Abstract: A gas turbine engine includes a compressor section and a turbine section. A first spool is rotatable with a first turbine of the turbine section and a first compressor of the compressor section. Additionally, a second spool is rotatable with a second turbine of the turbine section and a second compressor of the compressor section. An electric machine is positioned at least partially inward of the core air flowpath of the gas turbine engine along a radial direction of the gas turbine engine. Additionally, the exemplary gas turbine engine includes a gear assembly mechanically coupled to both the first spool and the second spool, such that the first and second spools may each drive the electric machine.

Abstract: A gas turbine engine includes a compressor section and a turbine section. A first spool is rotatable with a first turbine of the turbine section and a first compressor of the compressor section. Additionally, a second spool is rotatable with a second turbine of the turbine section and a second compressor of the compressor section. An electric machine is positioned at least partially inward of the core air flowpath of the gas turbine engine along a radial direction of the gas turbine engine. Additionally, the exemplary gas turbine engine includes a gear assembly mechanically coupled to both the first spool and the second spool, such that the first and second spools may each drive the electric machine.

Abstract: A brushless starter/generator includes a rotor rotatably mounted within a stator mounted within a housing and an oil cooling system using cooling oil from an engine accessory gearbox for cooling the rotor and the stator. The rotor is fixedly mounted on a rotor shaft having a rotor heat exchanger disposed therein. A stator heat exchanger for cooling the stator includes an oil jacket around the housing. The stator heat exchanger includes a grooved tube around the housing and axially extending axial passages connected to annular inlet and outlet manifolds in the grooved tube. The rotor shaft is operably connected to a power take-off shaft within the gearbox and rotatably supported by a shaft bearing in a gearbox casing of the accessory gearbox. The oil cooling system is a dry cavity oil cooling system which prevents cooling oil from entering an air gap between the rotor and the stator.

Abstract: An aircraft gas turbine engine includes a counter-rotatable generator driven by a turbine includes a generator stator and counter-rotatable radially inner pole and outer magnet rotors. A gearbox may be used for counter-rotating the pole and magnet rotors. Counter-rotatable first and second sets of booster stages may be co-rotatable with corresponding ones of the pole and magnet rotors. The generator and the gearbox may be disposed within a booster cavity or a tail cone of the engine. The magnet rotor, the pole rotor, and the stator may be concentric. A particular embodiment of generator includes the magnet rotor encircling the pole rotor, the pole rotor encircling the stator, a rotor air gap between the magnet and pole rotors, and a transformer air gap between the pole rotor and the stator. The counter-rotatable generator may be driven directly by a counter-rotatable turbine.

Abstract: A counter-rotatable generator includes a generator stator concentric with concentric counter-rotatable radially inner pole and outer magnet rotors. The magnet rotor encircles the pole rotor and the pole rotor encircles the generator stator. A rotor air gap is disposed between the magnet and pole rotors, and a transformer air gap is disposed between the pole rotor and the stator. The magnet rotor includes a circular array of magnets having circumferentially alternating north/south and south/north orientations, retained within a magnet retention ring, and the magnets are circumferentially separated from each other by non-magnetic material spacers. One stator includes an annular hub, axial windings around equi-distantly spaced axial poles on the annular hub, radial cores extending radially outwardly from and equi-angularly spaced about a pole hub on the annular hub between the first and second axial windings, and radial windings around the radial cores.

Abstract: A counter-rotatable generator includes a generator stator concentric with concentric counter-rotatable radially inner pole and outer magnet rotors. The magnet rotor encircles the pole rotor and the pole rotor encircles the generator stator. A rotor air gap is disposed between the magnet and pole rotors, and a transformer air gap is disposed between the pole rotor and the stator. The magnet rotor includes a circular array of magnets having circumferentially alternating north/south and south/north orientations, retained within a magnet retention ring, and the magnets are circumferentially separated from each other by non-magnetic material spacers. One stator includes an annular hub, axial windings around equi-distantly spaced axial poles on the annular hub, radial cores extending radially outwardly from and equi-angularly spaced about a pole hub on the annular hub between the first and second axial windings, and radial windings around the radial cores.

Abstract: An aircraft gas turbine engine includes a counter-rotatable generator driven by a turbine includes a generator stator and counter-rotatable radially inner pole and outer magnet rotors. A gearbox may be used for counter-rotating the pole and magnet rotors. Counter-rotatable first and second sets of booster stages may be co-rotatable with corresponding ones of the pole and magnet rotors. The generator and the gearbox may be disposed within a booster cavity or a tail cone of the engine. The magnet rotor, the pole rotor, and the stator may be concentric. A particular embodiment of generator includes the magnet rotor encircling the pole rotor, the pole rotor encircling the stator, a rotor air gap between the magnet and pole rotors, and a transformer air gap between the pole rotor and the stator. The counter-rotatable generator may be driven directly by a counter-rotatable turbine.

Abstract: A brushless starter/generator includes a rotor rotatably mounted within a stator mounted within a housing and an oil cooling system using cooling oil from an engine accessory gearbox for cooling the rotor and the stator. The rotor is fixedly mounted on a rotor shaft having a rotor heat exchanger disposed therein. A stator heat exchanger for cooling the stator includes an oil jacket around the housing. The stator heat exchanger includes a grooved tube around the housing and axially extending axial passages connected to annular inlet and outlet manifolds in the grooved tube. The rotor shaft is operably connected to a power take-off shaft within the gearbox and rotatably supported by a shaft bearing in a gearbox casing of the accessory gearbox. The oil cooling system is a dry cavity oil cooling system which prevents cooling oil from entering an air gap between the rotor and the stator.