Structure of rotary electric actuators

The rotary  electric actuator  mainly consists of a power unit (such as a motor and gear reduction mechanism), a control unit (such as a controller and position sensor), and mechanical transmission components (such as a worm gear and drive shaft). Some models also include auxiliary components like a handwheel and torque protection device.
1. Power components
① Motor: Typically uses AC servo motors or frequency conversion motors, responsible for providing rotational power. Depending on the power supply type, it can be categorized as AC (220V/380V) or DC (24V/48V) drive.
②减速 mechanism: Converts the high-speed, low-torque output of the motor into low-speed, high-torque output through a worm gear or planetary gear system. For example, a primary worm drives a helical gear, which then engages a clutch to drive a secondary worm gear, ultimately achieving an angular displacement output of 0-90°.
2. Control unit
① Controller (such as PM-2 control board): receive 4-20mA or switching value signal, and adjust motor action after comparing with position feedback signal to achieve closed-loop control.
② Position sensor: including limit switches, encoders, etc., used for real-time monitoring of output shaft position and feedback to the controller to ensure accuracy.
3. Mechanical transmission and auxiliary components
① Drive shaft and output components: directly connected to valves (such as butterfly valves and ball valves) to transmit torque.
② Torque protection device: Overload protection is achieved through compression springs and torque switches, such as triggering power outages due to the deflection of internal planetary gears.
③ Handwheel: Supports manual operation and can be used during power outages or debugging.
4. Special design (some models)
① Modular electronic cabin: The power board and control board of variable frequency  actuators  can be quickly replaced.
② Gearbox types: divided into GS direct connection type (for butterfly/ball valves) and GF base crank type (for dampers), suitable for different load requirements.