普通三相异步电动机在使用过程中,常因一相保险丝烧断或一相接触器接点烧坏造成缺相运行,使电动机烧坏。这里介绍一种简单电路,可使电动机在发生缺相运行时马上自动断电,从而防止烧坏电动机。电路见附图,其中缺相识别电路由3只按星形连接的电容器组成,与电动机相并联。在电路正常时,3只星形 Ordinary three-phase asynchronous motor in the use of the process, often due to one-phase fuse blowout or contact phase burnout contacts caused by lack of phase operation, so that the motor burn out. Here is a simple circuit that allows the motor to be automatically de-energized as soon as phase loss occurs, preventing the motor from burning out. The circuit sees the picture, among them the lack phase recognition circuit is made up of 3 pieces of the star-shaped connection condenser, and parallel with the electric motor. When the circuit is normal, 3 star