AC motor systems with drive circuits and methods of use

An alternating current (AC) motor system comprising:

• a three-phase AC motor having a first rated horsepower and configured to be coupled to a single-phase AC power source, the single-phase AC power source including first and second line input terminals, said three-phase AC motor comprising a first winding, a second winding, a third winding, a series-coupled switch device, and a capacitor;
• a drive circuit configured to be electrically coupled between the power source and said motor, said drive circuit having a second rated horsepower that is lower than the first rated horsepower;
• a bypass contactor electrically coupled, in parallel with said drive circuit, to the first and second line input terminals and said motor, said bypass contactor configured to enable said motor to operate at the first rated horsepower while bypassing said drive circuit;
• wherein the first winding is configured to be coupled to one of a first phase output of said drive circuit or a first line input terminal of the single-phase AC power source via said bypass contactor;
• wherein the second winding is configured to be coupled to one of a second phase output of said drive circuit or a second line input terminal of the single-phase AC power source via said bypass contactor;
• wherein the third winding is configured to be coupled to a third phase output of said drive circuit, wherein said first, second, and third windings are arranged in a wye connection pattern;
• and
• wherein the series-coupled switch device and capacitor are coupled between input sides of said second and third windings, said series-coupled switch device and said capacitor configured to generate a third phase of power when the single-phase AC power source is coupled directly to said motor.

An alternating current (AC) motor system comprising:

• a three-phase AC motor having a first rated horsepower and configured to be coupled to a single-phase AC power source, the single-phase AC power source including first and second line input terminals, said three-phase AC motor comprising a first winding, a second winding, a third winding, a parallel-coupled switch device, and a capacitor;
• a drive circuit configured to be electrically coupled between the power source and said motor, said drive circuit having a second rated horsepower that is lower than the first rated horsepower;
• a bypass contactor electrically coupled, in parallel with said drive circuit, to the first and second line input terminals and said motor, said bypass contactor configured to enable said motor to operate at the first rated horsepower while bypassing said drive circuit;
• wherein the first winding is configured to be coupled between first and second phase outputs of said drive circuit or to a first line input terminal of the single-phase AC power source via said bypass contactor,
• wherein the second winding is configured to be coupled between second and third phase outputs of said drive circuit or a second line input terminal of the single-phase AC power source via said bypass contactor;
• wherein the third winding is configured to be coupled between first and third phase outputs of said drive circuit, wherein said first, second, and third windings are arranged in a delta connection pattern;
• and
• wherein the parallel-coupled switch device and capacitor are coupled between the third phase output and the third winding, said parallel-coupled switch device and said capacitor configured to generate a third phase of power when the single-phase AC power source is coupled directly to said motor.

A method comprising:

• providing a motor having a first rated horsepower, the motor configured to be coupled to a power source;
• electrically coupling a drive circuit between the power source and the motor, the drive circuit having a second rated horsepower that is lower than the first rated horsepower, the drive circuit including a drive circuit controller;
• electrically coupling a drive output contactor in series between the drive circuit and the motor;
• and
• receiving, at the drive output contactor, a low speed command signal directly from an application controller;
• activating, in response to receiving the low speed command signal from the application controller, the drive output contactor to enable operation of the motor at the second rated horsepower utilizing the drive circuit.