US1545673A - Damper winding - Google Patents

Description

July 14, 1925.

R. A. M CARTY DAMPER WINDING Filed Nov. 5. 1923 INVENTOR Roy A./7-"Car7fy B! M ATTbRNEY WITNESSES:

% "M RMQQM Patented July 14-, 1925..

, 1,545,673 PATENT QFFICE.

nor a; masonry, or 'wrnnmsnoae,

PENNSYLVANIA, ASSIGNOB- T0 WESTINGHOUSE ELECTRIU;& MANUFACTURING- COMPANY, A CORPORATION OF PENNSYLVANIA.

DAMPER WINDING.

Application filed November 5, 1923. Serial No. 672,884.

provided with short-circuited damper wind-' ings or starting windings.

a machine of the above-described character having a rotating field member provided with an improved cage winding which shall be of an electrically eflioient and mechanically strong construction and -which shall permit the disassembly of the rotor without mg. a

Another object of my invention is to provide a damper winding for machines of the above-descm (1 character com rising a plurality of integral groups of, amping condestroying or damaging the damper windductors and detachable, unitary short-circuiting members for effecting a short-circuiting connection between the individual groups.

A still further object of my invention is to so supportthe damper winding upon the' rotor as to secure the same aga nstexcessive strains imposed thereon by centrifugal force, while providing also a argle radiating surface for dissipating the eat generated in the winding.

The damper windings of synchronous machines, while in themselves simple and not complicated elements of the machines, must conform to certain very definite requirements in order to perform satisfactorily the functions for which they are designed. The electrical resistance of the winding must, for certain conditions, be low and the-heatradiating surface must be suificientto d1ssipate theheat generated in the windings by the dampin currents flowing therein. Since the co rifugal force exerted upon the winding, especially in. cases of high speed machines, may assume large values,

particularcare must be taken also to avoid the addition of unnecessary weight to the,

winding and to make the same mechanically strong.

Improvement on both sides of improved mechanically and It is also desirable that the salient pole members of such machinesshall be easily detached and disassembled without destroying or seriously damaging the dam er winding. In prior structures, it has en proposed to secure the conducting damper bars,

which are embedded in the pole faces of the polar projections, to short-ci'rcuiting rings the rotor, by means of screw bolts. Such constructions are not very dc sirable since, on account of the size of the conductor, the screw bolts are necessarily I I small in diameter and give thus only a small One object of my invention is to provide degree of mechanical security, while adding exerted thereupon.

I have found that the performance of the damper winding may be, considerably electrically, without sacrificing any advantages in respect to the ease of. disassembly of the rotor. To this end I provide for. each pole member, a separate damping group consisting of individual conductors embedded in. the pole face and a pair of short-circuit.- ing segments which are welded or brazed to the conductors on both} sides fthereof. Each damping group thus constitutes an integral damping element of high conductivity and of a mechanically strong structure. The individual damping groups are short-circuited by means of specially constructed unitary short-circuiting rings which are clamped thereto by means of a relatively small number of easily detachable screws,

. thus permitting the disassembly of the rotor without the destruction'of the winding.

With the foregoing and other objects in view, my invention consists of the arrangements and details of construction hereinafter described and claimed and illustrated in the'accompanying drawing, wherein Figure 1 is a view in elevation of a portion of a salient-pole rotor member of a dynamo-electric machine provided with a damper winding constructed in accordance with my invention;

Fig. 2 is a sectional view of a pole member illustrated in Fig. 1 taken along the line II-.II thereof; and

Figs..3 and 4 are similar views illustratin modifications of my invention.

Tn Figs. 1 and 2 is shown a rotating field member of a dynamo-electric machine, comprojections areprovided'with axially-extending, partially closed slots 9, in which -are.embeddedconductor members 10 projecting beyond both ends of the slots. It will be noted that the upper portions of the end plates tare provided with fingers 11 forholding'and clamping together-the slotted part of the laminations.v 1

Short-circuiting segments'12, of angular cross-section, are provided on both sides of the end plates 4 1n such manner as to support the damper structure and at the same each polarprojection'and have shoulders 13 hearing against projecting portions 14 of time allow for expansion of .the damper bars 10 when they are heated. The outer peripheral surfaces 15 of the short-circuiting segments are so arranged as to be alined with the under surfaces of the projecting damping conductors "10. The conductors 10 are 'welded or brazed to theshort-circuiting segments at their contactingsurface 15 and thus constitute a unitary structure of highconductivity which is self-supporting witln out the need of additional fastening, bolts. A short-circuiting ring 16 is mounted within the cylindrical space which is bounded by the angular short-circuiting segments 12, the cross section of the ring being substantially rectangular and fitting into the rectangular space enclosed between the two arms of the angular short-circuiting segments. T The ring makes contact with the entireinner surface 17 of the short-circuiting segments, thereby assuring a perfect and reliable electrical contact. The rings 16 are furthermore clamped by means of bolts 18 to the individual segments and constitute the short-circuiting connection between the segments, thus completing the damper winding.

