US1227414A - Dynamo-electric machine. - Google Patents

Description

A. B. FIELD.

DYNAMO ELECTRIC MACHINE.

APPLICATION FILED nzc. 31. 1913.

1 ,227,41 4. Patented May 22, 1917.

2 SHEETS SHEET 1.

INVENTOR WM 7 ATTORNEY UNITED STATES PATENT oEEIoE.

ALLAN BERTRAM FIELD,-OF LONDON, ENGLAND, ASSIGNC R T0 \VESTINGHOUSE ELEC- TRIO AND MANUFACTURING COMPANY, A CORPORA'IZGN OF PENNSYLVANIA.

DYNAMIC-ELECTRIC MACHINE.

Application filed December 31, 1913.

To all whom it may concern:

Be it known that I, ALLAN B. FIELD, a subject of the King of England; and a resident of London, England, have invented a new and useful Improvement in Dynamo- Electric Machines, of which the following is a specification.

My invention relates to dynamo-electric machines and it has special reference to coll-retaining wedges adapted for use in such machines. a

One object of my invention is to provide a magnetizable core for dynamo-electric machines which shall permit of-ready and rapid winding of the coils therein andshall embody means for easily and securely maintaining the coils'in position.

Another object of my invention is to provide a machine of such construction that its internal reactance is appreciably increased, a characteristic which is of great value upon the occurrence of a sudden short-circuit of the machine.

A; further object of my invention is to secure, during operation, an approximately continuous area of magnetizable material adjacent to the machine air gap. The advantages ofthis closed slot construction,- in the line of improving; the operating characteristics of a machine, are wellknown to those skilled in the art and need not be eX- plained here.

Another object of myinvention is to remove the working conductors from the active field that is always present in the top of the core slots.

A further object of my inventionis to provide a coil-retaining wedge which shall be economically and readily manufactured, conveniently assembled and insulated in the machine, and which shall have. atendency to increase its wedging action when subjected to the inevitable 'magnetic pull of the field polar projections during operation. A still further object of my invention is to provide a wedge of the above-indicated characterwhich shall embrace means for allowing a full and suitable ventilation and cooling of the wedge itself and of the adj acent portions of the core and coils.

Accordingly, I have devised a machine core and a magnetizable coil-retaining wedge which mutually coact to fulfil the ends in view. In addition to the customarily provided coil-containing slots in the core, I

Specification of Letters Patent.

Patented Hay 22,1917. Serial No.- 809,596. r

provide contiguous and relatively deep openings substantially trapezoidal or wedgeshaped in form and disposed radially with.- out the slots. The well-known advantages of open slots for winding are thus provided.

The associated wedge is laminated, is substantially trapezoidal in form, having large flat surfaces, and has a longitudinal aperture therethrough for purposes of ventilation, ashereinbefore mentioned. It will be noted that the coils are thus disposed at an appreciable distance from the machineair gap proper, thereby considerably increas ing ,the effective air gap and internalflre actance of the machine. and excluding. the working conductors from the cross-flux inthe tops of the slots. Also, a' practically unbroken area. ofmagnetizable material confronts the air gap, thus securing for the machine the closed slot effect and advan-' cages. a

Moreover, wedges constructed as indicat above may be readily driven into the receiying openings, and the problem of insu latlon from the core is a simple one to solve,

since fish paper or other similar material may be conveniently positioned by reason of the large fiat surfaces of the'wedge. Again, the form and disposition of the wedge is such as to increase its wedging action when magnetically attracted during og eration toward the air gap, as will be rea Furthermore, a considerable view, partially in section, of the core of a d namo-electric machine embodvin my invention; Fig. 2 is a view, in end elevation, and Fig. 3 is a view, in longitudinal section, with parts broken away, of a wedge constructed in accordance with my invention; Fig. 4- is a view, in elevation, of the type of lamination employed in the Wedge shown in Figs. 2 and 3; Fig. 5 is a view, in perspective, of a complete Wedge; and Figs. 6 and .7 are yiewg; in end elevation and in side elevationwith a portion broken away,

clamping respectively, of a modification of my invention.

