An electric actuator is, essentially, a geared motor. The motor can be of various voltages, and is the primary torque-generating component. To prevent heat damage from overwork or excessive current draw, electric actuator motors are usually equipped with a thermal overload sensor embedded in the motor windings.
This sensor is wired in series with the power source and opens the circuit if the motor overheats. The circuit closes again when the motor reaches a safe operating temperature.
Pneumatic actuators, for quarter turn ball and butterfly valves, provide accurate and dependable control, especially in corrosive applications