Controller for ensuring start of operation of synchronous motor

摘要

A synchronous motor controller is provided which is designed to diagnose whether a failure is occurring or not in energizing one of phase windings of a synchronous motor which is required to be energized first to start the synchronous motor. When such a failure is found, the controller reverses the synchronous motor slightly to bring one of the phase windings which is possible to energize properly to a starting position where the energization of the phase windings is to be initiated to start the synchronous motor in a required direction, thereby ensuring the stability in starting the synchronous motor even if any of the phase windings is failing to be energized.