Abstract: A gas turbine engine assembly includes an electromagnetic machine for extracting power from the turbine engine. The electromagnetic machine includes an outer rotor and an inner rotor rotatably supported adjacent to a stator disposed between the inner and outer rotors. The stator has an inner set of windings disposed on an inner surface adjacent to the inner rotor, and an outer set of windings on an outer surface of the stator adjacent to the outer rotor. The inner stator windings form a set of multiple-phase windings, and the outer stator windings form a set of multiple-phase windings.

Abstract: An electromagnetic machine for extracting power from a turbine engine includes an outer rotor and an inner rotor rotatably supported adjacent to a stator. The stator is disposed between the inner and outer rotors. The stator has an inner set of windings disposed on an inner surface adjacent to the inner rotor, and an outer set of windings on an outer surface of the stator adjacent to the outer rotor. A plurality of permanent magnets are disposed on an inner surface of the outer rotor element and on an outer surface of the inner rotor element. Air gaps are defined between the outer surface of the stator and the outer permanent magnets, and between the inner surface of the stator portion and the inner permanent magnets. The inner stator windings form a set of multiple-phase windings. and the outer stator windings form a set of multiple-phase windings.

Abstract: A rotor for an electric machine includes a rotor core constructed of magnetically-permeable material. The rotor core may include a first cavity having a first curved end portion and a second cavity having a first curved end portion disposed adjacent the first curved end portion of the first cavity. The rotor may also include a permanent-magnet cluster. The permanent-magnet cluster may include a permanent-magnet layer that substantially magnetically isolates a portion of the rotor core disposed inside the permanent-magnet cluster from portions of the rotor core disposed outside the permanent-magnet cluster. The permanent-magnet layer may include one or more permanent-magnet pieces disposed in the first cavity and one or more permanent-magnet pieces disposed in the second cavity.