are introdliced to bring out the fact that, with proper care and design, the motor will operat ually well, no .matter which set of b hes is employed during the running of the motor, inasmuch as the functions of the,

pole face coils and field-.coils are interchanged with reference to the two sets of brushes. The motor can also be made to operate-with both sets of brushes in operative relation, their leads being separately interconnected, as shown.

In Fig. 1, a modification is shown, whereby the, fields and pole-face coils are so wound upon a field-ring as to make every other coil afield coil, and the intermediate coils ple-face coils. In this case, the effect of the field-coils J, through the medium of the conr nections, a lshown, is to create magnetic fields whicli ve g eatest intensity at N and the ma e iqields at N bein opposite in, polarity t e magnetic-fiel .s at S. On the other hand, the tendency of the. oleface. coils K is to promote magnetic elds N? and S2, the magnetic fields at N 2 being of opposite polarity to those at S2. The secon ary element; or the armature, isv located internalh to the iield or primary element. As here shown, the secondary element is sup lied withfa Gramme ring winding, the coi s A of hich are so located as to be in inductive rglation to the pole-face coils K. In this motor, as in the one shown in Fig. 1, the function of the field-coils J is to create magnetic poles. T-he function of the pole-face coils K is to induce electric currents in the amat-ure coils A, which currents electro-magnetically, by reacting upon the magnetic flux set up by the field coils J, produce relative motion between the primary and secondary elements. As regards all other mat-ters, except as has been heretofore or may be hereinafter explained, the arrangements of the motor shown in Fig. 4 are similar, in all essential details, to those of the motor shown in Fig. l.

Referring l'to Figs. 4, 5 and 6, attention is called to thecommutating impedance coils B connected in the commute-tor leads ofthe armature coils, and the linductance neutral- -4 izing electro-magnets C* superimposed upon bn, constitutes one of my impedance neutralizing electro-magnets, and the core C may, commercially, be so adjusted and designed as to admit of the air-gap L2 between the core of the incluctance neutralizing elec.- tro-magnet Ca and the core P of the commutating impedance coil B to be made as large .or as small as may be necessary to obtain the best results durin the operation of the motor. It will be evident that the arrangement -of the commutating impedance coils B relative to the inductance neutralizing electro-ma ets C4, the commutator-bars E and the brus es F, F, is such that currents delivered from or received by the armature coils, from the brushes, so react magnetically rents in the coils C2 of the said inductance neutralizing electro-magnets C; which currents thus induced in the coils C2 so react upon the commutating impedance coils B' as rents which circulate in the armature coils during the time when they are short-circuited by the brushesF, F, react magnetically in such manner during their passa e through the commutating impedance co1 s `commutation. 1ov

Asaid located 4in the commutator leads of said armature coils undergoi commutation as to add the inductance of t e two commutating impedance coils connected in the comunitator leads of each of the armature coils undergoin commutation, and place their combined inductance in series relation to the inductance of the armature coils undergoing By the arrangement shown, therefore, the inductance neutralizing electro-magnets C4 are not effective in diminishing the inductanceof the commutating impedance coils in the leads of the armature coils undergoing commutation, as related to currents which permeate the short-circuited armature coils.

The arrangement of arts shown in Figs. 4, 5 and 6 makes it evi ent that, by my invention, commutation of an armaturecoil is facilitated by the automatic introduction into the leads of the armature coils which are undergoingcommutation, of inductances so great as to prevent the development of currents of any considerable volume in the short-circuited armature coils. As shown, the inductance neutralizing electr@ magnets embrace but two of the commutation inductance coils. They may, however, embrace a greater number of these' coils with effectiveness. The position of the inductance neutralizing electro-magnets may be given an angle of advance or lag, as conditions ma require, or as indicated in Fig. 4.

In Fig. a combination of parts is shown whereby, through the introduction of suitable inductance neutralizing electro-mag nets, the act of commutation may be facilitated, when desirable, inthe motors of my invention. The commutating impedance coils B are wound over the slotted core 1:2

