Abstract: A driven rotary shaft system has a rotor including a core with a generally cylindrical surface, made from a stack of circular laminates of magnetic material which are clamped together in alignment. Permanent magnets are mounted in aligned windows formed in each laminate near diametrically opposed pole pieces for providing at least a pair of magnetic fields in positions which interact with magnetic fields of an adjacent stator. The permanent magnets and the windows have an arcuate cross section generally corresponding to the contours of the generally cylindrical surface. At least a pair of opposed air gaps are formed on diametrically opposed sides of the core, and between said pole pieces. These air gaps have internal concave contours which follow, correspond, and conform to the contours of flux lines produced by said permanent magnets. In one embodiment, the air gaps are completely within the perimeter of the circular laminates.

Abstract: A rotor has permanent magnets mounted on a core having a pair of opposing air gaps formed therein. Preferably, the permanent magnets are a material sold under the mark "NEOMAX", with an extremely high flux density, as compared to previously available permenant magnets. The contour of the air gap follows the contour of the naturally occurring flux lines which result from the mounting of the permanent magnets. The resulting rotor has a more efficient magnetic structure, with better overall characteristics than were available heretofore. The rotor may be used with any driven shaft system such as: motors, generators, dynamometers, and combinations thereof.