Answer: The three-way solenoid valve is a two-position, three-way normally closed solenoid valve, which is normally closed and opened by power. When a heavy vehicle is required, this valve is opened by power, so that the pressure in the system can be transmitted to the intake valve servo cylinder pipeline, thereby opening the intake valve and realizing heavy vehicle operation. When an empty vehicle is required, this valve is powered off and closed, cutting off the pressure supply of the intake valve servo cylinder pipeline, closing the intake valve, and realizing an empty vehicle (the discharge solenoid valve is discharged at this time). If the three-way solenoid valve fails, such as the valve core is stuck, when an empty vehicle is required, this valve cannot be closed when the power is off, and the intake valve cannot be closed. The air compressor will continue to load and run beyond the rated working pressure, causing the motor to overcurrent; In some cases, the motor thermocouple does not act, and the safety door acts when the air compressor safety door setting pressure is reached.