and connected-in between the junction points i coils C* have no effect whatever in diminishing the im edance of the commutating im pedance coi s B in their unctionof reactance coils connected in vseries with the local circuit tthrough the commutated coils A, the brushes F and the other elements linked therewith, as diagrammatically shown. By the arrangement of parts shown in Fig. 7, the counter-electromotive force which would ordinarily be develo d in the coil A2 by vcurrent vibrations ta ing place in it during the period of commutation is, in the present case, largely wiped 'out by the presence of the inductance neutralizing coil 'C yin :intimate relation withthe'said coil Atrand the effectiveness of such portion of the said counter-electromotive force of'selfeinduction whichstill remains in settin up a rush of current around through itseFf, the-commutator bars E andthe brush F is greatly diminished by an automatic introduction of commut-ating impedance coils B in the circuit through Which the coil A is short-circuited bythe brushes In Figs. 8 and -9, the arrangement of parts and 4the combinations rovide for carryin out of functions whic havebeen accorde to the commutating impedance coils, and the inductance neutralizing electro-magnets'of I'Fi l7 without the necessity of providing an additional core over which commutating impedancecoils can be wound, or of bringing into play more than one inductaiice neutralizing electro-ma et at each point of commutation. As iagrammatically shown, the commutatin impedance coi s B so actmagnetcally w en they are permeated by currents flowing-either to or from the armature coils A and the brushes F as to set u reactive currents 'in the .shortcircuited' coi of the inductance neutralizing electrom et C, which reactive currents set up int e c'oil C Ahave the e'ect of neutralizing the inductance of the coils fB yto the passage vof current or from the .armature coilsHA and the brush F. When, 'on the other hand, we consider 'the currents which rmeate the coil A2 during the time when its terminal bars `E are-bridged by the brush F, We find that the ycoil A is brou ht into such inductive relation Ito 'the in uctance' neutralizing coil C as to induce in said coil C currents which react magnetically to neutralize the inductance of the coil A. 'Aigaim the presence of'the=coil C has no effect u on the inductance of the coils B,considere as acting in series with the coil A -during the time oits commutation, =for and on -account Vof reasons that have -been explained. The number of coils embraced by the inductance neutralizin Aalectrmagnet'C vary under different con itions.

The arran ment of arts presented in Fi 10 willfully un erstood 'when considired in connection with descriptions of Figs.- 1, 2 and 9. The construction of the rimary winding removes the field coils om as intimate a relation to the pole-face coils as that 'which-obtains in Fig. 2,=thereby effecting a modification to Abe :preferred under certain conditions. The core of. the impedance neutralizing electro-m et. is magnetically insulated from the e d-riri R by V, while being held ri 'dly to the sai core by suitable su: ports. he core of the nductance neutra zing electro-ma et is entirely una'ected by lthe magnetic lux permeating the primary core R. The supl the currents to. flow through all coils in ports, however, admit of the core C being ,either raised ory lowered, or moved with or against the direction of rotation of the secondary element. Fig. 10b shows the arrange- -ment of the said parts for securing and cont-rolling the position of the core C. The part V2 embracesthe field core R and is secured thereto by the handwheel V5 attached vto the threaded pin R2, which is embedded in the4 field ring R. The slot V* is cut in thesupport V2, which permits the strip. V carrying the core C to be moved either with or against the direction of rotation ofthe secondary element. .In the' extremities of part V2, at V, are cut slots, through which project thumb-nuts V7 securing the ends of the strip V, which is rigidly secured to the core C, and ma etically insulates the core C from the fiel core R'. The thumb-nuts V7 give Iopportunity for adjusting the core C so that it can be raised or lowered, and

thereby be made to exert a greater or lessV inductive effect uponthe ,coils in the secondary element. By thepossibility of these adjustments, the effectiveness of the inductance neutralizing electro-magnet can be made a maximum for all conditions of loading of the. motor. As diagrammatically shown, the armature coils 'A can be individually short-circuited' by simultaneously closing the switchesU2. When the switches- U2 are closed, the Winding on the secondary element is changed to that of a closed coil winding, and, under these conditions, the motor will operate with greater economy if the switch Z2 is thrown to its other position and the pole face coils K thereby cut out of the rimary circuit.

T e arrangement of parts and connections shown 1n Fig. 11 will be thoroughly understood in viewof explanations previously given, especially in connection with Figs. 2 and 8. The core of the inductance neutralizing.electroma et is here so arranged as to admit o its being .'ven a movement either in advance or agging behind the neutral magnetic plane of commutation. Fig. 11 shows more forcibly the facility with which the dparts of my inven- 4tion can be modified an assembled to meet special conditions.

Fig. 12 shows an arrangementwhereby the v the same direction, thereby producin lields of maximum intensity at N2 and 2. In Fig. 12, the inductance neutralizing electromagnets are made a part of the field ring and are immovable in their position. A

connection is provided at Z2 whereby the- 'nections whereby the several field circuits of -each polar winding are connected in parallel With one another and in series with the pole-face coils, which are, in-turn, arranged in four parallel circuits. Connections are further rovided through the medium of the switch whereby the line of division between the several sets of field-coils can be either advanced or thrown back relative to the primary core. W'hen the held switch Z4 rests on the terminals Z", Z, th`e primary fields will have a maximum intensity at N5 and S5, and the neutral point will be at N and S9. When the'switch Z* rests'on the contact Z. Z?, the maximum intensity of the field will ibe at N and S, and the neutral point at N2 and S2. lVhen the switch Z rests on the terminal points Z7, Z7, the fields of maximum intensity will be found at N7 and S7, and the neutral point will be at N11 and S11.

