A valve actuator is a mechanical or electromechanical device that is used to control the opening and closing of a valve. It converts an input signal into a force or torque to move the valve mechanism. The actuator can be powered electrically, pneumatically, or manually.

Electric valve actuators use an electric motor to generate the necessary force or torque. They typically receive electrical signals from a control system or a programmable logic controller (PLC) to actuate the valve. Electric actuators offer precise positioning control and can be used for both on/off and modulating applications.

Overall, valve actuators play a crucial role in automating the control of valves, allowing for efficient and precise flow regulation in various industries and applications.