An aircraft includes a power source arranged to provide AC electrical power of varying frequency, and a brake cooling fan including an impeller which is driven by an electric motor powered by said AC electrical power for cooling brakes of the aircrafts wheels. The brake cooling fan has an operable mode when the frequency of said AC electrical power meets certain criteria indicating that the frequency of the AC power is suitable for powering the motor, and an inoperable mode to protect against unsuitable operation of the motor. The brake cooling fan may then be safely powered with AC power direct from a wild frequency power network on the aircraft without needing a power inverter or constant power supply generator.

An aircraft includes a power source arranged to provide AC electrical power of varying frequency, and a brake cooling fan including an impeller which is driven by an electric motor powered by said AC electrical power for cooling brakes of the aircrafts wheels. The brake cooling fan has an operable mode when the frequency of said AC electrical power meets certain criteria indicating that the frequency of the AC power is suitable for powering the motor, and an inoperable mode to protect against unsuitable operation of the motor. The brake cooling fan may then be safely powered with AC power direct from a wild frequency power network on the aircraft without needing a power inverter or constant power supply generator.

An example aircraft includes a parallel propulsion unit, the parallel propulsion unit comprising: a propulsor configured to provide forward propulsion of the aircraft; a gas turbine engine configured to drive the propulsor; an electrical machine configured to generate, for output via one or more electrical busses, electrical energy using mechanical energy derived from the gas turbine engine; and a power sharing module configured to control a ratio of the mechanical energy used to drive the propulsor and used to generate electrical energy; and a plurality of series propulsion units, each series propulsion unit comprising a respective propulsor of a plurality of propulsors that are configured to provide vertical propulsion of the aircraft and a respective electrical machine of a plurality of electrical machines, each respective electrical machine configured to drive a respective propulsor of the plurality of propulsors using electrical energy received from one or more electrical busses.

A system for controlling a plurality of motors includes: a variable frequency drive (VFD) configured to control at least one property of the motors, the VFD having a current interruption rating that is greater than a continuous current rating of all of the plurality of motors combined; a bus electrically connected to the VFD; and a plurality of protection modules, each protection module including: a motor overload device electrically connected to a particular one of the plurality of motors; and a switching relay in series with the motor overload device, the switching relay configured to connect the protection module to and disconnect the protection module from the bus. A state of the switching relay determines whether the protection module is electrically connected to the bus, the VFD is configured to control the state of the switching relay, and the switching relay has a current interruption rating that is less than the continuous current rating of the particular one of the plurality of motors.

An electric vehicle accomplishes speed changes through the use of electronically controlled, multiple electric motor configurations that are coupled to an output drive shaft instead of a speed change transmission. A parallel-coupled motor configuration includes at least two motors that are each coupled to the output drive shaft through respective gear arrangements, each gear arrangement having a respective gear ratio. In a serially-coupled motor configuration, the stator of the second motor is coupled to the rotor of the first motor, where the rotor of the second motor is coupled to the output drive shaft. The required torque to reach or maintain a desired vehicle speed can be obtained by selective energization of either one or both of the motors (in both multi-motor configurations). Two motors are also coupled to a differential gear so that the rotational speed contributed by both motors are additive at the output shaft.

A back-drive speed control system for incorporation into an actuated vehicle seating system includes an actuator having a permanent magnet and a coil that can move relative to each other to create a voltage across a first terminal and a second terminal. The actuator is adapted to move a linkage in an actuated vehicle seating system. A biasing member moves one or both of the permanent magnet and the coil such that the first terminal has a positive potential relative to the second terminal. The back-drive speed control system further includes a first diode and a Zener diode in series connected across the first terminal and the second terminal such that the forward current direction of the first diode is oriented in the opposite direction to the forward current direction of the Zener diode.

An aircraft includes a power source arranged to provide AC electrical power of varying frequency, and a brake cooling fan including an impeller which is driven by an electric motor powered by said AC electrical power for cooling brakes of the aircrafts wheels. The brake cooling fan has an operable mode when the frequency of said AC electrical power meets certain criteria indicating that the frequency of the AC power is suitable for powering the motor, and an inoperable mode to protect against unsuitable operation of the motor. The brake cooling fan may then be safely powered with AC power direct from a wild frequency power network on the aircraft without needing a power inverter or constant power supply generator.

An aircraft includes a power source arranged to provide AC electrical power of varying frequency, and a brake cooling fan including an impeller which is driven by an electric motor powered by said AC electrical power for cooling brakes of the aircrafts wheels. The brake cooling fan has an operable mode when the frequency of said AC electrical power meets certain criteria indicating that the frequency of the AC power is suitable for powering the motor, and an inoperable mode to protect against unsuitable operation of the motor. The brake cooling fan may then be safely powered with AC power direct from a wild frequency power network on the aircraft without needing a power inverter or constant power supply generator.

A driving apparatus which reduces power consumption as compared to conventional driving apparatuses. A voltage amplitude of first AC voltages is controlled based on a relative angle between a moving direction of a moving body, which is indicated by a driving command for moving the moving body, and a driving direction of a first vibrator, and a voltage amplitude of second AC voltages is controlled based on a relative angle between the moving direction and a driving direction of a second vibrator. Each of the first vibrator and the second vibrator is controlled based on a deviation between the driving command and a detected position of the moving body while the first AC voltages and the second AC voltages are being controlled. The driving direction of the first vibrator and the driving direction of the second vibrator cross each other.

A centralized control mechanism for a multi-motor drive, the mechanism including: a plurality of independent motor drive modules; a power source module; an interface control microprocessor; a communication module; and a plurality of interface modules of motors. The power source module supplies power for each circuit, and each independent motor drive module drives one permanent magnet motor. Each motor drive module includes a motor microprocessor, an inverter circuit, and a phase current detection circuit. The phase current detection circuit transmits detected data to the motor microprocessor, and the motor microprocessor outputs multiple paths of PWM signals to the inverter circuit and controls the inverter circuit. An output end of the inverter circuit is connected to a coil winding of the PM motor. The plurality of motor microprocessors communicates with the interface control microprocessor via a data bus. The interface control microprocessor communicates with the outside via the communication module.