Patent ID: 7402934

Claim:
A motor-generator for converting between electrical and rotational energy comprising: a rotor that rotates in a housing about an axis of rotation, and a stator that is stationary and magnetically acts upon said rotor; said rotor is constructed of two spaced apart co-rotating rotor portions that define therebetween an armature airgap, and magnetic poles on said rotor portions that drive magnetic flux across said armature airgap; said stator comprises an air core armature having a substantially nonmagnetic form with a free end and a support end, wherein said support end is coupled to the housing of said motor-generator and said free end extends into said armature airgap inside said rotor; said air core armature further comprising windings that are wound on to said form, said windings having active length portions that generate electromagnetic torque from interaction with the magnetic flux of said magnetic poles and end turn portions that circumferentially connect said active length portions, wherein said form transfers said electromagnetic torque of said active length portions of said windings to said housing; said windings are wound using wire formed of bundled individually insulated conductors, wherein said conductors are electrically connected in parallel but are electrically insulated between each other along their length in said active length portions, and said conductors of said wire are held together on said form by an outer insulating serve constructed from resin impermeable insulating material wherein said active length portions are substantially free from resin impregnation; AC voltage is induced in said windings as said rotor rotates.