System and method for detecting motor coil-to-coil faults

A fault detection system for detecting coil-to-coil faults in an electric motor having a plurality of phase coils, the fault detection system comprising:

• a driver circuit connected to a first one of the coils and applying a square wave signal to the coil;
• a capacitor and a resistor connected between a second one of the coils and a first switch, the first switch also connected to ground potential;
• a second switch connected between ground potential and a third one of the coils;
• an amplifier and peak detection circuit connected between the second one of the coils and an input of a control unit;
• and
• the control unit having a first output connected to the first switch, a second output connected to the second switch, a third output connected to the driver circuit, and an input receiving an output signal from the second one of the coils, the control unit closing be the switches and causing the driver circuit to apply a periodic current to the first one of the motor coils, the control unit generating a motor fault signal and preventing normal operation of the motor when the output signal is below a predetermined threshold.

A method for detecting coil-to-coil faults in an electric motor having a plurality of coils, the fault detection method comprising:

• connecting a capacitor and a resistor between a second coil of the motor and a first terminal of a switch, a second terminal of the switch connected to ground potential;
• connecting a third coil of the motor to ground potential;
• applying a time-varying current having a certain frequency to a first coil of the motor;
• monitoring a coil output voltage at the second coil;
• and
• receiving an input of the coil output voltage in a control unit, the control unit generating a motor fault signal if the coil output voltage is below a predetermined threshold.

A method for detecting coil-to-coil faults in an electric motor having a plurality of coils, the fault detection method comprising:

• applying a time-varying current having a certain frequency to a first coil of the motor;
• connecting a capacitor and a resistor between a second coil of the motor and a first terminal of a first switch, a second terminal of the first switch connected to ground potential;
• applying an output voltage from the second coil of the motor to an amplifying an peak detecting circuit;
• applying an output of the amplifying and peak detecting circuit to an input of a control unit;
• generating a motor fault signal if the coil output voltage is below a predetermined threshold;
• and
• preventing transmission of voltage signals from the coils to the control unit during normal operation of the motor.