Patent ID: 7479723

Claim:
A rotor for an interior permanent magnet machine, comprising: a cylindrical body comprising non-magnetic material having an axial shaft projecting therefrom, the cylindrical body having first and second ends and a cylindrical outer surface; an array of first cavities therein containing permanent magnets and array of second cavities therein that do not contain magnets, the cavities being separated by rotor bridges comprising the non-magnetic material, wherein the array of first cavities are distributed adjacent to each other at a first radial distance from the axial shaft and the second set of cavities are located at a second radial distance from the axial shaft, and wherein the first radial distance is greater than the second radial distance; an array of rods of non-magnetic material extending through the second cavities in the rotor, and first and second end plates disposed adjacent the first and second ends of the rotor and fixed to the array of rods; wherein at least one of the end plates has an insulating oxide layer between the rods and end plate.