Motor-operated valve. The actuator drives through a worm gear, stops on a limit switch at a set position or on a torque switch when output torque reaches a set value, and has a handwheel with a declutch lever for manual use. MOVs dominate large gate and butterfly valves in water, power and pipeline service, where thrust needs are high or there is no instrument air. Nuclear plants test them closely for thrust margin.
MOV on the intake tripped on torque halfway closed, something's in the gate, send a crew with a handwheel and a flashlight.
Also heard as
- motor operator
- motorized valve
Related terms
Actuator
The powered device that opens, closes or positions a valve using air, hydraulic oil or an electric motor.
Torque out
For a motor-operated valve to stop on its torque switch because it met more resistance than expected.
Stroke
To run an automated valve through its full travel to prove it moves, seats and reports position correctly.
Gate valve
A multi-turn isolation valve that lifts a flat or wedge-shaped gate clear of the flow path to open.