Abstract: A stator for a radial-flux rotary electric machine includes a yoke with a plurality of teeth, each tooth extending from a root at the yoke to a tip. The stator further includes a plurality of coils, each one of which being located on a respective one of the plurality of teeth, the coils being sized such that a slot fill factor is between zero and unity to define axial voids in the slots. The stator further includes a plurality of magnetic sealing members, each one of which being engaged with the tips of adjacent teeth to circumferentially and axially seal the axial voids in the slots for retaining an axial flow of coolant therein, the magnetic sealing members being composed of a magnetic material to provide a flux path between adjacent tooth tips to increase an amount of leakage flux.

Abstract: An electrical system having a first dual-wound rotary electric machine mechanically coupled with a first gas turbine spool and having a first three-phase sub-machine and a second three-phase submachine; a second dual-wound rotary electric machine mechanically coupled with a second gas turbine spool and having a third three-phase sub-machine and a fourth three-phase submachine; and a set of N = 4 bidirectional converter circuits for conversion of alternating current (ac) to and from direct current (dc), each of which has an associated index n = (1, ... , N), and for all n, the ac side of the nth bidirectional converter circuit is connected with the nth three-phase sub-machine. The dc side of the first converter circuit is connected with the dc side of the third converter circuit, and the dc side of the second converter circuit is connected with the dc side of the fourth converter circuit.

Abstract: Electrical systems for connecting rotary electric machines with gas turbine spools are provided. One such electrical system includes: a first rotary electric machine; a second rotary electric machine; a first set of bidirectional converter circuits; a second set of bidirectional converter circuits; and DC outputs for connection with an R-channel network. Each electrical machine is mechanically coupled with a respective gas turbine spool and has an identical even number N?4 of phases, each phase having a respective index and including an identical number P?1 of coils wound in a P-plex configuration in which adjacent phases are radially separated by 2?/NP mechanical radians. Each of the first and second converter circuits converts AC to and from DC, has a respective index n, and is connected with the P coils in the nth phase of the first and second rotary electric machines, respectively.

Abstract: Electrical systems for connecting rotary electric machines with gas turbine spools are provided. One such electrical system comprises: a first rotary electric machine mechanically coupled with a first gas turbine spool and a second rotary electric machine mechanically coupled with a second gas turbine spool, each said electric machine having an identical even number N?4 of phases, each phase having a respective index n=(1, . . .

Abstract: Gas turbine engines and methods of starting gas turbine engines, the gas turbine engine including: an electronic engine controller; one or more spools designated a starting spool for starting the engine, and has a required starting torque ?s; a permanent magnet alternator mechanically coupled with the starting spool, the alternator, in a motor mode, provides a peak torque of ?a, and, in a generator mode, generates electrical power for the electronic engine controller; and an electrical starter-generator mechanically coupled with the starting spool. The starter-generator in a motor mode, provides a peak torque of ?sg, and, in a generator mode, generates electrical power for an external load. ?sg+?a??s and ?sg, ?a<?s, and the electronic engine controller, during a start procedure, operates both the permanent magnet alternator and the starter-generator in a motor mode to drive the starting spool.

Abstract: A power electronics unit for an aircraft and a method of determining the integrity of a power electronics unit are provided. The power electronics unit comprises an electric machine controller; a heatsink arranged to conduct heat from the electric machine controller; a housing comprising a sealed internal volume enclosing the electric machine controller and heatsink; a dielectric liquid partially filling the internal volume to cover the electric machine controller; a gas pocket within the internal volume; a pressure sensor arranged to measure a pressure of gas within the gas pocket; a temperature sensor arranged to measure a temperature within the internal volume; and a controller. The controller is configured to receive signals from the pressure sensor and temperature sensor, determine a pressure and temperature from the received signals and provide an output signal dependent on the determined temperature and pressure.

Abstract: A multi-logic device system, an electronic engine controller, and a method of operating the multi-logic device system. The multi-logic device system includes a primary logic device which is more resilient to single event effects, and one or more secondary logic devices, each secondary logic device being powered by a respective power supply unit and being more susceptible to single event effects. The primary logic device is configured to run, for each secondary logic device, a respective watchdog timer. Each watchdog timer is restarted upon receipt of a restart signal from the respective secondary logic device. The primary logic device is also configured, in response to a watchdog timer timing out, to identify and reset the secondary logic device corresponding to the timed out watchdog timer.

Abstract: A turboelectric generator system includes a gas turbine engine which includes, in fluid flow series, a gas-generator compressor, a combustor, a gas-generator turbine, and a variable-speed free power turbine. The system further comprises a variable-frequency electric machine rotatably connected with the free power turbine and a power converter configured to convert a variable frequency electrical output from the electric machine to a fixed frequency output.

Abstract: Gas turbine engines and methods of starting gas turbine engines, the gas turbine engine including: an electronic engine controller; one or more spools designated a starting spool for starting the engine, and has a required starting torque ?s; a permanent magnet alternator mechanically coupled with the starting spool, the alternator, in a motor mode, provides a peak torque of ?a, and, in a generator mode, generates electrical power for the electronic engine controller; and an electrical starter-generator mechanically coupled with the starting spool. The starter-generator in a motor mode, provides a peak torque of ?sg, and, in a generator mode, generates electrical power for an external load. ?sg+?a??s and ?sg, ?a<?s, and the electronic engine controller, during a start procedure, operates both the permanent magnet alternator and the starter-generator in a motor mode to drive the starting spool.

