Patent ID: 7750521

Claim:
An electromagnetic machine for extracting electrical power from a gas turbine engine comprising: an outer rotor element and an inner rotor element rotatably supported adjacent to a fixed stator portion, the stator portion disposed concentrically between the inner and outer rotor elements about a central axis; opposing frame portions connected at a first end and a second end of the stator portion to support the stator portion within the gas turbine engine; the stator portion having an inner set of stator windings disposed on a radially inner surface of the stator portion adjacent to the inner rotor, and an outer set of stator windings disposed on a radially outer surface of the stator portion adjacent to the outer rotor; the inner rotor element driven by a first turbine shaft and the outer rotor element driven by a second turbine shaft of the gas turbine engine, each of the first turbine shaft and the second turbine shaft independently rotatable with respect to the other of the first turbine shaft and the second turbine shaft, the first turbine shaft and the second turbine shaft concurrently rotatable in the same or in opposite directions and controllably operable at matching velocity or at separate and distinct velocities; a plurality of outer permanent magnets disposed on an inner surface of the outer rotor element and a plurality of inner permanent magnets disposed on an outer surface of the inner rotor element; an outer air gap defined between the outer surface of the stator portion and the outer permanent magnets, and an inner air gap defined between the inner surface of the stator portion and the inner permanent magnets; the inner stator windings electrically interconnected to form a first set of multiple-phase windings and the outer stator windings electrically interconnected to form a second set of multiple-phase windings for powering an electrical load.