Selection of electric actuators

Selection of electric actuators

Its working principle is powered by a single-phase AC power source, receiving a unified standard DC signal, outputting corresponding angular displacement, operating adjustment mechanisms such as air doors and baffles, and can be equipped with various electric operators to complete the "manual automatic" undisturbed switching of the adjustment system, as well as remote manual operation of the regulated object. The electric actuator is also equipped with dual protection of electrical and mechanical limits to complete the task of automatic adjustment.

The main advantages of electric actuators are high stability and a constant thrust that can be applied by users. The maximum thrust generated by the actuator can reach up to 225000kgf, and only hydraulic actuators can achieve such a large thrust. However, the cost of hydraulic actuators is much higher than that of electric actuators.

Selection of electric actuators

The anti deviation ability of electric actuators is very good, and the output thrust or torque is basically constant, which can effectively overcome the unbalanced force of the medium and achieve accurate control of process parameters. Therefore, the control accuracy is higher than that of pneumatic actuators. If equipped with a servo amplifier, it is easy to achieve the exchange of positive and negative effects, and it is also easy to set the cut-off signal valve position state (hold/fully open/fully closed). In case of a fault, it must stay in its original position, which pneumatic actuators cannot do. Pneumatic actuators must rely on a combination protection system to achieve position protection.

There are two types of electric actuators, generally divided into part turn electric valve actuators and multi turn electric valve actuators. The former mainly controls valves that require partial rotation, such as ball valves and butterfly valves, while the latter requires valves that require multiple turns of rotation, such as gate valves.

Electric driven multi turn actuators are one of the commonly used types of actuators. Using a single-phase or three-phase motor to drive gears or worm gears, and finally driving the valve stem nut, the valve stem nut causes the valve stem to move and open or close the valve. Multi turn electric actuators can quickly drive large-sized valves. In order to protect the valve from damage, the limit switch installed at the end of the valve stroke will cut off the motor power supply. At the same time, when the safety torque is exceeded, the torque sensing device will also cut off the motor power supply. The position switch is used to indicate the on/off status of the valve. The handwheel mechanism installed with the clutch device can manually operate the valve in case of power failure.