In this product, by optimizing the design, the electromagnetic distributing valve, oil valve and emergency distributing valve in conventional GC overspeed governor are integrated into one unit with smaller size and more reliable action. Provided with a hydraulic buffer unit, this product overcomes the shortcoming of roaring noise during the operation of GC overspeed governor, and ensures smooth action and longer service life. In addition, provided with a throttling unit, it can adjust the turn-off time of servomotor. It can be installed vertically or horizontally, thus ensuring convenient installation and small floor space.

Characteristics

The electromagnetic distributing valve, oil valve and emergency distributing valve in conventional overspeed governor are integrated into one unit, thus ensuring high level of integration, small size, low weight, small floor space, and convenient installation.

Provided with the hydraulic buffer unit, it generates no vibration noises, but ensures longer service life.

After completing the setting of its throttling unit, it will not drift, thus ensuring stable and reliable operation.

Operational principle

During the normal operation of hydrogenerator unit, the pressure oil is supplied to Pipe 1 and Pipe 2, and the Spool 3 is located is upper position due to differential pressure. At this moment, the P-chamber and O-chamber of emergency distributing valve are cut off, and the opening chamber and closing chamber in the main distributing valve of governor respectively connect with the opening chamber and closing chamber of servomotor, that is: B-chamber is connected with A-chamber, and D-chamber is connected with C-chamber. During the running of hydrogenerator unit, the servomotor operated by the main distributing valve of governor can adjust the working condition.

When the governor fails and results in overspeed of hydrogenerator unit, and the governor cannot shut off the distributor via the servomotor, the two-position two-way solenoid valve at the front end of Pipe 2 acts after receiving the overspeed protection signal. Then, the two-position two-way solenoid valve reverses, and cut off the pressure oil. After that, Pipe 2 connects with return oil, Spool 3 of emergency distributing valve moves under differential pressure, and the valve completes the reversing to cut off the control loop of governor, so that P-chamber can connect with C-chamber, and A-chamber can connect with O-chamber. Then, the emergency distributing valve connects the pressure oil of oil system with the closing chamber of servomotor, the opening chamber of servomotor receives the return oil, and the distributor of hydroturbine is shut off under the operation of servomotor, so as to stop the hydroturbine and prevent the runaway accident of hydrogenerator unit.