１引言先导控制技术用于控制煤矿大中型设备的启动、运行和停机。一般的先导控制电路如图１所示，其工作过程分为３个阶段：停止、启动和运行。按下常闭的停止按钮，设备停止运行。此后，即使松开停止按钮，由于线路中串接有３０Ω左右的电阻，设备不会自行启动；按下常开... 1 Introduction Pilot control technology used to control the large and medium-sized coal mine start-up, operation and shutdown. The general pilot control circuit shown in Figure 1, the work process is divided into three stages: stop, start and run. Press the normally closed stop button, the device stops running. After that, even if the stop button is released, the device will not start up due to the series resistance of about 30Ω in the circuit;