Referring to the drawings, the portion of a dynamo-electric machine here shown cornprises a preferably laminated core 1. having a plurality of slots 2 within which coils 8 are disposed and a plurality of contiguous, relatively deep Openings 2 that are substantially trapezoidal in form and are disposed radially without the slots 2, and a plurality of wedges 4: severally disposed in the openings 2. A plurality of longitudinally disposed ventilating openings 5 and of radially disposed communicating openin s (not shown) are preferably employed.

he wedges 4: severally comprise a plurality of apertured and substantially trapezoidal laminations 6, a pair of apertured end-plates 7 and a plurality of rivets 8 for the laminations intermediate the end plates.

The laminations 6, best shown in Fig. 4-, are preferably of magnetizable material and severally comprise two non-parallel. side walls 9 and substantially parallel, relatively narrow, upper and lower integral bridging members 10 and 11, respectively. A relatively large internal aperture l2 is thus formed, and two contiguous arcuate slots 13 6 30 are disposed adjacent to the ends of the longer parallel side of the lamination, for a purpose hereinafter described. the complete internal opening thus being substantially of acorn-shape and leaving a. margin of material on all sides sufficiently only for adequate mechanical stiffness and for conveyance of the intended flux.

The'end-plates 7 are preferably of nonmagnetizable material and have a substantially oval aperture 14 having an internally disposed flange 15, and a pair of" openings 16 that register with the slots 13, for a purpose hereinafter explained.

The rivets 8 are preferably tubular and of high-resistance non-magnetizable material to minimize the eddy current losses there.

in. Moreover, the rivets are severally disposed in the arcuate slots 13, which, it will be noted are located a considerable distance from the path of the active cross-flux in the slot tops.- Consequently, it has been found unnecessary to insulate the rivets from the laminations. The ends of the rivets extend through the openings 16 and are suitably turned over upon the outer surfaces of the end-plates 7, thereby tightly clamping the laminations intermediate the end plates. The completed wedge 4 is thus rugged, compact and entirely self-contained, and its relatively large, flat surfaces may be readily and economically insulated from the core. Fur- "7', in which a modification of my invention is shown, Such a construction may be employed to advantage in core slots wherein a very tight fit is desirable. In addition, the majority of the advantageous features heretofore enumerated in connection with the preferred form of my invention are also incorporated in the wedge 17 of Figs. 6 and 7.

The laminations l8 embodied in the wedge 17 severally have three sides surrounding an internal aperture, and the fourth or upper side is partially open and is adapted to receive an auxiliary wedging member 19 that may be driven into place after the wedge proper has been suitably positioned in the core, thereby causing the main wedge to tightly enga the core teeth. A plurality of hollow rivets 20 preferably insulated from the laminations to reduce eddy current sire that only such limitations shall. be im-v posed as are indicated in the accompanying claims.

I claim as my invention:

1. A coil-retaining wedge for dynamoelectric machines comprising a plurality of similar substantially trapezoidal lamina-. tions having registering apertures and a plurality of arcuate slots located in the base portions of said laminations and a plurality of tubular rivets disposed in said slots for securing said laminations together.

2. A coil-retaining wedge for dynamoelect-ric machines comprising a plurality of similar substantially trapezoidal laminations of magnetizable material having registering apertures and a. plurality of arcuate slots located in the base portions of said laminations, a pair of apcrtured end-plates of nonmagnetizable material and a plurality of tubular rivets ot' non-magnetizable material disposed in said slots for clamping said laminations and said end-plates together.

In testimony whereof, I have hereunto subscribed my name this tent-h day of December 1913.

A. SCAM-IEWAILLE, VJ. J. Snnn'rrn.

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