A drive circuit for an electric pump motor is provided. The drive circuit includes an inverter and a contactor. The inverter is configured to supply variable frequency current to the electric motor. The contactor is configured to supply the line frequency current to the electric motor.

A drive circuit for an electric pump motor is provided. The drive circuit includes an inverter and a contactor. The inverter is configured to supply variable frequency current to the electric motor. The contactor is configured to supply the line frequency current to the electric motor.

A hard start capacitor replacement unit has a plurality of capacitors in a container sized to fit in existing hard start capacitor space. The capacitors are 4 metallized film capacitors wound in a single cylindrical capacitive element. The container has a common terminal and capacitors value terminals for the plurality of capacitors, which may be connected singly or in combination to provide a selected capacitance. An electronic or other relay connects the selected capacitance in parallel with a motor run capacitor. The hard start capacitor replacement unit is thereby adapted to replace a wide variety of hard start capacitors.

A hard start capacitor replacement unit has a plurality of capacitors in a container sized to fit in existing hard start capacitor space. The capacitors are 4 metallized film capacitors wound in a single cylindrical capacitive element. The container has a common terminal and capacitors value terminals for the plurality of capacitors, which may be connected singly or in combination to provide a selected capacitance. An electronic or other relay connects the selected capacitance in parallel with a motor run capacitor. The hard start capacitor replacement unit is thereby adapted to replace a wide variety of hard start capacitors.

A drive circuit for an electric motor includes a first filter, a rectifier, an inverter, and a line contactor. The first filter is configured to be coupled to an AC source and produces a filtered line frequency AC signal. The rectifier is coupled to the filter and produces a DC signal from the filtered line frequency AC signal. The inverter is coupled to the rectifier and produces an AC signal on an output node of the inverter. The AC signal is supplied to the electric motor to energize its stator windings. The line contactor is coupled between an output node of the first filter and the output node of the inverter. The line contactor supplies the output node of the inverter directly with the filtered line frequency AC signal to energize the stator windings when the inverter is disabled.

A motor control system for induction-type AC electric motors having starting and run windings has a multiphase VFD drive with first and second phase outputs. A switching device with a first position, where a first output of the VFD drive is coupled to the run winding and a second output of the VFD drive couples to the start winding; and with the switching apparatus in second position, the run winding of the AC electric motor couples to an AC line input and the start winding of the AC electric motor couples through a capacitor and start switch to the AC line input. With the switching device in the first position, the second output of the VFD is configured to discontinue driving the start winding of the motor after the motor begins rotating.

The invention relates to a control apparatus for a refrigerator compressor having at least one two-phase AC asynchronous motor (K1, K2), having mains connection means (10) for connection to a preferably public voltage supply network Which nominally provides a mains AC voltage of between 85 V and 264 V, in particular between 100 V and 230 V, first voltage converter means (14) which are connected downstream of the mains connection means and are intended to generate an intermediate voltage, in particular an intermediate DC voltage, from the mains AC voltage, second voltage converter means (16-1, 16-2) which are connected downstream of the first voltage converter means and are intended to generate an output signal which is independent of a level and a mains frequency of the mains AC voltage, in particular has a constant voltage and/or frequency in periods, and is intended to control the refrigerator compressor with an AC voltage of a plurality of differently predefinable voltage levels, wherein the mains connection means are assigned voltage detector means (12) for capturing the mains AC voltage, the detector output signal from which can be evaluated by the second voltage converter means or control means (24) assigned to the latter for the purpose of generating a mains-voltage-dependent maximum value for a current of the output signal.

Start capacitor assemblies and methods for operating electric motors are described. In one example, a start capacitor assembly for connection to an electric motor includes a film capacitor and a resistor. The film capacitor has a first terminal and a second terminal. The resistor is coupled to the film capacitor in parallel with the first terminal and the second terminal of the film capacitor

Start capacitor assemblies and methods for operating electric motors are described. In one example, a start capacitor assembly for connection to an electric motor includes a film capacitor and a resistor. The film capacitor has a first terminal and a second terminal. The resistor is coupled to the film capacitor in parallel with the first terminal and the second terminal of the film capacitor

A system in which the operation of an electric motor is controlled by electronically controlled switches. The system includes the motor having a run winding and a start winding, a heating component, and a motor control subsystem. A control unit closes a first switch to energize the run winding, closes a second switch to energize the start winding, determines based on an amplitude and a lag time of a current flowing through the motor whether the motor has started and is running normally, and if so, opens the second switch to de-energize the start winding and closes a third switch to activate the heating component. The control unit determines whether the motor has started and is running normally by comparing the real time amplitude and lag time of the current to a plurality of stored amplitudes and lag times associated with different operating conditions.