US1075502A - Commutator for dynamo-electric machines. - Google Patents

Description

T. s; SCOTT. Y GOMMUTATOR FOR DYNAMO'ELBGTRIC MACHINES. APPLICATION FILED DEU. I4, l908.`

Y Patented Dot. 14, 1913.

WITNESSES:

d IENTO 2PZ-Q ATTORNEY UNITED sTETEs PATENT oEETcE.

THOMAS S. SCOTT, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMIANY, A CORPORATION OF PENNSYLVANIA.

COMIVIUTATOR FOR DYNAMIC-ELECTRIC MACHINES.

Specification of Letters Patent.

Patented Oct. 14, 1 91.3.

Application filed December 14, 1908. Serial No. 467,463,

To L7/Z tolto/m it may concern.'

Be it known that I, Tnoinxs S. SCOTT, a citizen of the United States, and a resident or" Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Commutators for Dynamo-Electric lilachines, of which the following is a specification.

My invention relates to commutatore for dynamo-electric machines, and it has for its object to 'provide a simple device of this character which shall be specially adapted for use with machinesl to be operated at relatively high speeds, by steam turbines, or otherwise.

1Vhen large machines of the commutator type are operated athigh speeds, the devices usually employed for clamping the commutator bars in position are inadequate, by reason of the very large centrifugal force to which the comniutators are subjected. AC- cording to my present invention, I provide a plurality of rings which severally comprise a large number of turns of steel band Wire and are located either on the surface of the commutator cylinder or in annular grooves in said surface for the purpose of holding the bars or segments securely 1n po sition, the rings being suitably insulated from the commutator cylinder to avoid short-circuiting the commutator bars.

Figure 1 of the accompanying drawings is a longitudinal section. of one-half of a com' mutator cylinder constructed in accordance with my invention, and Fig. 2 is an en- .larged sectional view ot one of the binding rings shown in Fig. 1. Fig. E is a View similar'to Fig. 1 but illustrating a modification of my invention and Fig. 4.- is a sectional View of one of the binding rings sloivn in Fig. 3.

Referring to Figs. 1 and 2 of the draw-- ings, the mattei illustrated comprises an i armature of a dynamo-electric machine having a magnctizable core membernl, end rings 2, a supporting frame or spider 3 and ai connnutator cylinder 4. The commutator cylinder et comprises a cylindrical projec tion 5 of the spider 3, a plurality of bars or segments 6 which are mounted on the surface of the cylinder 5 and are separated therefrom by a bushing I of insulating material. Each ot the bars-G is provided. with a neck or connector which extends radially outv ard from its inner end and with a notch 9 at its outer end. vVhen the bars are assembled, the notches 9 forni a cylindrical projection 91 at the outer end of the commutator cylinder, the diameter of which is somewhat lessy than that of the contact. surface of the cylinder'. The bars (3 are held in position. by rings 10 and 11 which encircle the cylinder, one being disposed adjacent to the necks 8 and the other being located on the cylindrical projection 9a. The rings 10 and 11 are separated from the bars 6 by stripslQ of insulating material and' each of them comprises a metal ring 13 ot' U-shape in cross section, which may be split transversely or composed of a plurality of segments, a large number of turns or convolutions l'of steel band Wire and a superposed metal ring 15, which may also be either split or of segmental structure, the edges of the ring 13 being bent inward tohold the ring 15 in position. The splitting of either or both oi' the rings 13 and 15 or the dividing of them, or either of them, into a plurality of segments is a matter of expediency in manufacturing and assembling, and neither structure is presented as a feature of patentable novelty. After the rings 10 and 11 are formed, as above indicated, each of them is provided With a Wrapping 1G of insulating material which is overlapped on the outer cylindrical surface 'of the ring and is held in position by a layer of convolutions 1.7 of twine or cord, a linal covering 18 being` Wrapped around the circuinterence of the ring on top of the cord and held in position by sewing to the insulating Wrapping 16. lVhen the rings 10 and 1l are completed, they may be handled in the saine Way as a solid metal ring so that it it is desired` to dismem'ber the coininutator, for any reason, the rings may be heated until they expand suiiciently to be readily removed from the commutator cylinder. The rings 10 and 11 are preferably constructed by Winding the necessary Aconvoll'itious of bandwire upon the U-shaped rings 18 after the latter and the Wrappings 1G have been placed in position upon the commutator cylinder. The sides of the metal rings 13 are preferably slotted to form fingers 132L which may be easily bent over the edges of the ring 15.

)teterring to Figs. 3 and 4; of the drawings, commutator bars or segments 19 are mounted on a bushing 20 from which they are separated by means of insulating rings 2l. The bushing 20 is provided with an .enlargement 22 having a truste-conical outer surface, and a ring 28, having a similar ouixfisurface, is mounted on the opposite en d of the bushing. The position of the ring 23 may be varied by means of an adjusting nut 24 which is screwed upon the outer end of the bushing 20. The inner edges of the bars or segments '19 are adapted to fit against the frusto-eonical surface provided by the enlargement 22 and the ring 23 and the segments are of Wedge shape in cross section so that they may be readily assembled to 'form a, cylindrical eonnnutator structure, in the usual manner. The commutator cylinder is provided with a plurality of annular grooves 25 which are intended to receive suiiicient turns 26 of steel band wire to hold the bars in position. The walls of the grooves are first insulated by means of rings 27 of U-shape in cross section. A similar ring or casing 28 of sheet brass is fitted into the insulating ring 27, the band Wire being disposed Within the brass Veasing which is intended to prevent injury to the insulation by the band Wire. Afterdhe band Wire is' Wound upon the brass rings, the cas-ing is closed by bending tlle/ edges of said rings over a cover strip 29, an insulating strip BO being held in position by any suitable means such as a layer of ttt'ine. 3l. Bylproperly designing the grooves 25 to receive the necessary nana wire and insulation, the surface of the insulating twine may be substantially flush with the cylindrical surface oithe commutator. It will, of course, be understood that the parts 27, 28, S29 and 30 will be severally split transversely or composed of a plurality of segments in order that they may be as sembled in the grooves 25.

I desire that structural modifications which do not depart from the spirit of my invention shall be included Within its scope.

l Claim as my invention:

l. A commutator comprising a plurality of bars or segments and a plurality of clamping rings therefor, each of Which comprises eonvolutions of Wire, a sheet nie-tal easing for the Wire and an insulating casing for the sheet metal.,

2. A commutator compris-ing a cylindrical bushing, a plurality ot bars or segments mounted thereon and insulated therefrom THS. S. SCOTT, l'Vitnesses F. C. HALL, Binner Hines.

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