Patent ID: 7550889

Claim:
An electric motor rotor comprising: a core having a central longitudinal axis, said core having a pair of opposing first slots radially spaced from the longitudinal axis and extending parallel to the axis wherein said longitudinal axis is positioned between the pair of first slots, said core having a pair of opposing second slots radially spaced from the longitudinal axis and extending parallel to the axis wherein said longitudinal axis is positioned between the pair of second slots, wherein the first slots are not angularly aligned with the second slots with respect to the longitudinal axis such that in a cross section of the rotor perpendicular to the longitudinal axis of the rotor, the first slots are not in a line through the longitudinal axis with the second slots; first magnets extending parallel to the longitudinal axis, said first magnets positioned in the first slots and positioned in the second slots; and second magnets extending parallel to the longitudinal axis, said second magnets positioned in the first slots only such that a cross section of the rotor perpendicular to the longitudinal axis of the rotor is asymmetrical with respect to a line perpendicular to the central longitudinal axis positioned evenly between the first slots and the second slots, wherein the second magnets are positioned between the first magnets and an outer surface of the core, and wherein the second magnets are a different material than the first magnets.