US1013218A - Induction-motor. - Google Patents

Description

W. E. REED.

DTON MOTR4 APPLIUA'MQN FILED Alisha we@ Patented J an. 2, 1912.

BSHEBTS-SHEET l,

lNVENTR WITNESSESI AUDRNEY W. B. REED.

INDUOTION MOTOR.

APPLXUATION FILED AUG.2, 1906. v 1,01 3,218. Y Patented Jan. 2, 1912.

3 SHEETS-SHEET 2 WH NESStS; INVENTOR Z ATTbRNEY I. REED.

INDUCTION MOTOR.

APPLICATION FILED M1942 1906A Patented Jan. 2, 1912.

3 SHEETSSHEBT S.

GEA/ERA TDR lNvENToR eam, az/

WITNESSES:

f ATTURNEY for including a suitable resistance in circuit the ro'tatin sarily confined to use with relatively small so that `of Pittsburgh, and State of Pennsylvania, lave invented a tion to external stationaryresistances.

UNITED. sTATEs `l'ATENT OFFICE.

WILLIAM EDGAR RED, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO MANUFACTURING COMPANY A. CORPORATION OF HOUSE ELECTRIC & VANIA.

Waerme- #ENNSYL- To all whom, it may concern: ,l

Be it known that I,`WILL1AM EDGAR REED,

a citizen of the United States, and a resident in the c'ount of Allegheny new and useful Improvementy in Induction- Motors, of which the following is a specifi-- cation.A

My invention relates to d name-electric machines, and lhas special re erence to motors of the induction pe,` the rotating windings of which are a apted for connec- The ,object of my invcntlonlis to'provide means .for short-circuitin a Iplurality of current collectors in a mac ine of the aforesaid class that shall be sinple and durable in construction and that shall .be operative when the motor is either at rest or in motion.

In order to avoidlan overload upon the supply circuits when inductionmotors are started,'it has been usual to provide means with the seconder ,windingof the motor which may be s ort-circuited after the motor has attained a desired speed. This resistancehas sometimes beenmounted upon member of the Vmachine fand an automaticm'eans has beenprovided for short-circuiting the resistance which was dependent upon the centrifugal force exerted when the motor attained a predetermined speed, but a device of this character is necesmotors'because of operating contact stick together. v f,

For ,startin relatively `large induction` motors when t e resistance occupied a-considerable amount of s ace, slip'rmgs or current` collectors have been provided on the rotating members which were engaged by suitable'stationar 'contactlbrushea the resistanoes being o any convenient form, located in any4 desirable position and con nected-to the stationar brushes. This is a very satisfactory starting arrangement, but relativel large values of current must be carried by the current collectors when the motor is in operation, since the stationary brushes are' then interconnected.

The brushes themselves usually o'er relatively hi h resistance to the flow of current, e slip of the motor is increased,

the tendency of the by members toV vibrate r Specification of Letters Patent. Application sled august 2, 1906.

j respectively 'of the bushing 7 b Patented J an. 2,1912. ,$erial No. 328,885.

and thebrushes and the collector rings .are t5 'llgjected to such vibration in servicethalt s'u cient-sparking often occurs to seriousl;- impair the contact surfaces and materially diminish the efficiency of the motor.

In accordance with my present invention; faoA 4I provide means for so short-circuiting the current collecting devices that no current will traverse the sliding contact members durin the normal operation of the motor.

In t 1e accompanying drawings, Figure 1 isA 65 a view partially diagrammatic and partially in sectional elevation, of amotr constructed.' in acordance-with y invention.v Fig. 2 is f adetail .view of the operating lever and. Fig.;3 isasectional elevation of the short-"17o circuitin'g device on a line III`-III of Fig.. 1., Figs'. 4 and 5 correspond to Figs.` land", 3,anfl are partially diagrammatic views of,` I a modified device which may be substituted 1 for the deviceshown in Figs. 1, 2 and 3. i ,..75` Referring to the drawings, the motor2 illustrated comprises a stationary memberV havine' a'winding l and end-bells 2, and al rotatable member 3 which is provided witha windin "4. The rotatable memberof the ,80 machinels fixed to a shaft 5 which is rotatably mounted in stationar bearings 6 and upon which a sleeve or bus ing 7 ismounted. Aplurality .of collector rings 8, 9 and 10 are mounted upon and insulated from the 85 bushing 7, concentric with the axis of rotation of the cylindrical core member, and areVv engaged by stationary brushes 11, 12 and 13.

