GB318313A - Improvements in electric motors and dynamo machines - Google Patents

Abstract

318,313. Daun, C. L. June 5, 1928. Dynamos and motors, cooling; casings.-An open type of dynamo-electric machine is converted into a closed type machine or a closed type is produced during manufacture by fitting the machine with a member or members rotating with the rotor and having pleated or fluted surface portions constituting a number of radiallyextending channels which are exposed to atmosphere completely on one side. These members make a running joint with a fixed member in the machine whereby the machine is protected against the entry of external air, dirt, fumes or the like. In the form shown, the enclosing members 19, which are fitted, by means of hubs 18, at both ends of the rotor 9, consist of conical runners pleated or ribbed to give an increased heat transmitting area and made of metal of high thermal conductivity. The periphery of the runners is preferably turned back, as shown at 20, Fig. 2, to enter troughs 26 in fixed sleeves 21 in the motor casing and so prevent the entry of dirt &c. into the machine. The screening action is assisted by a peripheral extension 30 of the runners which further protects the trough 26 and assists in directing towards the outlets 16 the air currents which enter through the openings 14. A further sealing action may be obtained by means of a felt ring of L-section secured to the flanges 20, 30, Fig. 2, and loose enough to make running contact with the fixed annular rim 34 under centrifugal action. This pad may be saturated with oil to give a. fume-tight packing.