Patent ID: 7038423

Claim:
A method for controlling ride through of an induction motor comprising the steps of: a) detecting a power loss from a power supply connected to the induction motor by comparing one of a supply phase voltage with a predetermined supply dropout voltage value and a supply phase voltage delta with a predetermined supply event voltage delta; b) disconnecting the induction motor from the power supply when the supply phase voltage is less than the predetermined supply dropout voltage value or the supply phase voltage delta is greater then the predetermined supply event voltage delta; c) monitoring a line voltage of the power supply; d) monitoring a back emf voltage generated by the induction motor; e) monitoring a phase differential between the line voltage and the back cuff voltage; f) determining whether the monitored voltages are within a predetermined voltage limit; g) determining whether the phase differential is within a predetermined phase limit; and h) re-connecting the power supply to the induction motor in response to the monitored voltages being within the predetermined voltage limit and the monitored phase differential being within the predetermined phase limit.