Near one end of the bushing 7, a plurality 90 of similar segments of conducting znajteri'alz.'A 14, 15 and 16are eqni-distantly disposed and are insulated from the bushing 'and from each other. These segments are respectively connected by rods 17, to the collector rings S, 9 and 10 and each of them is provided with exible contact ngers 20 that extend beyond the inner extremity of the bushing 7. All of the fingers are adapted to be' simultaneously 'engaged by 100 a short-circuiting ring 21 which 1s adjustably-mounted upon the shaft 5 near one end ofthe bushin Y I f The 'short-circuiting ring 21 is connected to` a p collar 22, which is also adjustably '1055 mounted upon shaft 5, at the op osite end y means of boite or-rods` 23 which are su stantially parallel to au@ equally dis osed about theaxis of the shaft and exten lloosely through holes 24 ii the 'bush'in 7 sotliatfany movement of th collar wil be transmitted to the short-circuiting ring 21. V*"Ithis way, the ring 21 in a be moved into and out of engagement wit the fingers 20 at the will of an attendant by means of a stationary operating handle lev `ver 24 which is fulcrumed upon a stationary shaft 25.

The lower extremity of the lever 1s pivotally connected to a forked link 26 that is fulcrumed upon a stationary shaft 26 and is provided with inward projections 26b ou which rollers 27 are mounted. These rollers are adapted to engage an annular groove 28 in the outer surface of the collar 22.

The collar 22-is free to rotate in either of its two extreme positions which are accentuated bythe engagement of the springs 29 with notches 30 and 31 in the segments 14, 15 and 16, with no a preciable resistance bctween the rollers 2 and 4the sides of the groove 28, since the lever projections tend to center themselves in the roove. The extreme positions of the hand e lever may also be accentuated by an convenient means, if this is found to be a vantageous.

A s ecially good electrical connection is electe' between the fingers 2() and the shortcircuiting ring 21, since these parts are relatively stationaryl at 4all times, and since the centrifu al forces exerted during the operation of t e motor tend to increase the pres sure between the fingers and the interconnectin ring on account of the spring structure o the lingers.

By connectin'a suitable resistance to the stationary bruslies 11, 12 and 13 and separating the short-circuiting rin from the brushes, the motor may be ecce erated, and when the current supplied to the motor is suiliciently decreased, the resistance and also the collector rings may be short-circuited by moving the ringZl into engagement with the brushes 20.

The segments 1.4, 15 and 16 are provided with projections 32 which may be connected by conductors 32S to suitable points in the winding 4.

Special reference may now be had to Figs. 4 and' 5, in which three-phase alternating current energy is supplied from a generator 34 tothe primary windings 1 of the motor. Suitable points in the secondary winding 4 are connected to'thc conducting segments 14, 15 and 16 and the slip rin '8, 9 and 10 'are severally connected by stationary brushes 11, 12 and 13 to external resistances 35.

Each o the conducting se ments is provided w h a' forked switch lade 36 that is adaptelllk-to be engaged by a knife blade 40, disposed'upon the conducting ring 21. The ring 21 may be moved so as to eect the en;

g'agement and disengagement of the coperating contact members by means of a plunger 41 which is located in a hole in the shaft and is connected to the ring by means of a cross strip 42 that extends through a slot in the shaft 5 and is attached at its middle point to the end of the plunger 41.

It may be found d'esirab e to provide a nick-acting circuit making and breaking evice for these contacts but, as such arrangements are well known, I deeml it unnecessary to show a device of this character applied to the contacts in question. 4

It will be understood that the device described is not restricted in its use to a threephase winding and that various modifica'- tions may be effected. For example, it may be desirable to ground one of the collector rings and to provide similar Ameans for interconnecting the other collectors.

Variations in the size and arrangement of 'parts may also be effected within the scope ibi m invention, and I desire that` onlysuch limitations'shall be imposed as are indicated in the appended claims.

