GB276433A - Improvements in and relating to the cooling and ventilation of dynamo electric machines - Google Patents

Abstract

276,433. Major, C. W., and Crompton & Co., Ltd. May 28, 1926. Dynamos and motors, cooling and ventilating.-A cooling and ventilating system for a machine in which the windings are completely enclosed comprises radiator members with heattransmitting fins of high thermal conductivity screwed at their outer peripheries to the stator and having running packed joints with the shaft at their inner peripheries in combination with an arrangement of fans, guides and baffles within the enclosure such as to circulate, the heated internal air in contact with the radiators and with fins and passages which pass air from the surrounding atmosphere over the external surfaces of the radiators, the whole system being contained within the framework of the machine between the bearings thereof. In the form shown in Fig. 1, the radiators 8 and 9 consist of dished members of aluminium attached by spigot joints to the end rings 2 of the stator core and enclosing the windings by air-tight packed joints. 14 on the shaft. The radiators have internal and extemnal ribs 11. 10. and at their inner openings they have annular curved guides 12, which run freely within the end flanges of circular baffles 19, 20 mounted on the shaft. These baffles, as shown in Fig. 4, have semicircular orifices in their end discs and semcircular axial flanges oppositely directed. By this arrangement, while one-half of the ducts 24, Fig. 1, in the rotor hub are in connection with the space 22 within the radiator at one end and with the space 23 below the guide 12 at the other end, the other half of the rotor ducts 24 are reversely connected. The outer casing 3 has air inlets 4, leading to an annular air jacket 6. and outlets 13 are formed in the bearing brackets. Fans 13 or the ends of the rotor coils circulate the air within the enclosed machine over the internal fins of the radiators and centrifugal fans 15, mounted on the shaft between the bearings, draw outside air over the external fins as shown by the arrows. In an alternative form, there are no openings such as at 4, and a single fan such as 25 is used at one end of the shaft to draw external air in through a single opening in the lower part of the end plate of the opposite end of the machine and expel it through a similar opening in the end plate which adjoins the fan. According to the Provisional Specification, the projecting fins on the radiator members may be replaced by passages through the radiators.