A gearbox arrangement of an electric machine of an engine includes a planetary gear arrangement configured to receive rotational input from the electric machine and from the engine and to mechanically couple the electric machine and the engine in first and second power flow directions, the planetary gear set comprising a ring gear, a ring brake, a free-wheel clutch attachable to a fixed structure and the ring brake, the tree-wheel clutch permitting rotation of the ring brake in a first direction and preventing rotation of the ring brake in an opposite second direction, and an arrangement for moving the ring gear between a first position in which the ring gear is non-rotatably engaged with the ring brake and a second position in which the ring gear is non-rotatably engaged with the carrier. An engine starter and power generator device Is also provided.

An AC electrical system for a vehicle and methods of operating the same are provided. In one aspect, an AC electrical system includes a first electric machine mechanically coupled with a first spool of a gas turbine engine and a second electric machine mechanically coupled with a second spool of the gas turbine engine. The system also includes a first AC bus and a second AC bus. A first electrical channel electrically couples the first electric machine to the first AC bus and a second electrical channel electrically couples the second electric machine to the second AC bus. The system also includes one or more connection links and one or more power converters for selectively electrically coupling the first and second electrical channels so that electrical power generated by one electric machine can be converted and shared with the other electric machine and electrical loads of the other channel.

An AC electrical system for a vehicle and methods of operating the same are provided. In one aspect, an AC electrical system includes a first electric machine mechanically coupled with a first spool of a gas turbine engine and a second electric machine mechanically coupled with a second spool of the gas turbine engine. The system also includes a first AC bus and a second AC bus. A first electrical channel electrically couples the first electric machine to the first AC bus and a second electrical channel electrically couples the second electric machine to the second AC bus. The system also includes one or more connection links and one or more power converters for selectively electrically coupling the first and second electrical channels so that electrical power generated by one electric machine can be converted and shared with the other electric machine and electrical loads of the other channel.

An architecture for an aircraft comprises two air-conditioning systems, two converters, each intended to supply one of the air-conditioning systems, and at least one first electric machine which starts up a first main engine of the aircraft. The electrical architecture is configured such that the two converters can together supply the first electric machine. A method of operating the architecture is also provided.

An architecture for an aircraft comprises two air-conditioning systems, two converters, each intended to supply one of the air-conditioning systems, and at least one first electric machine which starts up a first main engine of the aircraft. The electrical architecture is configured such that the two converters can together supply the first electric machine. A method of operating the architecture is also provided.

Gas turbine engine starter systems and associated methods. A gas turbine engine starter system includes an engine starter with a starter torque output configured to convey a starter torque to a gas turbine engine. An engine startup process includes a spool-up time interval in which the engine rotational speed increases to a speed within an engine starting speed envelope. During at least a portion of the spool-up time interval, the starter torque is less than a speed-dependent maximum torque value of the starter torque that the engine starter is configured to produce. A method of operating a gas turbine engine starter system includes operating an engine starter to accelerate the gas turbine engine such that the starter torque is less than a speed-dependent maximum torque value of the starter torque that the engine starter is configured to produce during at least a portion of a spool-up time interval.

Gas turbine engine starter systems and associated methods. A gas turbine engine starter system includes an engine starter with a starter torque output configured to convey a starter torque to a gas turbine engine. An engine startup process includes a spool-up time interval in which the engine rotational speed increases to a speed within an engine starting speed envelope. During at least a portion of the spool-up time interval, the starter torque is less than a speed-dependent maximum torque value of the starter torque that the engine starter is configured to produce. A method of operating a gas turbine engine starter system includes operating an engine starter to accelerate the gas turbine engine such that the starter torque is less than a speed-dependent maximum torque value of the starter torque that the engine starter is configured to produce during at least a portion of a spool-up time interval.

A gas turbine propulsion system includes a shroud that defines a fluid flow path. A gas turbine engine in the fluid flow path includes a compressor, a combustor downstream from the compressor, and a turbine downstream from the combustor. An electric generator in the fluid flow path defined by the shroud includes a rotor coaxially aligned with the turbine. A propulsor is upstream from the gas turbine engine, and an electric motor is operably coupled to the propulsor to rotate the propulsor. The propulsor is rotationally isolated from the gas turbine engine so that the propulsor rotates independently from operation of the gas turbine engine.

An assembly for manually rotating a rotor includes a housing enclosing a first shaft and a second shaft accessible through an exterior wall of the housing. The first shaft extends from a first end rotationally coupled to the rotor to a second end selectively engageable with the second shaft. The second shaft includes a thrust plate extending from and rotatable with the second shaft. A spring disposed between the thrust plate and the housing biases the second shaft towards the exterior wall of the housing.

An assembly for manually rotating a rotor includes a housing enclosing a first shaft and a second shaft accessible through an exterior wall of the housing. The first shaft extends from a first end rotationally coupled to the rotor to a second end selectively engageable with the second shaft. The second shaft includes a thrust plate extending from and rotatable with the second shaft. A spring disposed between the thrust plate and the housing biases the second shaft towards the exterior wall of the housing.