The AST solenoid valve 0508.919T0301.AW027 is controlled by the ETS system of steam turbine, and the four solenoid valves are arranged in series and parallel to form the AST component. During normal operation, these four AST solenoid valves are electrically closed, sealing the oil drain channel of the AST main pipe, establishing oil pressure in the lower chamber of the piston rod of the main throttle valve actuator and regulating valve actuator. When a critical situation occurs in the unit, the AST signal is output, and these four solenoid valves lose power and open, causing the AST main pipe oil to be discharged to the EH oil tank through the pressure free return pipeline. In this way, the unloading valves on the main throttle valve actuator and regulating valve actuator quickly open, causing each valve to close quickly.

The series-parallel connection of four AST solenoid valves is to ensure the safety and reliability of steam turbine operation. When solenoid valves 1 and 2 malfunction, their oil pressure will increase. When solenoid valves 3 and 4 malfunction, their oil pressure will decrease to determine whether the AST solenoid valve is working properly.

The interior of the solenoid valve is an electromagnet, and the DC electromagnet will not burn out due to the iron core getting stuck. It is small in size, reliable in operation, allows for a switching frequency of 120 times/min, has low commutation impact, and has a long service life. But the starting force is smaller than that of an AC electromagnet.

The steam turbine AST and OPC system uses different types of solenoid valves. Yoyik offers various AST / OPC valves for power plant users.
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OPC SOLENOID VALVES 0508.919T0301.AW027
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