The diagrammatic arrangement of the parts which is shown in Fig. 14 admits of an arrangement of the primary field winding andI the pole-face coils which entirely removes them from an intimate electromagnetic relation. According to this construction there are two cores R, R2, placed side by side and constituting the primary element. The core R is wound with the primary field coils J, and the core R2 with the primary pole-face coils K. It will thus be seen that the field coils and pole face coilslare wound upon independent cores; and it will be understood that the armature will be constructed of such length asto be in inductive relation to both cores. In the ligure, one-.half of each core has been illustrated, the line 14:--14 cutting olf half of the core R and permitting half of the core R2 in rear to be seen. The functions of the field coils J and the pole-face coils K, herein shown, are precisely the same as those which have been accorde to these coils in the description of Figs. l and 2, etc., the coils J being effective 1n promoting magnetic fields so sltuated and placed that the currents which are induced 1n the secondary windings 'by primary currents owing in the pole-face the currents flowing in the coils A on the secondary element is not greatly to `change the intensity of the magnetic flux due to the currents which permeate thecoils J of the primary element R.

The diagrammatic arrangement presented in F i 15 is 'applicable where 1t is not deeme desirable to make use of field rings such as are common in the construction of induction motors. Here again there are two rings R, R2 constituting the primary element arran ed side'by side. The ine 15-15 cuts off ha f of the core R, and the half of the core R2 corresponding to the half of th core R removed appears on the other side of this line. In this case, the coils K of the primary element R* act ma etically upon the coils A of the secondary e ementto induce in them electric currents. These secondary currents in turn react magnetically upon the currents in the coils K largely to neutralize their effect setting up magnetic flux around through the core' O of the'secondary element, and the core It2 of the primary element. The coils J of the primary element R have the samefunction as the coils J of the primary element of Figfl. From this, it will be seen that the functions of the coils J and K have not, in this case, been changed in the least from those to which they are common in the diagrammatical arrangement of parts previously outlined in this specification.

As has been previously pointed out," I do not limit m'ysel to a four-pole construction,

inasmuch as my lnvention can be made to a ply equallywell to all forms of 4magnetic cii'cuits whether they be bipolar orymultipolar.

In all ofthe constructions resented here-` in, laminated rather than soli metal should,

- preferably, be 'used in building up the mag` netic circuit, and commercially formed coils will be found referable'to the Gramme ring construction s own in the 'arrangement of the insulated windings of these motors.

Although not shown in the drawings, it

Vis to be understood that, in the primary mit of a ready balance being maintained between the different parts thereof in the case of all parallel arrangements.

I-Iavin thus fully described my invention, what I c aim as new and desire to secure by .Letters Patent of the United States is:

1. In a commutating alternating current motor, the combination of energizing coils, inducing coils, an armature arranged within the infiuence ofsaid several coils, a commutator,'induction coils connected in series with the commutator leads of the armature of said motor, and short circuited coils ar ranged'in inductive relation to said induction coils, as set forth.

-2. In an alternating current motor, the

combination of a field ring, an armature and an 1ron corehavlng a short-circulted Vwinding, and mea-ns whereby the said core hav- 'inga short-circuited winding can be moved in or opposite to the direction of rotation of lsaid armature, or be brought in closer or more distant inductive relation with said armature, while firmly attached to the fieldV ring, as set forth.

3. In an alternating current motor, the` combination of a field ring and armature, armature colls and impedance elements connected in lead wires from said armature coils; and of an iron core havinga short-circuited winding in inductive relation to said impedance elements: and of means whereby the said core having the short-circuited windings can be moved in or opposite to theidirection of rotation of the said arma- 'ture to a predetermined extent, as set forth.

4: In an alterna-ting current motor, the combination. of a field ring and armature, armature coils and impedance elements connected in leads from said armature coils; and of an iron core 'having a short-circuited winding; and of means whereby the said core having a short-circuited windingcan be brought into closer or more distant lnductive relation with the impedance elements, as set forth.

In testimony whereof, I aiiix my signature, in the presence of two subscribing Witnesses. l'

WINDER E. GOLDSBOROUGI-I.

Witnesses:

Jnssm L. Cowr'NG, S. Rouen.'

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