US1272420A - Turbo end bell. - Google Patents

Description

Patented July 16, 1918.

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R. E. GILMAN.

- TURBO END BELL.

APPLICATION man MAR. 4. I915.

Patented July 16, 1918.

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. UNITED STATES PATENT oFFioE.

RALPH E. GILIVIAN, OF PITTSBURGH, PENNSYLF'ANIA, ASSIGlN'OR TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

TURBO END BELL.

It all whom it may concern:

Be it known that I, RALPH E. GILMAN, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pemisylvania, have invented a new and useful Improvement in Turbo End Bells, of which the following isa specification.

My invention relates to inclosing end members or end bells for dynamo-electric machines, and it has for its object to provide an end bell in which the heating caused by ma netic conditions within the dynamo electric machine is reduced to a minimum.

A further object of my invention is to provide a device that is simple and ineX- pensive to construct and which may be readily embodied in existing types of end bells and thereby improve the efficiency and operating characteristics of the associated dynamo-electric machines.

In the design and construction ofdynamoelectric machines and especially of turbo generators of large capacity it has been found desirable to provide end bells that completely inclose the end port ions'of, themachine, owing tothe necessity of having the "entilating system under pressure. I The iron or steel end bells that'have heretofore been employed have been subject'to excessive heating caused by fringing magnetic lines of force from both the field magnet and armature members of the machine that enter the end bells in a direction substantially normal to the faces thereof- The eddy currents produced by the above fringing magnetic field are particularly noticeable in turbo generators of a well-known type of construction in which the end portions of the armature coils extend beyond the core and into theend bells.

'The above-mentioned objections may be overcome by the obvious expedient ofmoving the end bells far enough away from the field magnet and armature members to limit the number of magnetic lines of force entering them to a reasonable value. The use of such expedient is, however, open" to serious objections for the reason that it necessitates a further separation of the shaft bearings, and it is well known that, in the design of high-speed turbo generators, the distance between bearings should be reduced to the smallest possible limit.

By my invention, I propose to eliminate Specification of Letters Patent.

mentioned an outwardly what larger than that of the Patented July 16, 1918.

Application filed March 4, 1915. Serial m5. 12,132.

the heating due to the circulation of eddy currents in the end bells, and to provide end bells that may be mounted as closely to the field magnetand armature members as may be desirable, thereby allowing the shaft bearings to be brought as closely together as clearances will permit. In the construction bf an end bell in accordance with my invention, that portion of the end bell adjacent to the field magnet and armature members is formed of non-magnetizable and insulating materials for the purpose of eliminating the objectionable eddy current losses. The complete end bell is preferably formed of two half sections to facilitate its assembly.

In the accompanyingdrawings, Figure 1 is aview, in front elevation, of a'portion of an end bell constructed in accordance with my invention; Fig. 2 is a View, in side elevation, of an end bell mounted on the stator of a dynamo-electric machine; Fig. 3is asectional View along the line CD of Fig. 1; Fig. i is a sectional View. along the line AB of Fig. 1; Fig. 5 is a sectional View along the line EF of Fig. 1, and Figs. 6, 7 and 8 are detail views of parts of the structure shown in Fig. 1. "A dynamoelectrie machine comprises a stationary armature member 1 provided with apluralityof windings 2, and a field magnet member-3 rotatably mounted on a shaft 4. A half-section 5 of an end-bell member, preferably formed of cast iron or any other suitable material,is provided with projecting flange 6 that is adapted to be secured to the stator frame 1 by means of a plurality of bolts 7 and is disposed betWeen the field-magnet member 3 and the pedestal bearing 8 forthe shaft 4. The member 5 is so formed as to inclose onehalf of the end portion of the machine and is provided with a plurality of lugs 9 whereby two similar half-sections may be drawn toward each other and secured together to form a complete end bell by means of through-bolts l0. A se mi-circular opening 11- is provided in the member 5, and that portion thereof surrounding the opening is provided with a concentric annular groove 12. An annular ring 13, preferably formed of brass or other suitable non-magnetizable material and with an inside diameter someshaft 4, is sup ported concentrically, with respect to the Shaft, by meanest a plurality of equally spaced and radially extending arms 1 k that are secured, at their outer ends, in the groove 12 of the member 5 by means of bolts 15. The arms 14 are formed of brass orother suitable non-magnetizable material and are formed with parallel end portions connected by an'inclined middle portion so that the ring 13 is held inwardly toward the rotatable field-magnet member 3, thereby allowing .'the shaft bearing 8 to be located closely adin order to prevent the existence of a closed jacent to the machine. The arms 14 are secured, at their ends, in an annular groove 16 formed in the ring 13, by means of bolts 17. The skeleton frame, thus formed by the arms'14 and ring 13, serves to support a plurality 'of sections 18 formed preferably of micarta or other hard and durable insulating material and provided, along their edges, with notches 19-, as best shown in Fig. 6. The inclined portions of the arms 14 and a plurality of strips 20 of insulating material are provided with corresponding holes 21 so that adjacent sections 18 may be secured be tween the arms 14 and strips 20 by means of bolts 'A plurality of insulating washers 23 are inserted between the ring 13 and the arms 14, or at any other suitable point,

electric circuit between the ring 13 and the end bell member.

From the foregoing description, it is apparent that that portion of the complete end bell adjacent to the extending portions of the armature windings 2 and the field magnet member 3 is formed entirely of insulating and non-magnetizable material in order to avoid excessive heating of the end bell produced by the cutting of the, magnetic lines of force surrounding the armature and traversing the field magnet and .armature core members. I

While I have shown my invention in its simple and preferred form, it is not so limited but is susceptible of various modifica-;

tions within the scope of theappended claims. r

I claim as my invention:

1. In adynamo-electric machine, the combination with a metallic end bell for 5G tially closing one end of said machine, of an annular disk of 1nsulating"mater-ial extending from said end bell to the shaft of said machine for completely inclosing the end of said machine.

2. Ina dynamo-electric machine, the combination with a metallic end bell for par-,

tially closing one end of said machine, of an annular disk of insulating material extend Iing from said end bell to the shaft of said metallic ring closely encircling the shaft of said machine, a plurality of radial supports secured to said bell and said ring and insulated from said ring, and a plurality of seg ments of insulating material positioned between said supports and held in place thereby.

4. In a dynamo-electric machine, the combination with a metallic end bell for partially inclosing the ends of said machine, of

annular disks for completing the closure of the ends of said machine, each of said disks comprising a metallic ring closely surrounding the shaft of said machine, a plurality of radial supports rigidly connected to said bell and said ring and insulated from one of said members, a plurality of notched segments of insulating material, and a plurality of strips adapted to be secured to said supports for holding said segments in place.

In testimony whereof, I have hereunto subscribed myjname this 24th day of Feb.

RALPH E. GILMAN. Witnesses:

E. E. WISCHMEYER, B. B. HINES.

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