GB255981A - Improvements in and relating to dynamo electric machines - Google Patents

Abstract

255,981. British Thomson-Houston Co., Ltd., and Pollock, A. A. May 14, 1925. Dynamos and motors, cooling.- A dynamo electric machine has a main casing, such as 3, Fig. 1, through which the magnetic part 4 of the frame projects into a space 5 between the main casing and a similarly shaped outer casing 6, cooling air being passed axially through this space, for instance by means of a fan 13. The inner casing and end plates may be ribbed internally or externally and the field coils 12 are pressed closely against the inner casing through which their heat is coducted to the air space 5. The upper and lower parts of Fig. 2 show sections respectively on the lines A B, C D of Fig. 1. The field system is made of stampings 4 which are slotted at their outer edges at 7 so that part of their idle magnetic material is removed and the remainder is used as a heat conductor. In the form shown, the casing 3, which may be of aluminium or other light weight metal, is ribbed only on its outer surface and the end plate 10 is ribbed internally and externally at 11. The fan 13 is enclosed by a bell-shaped cap 14 forming an intake from the space 5. When the machine is a generator driven by an internal combustion engine, the radiator cooling fan may be used for drawing the air through the space 5. Specification 18087/12 is referred to.