Patent ID: 7902700
Filing Date: 2011-03-08
Classification: H02K

Abstract:
1. A brushless permanent magnet motor for converting between electrical and mechanical energy comprising: a rotor that rotates about an axis of rotation and a stator that is stationary and magnetically exerts torque upon said rotor; said rotor comprising a ferromagnetic backiron and a circumferential array of alternating polarity magnetic poles that drives magnetic flux back and forth across an armature airgap; said stator comprising an air core armature with windings comprised of bundled multiple individually insulated strand conductor wire, said windings are assembled together in a substantially non-ferromagnetic structure that is located in said armature airgap and are energized by an inverter, such that when said windings are electrically energized, alternating magnetic flux from said alternating polarity magnetic poles passes through said windings as said rotor rotates and a torque is exerted on said rotor; said motor further comprising a thin non-ferromagnetic and electrically conducting shield located inside said armature airgap adjacent to said air core armature surface that reduces the eddy current losses incurred in said rotor from a ripple current in said windings.