An electric machine and a turning gear system for aircraft gas turbine engines are provided. The system has an electric machine designed for dual mode operation and a controller. The stator winding arrangement in the electric machine enables operation in either generating mode, during normal flight or motoring mode, during active engine turning. The controller is configured to reconfiguration connections of the windings external to the electric machine.

A power tool that includes an electric motor. The electric motor includes a plurality of stator windings, a plurality of switches for selectively coupling the plurality of stator windings in a first configuration or a second configuration, and a controller connected to the plurality of switches. The controller is configured to control the plurality of switches to configure the plurality of stator windings in the first configuration, monitor a condition of the power tool, and control the plurality of switches to configure the plurality of stator windings in the second configuration based on the condition of the power tool.

An electric drive unit for a hybrid drive, in particular for a vehicle, has an increased power output and degree of efficiency, while thermal loading as well as required installation space and manufacturing costs are minimized. The electric drive unit has an asynchronous machine with a rotor with a rotor cage, in particular a rotor cage which is formed with copper conductors. The asynchronous machine is formed with a stator having a shaft winding. The shaft winding is formed with a device for star-delta changeover. The rotor is formed with a rotor internal cooling device. A step-up gear mechanism is arranged in a power train between the rotor and the output element. There is also described a hybrid drive device with an electric drive unit, and a vehicle that has an electric drive unit and/or a hybrid drive device.

A permanent-magnet synchronous machine comprises a rotor and a stator for holding at least one first stator winding and a second stator winding which is electrically insulated from said first stator winding. The second stator winding has a smaller conductor cross section and a larger number of turns than the first stator winding, wherein a first operating voltage is provided for motor operation of the first stator winding and a second operating voltage is provided for motor operation of the second stator winding. The second operating voltage has a higher rated voltage than a rated voltage of the first operating voltage.

Various embodiments include determining an alternating current (AC) voltage and frequency of a supply voltage coupled to a circuit input. The circuit includes a soft starter circuit that is coupled between the circuit input and a first side of an AC motor. A stator winding configuration of the AC motor is determined. A control transformer is configured in response to the AC voltage and frequency, wherein the control transformer is coupled to the circuit input. A jumper device is configured on a second side of the AC motor in response to the stator winding configuration of the AC motor.

An air conditioner includes a compressor to compress a refrigerant used in a refrigeration cycle, a converter to generate DC voltage, an inverter to generate three-phase AC voltage from the DC voltage, a motor to generate driving force to drive the compressor by using a plurality of coils to which the three-phase AC voltage is applied, a connection switching unit to switch connection states of the plurality of coils, and an outdoor control device to control the connection switching unit. The outdoor control device restricts the switching of the connection states when a switching count of the connection states exceeds a count threshold value.

In a motor driving apparatus including a DC power supply circuit of variable output voltage value, an inverter of variable frequency, and a connection switching device for selecting connection, switching of the connection switching device is performed in a state where an output voltage of the DC power supply circuit is increased, a rotational speed of a motor is increased, and a current flowing through the motor is made not greater than a predetermined threshold. For example, the switching of the connection switching device is performed in a state where the current through the motor is made zero. For example, the switching is performed in a state where the output voltage of the DC power supply circuit is set at a value corresponding to the rotational speed of the motor during the switching. It is possible to prevent increase in apparatus size and switch the connection of windings while the motor is rotating.

An electric motor drive device includes: a main substrate mounted with a power supply circuit that generates, on the basis of alternating-current power supplied from an alternating-current power supply, a drive power to drive a compressor motor; a plurality of connection switching relays that perform switching between connections for the compressor motor; a small substrate mounted with the connection switching relays; a relay drive circuit that switches the connection switching relays; lead wires that connect the compressor motor and the small substrate to the power supply circuit; and lead wires that connect the small substrate and the compressor motor.

A motor driving device that is a device for driving a motor including stator windings, includes: a connection switching unit that includes relays as mechanical switches connected to the stator windings and excitation coils opening or closing the relays by being energized or non-energized with excitation current and switches connection condition of the stator windings to either of first connection condition (star connection) and second connection condition (delta connection) different from the first connection condition by opening or closing the relays; and an inverter that supplies AC drive voltages to the stator windings.

The motor driving apparatus includes a switch that is a mechanical switch for changing coil connection states of a motor; an inverter that generates alternating voltage from direct voltage and outputs the alternating voltage to the motor; and a control device that controls the switch and the inverter. The control device causes the switch to change the coil connection states while the alternating voltage output from the inverter is zero.