Patent ID: 7659650

Claim:
A motor, comprising: a stator; a rotor mounted inside the stator, the rotor comprising: a cylindrical rotor core; a magnetic material that surrounds an exterior surface of the cylindrical rotor core such that the magnetic material defines an exterior cylindrical surface of the rotor and a separation air gap “G” is maintained between an exterior surface of the magnetic material and a corresponding interior surface of the stator; and a plurality of conductive bars arranged along the circumference of the cylindrical rotor core, wherein a spacing distance “t” is maintained between and outermost tip of the each of the conductive bars and a corresponding interior surface of the magnetic material, and wherein the spacing distance t is greater than the air gap G; and a magnetizing unit that can selectively magnetize the magnetic material, wherein the magnetizing unit is mounted adjacent to the exterior cylindrical surface of the rotor, the magnetizing unit comprising: a plurality of magnetizing poles each having an end adjacent to the exterior cylindrical surface of the rotor; and a corresponding plurality of magnetizing coils each wound around a respective magnetizing pole.