US2393956A

US2393956A - Generator

Info

Publication number: US2393956A
Application number: US537588A
Authority: US
Inventors: Rene A Baudry; Ernest I Pollard
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1944-05-27
Filing date: 1944-05-27
Publication date: 1946-02-05
Anticipated expiration: 1963-02-05

Description

Feb. 5, 1946. R. A. 'BAUDRY EI'AL GENERATOR Filed May 27, 1944 WITNESSES: INVENTORS Fe flBac/d d axial/91232:;

ATTORN EY Patented Feb. 5, 1946 GENERATOR Ren A. Baudry and Ernest I. Pollard, Pittsburgh,

Pa., asslgnors to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application May 27, 1944,Serial No. 537,588

2 Claims.

Our invention relates to the cooling of enclosed dynamo-electric machines and more particularly the stator-laminations thereof, although the invention is also applicable to the cooling of rotorlaminations. Our invention more particularly relates to the cooling of a machine in which the useful magnetic flux passes substantially radially through the core-laminations which are to be cooled, which is a characteristic feature of the stator-member of some inductor-type electrical generators.

Our invention is an improvement over the inductor-generator structure which is shown in our Patent 2,315,653, granted April 6, 1943, for a hydrogen-cooled motor-generator set. In the previously used construction, as shown in said patent, the hydrogen was cooled by means of a cooler which was placed in the central section of the motor-generator unit, around the coupling between the generator-shaft and the motor-shaft, and about half of the heat produced in the generator-windings was carried oil? in this manner,

the other half of the heat being removed by means of a water-cooler built in the stator-core of the generator. The cost oi this separate, centrally located cooler in the motor-generator set, was quite high, and the labor-cost of the extensive pipe-fitting which was involved was another considerable item of expense.

The object of our present invention is to provide a much simpler generator-construction, with a much simpler water-cooling system and pipingsystem, having greater accessibility, and resulting in a machine of much lower cost.

A more specific object of our present invention is to provide a construction in which all of the heat which is produced in the generator-windings may be Withdrawn by means of the cooler which is built in the stator-core. We accomplish this by utilizing the stator-core which is somewhat larger, thus demanding a somewhat larger statorframe, but the stator-frame and the core-laminations are relatively cheap, compared with the cost and inconvenience of the double-cooler ventilating-arrangement which is shown in our aforesaid patent. In the enlarged stator-core laminations of our generator, we provide ventilating ducts which are disposed between the coolant-circulating ducts of the water-cooler and the outer periphery of the core, and We provide bailling and ventilating means for causing the hydrogen or other gaseous ventilating medium to recirculate, flowing axially in the air-gap in one direction, and back through'the aforesaid ventilating ducts in the other direction. The water-pipes are passed longitudinally through the core, in good heat-exchanging relation to both the statorwindings and the ventilating ducts, the watertubes occupying an intermediate position be tween these two parts which are to be cooled.

With the foregoing and other objects in view, our invention consists in the combinations, structures, elements, systems and methods hereinafter described and claimed, and illustrated in the accompanying drawing, wherein Figure l is a longitudinal sectional view of the top half of a hydrogen-cooled high-frequency inductor-type generator, and Fig. 2 is a fragmentary view illustrating the construction of one of the stator-core punchings.

The inductor-type electrical generator which is illustrated in the drawing comprises a stator member 3 and a rotor member 4, separated by an air-gap 5. The stator member 3 is illustrated as comprising a plurality of cylindrical

magnetizable yokes

6A, 6B, and 6C which are disposed in alignment with each other, in such manner that the axial flow of magnetic flux from one yoke-portion directly across to the next adjacent one is at least partially restricted, by any means which limits the amount of this magnetic flux-flow, as by means of non-magnetizable rings 1 and 8, which are welded between the corresponding ends of the successive sections of the

magnetizable yokes

6A, 6B and 6C.

Suitable field-coil means are employed for energizing the generator, and there are various Ways of mounting said means. In the preferred form of embodiment of our invention, as illustrated, the excitation-means consists of two field-coils 9 and I0 which surround the respective non-magnetizable rings 1 and 8, and which are, in turn, surrounded by annular magnetizable members l2 and 13, which complete a flux-path around the coils 9 and I0, respectively.

In the illustrated embodiment of our invention, we utilize four laminated magnetizable statorcore members MA, MB, I53, and I50, which are carried by the bores of the cylindrical yoke-

members

6A, 6B, and 6C. The core-sections NA and MB are on opposite sides of the non-magnetizable ring I, while the core-sections I5B and I5C are on opposite sides of the non-magnetizable ring 8.

The laminations of which the various statorcore members are composed are of special construction, in accordance with our invention, as shown at M in Fig. 2. These several stator core laminations l4 have axially aligning windingreceiving slots It in their bores, said slots receiving the stator-winding H, which is connected to terminal-leads it. Back of the windingreceiving slots IS, in good heat-transfer relation thereto, and preferably (but not necessarily) spaced slightly therefrom, th respective laminations H are provided with a: 1 1 aligned coolant-receiving holes 2 which receive pipes 2| through which cocling-water is circulated, through externally connected means, as indicated by the arrow 22. Back of the coolantreceiving holes 20, the several laminations are provided with axially aligned ventilating ducts 23, which are disposed in good heat-transfer relation to the coolant-receiving holes 2! being preferably spaced slightly therefrom, and being disposed between said coolant-receiving holes and the outer periphery of the laminations.

