relay contactor control

例句：

1. 1.The relay controller is responsible for monitoring the electrical signals between two circuits.
   继电器控制器负责监控两个电路之间的电气信号。
2. 2. The relay controller was designed to ensure safe operation of the power system.
   继电器控制器被设计成确保电力系统的安全可靠运行。
3. 3. The relay controller is used to switch power from one circuit to another when necessary.
   当需要时，继电器控制器用于将电力从一个电路切换到另一个电路。