An electric motor drive unit includes a winding switching unit that switches a configuration of windings of an electric motor, a winding switching instruction unit that generates an instruction signal for the winding switching unit, and a winding configuration retention unit to which the instruction signal generated by the winding switching instruction unit is input, and if the input instruction signal has a first value, outputs a signal corresponding to the input instruction signal to the winding switching unit, and if the input instruction signal has a second value different from the first value, continues outputting a signal that has been output to the winding switching unit before the reception of the second value, the first value indicating an instruction on the configuration of the windings.

An electric motor drive unit includes a winding switching unit that switches a configuration of windings of an electric motor, a winding switching instruction unit that generates an instruction signal for the winding switching unit, and a winding configuration retention unit to which the instruction signal generated by the winding switching instruction unit is input, and if the input instruction signal has a first value, outputs a signal corresponding to the input instruction signal to the winding switching unit, and if the input instruction signal has a second value different from the first value, continues outputting a signal that has been output to the winding switching unit before the reception of the second value, the first value indicating an instruction on the configuration of the windings.

This method for controlling asynchronous electrical motors of a compressor system, comprises: —receiving an order to start a first asynchronous electrical motor and a second asynchronous electrical motor of a compressor system; —unloading said first and second motors, by operating respectively a first load control unit of the first motor and a second load control unit of the second motor, in order to reduce the mechanical load associated to said motors; —starting the first motor and, only once the first motor is running at nominal speed, starting the second motor, —loading both the first and second electrical motor only once the second motor has started and is running at nominal speed, by operating the first load control unit and the second load control unit, in order to increase the mechanical load associated to said motors.

A vacuum pump drive comprising at least one electric motor which is connected to the rotor of a vacuum pump via a drive shaft, a frequency converter which is electrically connected to the motor and which supplies a motor input voltage to the motor, and a switchover device with at least one electric switch. The switchover device is designed to connect the motor windings in a star or delta shape depending on the switching position of the switch in order to change the motor characteristic curve. The vacuum pump drive also comprises a measuring device with sensors for detecting physical operating variables of the vacuum pump and a controller which is electrically or optically connected to the switchover device and the measuring device and which is designed to actuate the at least one switch on the basis of the measured value of the operating variable of the vacuum pump in order to produce the star-delta switchover.

A vacuum pump drive comprising at least one electric motor which is connected to the rotor of a vacuum pump via a drive shaft, a frequency converter which is electrically connected to the motor and which supplies a motor input voltage to the motor, and a switchover device with at least one electric switch. The switchover device is designed to connect the motor windings in a star or delta shape depending on the switching position of the switch in order to change the motor characteristic curve. The vacuum pump drive also comprises a measuring device with sensors for detecting physical operating variables of the vacuum pump and a controller which is electrically or optically connected to the switchover device and the measuring device and which is designed to actuate the at least one switch on the basis of the measured value of the operating variable of the vacuum pump in order to produce the star-delta switchover.

A drive device that includes a rotating-field rotary electric machine; and an inverter that drives the rotary electric machine, wherein: the rotary electric machine includes a stator core, and a coil wound on the stator core; the coil includes a first coil and a second coil electrically insulated from each other; and the inverter includes a first inverter circuit that supplies AC power to the first coil, and a second inverter circuit that supplies AC power to the second coil.

The present disclosure relates to an apparatus and method for controlling switching of a wiring mode of a motor capable of being operated in a plurality of wiring modes, a motor control apparatus includes a motor including a rotor that rotates according to a motor torque by a pulse width modulation (PWM) control, a switching unit provided at the motor and switching a wiring method inside the motor so that the motor is driven according to another wiring mode, and a controller generating a speed command frequency for controlling a rotation speed of the rotor, and controlling the switching unit so that the wiring mode of the motor is switched according to a result of comparing the speed command frequency with a switching boundary frequency according to the wiring mode of the motor, wherein when the PWM control is stopped in response to the switching of the wiring mode, the controller estimates a rotation state of the rotor that rotates inertially, and when the PWM control is restarted, the controller sets the estimated rotation state of the rotor as an initial value of the rotor, and controls a rotation speed of the motor of which the wiring mode is switched based on the set initial value of the rotor.

One embodiment describes a method that includes determining, using a control circuitry, temperature of a switching device before a make operation by applying a measurement current to an operating coil of the switching device, wherein the measurement current is insufficient to make the switching device; and determining voltage at the operating coil when the measurement current is applied, in which the voltage at the operating coil is directly related to the temperature. The method further includes determining, using the control circuitry, when to apply a pull-in current to the operating coil to close the switching device based at least in part on the voltage at the operating coil, such that the switching device makes at a desired time.

One embodiment describes a method that includes determining, using a control circuitry, temperature of a switching device before a make operation by applying a measurement current to an operating coil of the switching device, wherein the measurement current is insufficient to make the switching device; and determining voltage at the operating coil when the measurement current is applied, in which the voltage at the operating coil is directly related to the temperature. The method further includes determining, using the control circuitry, when to apply a pull-in current to the operating coil to close the switching device based at least in part on the voltage at the operating coil, such that the switching device makes at a desired time.

A power supply device includes connector from a power source, a rectifying module, a power supply module, and a bulk capacitor. The capacitor stores and smoothes the rectified power, and outputs the smoothed power to the power supply module. The connector is capable of connecting to the power source through a Delta connection and a Wye connection.