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.

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.

A driving device drives a motor having coils. The driving device includes a converter to generate a bus voltage, an inverter to convert the bus voltage to an AC voltage and supply the AC voltage to the coils, and a connection switching unit to switch a connection state of the coils. The bus voltage generated by the converter is switched in accordance with the connection state of the coils.

In the field of motor protection for industrial automation systems, HVAC systems, pumping systems, and/or similar implementations, improved motor starters and overload electronics can be configured to offer substantially automatic levels of protection for motors, independent of such starters and/or overload electronics first being calibrated for, or properly calibrated for, the motor.

An electric-motor driving device includes an inverter connected to terminals connected to windings of an electric motor including the windings, the inverter applying an alternating-current voltage to the electric motor, a switching unit connected to the terminals and capable of switching a connection state between the terminals, a detecting unit that detects at least one of a voltage and an electric current of the inverter, and a control unit that determines on the basis of a detection value detected by the detecting unit that an abnormality occurs in the switching unit and controls the inverter to short-circuit at least two of the terminals.

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.

Method for controlling the speed of rotation of an electric motor by means of a variable speed drive supplied with power by a mains electrical power supply, in which method in a variable speed mode of operation the motor is supplied with power by the variable speed drive and in a fixed speed mode of operation the motor is supplied with power directly by the mains supply, and in which method before the changeover from the supply of power by the variable speed drive to the direct supply of power by the mains supply, the motor is first accelerated by the variable speed drive, the variable speed drive operating beyond its nominal current during the acceleration preceding the changeover.

A driving device is used with a compressor including a motor including coils. The driving device drives the motor. The driving device includes an inverter connected to the coils, a connection switching unit to switch a connection state of the coils between a first connection state and a second connection state, a controller to control the inverter and the connection switching unit, and a compressor state detection unit to detect a state of the compressor. When the connection state of the coils is the first connection state, the controller controls the motor based on a first detection value detected by the compressor state detection unit and a first threshold. When the connection state of the coils is the second connection state, the controller controls the motor based on a second detection value detected by the compressor state detection unit and a second threshold.

A driving device drives a motor having coils. The driving device includes a converter to generate a bus voltage, an inverter to convert the bus voltage to an AC voltage and supply the AC voltage to the coils, and a connection switching unit to switch a connection state of the coils. The bus voltage generated by the converter is switched in accordance with the connection state of the coils.