Small brushless DC motor - with additional reluctance effect to compensate for electromagnetic torque fluctuations

摘要

The motor has a permanent magnet rotor and flat stator. It is of a type normally used for driving turntables or tape recorders. The flat stator (36) has several discrete disc coils energised sequentially by an external control circuit. Due to the sequential switching and the stator winding construction the driving torque fluctuates. Therefore, and iron ring (55), situated in the rotor leakage field, is added to the stator. The iron ring (55), which may also be used as a location for the stator winding disc (36), has notches on its outer perimeter. In conjunction with the turning rotor a reluctance motro action takes place which provides the torque compensation necessary for a more even drive.