US2459586A - Rotor ventilation for turbogenerators - Google Patents

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Jan. 18, 1949. M. D. ROSS ROTOR VEN'I'iLATION FOR TURBO-GENERATORS Filed May 13, 1947 WITNESSES:

ATTORNEY Patented Jan. 18, 1949 2,459,586

ROTOR VENTILATION FOR TURBOGENER-ATORS Malcolm D. Ross, 'Pittsburgh, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application May 13, 1947, Serial No. 747,683 2 Claims. (Cl. 171-252) My invention relates to turbogenerators, Figure 1 shows a turbo-generator having a which are synchronous dynamo-electric mastator-member I, carrying a S-phase primary chines adapted to be direct-connected to a steam Winding 2, and a rotor-member 3 which emturbine. Such generators have a very special bodies the novel Ventilation-system of my present design, which has been successfully developed 5 invention. .The rotor-member comprises arotorafter years of experience, the principal difilculty core 4 which is integral with a shaft 5., As shown being to design the rotor-member to be able to in Fig. 2, the rotor-core is provided with subwithstand the extremly large stresses due to stantially axially extending slots 6 which carry centrifugal force. The design of turbogenerators the coil-sides l of a. concentric field-winding. is in a large measure the design of its rotor. The 10 The field-winding has end-turns 9 which extend' diameter or the rotor is strictly limited by the beyond the ends 01' the rotor-core 4, and which peripheral speed, resulting in a machine-design are restrained against centrifugal force by a reof great axial length. The rotor-member has taming-ring II, which surrounds th -t become standardized as a cylindrical core hav- 9 at each end of the rotor. The outer end of ing axially extending peripheral slots carrying each retaining-ring II is closed by an end-plate concentric-coil field-windings. l2 which has a centrally disposed gas inlet open- The object of my present invention is to proing l3, and sometimes also additional openings vide such a turborotor with reamed-out radial M, for the admission of a gaseous ventilatingoutlet-holes in the retaining-rings, and prefermedium, which is usually hydrogen in modern ably also in the rotor teeth, so that these outletmachines, although air has sometimes been used. holes are shaped in the form of diflusers. By As pointed out in the Fechheimer Patent No. this simple method, at a very trifling cost, I have 1,927,890, filed December 19,1930, the ventilabeen able to achieve an increase of at least three tion of these end-turns 9 has long been a problem, or four percent in the rotor-output of turbo- Which Fechheimer Solved y the e 0 i generators. This increase is due, I believe, to a velocities of the gaseous medium. thro h" reduction in the gas-pressure which is lost in n rr w sp c s between the end-turns 9, this producing high-velocity jets leaving these radial gaseous medium being thrown radially outwardly outlet-holes. The importance of recovering as y c ntrif al for nd escapin through a much as possible of the energy in these highplurality of substantially radial ventilatingvelocity jets-once said problem is given serious Openings or outlet-holes l5, which are provided considerationwill be appreciated when it is n a h d f r pla l Prior t my p sent inrealized that a large part of the total available Vention. t ese O tlet-holes l5 have been of unigas-pressure, for ventilating a turbogenerator form cross-section, and they have resulted in the rotor, is dissipated in producing these highformation 01' high-Velocity je s of venti at ngvelocity jets, considering also that almost oneas. discharging from these holesc di to half of the total losses in a turbogenerator is the my present ve t on, I ream out these ventilatfriction-loss, which is primarily the power reo es l5 in the orm of a diffuser, with an quired to ventilate the stator and rotor members angle f about 11 (more or less) between the of the machine. And yet, notwithstanding the Opposite Side Walls Of the t at ng-holes l5, so almost negligible cost of reaming these radial that these Ventilating-holes are of ng outlet-holes in the rotor, turborotors have been diameters as the gaseous v n ilating-medium standardized, for many years, with radial outpasses out through said ventilating-holes in the let-holes of uniform cross-section. retaining-rings- My invention consists in the structures, comn h de i n of most tur o en rator rotors, it binations, parts, design-methods, and systems, is desirable, in addition to the end-turn ventilah reinafter described and claimed, and m tion,-to ventilate the coil-sides 1 which lie in the trated in the accompanying drawing, wherein; slots 5 Of the rotor-core l. A desirable way t0 ac- Figure 1 1 a, m wh t di m ti 51mph- I complish this coil-side ventilation is shown in the fled, longitudinal sectional view of a part of a Kllgore Patent No 2 094 358, filed May 29, 1 3

turbogenerator; according to which the rotor-slots 6 are provided Fig. 21s a cut-away diagrammatic perspective wi h enlargements I 6, which r Sh wn, in my view of one end of the rotor; and drawing, as being underneath the winding-receiv- Fllgs. 3 and 4 are detailed sections showing the ing portion of the rotor-slots. Thus, the slotradial outlet-holes through a retaining-ring and enlargements I6 constitute axial ventilatingceiving the gaseous ventilating methrough a rotor-tooth, respectively. 05 passages for re dium, for coiling the coil-sides I of the rotorwinding. Near the axial center-line of the machine, as covered by the Kilgore patent, substantially radial outlet-vents or holes I"! are provided, preferably in the form of slightly inclined toothopenings or holes which are drilled through the rotor-teeth l8, between the rotor-slots 6. These approximately radial tooth-holes l8 provide a communication between the rotor-periphery and the axial ventilating-passages l6 of the rotor, so as to provide outlet-ducts for the rotorventilation.

In accordance with my present invention, it is preferable also to ream out the outer portions of these outlet-holes in the rotor-teeth, as shown at 19, so that these tooth-openings will be of widening diameters as the ventilating-gas passes out therethrough to the rotor-periphery. Although the advantages which have been discovered to result from the reaming of these tooth-openings are not as great as the advantages which have been discovered to flow from the reaming of the outlet-holes in the retaining-rings, the cost of the reaming is so slight that it is usually desirable to ream both sets of outlet-holes, as described.

I claim as my invention:

1. A turbogenerator having a rotor comprising a slotted rotor-core having rotor-teeth between the rotor-slots, a concentric field-winding having coil-sides in the rotor-slots and having end-turns extending beyond each end of the rotor-core, a

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retaining-ring surrounding the end-turns at each end of the rotor, and an end-plate at the end 0! each retaining-ring, each end-plate having a centrally disposed gas-inlet opening for the admission of a gaseous ventilating-medium, and each retaining-ring having a plurality of approximately radial diffuser-type ventilating-openings therethrough, being of widening diameters as the gaseous ventilating-medium passes out through said ventilating-openings in the retaining-rings.

2. The invention as defined in claim 1, characterized by said rotor-slots having enlargements constituting axial ventilating-passages, and said rotor-teeth having approximately radial, diflusertype tooth-openings extending from the rotorperiphery into communication with said axial ventilating-passages, said tooth-openings being of widening diameters as the gaseous ventilatingmedium passes out therethrough to the rotorperiphery.

MALCOLM D. ROSS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Criner Aug. 19, 1947

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