Patent ID: 6472784
Filing Date: 2002-10-29
Classification: B60L,H02K,Y02T

Abstract:
A brush timed permanent magnet electric motor, comprising:a stationary portion including: a housing having an inner surface and end caps, and a plurality of permanent magnets each being disposed on said inner surface of said housing, and having a direction of magnetization and poles; said poles of said permanent magnets facing inward in a radial direction and alternating with each successive of said permanent magnets; a rotatable portion including: a shaft rotatably attached to said end caps of said housing; and a plurality of electromagnets each being attached to said shaft, having a direction of magnetization and poles, and having a winding capable of conducting current; said poles of said electromagnets facing outward in said radial direction and alternating with each successive of said electromagnets; position circuitry for sensing a position of said plurality of permanent magnets with respect to said plurality of said electromagnets and for providing a signal based on said position of said plurality of electromagnets to cause said rotatable portion to rotate; a power supply; said power supply providing sufficient power to said electromagnet windings to demagnetize said permanent magnets at stall conditions; and current limiting circuitry that reduces current in said windings to a level sufficient to prevent demagnetization of said permanent magnets.