Patent ID: 7554241

Claim:
A three-gap electrical device comprising: an elongated shaft; a stator and a rotor supported by said elongated shaft; said stator supports a plurality of coils, each coil having an essentially flat front face and an essentially flat rear face and a first radial extent and a second radial extent, an outer axial extent and an inner axial extent between said first and said second radial extent with said first radial extent and said second radial extent axially separated; said rotor supports a plurality of permanent magnet sets; a first set of permanent magnets extend axially on said rotor radially outward from said coils outer axial extent on said stator; a second set of permanent magnets on said rotor extends radially adjacent said first radial extent of said coils on a first axial side of said coils on said stator; said stator on a first axial side of said first set of permanent magnets; a third set of permanent magnets on said rotor extends radially adjacent said second radial extent of said coils on a second axial side of said coils on said stator; a first gap formed between said first set of permanent magnets and said coils outer extent; a second gap formed between said second set of permanent magnets and said coils first radial extent; a third gap formed between said third set of permanent magnets and said coils second radial extent; tapered pole pieces extend between said plurality of flat faced coils and said plurality of permanent magnets; said first set of permanent magnets facing said stator has the same polarity facing said stator that said second set of permanent magnets and said third set of permanent magnets facing said stator have at the same radial positions such that a plane extending through the centerline of the elongated shaft extending radially outward encounters the magnets of the first set and second set and third set of the same polarity.