US931130A - Commutator for dynamo-electric machines. - Google Patents

Description

B. G. LAMME.

COMMUTATOB POB. DYNAMO ELECTRIC MACHINES'. ArPLIo'ATIoN FILED 00T'. '1, 1908.

UNITED srArEs PATENT oEEIoE.

BENJAMIN G. LAMME, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR, BY MESNE ASSIGNMENTS, TO WESTINGHOUSE ELECTRIC A: MANUFACTURING COMPANY, OF EAST PITTSBURG, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

COMMUIATOR FOR DYNAMIC-ELECTRIC MACHINES.

To all whom it may cof/wem:

- Be it known that I, BENJAMIN G. LAMME, a citizen of the United States, and a resident of Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Commutators for Dynamo-Electric Machines, of which the following is a specication.

My invention relates to dynamo-electric machines of the commutator type and it has for its object to provide a simple device of this character that shall be specially adapted for use with high speed machines of large capacity, such as direct current turbine-driven generators.

In order to obtain a relatively large working surface without abnormally increasing the total length of the commutator, it has heretofore been proposed to so construct the coi'mnutator as to provide annular projections having a plurality of exposed plane surfaces which are perpendicular to the axis. Connnutators constructed in the manner ust referred to are very hard to ventilate and consequently tend to become over-heated in operation.

According to my present invention, I have so improved the construction of the commutator that the centrifugal forces to which it is subjected,v when operating at highv speeds, are completely counteraeted and a forced circulation of air is automatically established where it is most useful for cooling purposes.

Commutator cylinders of the usual type have sometimes been cooled by forcing air across their working surfaces parallel to their axes but this method is found to be ineffective under high speed operation because the cool air is thrown from the snrfaces centrifugally.

rIhe segments of my improved commutators are of unequal depths so that ventilating ducts parallel to the aXis are thus formed and I connect the shallow segments in longitudinal rows by any suitable means, such as relatively thin conducting strips disposed in radial planes, said strips being either integral with or fastened to the vbars and separated by radial passages that communicate with the aforesaid ducts.

IVhen the commutator is in operation, the warm air adjacent to the working surfaces of the connnutator is thrown outward by Specification of Letters Patent.

Appneaaon sied october 7, 1908.

Patented Aug. 17, 1909.

Serial No. 456,556.

centrifugal action and cool air is taken in at the ends of the commutator through the longitudinal ducts, a circulation of air being thus established.

My improved method of ventilating commutators is not restricted in its application to connnutators of the so-called radial t-ype and may be employed with similar devices of any well kno wn construction.

Figure l of the accompanying drawings is a longitudinal section of a portion of a connnutator constructed and ventilated in accordance with my invention. Figs. 2 and 3 are sectional views on the lines II-II and IIIIII of Fig. l.

Referring to the drawings, the device here illustrated comprises a substantially cylindrical sleeve or bushing l and a plurality of notched bars or segments 2 which are mounted on the .bushing in radial planes and are separated therefrom by an insulating sleeve il. The bars 2 are similar to each other and the notches 4f with which they are provided are so cut that the edges of the bars adjacent to the notches lie in parallel planes to form contact surfaces perpendicular to the axis of the connnutator and so that the projections 5 form a plurality of rings. l

The outv-Jardly projecting portions of adjacent bars are separated from each other by wedge blocks 6 which constitute shortbars, and serve to complete the ring projections. The blocks G are connected in longitudinal rows by relatively thin conducting strips 7 and are relatively shallow so that they are materially separated from the bushing l to provide longitudinal ducts l2.

The outer edges of the strips are fitted into .notches 8 in the bottoms of the blocks 6 and are held in position by rivets S), the arrangement of parts being such that the botto-nis of the notches l in the bars 2 lie in substantially the saine cylindrical surface as the outer edges of the narrow strips.

The inner edges of the connecting strips 7 are preferably rounded and insulating channel strips l0 of U-shaped section are iitted over the portions of the strips 7 which are directly under the wedge-blocks, said blocks being separated from each other and from the bars or segments by thin plates or layers .l1 of insulation, which lie in radial planes.

Between adjacent wedge-shaped blocks in the same row, the strips 7 are some distance apart, the spaces between them being unobstructed in order that radial Ventilating passages 13 may be provided to communicate with the ducts 12. The outer ends of the annular projections or rings 5 are finished into cylindrical surfaces on which steel shrink rings 14 are mounted. The rings 14 are insulated from the commutator segments by wrappings or sleeves 15 of insulation and their inner edges are provided with annular recesses 16 in which insulating rings 17 are located in order to increase the surface distance between the bars and the rings.

Each of the bars 5 and blocks G which constitute the inner annular ring projection 5a is provided with an outwardly extending neel; 18 of conducting material by which it is connected to the coils of the dynamoelectric machine of which the commutator forms a part.

The inner end of the bushing 1 is provided with a clamping tf-ring 19 which is screw-threaded onto the bushing and engages suitable recesses Q0 in the ends of the bars. A second t -ring 21 is provided at the opposite ends of the commutator and engages recesses 22, in the commutator bars, the rings being forced toward each other by set screws 23 which are screw-threaded through a collar or wiper-ring 24 that is held in position by a key 25. The `v-rings and the wiper-ring are all provided with annular segmental openings 26 which are in alinement witthe longitudinal passages 12.

rEhe V-rings are made relatively light since the shrink-rings 14 are adapted to oppose the centrifugal forces which tend to displace the bars when the commutator is in operation. Y

lt will be understood that structural modifications may be eifected within the scope of my invention, if desired.

l claim as my invention:

1. A commutator comprising a bushing or cylinder, a plurality of notched bars or segments disposed on the surface thereof in radial planes to form annular projections and means for establishing Ventilating passages longitudinally adjacent to the surface of the bushing and radially between the annular projections.

2. A commutator comprising a bushing or cylinder, a plurality of notched bars or segments disposed on the. surface thereof in radial planes to form annular projections, wedge blocks interposed between the bars or segments in the annular projections for establishing Ventilating passages longitudinally adjacent to the surface of the bushing and radially between the annular projections.

3. A commutator comprising a plurality of notched bars or segments radially disposed and separated by relatively short wedge-shaped blocks located adjacent to the notches and electrically connected in longitudinal rows.

4. A commutator comprising a bushing or cylinder, a plurality of notched bars or segments disposed on the surface thereof in radial planes to form annular projections, wedge-blocks interposed between the bars or segments in the projections and relatively thin strips of conducting material joining the inner ends of the wedgebloclrs in longitudinal rows.

5. ln a commutator, the combination with a plurality of notched segments or bars assembled in radial planes'to provide a series of wedge-shaped projections, of wedgeblocks interposed between the projecting ends of the bars, relatively thin conducting strips connecting the blocks in longitudinal rows and shrink rings mounted on'the annular project-ions and insulated therefrom.

6. A commutator comprising a bushing or cylinder, a plurality of radial bars mounted thereon, relatively short wedgeblocks constituting bar segments and interposed between the bars at intervals to provide longitudinal and radial passage ways., said blocks being electrically connected in longitudinal rows.

7. A commutator comprising a bushing or cylinder, a plurality of radial bars mounted thereon and notched to provide annular projections in the commutator, relatively short wedge-bloclrs, constituting bar segments and interposed between said notched barsin said annular projections for establishing Ventilating passages longitudinally adjacent to the surface of the bushing and radially between the annular projections.

ln testimony whereof, l have hereunto subscribed my name this 30th day of Sept.,

BENJ. G. LAMME. Witnesses:

E. LIVINGSTON, BIRNEY Hines.

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