1,135,790. Cooling dynamo-electric machines. GENERAL ELECTRIC CO. 4 Nov., 1966 [9 Nov., 1965], No. 49526/66. Heading H2A. A dynamo-electric machine is cooled by air blown axially along the external casing of the machine by a rotor mounted fan with a subsidiary circulation of part of this main air flow around the end windings. The machine includes a conventional stator 4 having windings 5, 6 housed within a casing 1 provided with axial fins 30, and a squirrel-cage rotor 7 having end rings 9, 10 which are extended to form impellers 31. The rotor shaft is mounted in a bearing located in spider 2 which has radial ribs extending to an outer ring 13 which is secured to a ring 15 by legs 16. A fan 21 is mounted on the rotor shaft and draws air through the space between ring 13 and the hub and expels it between rings 13 and 15 where baffle 28 directs the flow in an axial direction. Ring 15 extends into the plane of the fan and directs part of the air flow through gap 26 into the end winding cavity. The diverted air is exhausted through orifice 25 in the fan to mix with the main cooling air flow again. The drive end of the machine which is shown totally enclosed is cooled by heat transfer along the rotor conductors, or alternatively a similar fan construction may be used.
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