GB826423A - Improvements relating to the cooling of flame proof motors - Google Patents

Abstract

826,423. Cooling electric motors. METROPOLITAN-VICKERS ELECTRICAL CO. Ltd. Jan. 15, 1958 [Jan. 28, 1957], No. 3049/57. Class 35. Explosion within the casings of flameproof motors is restricted by not allowing complete axial ventilating passages through the rotor core. Instead, cooling fluid, which is itself cooled in a heat-exchanger, enters and leaves the rotor by ducts at the same end. In one form, Fig. 1, the rotor laminations 3 at each end of the motor are cut out to accommodate a series of radial webs 15 joined by webs 12 connected by a cylindrical baffle 10 to a fan 5. The cooling medium enters and leaves the rotor by ducts 11, 18, and passes round baffle 7, 8 to the inwardly directed fins 6 of the heat-exchanger, which has further, outwardly projecting fins 6<SP>1</SP> yielding the heat to the medium outside the motor casing 1. In a modification, the ducts 18 extend radially into the laminations 3. In further modifications the ducts are provided by axial holes in the laminations joined at their inner ends by radial ducts in some of the laminations. As shown in Fig. 10, these ducts 30, 31 and 32, 33 are each arranged to extend the whole length of the rotor without providing a through passage from one end of the rotor to the other. Ethylene and similar gases may be contained in the coolant.