Abstract: The present application discloses a fuel system for a gas turbine engine. The engine includes a main alternating current electrical generator driven by an engine shaft such that the electrical output frequency of the electrical generator varies in dependence on shaft rotational speed. The fuel system includes a variable flow fuel pump for providing a fuel flow to the engine, a frequency and/or voltage controller configured to provide electrical power having at least one of a predetermined output frequency and a predetermined voltage, and a variable speed electric motor configured to drive the fuel pump. The electric motor includes an induction motor having a stator and at least a first rotor, the stator having first and second sets of stator windings. Each set of stator windings is configured to impart a torque on the rotor in use.

Abstract: This invention relates to a multi-spool gas turbine engine, including: a first generator for providing electrical power to an electrical system, the generator being driveably connected to a first spool; a second generator for providing electrical power to the electrical system, the generator being driveably connected to a second spool; a disconnection device for disconnecting the second generator from the second spool; and, a controller configured to selectively operate the disconnection device under predetermined powered engine conditions.

Abstract: An aircraft electrical power generation system includes an AC generator having a rotor including a plurality of electromagnetic rotor-windings and stator including plurality of electrical stator-windings. The rotor mechanically coupled to a shaft of a gas turbine engine by transmission-system. The generator includes a frequency controller, a torque sensor determining a torque on the transmission-system by the generator and controller to operate the system in first and second modes. In first mode, the power output frequency of the generator controlled by the frequency controller within limits, and reduced idle signal going to a turbine engine controller. In second mode, the power output frequency of the generator not controlled by the frequency controller and increased idle signal going to the turbine engine controller. The controller operates the system in first mode when the torque is below a limit, and in second mode when the torque is above a limit.

Abstract: This invention relates to a superconducting electrical network, comprising: an electrical system including a plurality of superconducting electrical equipment; a cryogenic system including one or more refrigeration units for providing coolant to the plurality of superconducting electrical equipment; a controller configured to control the flow of coolant to the plurality of superconducting electrical equipment, wherein the controller is configured to isolate the supply of refrigerant to one or more of the plurality of electrical equipment upon demand and increase the flow of coolant to one or more of the non-isolated plurality of electrical equipment.

Abstract: A fuel system for a gas turbine engine, the gas turbine engine including a combustor having a pilot fuel injector and a main fuel injector, the fuel system including first and second variable flow fuel pumps configured to provide metered fuel flow to the pilot injector, and the main injector respectively; first and second variable speed electric motors configured to drive respective first and second fuel pumps; wherein each of the electric motors includes a polyphase motor including a stator having concentrated windings.

Abstract: There is provided apparatus for propagation of a wireless signal through a barrier comprising a first antenna for location on a first side of the barrier, a second antenna for location on a second side of the barrier and a waveguide. The waveguide comprises a conducting member passing through the barrier between the first and second sides. The conducting member is held within an insulator sleeve such that it is spaced from a surrounding metal wall of the waveguide. A wireless signal received by the waveguide on the first side of the barrier is transmitted through the barrier by Transverse Electro-Magnetic (TEM) mode propagation along the waveguide is re-radiated on the second side.

Abstract: A magnetic shielding arrangement, including: at least one magnetic flux source; a superconductor magnetic shield at least partially surrounding the magnetic flux source; a second shield at least partially surrounding the superconductor magnetic shield.

Abstract: The present application discloses a fuel system for a gas turbine engine. The engine includes a main alternating current electrical generator driven by an engine shaft such that the electrical output frequency of the electrical generator varies in dependence on shaft rotational speed. The fuel system includes a variable flow fuel pump for providing a fuel flow to the engine, a frequency and/or voltage controller configured to provide electrical power having at least one of a predetermined output frequency and a predetermined voltage, and a variable speed electric motor configured to drive the fuel pump. The electric motor includes an induction motor having a stator and at least a first rotor, the stator having first and second sets of stator windings. Each set of stator windings is configured to impart a torque on the rotor in use.

Abstract: An aircraft electrical power generation system includes an AC generator having a rotor including a plurality of electromagnetic rotor-windings and stator including plurality of electrical stator-windings. The rotor mechanically coupled to a shaft of a gas turbine engine by transmission-system. The generator includes a frequency controller, a torque sensor determining a torque on the transmission-system by the generator and controller to operate the system in first and second modes. In first mode, the power output frequency of the generator controlled by the frequency controller within limits, and reduced idle signal going to a turbine engine controller. In second mode, the power output frequency of the generator not controlled by the frequency controller and increased idle signal going to the turbine engine controller. The controller operates the system in first mode when the torque is below a limit, and in second mode when the torque is above a limit.

Abstract: This invention relates to a multi-spool gas turbine engine, including: a first generator for providing electrical power to an electrical system, the generator being driveably connected to a first spool; a second generator for providing electrical power to the electrical system, the generator being driveably connected to a second spool; a disconnection device for disconnecting the second generator from the second spool; and, a controller configured to selectively operate the disconnection device under predetermined powered engine conditions.

Abstract: A method of operating an electrical power generation system on an aircraft. The method includes assessing a required electrical power of the aircraft, assessing whether a first and a second electrical power source are able to provide the required electrical power in combination, assessing a predetermined condition, determining an operating mode of the first and second electrical power sources to match the predetermined condition, and operating the first and second electrical power sources according to the determined operating mode.

Abstract: There is provided apparatus for propagation of a wireless signal through a barrier comprising a first antenna for location on a first side of the barrier, a second antenna for location on a second side of the barrier and a waveguide. The waveguide comprises a conducting member passing through the barrier between the first and second sides. The conducting member is held within an insulator sleeve such that it is spaced from a surrounding metal wall of the waveguide. A wireless signal received by the waveguide on the first side of the barrier is transmitted through the barrier by Transverse Electro-Magnetic (TEM) mode propagation along the waveguide is re-radiated on the second side.

Abstract: A magnetic gear arrangement includes: a first gear member for generating a first magnetic field, a second gear member for generating a second magnetic field, and a coupling device which provides an arrangement of interpoles between the first gear member and the second gear member. The interpoles couple the first and second magnetic fields to produce a gearing between the first and second gear members. The first gear member has superconducting magnets or coils for generating the first magnetic field and/or the second gear member has superconducting magnets or coils for generating the second magnetic field.

Abstract: A magnetic gear arrangement is provided comprising a first gear member for generating a first magnetic field and a second gear member for generating a second magnetic field. A coupling element is disposed between the first and second gear members and provides arrangements of interpoles which couple the first and second magnetic fields. The coupling element comprises a plurality of magnetisable lamellae, each interpole in an arrangement of interpoles being formed from a group of neighboring lamellae. Selected lamellae are deactivatable to provide boundaries between adjacent interpoles. This allows different numbers and arrangements of interpoles to be formed, so as to provide different gear ratios between the first and second gear members.

Abstract: A magnetic gear arrangement includes: a first gear member for generating a first magnetic field, a second gear member for generating a second magnetic field, and a coupling device which provides an arrangement of interpoles between the first gear member and the second gear member. The interpoles couple the first and second magnetic fields to produce a gearing between the first and second gear members. The first gear member has superconducting magnets or coils for generating the first magnetic field and/or the second gear member has superconducting magnets or coils for generating the second magnetic field.