| 摘要 |
PURPOSE:To improve the demagnetizing withstand force at low temperature time by setting the coercive force of a permanent magnet and the temperature coefficient of the remaining magnetic density used at demagnetizing field side of an armature reaction to negative. CONSTITUTION:A plurality of composite field poles 3 are provided on the inner periphery of the yoke 2 of a stator 1. The poles 3 are formed of ferrite magnet, the second permanent magnet 32 having 0.2-0.5 of coercive force, -0.18--0.20 of the remaining magnetic flux density is aligned and secured to part of demagnetizing field mainly in the increasing magnetic field of armature reaction at temperature coefficient, and the first permanent magnet having negative coercive force and remaining magnetic flux is aligned and secured to the demagnetizing field side. Thus, as the temperature decreases, the coercive force increases to improve the permanent demagnetizing withstand force. Further, since the remaining magnetic flux density also increases, the torque increases to readily start an engine. |
