GB789038A - Rotating-field motors - Google Patents

Abstract

789,038. Squirrel cages for electric motors. PAPST, H. Dec. 23, 1955 [Oct. 24, 1955], No. 36967/55. Class 35. An electric motor has an external rotor comprising a laminated core 1 with a squirrel cage winding having bars 2 and rings 3. Ventilation ribs 4 and outer rings 5, forming a jacket, are mounted on the members 3 as well as a hub 6 receiving a shaft 8. The parts 2, 3, 4 and 6 may be produced by a single pressure casting operation, the jackets being cast at the same time or fitted later. The hub 6 supports a steel bush 7 which is serrated for better anchorage and forms a secure seating for the shaft 8. The casting is provided with points 9 which engage and compress the laminations 1 during the casting operation. Air outlet apertures may be formed in the jackets 5. In a modification, the two separate jackets are replaced by a single jacket extending over the laminations, the squirrel-cage rings at one end being joined to the hub by means of a thin closure plate, Fig. 2 (not shown). The internal winding assembly is mounted on a tube carrying the machine bearings. In another arrangement, the laminated core is replaced by a solid iron or steel ring within a cylindrical jacket which is extended to form the end-rings of the squirrel cage, Fig. 3 (not shown). The jacket may be provided with internal axial ribs on which the iron or steel ring rests, and a separate end-ring of the squirrel-cage winding is offset from the solid core to allow for the passage of air, Fig. 4 (not shown). Additional rings on the rotor reduce the leakage of flux.