What Is the Circuit Design of the Electric Actuator?

An electric motor actuator is a driving device that can provide linear or rotational motion. It uses a certain driving energy and works under a certain control signal.

 

The rotary actuators and linear actuators are mostly modified on the basis of multi-turn. The multi-turn type is the basic accessory and the worm gear and worm two-stage reduction box form a 0-90° angular stroke electric actuator. It is matched with a screw rod component to form a linear electric actuator.

 

The angular stroke (0~90° angular stroke) is used to control the angular stroke valves such as spring return ball valve, bibcock ball valve, signal butterfly valve and louver valve.

 

The multi turn electric actuator needs to operate more than 360° to realize the opening and closing of the valve. It is mainly used for electric actuated globe valve, pinch valve and diaphragm valve.

 

The output of the straight stroke is the force and the displacement is produced, which is mainly used for gate valves and slide valves.

 

It is often used to form electric valves or electric regulating valves with various valves (such as, gate valves, regulating valves, single-seat valves and other linear movement valves).

 

According to the action mode, it is divided into two categories, including electric switch actuators and electric regulating actuators. The advantages are convenient energy access, fast signal transmission speed, long transmission distance, convenient centralized control, high sensitivity and precision, easy coordination with electric adjustment instruments, and simple installation and wiring. The disadvantage is that the structure is complex, and the average failure rate is higher than that of keystone pneumatic actuators. It is suitable for places with low explosion-proof requirements and lack of air source.

 

Circuit Design

 

1. The actuator mainly controls the driving device that drives the valve, in short, it controls the forward and reverse rotation of the method. The first thing to consider is to choose the size of the actuator motor according to the torque of the valve. The torque of the valve is generally between 1NM-30000NM, and the selection of the motor is about 0.25KW-15KW. Motors below 3KW can be controlled by contactors and thyristors, and those above 3KW must be controlled by contactors.

2. According to the process requirements of the customer's site, it is necessary to see whether the valve is on-off or regulating. If it is an adjustable type, and the adjustment is very frequent, SCR must be used, because the dark contact of the SCR can be used as unlimited times.

3. The stop mode is to stop by the limit of the valve actuator. Each actuator must be equipped with a limit switch and a torque switch. If a limit stop is used, the torque switch is used for protection, and if a torque stop is used, the limit switch is used for protection.

 

4. The switch-type electrical control method is relatively simple. It can be said to be the simplest one that can be made into a forward and reverse control circuit. Regulating type requires potentiometer or Hall element for feedback, which can be designed in combination with PLC or single-chip microcomputer.

 

5. The power supply mode can be selected according to the power board.

 

In some occasions, electric actuators with explosion-proof grades must be used, such as explosion proof electric actuators.