A device for switching in and out a start winding of a single phase AC motor using an energizer winding to generate voltage which can be used to power a simple timing switch circuit. The AC voltage is rectified and converted to DC voltage. The DC voltage is then used to drive a normally closed solid state switch to an open state which in turn inactivates a triac connected to the start winding in the motor. The “on time” of the start winding is controlled by a RC circuit that ramps the voltage to the gate of a FET that drives current through the normally closed solid state switch.

A device for switching in and out a start winding of a single phase AC motor using an energizer winding to generate voltage which can be used to power a simple timing switch circuit. The AC voltage is rectified and converted to DC voltage. The DC voltage is then used to drive a normally closed solid state switch to an open state which in turn inactivates a triac connected to the start winding in the motor. The “on time” of the start winding is controlled by a RC circuit that ramps the voltage to the gate of a FET that drives current through the normally closed solid state switch.

A method of controlling a brushless permanent magnet motor includes measuring a mains power supply voltage of the motor. The method includes determining whether the mains power supply voltage lies within a first range representative of a first country's mains power supply or a second range representative of a second country's mains power supply. The method includes advancing commutation of a winding of the motor relative to a zero-crossing of back EMF in the winding where the mains power supply voltage lies within the first range, and retarding commutation of the winding relative to a zero-crossing of back EMF in the winding where the mains power supply voltage lies within the second range.

A control method includes setting, when a space phase difference of in-phase coils of the respective groups is represented by α, a time phase difference of electric currents to be supplied to the in-phase coils of the respective groups is represented by β, and a time phase difference of carrier frequencies with which the three-phase inverters are PWM-controlled, respectively, is represented by γ, values of β and γ so that any one or both of the following relationships are satisfied: γ=±(α+2β), and γ=±(α−β)/2, based on a result of comparison between a current amplitude of a primary component and a current amplitude of a secondary component of a carrier harmonic current, to control the dynamoelectric machine.

A power tool includes a tool accessory, a motor, a control module, a power supply, and an operating switch. The operating switch includes a trigger mechanism, a current switch coupled to the trigger mechanism to be actuated by the trigger mechanism for connecting and disconnecting the electrical connection between the power supply module and the motor, and a signal switch coupled to the trigger mechanism to be actuated by the trigger mechanism at least configured to output a control signal to the control module to control the start of the motor.

Controllers for controlling hybrid motor drive circuits configured to drive a motor are provided herein. A controller is configured to drive the motor using an inverter when a motor commanded frequency is not within a predetermined range of line input power frequencies, and couple line input power to an output of the inverter using a first switch device when the motor commanded frequency is within the predetermined range of line input power frequencies.

The present invention provides a control system (100, 200, 300) for controlling a single phase induction motor (150, 250) with a main winding (151, 251) and with an auxiliary winding (152, 252), the control system (100, 200, 300) comprising a first bidirectional switching element (101) and a second bidirectional switching element (102), wherein the first bidirectional switching element (101) is arranged between a phase supply input (103, 203) of the single phase induction motor (150, 250) and the main winding (151, 251) and wherein the second bidirectional switching element (102) is arranged electrically parallel to the main winding (151, 251), and a control unit (105, 205) coupled to the first bidirectional switching element (101) and the second bidirectional switching element (102).

The present invention provides a control system (100, 200, 300) for controlling a single phase induction motor (150, 250) with a main winding (151, 251) and with an auxiliary winding (152, 252), the control system (100, 200, 300) comprising a first bidirectional switching element (101) and a second bidirectional switching element (102), wherein the first bidirectional switching element (101) is arranged between a phase supply input (103, 203) of the single phase induction motor (150, 250) and the main winding (151, 251) and wherein the second bidirectional switching element (102) is arranged electrically parallel to the main winding (151, 251), and a control unit (105, 205) coupled to the first bidirectional switching element (101) and the second bidirectional switching element (102).

An induction-type AC electric motor system has a variable frequency motor (VFD) drive having at least two outputs, the VFD drive coupled to be powered by a solar input and to power the motor with a switching device in a first setting. With the switching device in a second setting, a run winding of the AC electric motor couples to an AC input and a start winding of the AC motor couples through a capacitor and start switch to the AC input. The system is configured to, upon determining motor start, put the contactor in first setting and use the VFD drive to continue running the motor, and, when the AC motor is not rotating, the system is configured to periodically measure available solar power and to start the AC motor if the available solar power exceeds a first threshold power determined sufficient to run the AC motor.

A compressor unit (2) for use in a refrigeration circuit, comprises at least two compressors (8, 10); and a common variable frequency drive (6), configured to be connected to a three phase grid voltage supply (4); each compressor (8, 10) having an inlet port (12) configured to be in refrigerant communication, via a suction line, with an outlet of an evaporator; an outlet port (14) configured to be in refrigerant communication, via a pressure line, to an inlet of a condenser; a compressor motor (18), particularly an alternating current induction motor, with a three phase supply line (32-1, 32-2); a power modulation means (24) for controlling the power of the compressor (8, 10) according to its load needs; wherein each compressor (8, 10) is switchable, independently from the respective other compressor(s) (8, 10), to be connected, during start-up and acceleration of the respective compressor (8, 10), to the common variable frequency drive (6), and to be connected, during rated-speed operation of the respective compressor (8, 10), to a common three phase grid voltage supply (4).