| 摘要 |
An over temperature protection circuit for a poly-phase compressor motor (10) is provided. One phase of the inverter (14) output has a current sensor (36) associated therewith which is able to detect zero current flow. That same phase of the inverter output to the motor (10) is provided with an overload thermal protection device (34) adapted to open at a temperature designed to protect the motor windings. When the temperature at the overload device (34) reaches the trip point, the overload opens the phase in which both the current detector (36) and overload detector (34) are located. The inverter drive is provided with a signal in response to the current sensor (36) detecting a zero current flow, and turns off the output for all three phases of the inverter (14). <IMAGE> |
