Miniature single phase motor with narrow air gap - has airgap width defined by rotor outer surface and stator salient pole surfaces

摘要

The laminated stator rim has inwards protruding poles whose inner surfaces define bore, in which is mounted rotatably a rotor. The latter outer surfaces form with the pole inner surfaces radial air gap. The width of the gap in radial direction ranges from 0.025 to 0.152 mm. The ratio of the air gap width to the rotor diameter is between 0.0009 to 0.005. Preferably the gap width ranges from 0.051 to 0.102 mm and the gap width ratio to the rotor diameter is 0.0018 to 0.0035. Salient poles may be used. Typically the motor is for alternating current and has a squirrel-cage rotor for a single-phase operation.