The rotor-member 4 comprises a. pair of magnetizable

annular members

24A and 24B. The rotor-member 24A cooperates with the north and south stator-cores MA and MB, respectively, which are magnetized by the coil 9; and the rotor-member 24B cooperates with the south and north stator-cores I53 and |EC, re pectively, which are magnetized by the coil IE. These nular rotor-members 2 A and 24B provided with inductor-type peripheral tooth-projections 25 which cooperate with the stator-slots IE to produce tooth-flux pulsations so as to induce high-frequency current in the stator windingconductors IT. The north and south-pole teeth of either the stator-member or the rotor-member have to be oiiset 180 electrical degrees. or the thickness of one tooth, with respect to each other, in order that the induced electromotive forces may add to each other in the winding H. In order that the coil-sides of the Winding T, which lie in the stator-slots l8, may be straight, it is preferred to have the stator-slots l6 aligned axially with each other, as described, while the rotor-teeth 25 which are under stator-cores of oppositepolarity are staggered with respect to each other.

The machine is totally enclosed in gas-tight housing which includes the stator cylinder-member 6A'|-6B88C, closed at its two ends by end-brackets 25 and 2'1, or by any other ga "tight closure-means. The interior of the space within the generator-housing is filled with hydrogen, or other gaseous ventilating medium. We provide an internal gas-recirculating system by means of suitable baflies and blowers. ,At one end, the stator is provided with an annular bafile which directs the recirculating gaseous medium into rotor-carried fan 3| at that end of the rotor. At the other end of the machine, the electrical connections 32 may constitute a bafile which directs the gaseous cooling medium into a rotor-borne fan 33 at that end of the rotor. The recirculating path for the gaseous ventilating medium is from each of the fans BI and 33 into the airgap 5, flowing axially or longitudinally inwardly along the air-gap, from each end of the machine, to a central portion, where an annular space 34 makes it possible for the combined streams of gas to flow radially outwardly and enter the ventilating ducts 23, through which the gas now flows longitudinally or axially in the opposite direction, emerging from the two extreme ends of the ventilating ducts 23, and circulating around back again into the fans 3| and 33. respectively.

In operation, the internal heat, generated within the machine, is withdrawn by the water which is circulating in the pipes 2|. Heat is radiated to these pipes 2| from both sides, by

reason of the neamess of said pipes to both the winding-receiving slots l6 of the stator-core laminations, and the ventilating ducts 23 of the same laminations. In this way, some of the heat which is generated is withdrawn by direct conduction to the cooling-pipes 2|, while the rest of the heat is withdrawn through the medium of the recirculated gaseous medium which, in turn, is cooled by heat-radiation to the outer peripheries of the cooling-pipes 2|.

It will be noted that the inductor-type generator, which is ventilated by our new means, is a machine which is generally characterized by a core-member which does not have much depth in the radial direction, because the flux travels radially in the stator-core, the north and south poles being displaced from each other in a longitudinal or axial direction. In dynamo-electric machines in which the north and south poles are displaced circumferentially with respect to each other, it is customary and necessary to pro vide stator-cores which are deeper in the radial direction, so as to provide for the circumferentially flowing flux which flows back of the stator windings. Our new inductor-type generator is distinctive in having stator-core which are abnormally deep (for aradial-flux core) in the radial direction, so as to make room for the ventilating-ducts 23. It is noted, however, that these ventilating-ducts 23 are preferably longer in a radial direction than in a circumferential direction, as shown in Fig. 2, so as to facilitate the radial fiow of the magnetic flux.

From the foregoing description and explanation, it will be apparent that we have provided an extremely simple and economical construction for ventilating a hydrogen-cooled machine, or other totally enclosed machine, particularly a machine of the high-frequency inductor-type, as set forth in the original statement of objects of our invention.

We claim as our invention:

1. An inductor-type electrical generator comprising a stator-member and a rotor-member; said stator-member comprising a plurality of cylindrical magnetizable yokes disposed in alignment with each other in such manner that the axial flow of magnetic flux from one cylindrical magnetizalble yoke directly across to the adjacent oneis at least partially restricted, field-coil means encircling the ends of the cylindrical magnetizable yokes in such manner as to overlie the place where the axial flow of magnetic flux from one cylindrical magnetizable yoke directly across to the adjacent one is at least partially restricted, annular magnetiza-ble means surrounding said field-coil means for completing a magnetic path around the same, a laminated magnetizable stator-core member disposed within each cylindrical magnetizable yoke, the stator-core laminations having winding-receiving slots in their bores, coolant-receiving holes close to said winding-receiving slots, and ventilating ducts close to the coolant-receiving holes, between said coolantreceiving holes and the outer peripheries of said laminations, externally connected means for circulating a coolant axially through said coolantreceiving holes, and stator-windings disposed in said stator-core slots; said rotor-member being a magnetizable annular inductor-type rotor-member disposed within the bore of said stator-core members with an air-gap in between, and having peripheral tooth-projections, and bailling and ventilating means arranged in such manner as to for the gaseous ventilating medium, flowing axially inwardly through each half of the airgap from each end of the rotor-member to the approximate center of the length of the rotormember, then flowing radially outwardly to said 5 ventilating ducts, then returning to the two ends of the machine through said ventilating ducts.

RENE A. BAUDRY. ERNEST I. POLLARD.