main limit switch

例句：

1. 1. The main limit switch is responsible for controlling the speed of the conveyor belt.
   主限位开关负责控制输送带的速度。
2. 2. The main limit switch is located at the top of the machine, and it can be used to prevent overloading.
   主限位开关位于机器顶部，可以用来防止过载。
3. 3. Main limit switches are often used in industrial machinery to ensure safe operation.
   主限位开关常用于工业机械中，以确保安全运行。