Compressor protection and grid fault detection device

A method performed by a compressor monitoring system, comprising:

• measuring a current drawn by a motor of a compressor;
• generating first and second average current values based on the measured current;
• measuring a utility power voltage;
• generating first and second average voltage values based on the measured voltage;
• determining a first ratio based on the first and second average current values;
• determining a second ratio based on the first and second average voltage values;
• and
• selectively generating a fault signal when the first ratio is greater than a first predetermined threshold and the second ratio is less than a second predetermined threshold.

A compressor monitoring system comprising:

• a current monitor that measures a current drawn by a motor of a compressor;
• a voltage monitor that measures a voltage of the motor;
• a power factor monitor that calculates a power factor of the motor based on the measured current and the measured voltage and generates power factor values;
• an averaging module that generates a first average power factor value based on the power factor values and that later generates a second average power factor value based on the power factor values;
• and
• a control module that selectively generates a fault signal when a ratio is less than a predetermined threshold, wherein the control module calculates the ratio based on the second average power factor value divided by the first average power factor value.