Patent ID: 7705502

Claim:
A rotor comprising: a cylindrical periphery having a central axis of rotation; a cross-section taken perpendicular to the central axis of rotation, said cross section of the rotor comprising: a plurality of interior permanent magnets, each interior permanent magnet having two poles and having a longitudinal dimension which is greater than a transverse dimension; a plurality of non-magnetic peripheral slots, at least two non-magnetic peripheral slots associated with each pole of the interior permanent magnets, each non-magnetic peripheral slot positioned between the cylindrical periphery and its associated interior permanent magnet and each non-magnetic peripheral slot is not contiguous with its associated interior permanent magnet, each non-magnetic peripheral slot having a longitudinal dimension which is greater than a transverse dimension, wherein an axis of the longitudinal dimension of each non-magnetic peripheral slot is not perpendicular to an axis of the longitudinal dimension of its associated interior permanent magnet, wherein the axis of the longitudinal dimension of each non-magnetic peripheral slot is not coaxial with a line within the cross-section intersecting the central axis of rotation, and wherein the non-magnetic peripheral slots associated with each interior permanent magnet pole have different lengths; and a plurality of non-magnetic end slots, each non-magnetic end slot contiguous to and integral with each end of each pole of each interior permanent magnet wherein at least part of each non-magnetic end slot has a central axis which is coaxial with a radius of the rotor.