Pressure relay is a hydraulic electrical switching element that uses liquid pressure to open and close electrical contacts. When the system pressure reaches the setting value of the pressure relay, the electrical signal is sent out, so that the electrical components (such as electromagnet, motor, time relay, electromagnetic clutch, etc.) action, so that the oil circuit pressure relief, reversing, the implementation of components to achieve sequential action, or shut down the motor to stop the system, play the role of safety protection.
When the liquid pressure entering from the oil inlet 3 at the lower end of the relay reaches the set pressure value, push the plunger 2 to move up, and this displacement is amplified by the lever to push the micro switch 4 to act. The operating pressure of the relay can be adjusted by changing the compression of spring 1.