According to reports, electric actuators (electric actuating devices) are generally divided into part-turn and multi-turn types.

 The former is mainly used to control valves that require partial rotation, such as ball valves and butterfly valves, 

while the latter is used for multi-turn valves, such as gate valves.

Electric multi-turn actuators are one of the common types of actuators. A single-phase or three-phase motor drives a gear or worm gear, which in turn drives the valve stem nut. The valve stem nut moves the valve stem to open or close the valve. Multi-turn electric actuators can quickly operate large valves. To prevent valve damage, limit switches installed at the end of the valve travel will cut off the motor power. Additionally, if the torque exceeds the set limit, the torque sensing device will cut off the motor power. Position switches are used to indicate the open or closed status of the valve. A manual override with a handwheel and clutch mechanism allows the valve to be operated manually during a power outage.

The main advantage of this type of actuator is that all components are installed within a single housing, and all basic and extended functions are integrated into this waterproof and dustproof enclosure. The main disadvantage is that the valve can only be held in its position when the power is off. Only when a backup power system is used can the valve reach its fail-safe position (fail-open or fail-close).

This type of actuator is similar to a multi-turn electric device. The main difference is that the actuator output consists of 90-degree movement over 14 turns. The new generation of single-turn electric actuators combines most of the complex functions of multi-turn actuators, such as parameter setting and diagnostic functions through a non-intrusive, user-friendly interface. Single-turn actuators have a compact structure and can be installed on small valves. Typically, the output torque can reach 800 KGM. Additionally, they require low power and can be equipped with batteries to perform fail-safe operations.