External rotor motor for operation in aggressive media - has bushing in one piece with squirrel cage penetrating stator winding and surrounded by insulator

摘要

The motor is intended for driving a large diameter, but short axial length extractor fan. It has a suspended external rotor whose bottom connecting it to the shaft is closed, and made in one piece with the squirrel cage. The assembly is integrally cast with a bushing for its fastening on the shaft. In order to achieve short motor length, the bushing (6) projects into the stator winding (23-25) where an insulating element (21) surrounds the bushing upper part with a clearance. Preferably the air gap (55) between the insulator and the bushing is in the form of a cone envelope.