I claimas my invention:

1. AIn an electric motor, the combination with a stationary member having a primary winding, a rotatable member having a secondary windingand collector rings colinected' thereto, stationary brushes for the rings and an external resistance connected to t ie brushes, of contact fingers having supporting members that are electrically connected to the several rings and vare'provided with longitudinally spaced notches, of interconnecting means for the fingers com rising an adjustableK short-circuitlng ring aving aninternal cylindrical contact surface, non-rotatable means for adjusting the ring to make and break engagement between its contact surface and the outer' faces ofthe fingers and accentuating fingers secured to` the short circuiting ring to engage either *he inner or the outer notches 1n the supporting members for the contact fingers.

2. In a dynamoelectric machine, the coinbination with a. plurality of collector rings, and stationary engaging contact brushes therefor, of a short-circuitirig means for said rings compris-in a. plurality of groups of resilient contact ngers having supporting members that are severally connected to the collector rings andare provided with longitudinally spaced notches, a short-circuitmg rin iaving an internal cylindrical contact sur ace, means for moving said ring to make and break engagement between its contact surface and the outer faces of said contact fingers and accentuating fingers carried by sald short-circuiting ring to engage said notches.

3. In an electric motor,V the combination 'with a rota-table member, a plurality of collector rings which are stationary relative thereto and are insulated therefrom and of the operation of the machin and fingers from each other, groups of flexible contact fingers having supporting members that are severally connected to the collector rings and are several] provided with two longitudinally space notches, and a short-clrcuiting ring having a cylindrical contact surface, of means' for moving said shortcircuitng ring to make and break engagement between its contact surface and the faces of the contact fingers, independently carried y the short-circuiting ring to en; gage said notches for accentmatingl the adjustment positions thereof.

4. In a dynamo-electric machine, the combination with a rotatable core member having a cylindrical shaft, a bushing or sleeve fixed to the shaft and collector rings mounted on said bushing, of a plurality of com ducting segments disposed about the bushing and having longitudinally spaced notches in their outer surfaces, groups of resilient contact fingers attached to the rel spective segments and projecting therefrom substantially parallel to the shaft, adjustable interconnectin means for engaging the outer surfaces of the fingers and accentua ing fingers secured to the ad'ustable interoonnectlng means and adapte to engage he notches in the conducting segments.

5. A dynamo-electric machine comprising a stationary member a rotatable core mem ber having a cylindrical shaft, a bushing or sleeve fixed to the shaft, collector rings mounted 'on said bushing and insulated therefrom, a plurality of conducting segments equally disposedabout the bushing and corresponding m number to the rings to which they are severally'connected and having notches in their outer surfaces, groups of contact fingers attached to the respective segments and projecting therefrom substantially parallel to the shaft, a ring adjustably mounted upon the shaft and having an internal cylindrical contact surface, means for moving the ring to effect simultaneous engagement between its contact surface and the outer faces of the fin rs and accentuating fingers secured to t e adjustable ring and adapted to engage the notches in the conducting segments.

6. A dynamo-electric machine comprising a stationary member, a rotatable core member having a cylindrical shaft, a bushing or 4sleeve fixedv to the shaft, collector rings ed u on the shaft at one end of the bushing,

a co lar adjustably mounted upon the sha at the other end of the bushing, rods which connect the adjustable members and extend through holes in the bushing, and means for moving said ring into and out of engagement with the contact fingers.

7. In a dynamo-electric machine, the combination with a stationary member, of a rotatable core member having a cylindrical shaft, a bushing' or sleeve fixed to the shaft, collector rings mounted on said bushing and insulated therefrom, conducting segments symmetrically disposed about the bushing and corresponding in number to the rings to which they are severally connected, contact fingers attached to the segments and projecting therefrom, a ring adjustably mounted upon the shaft at one end of the bushing, a collar adjustably mounted upon the sha. t at the other end ofthe bushing and rovided with an annular groove, rods w ich connect the ad'ustable members and extend through holes in the bushing, and a forked lever which projects into the groove in the collar and by which the ring may be moved into or out of engagementwith the Contact fingers.

In testimony whereof, I have hereunto subscribed my name this 30th day of July, 1906;

WILLIAM EDGAR REED.

`Witnesses:

GEO. A. SAA'rnorr, Binner Hines.

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