PLC对三相异步电动机降压起动控制的应用

Application of Voltage Dropping Starting of Three-Phase Asynchronous Motor Controlled by PLC

继电器控制电机降压起动方法存在很多不足,如连线复杂、体积大、功耗大、触点数量有限、触点寿命短、可靠性和维护性较差等。采用PLC和接触器相结合对三相异步电动机降压起动的方法能改善上述的不足。文中介绍了矿用plc对三相异步电动机的星—角降压起动、串电阻降压起动、串自耦变压器降压起动的I/O口分配表、接线图、梯形图编程。

Relay control motor voltage dropping starting way have many shortages, such as： wiring complexity, big volume, large power consumption, and limited contact number, short contact life, poor reliability and maintainability. Combining PLC with eontactor, three-phase asynchronous motor voltage dropping starting way can improve the shortages of the above phenomenon. This paper introduced mine PLC for I/O port distribution table, wiring diagram and ladder dia- gram programming o{ the star-angle voltage dropping starting of three-phase asynchronous motor, series resistance voltage dropping starting, series autotransformer voltage dropping starting.