启动按启动按钮SB1KM1线圈得电KM4的线圈也同时得电此时电机正转延时3S后KM1的线圈失电KM2的线圈得电此时电机反转;按启动按钮SB2KM2线圈得电KM4的线圈也同时得电此时电机反转延时4SKM2的线圈失电KM1的线圈得电此时电机正转;按停止按钮SB3电机停止运转。

Translation:

Start: Press the start button SB1, the coil of KM1 is energized, and the coil of KM4 is also energized at the same time. At this time, the motor rotates forward. After a delay of 3 seconds, the coil of KM1 is de-energized, and the coil of KM2 is energized. At this time, the motor rotates in reverse. Press the start button SB2, the coil of KM2 is energized, and the coil of KM4 is also energized at the same time. At this time, the motor rotates in reverse. After a delay of 4 seconds, the coil of KM2 is de-energized, and the coil of KM1 is energized. At this time, the motor rotates forward. Press the stop button SB3 to stop the motor.