Motor operated valve (MOV) is an ordinary ball valve or any other valve that operated by an electric actuator. In general, the MOV is used as isolation valves for equipment which requires regular access.
The MOV is also used on any valve that the total energy required to open or close the valve manually is large. No specific reason regarding why MOV is used except from ease of operation point of view.
The typical MOV construction consist of electric motor actuator, gear box, and the valve it self. First of all, the motor is rotated by applied an AC voltage to it.
The motor rotation then transferred through a gear mechanism to the output thrust part. The output thrust is then transferred to the gear mechanism in the gear box to rotate the valve stem.
Motor operated valve (MOV)