Patent ID: 7342339

Claim:
A reluctance machine, comprising: a stator having a stator core including a central bore and at least a first and a second stator pole extending inwardly from the stator core, each stator pole having a stator pole face; and a rotor having a plurality of rotor poles, each rotor pole having a rotor pole face, each of the rotor pole faces having a first portion, a second portion that is radially inwardly stepped with respect to the first portion to create a non-uniform air gap between the rotor pole face and a corresponding stator pole face, and a graduated protrusion located at an edge of the second portion of the rotor pole face; wherein the arclength of the second portion of the rotor pole face is approximately the arclength of the stator pole face, wherein each rotor pole face is dimensioned such that the graduated protrusion is proximate a leading edge of the second stator pole face when the first portion of the rotor pole face is in alignment with the first stator pole face.