By means of my construction, the indlvrdual dampinggroups and the damping winding as a Whole, have a maximum of conductivity and, therefore, a maximum of efi'ectiveness, which is obtained without-the use ofan excessive number of bolts and, at the same time, the readily detachable shortcirculting rings 16 do not interfere with the disassembly of the rotor member. By means-of my construction, I also obtain a high degree of mechanical strength while providing a maximum radiating surface for dlssipating the heat generated in the winding, since most of the surface of the damperwinding structure is indirect contact with the air and moves in the same. a

In Fig. 3 is shown a modification of my invention in which the short circuiting ring 19 is not made solid in cross. section, butfinstead, is a helically wound copper strap conductor 20. The copper strap preferably has a small thickness and a fairly great depth for increasing its mechanical strength 1n the direction 1n which it 1s exposed to excessive centrifugal forces.

V The coils or 5 layers of the short-circuiting ring may be riveted or welded together, and I may also or mechanical strength. The mechanical strength of the ring 19 is suflicent to withstand the stresses in the unsupported portion between the individual poles, while aflording liberal radiating surfaces for dissipating the heat generated in the winding.

In Fig. at is shown a modification of m invention comprising a somewhat simplified construction which is employed in medium speed machines. ductors10 are welded or brazed to short- The short-circuting concircuiting segmentsg23 ofangular form. On

account of the lower speed at which the construction is operated, I dispense with the shoulders 13 used in the constructions illustrated in Figs. 2 and 3, obtaining thereby a cheaper unit. A metallic ring 24 is clamped to the individual segments 23'by means of bolts 18 and short-circuits the individual damping groups upon the several pole members.

My invention is susceptible of various other modifications and changes and I desire. therefore, that only such limitations shallbe placed thereupon as are imposed by the prior art or set forth in the appended claims. 4

I claim as my invention:

1. In a dynamo-electric machine, a rotor member comprising a central body portion, a plurality of detachable polar projections secured to said central body portion, axially disposed conductors in the pole faces of said polar pro ections, a pair of short-circu ting segments for each polar projection, said segments being integrally united with the end portions of said conductors, a pair of continuous annular short-circuiting members-disposed on both sides. of said rotor respectively, and means for detachably clamping said short-circuiting sex;

' posed toward said end merits to said annular short-circuiting members.

2. In a dynamo-electric machine, a rotor member comprising a central body portion, a plurality of detachable pdlar projections secured to said central body portion, each projection being provided on both sides thereof, with end plates having at their outer ends outwardly projecting lips, shortcircuiting segments of angular cross-section for each side of each polar projection, one side of said angular segments being displates and provided with a projecting member bearing outwardly against said lips, the other side of said segments being in contact with the end portions of said conductors and integrally united thereto for short circuiting the same, unitary continuous short-circuiting rings fitting into the circular spaces bounded by said segments and means for detachably clamping said rings to said segments. 7

3.111 a dynamo-electric machine, a rotor member comprising a central body portion, a plurality of detachable polar projections secured to said central body portion, each projection being provided on both sides thereof, with end plates having at their outer ends outwardly projecting lips, short circuiting segments of angular cross-section for each side of each polar projection, one

side of said angular segments being disposed toward said end lates and secured to the same, the other si e of said segments beingin contact with the end portions of said-conductors and integrally united thereto ,for short-circuiting the same, unitary short-circuiting rings fitting into the circular spaces bounded by said segments, the cross section of said rings being such as to fit into the angular spaces of said segments and make contact over the entire surface of the same, and detachable means for clamping said rings to said segments.

,4. A rotating field member for a dynamo-electric machine, comprising a salientpole core member, field-magnet coils thereon, the salient pole members having overhanging pole-face members thereon, a damper unit on each salient-pole member comprising conductor bars embedded in the pole-face portion thereof and a short-circuiting segmental member permanently united to the ends of said bars on each end of the, salient-pole member, and continuous short-circuiting rings detachably united to the respective short-circuiting members of all of the salient-pole members at each end of said rotating field member.

In testimony wliereof, I have hereunto subscribed my name this th day of October 1923.

ROY A. McCARTY.

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