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.

A fan drive gear system for a turbofan engine includes a geared architecture and a gear controller supporting the geared architecture and controlling rotation of the geared architecture relative a static structure.

A method for operating a gas turbine engine comprises providing fuel flow and compressed airflow to a combustor with a fuel-to-air ratio, the compressed airflow being from a compressed air source; detecting at least one parameter indicative of the fuel-to-air ratio being below a predetermined value; and bleeding compressed air from the compressed air source when the at least one parameter indicative of the fuel-to-air ratio is below the predetermined value to increase the fuel-to-air ratio to at least the predetermined value.

Herein provided are methods and systems for controlling an engine having a variable geometry mechanism. A power level difference between a requested engine power level and a current engine power level is determined at a computing device. The power level difference is compared to a predetermined power threshold at the computing device. When the power level difference exceeds the predetermined power threshold, a position control signal for changing a position of the variable geometry mechanism is generated and output at the computing device, the position control signal generated based on a requisite bias level, the requisite bias level being based on the power level difference.

Various embodiments of the present application provide one or more of: (1) auxiliary wheel that (a) enables accurate speed detection of a turbine disc and/or (b) presents a machining surface for balance correction; and/or (2) techniques for mounting an auxiliary wheel to a rotor, such as a turbine disc.

A unit (1, 10, 100) for generating non-propulsive electrical power for use on board an aircraft, the unit (1, 10, 100) comprising an electricity production device (3, 30) comprising a gas turbine (31) and an electricity generator (32) mechanically connected to an outlet shaft (33) of the gas turbine (31), said electricity generator (32) including output electrical connections (320) for being electrically connected to an electrical power supply network (2, 20, 200) on board an aircraft.

The unit (1, 10, 100) includes energy storage means (5) and regulator means (6) configured to control the speed of rotation of the gas turbine (31) as a function of the electrical power required by the on-board electrical power supply network (2, 20, 200).

A fuel cell system includes an air compressor that supplies oxidant gas to a fuel cell installed in a fuel cell vehicle, a measured rotational speed acquirer that acquires a measured value of rotational speed of the air compressor, and a controller that calculates a rotational speed command value of the air compressor based on required generated power of the fuel cell, calculates a torque command value of the air compressor based on the calculated rotational speed command value and current rotational speed of the air compressor, and controls rotational speed of the air compressor based on the calculated torque command value. The controller estimates the current rotational speed of the air compressor baaed on the measured value of the rotational speed acquired by the measured rotational speed acquirer and a history of the calculated torque command value, and calculates the torque command value by using the estimated rotational speed.

A direct drive electrically-geared turbofan is provided via a first magnetic gearbox assembly connected to a fan of a turbofan engine; a second magnetic gearbox assembly connected to a spool shaft of the turbofan engine; and a speed controller configured to adjust a rotational speed of the fan based on a rotational speed of the spool shaft by selectively coupling and decoupling the first magnetic gearbox assembly with the second magnetic gearbox assembly. In various aspects, the first or second magnetic gearbox assembly includes a permanent magnet array, while a different one of the first or second magnetic gearbox assemblies includes a rotor winding separated from the permanent magnet array by an air gap; and the speed controller is configured to selectively couple and decouple the first and second magnetic gearbox assemblies with each other via controlling a switch in a winding circuit with the rotor winding.

Devices and methods for the efficient disaggregation of tissue samples, separating the tissue into individual intact cells or small aggregates of cells for analysis. A device may include a chamber to receive fluid and a tissue specimen containing more than one cell to be disaggregated. The chamber may include an opening and an agitator in fluid contact with the fluid and the tissue specimen. The agitator may include a micromotor which provides rotational motion to a shaft and an impeller fixed to the shaft such that the impeller and the shaft rotate together upon provision of the rotational motion by the micromotor. The device may include an electrical energy source electrically coupled to the micromotor to rotate the impeller sufficient to disaggregate the one or more individual cells from the tissue specimen and in a manner which does not lyse the one or more individual cells.

A grow light fan is provided including a motorized housing, a fan assembly attached to the motorized housing and including a plurality of fan blades and a plurality of grow lights mounted on an underside of each fan blade. A controller is provided in the motorized housing and receives signals remotely, from a transmitter held by a user, to control the intensity of the grow lights and the speed and direction of the motor. A shroud and mounting bracket are also provided to secure and protect the grow light fan within a grow room.