Patent ID: 7791236
Filing Date: 2010-09-07
Classification: B60L,H02K,Y02T

Abstract:
1. A permanent magnet machine comprising: a rotor, a stator in close proximity to the rotor, and electrical windings in the stator; the rotor being rotatable relative to the stator with an air gap between the stator and the rotor; multiple pairs of magnets carried by the rotor in close proximity to the stator windings; and at least one opening in the rotor adapted for accommodating flow of a cooling medium for weight reduction; each opening being generally asymmetrically positioned with respect to pairs of adjacent magnets whereby a magnetic flux distribution developed by the magnets interacts with a magnetic flux distribution developed by the stator windings to effect a resultant flux distribution characterized by a reduced overall flux density in the rotor when the machine functions as a motor.