Abstract: A gas turbine engine having first and second rotary electric machines mechanically coupled with a spool is provided. The first rotary electric machine is mechanically coupled with the spool and has connected therewith a first power converter to interface the electric machine with a first dc network operating at a first voltage. The second rotary electric machine is mechanically coupled with the spool and has connected therewith a second power converter to interface the electric machine with a second dc network operating at a second voltage greater than said first voltage. The first electric machine and the second electric machine are operable as a motor-generator set for transfer of electrical power to the first dc network from the second dc network.

Abstract: A rotor for an electrical machine is provided. The rotor comprises: a rotor body; one or more magnets arranged around the rotor body; and a non-magnetic containment sleeve positioned radially outwardly of the one or more magnets. The containment sleeve has axially-alternating solid ring sections and reticulated ring sections.

Abstract: A turboelectric generator system includes a gas turbine engine which includes, in fluid flow series, a gas-generator compressor, a combustor, a gas-generator turbine, and a variable-speed free power turbine. The system further comprises a variable-frequency electric machine rotatably connected with the free power turbine and a power converter configured to convert a variable frequency electrical output from the electric machine to a fixed frequency output.

Abstract: Electrical systems for connecting rotary electric machines with gas turbine spools are provided. One such electrical system comprises: a first rotary electric machine mechanically coupled with a first gas turbine spool and a second rotary electric machine mechanically coupled with a second gas turbine spool, each said electric machine having an identical even number N?4 of phases, each phase having a respective index n=(1, . . .

Abstract: Stators for radial-flux rotary electric machines and methods of assembling stators for radial flux rotary electric machines are provided. One such stator comprises: a yoke with a plurality of teeth, each tooth extending from a root at the yoke to a tip, the width of each tooth at the root being greater than or equal to the width at the tip thereof to define open slots therebetween; a plurality of coils, each one of which is located on a respective one of the plurality of teeth, wherein the coils are sized such that the slot fill factor of between zero and unity to define axial voids in the slots; and a plurality of magnetic sealing members, each one of which is engaged with the tips of adjacent teeth to circumferentially and axially seal the axial voids in the slots for retaining an axial flow of coolant therein.

Abstract: Electrical systems for connecting rotary electric machines with gas turbine spools are provided. One such electrical system comprises: a first dual-wound rotary electric machine mechanically coupled with a first gas turbine spool and comprising a first three-phase sub-machine and a second three-phase submachine; a second dual-wound rotary electric machine mechanically coupled with a second gas turbine spool and comprising a third three-phase sub-machine and a fourth three-phase submachine; and a set of N=4 bidirectional converter circuits for conversion of alternating current (ac) to and from direct current (dc), each of which has an associated index n=(1, . . . , N), and for all n, the ac side of the nth bidirectional converter circuit is connected with the nth three-phase sub-machine. The dc side of the first converter circuit is connected with the dc side of the third converter circuit, and the dc side of the second converter circuit is connected with the dc side of the fourth converter circuit.

Abstract: Electrical systems for connecting rotary electric machines with gas turbine spools are provided. One such electrical system comprises: a first rotary electric machine mechanically coupled with a first gas turbine spool and a second rotary electric machine mechanically coupled with a second gas turbine spool, each said electric machine having an identical even number N?4 of phases, each phase having a respective index n=(1, . . .

Abstract: A power electronics unit for an aircraft and a method of determining the integrity of a power electronics unit are provided. The power electronics unit comprises an electric machine controller; a heatsink arranged to conduct heat from the electric machine controller; a housing comprising a sealed internal volume enclosing the electric machine controller and heatsink; a dielectric liquid partially filling the internal volume to cover the electric machine controller; a gas pocket within the internal volume; a pressure sensor arranged to measure a pressure of gas within the gas pocket; a temperature sensor arranged to measure a temperature within the internal volume; and a controller. The controller is configured to receive signals from the pressure sensor and temperature sensor, determine a pressure and temperature from the received signals and provide an output signal dependent on the determined temperature and pressure.

Abstract: A multi-logic device system, an electronic engine controller, and a method of operating the multi-logic device system. The multi-logic device system includes a primary logic device which is more resilient to single event effects, and one or more secondary logic devices, each secondary logic device being powered by a respective power supply unit and being more susceptible to single event effects. The primary logic device is configured to run, for each secondary logic device, a respective watchdog timer. Each watchdog timer is restarted upon receipt of a restart signal from the respective secondary logic device. The primary logic device is also configured, in response to a watchdog timer timing out, to identify and reset the secondary logic device corresponding to the timed out watchdog timer.

Abstract: A rotor for an electrical machine is provided. The rotor comprises: a rotor body; one or more magnets arranged around the rotor body; and a non-magnetic containment sleeve positioned radially outwardly of the one or more magnets. The containment sleeve has axially-alternating solid ring sections and reticulated ring sections.