Electric actuators are an important type of actuator, consisting of an actuator and a regulating valve. It is composed of a servo system scheme, where the signal from the regulator drives the motor through the servo amplifier, drives the regulating valve through the reducer, and feeds back the stroke of the valve stem to the servo amplifier through the position transmitter, forming a position servo system. By relying on negative position feedback, it ensures that the input signal is accurately converted into the stroke of the valve stem.

Introduction to three control methods of electric actuators

1. Local adjustment method

When on-site manual operation is required, when the electric operator switch is placed in the "manual" position, turn the motor end knob to the "manual" position, pull out the handwheel on the actuator, and shake the handwheel to achieve manual operation. When not operating locally, be sure to turn the knob at the end of the motor to the "automatic" position and push the handwheel in.

2. Remote control adjustment method

When the electric operator switch is placed in the "manual" position, it is in the manual remote control state. When operating, simply pull the rotary switch to the "on" or "off" positions to drive the motor forward or backward, and the output shaft of the actuator can achieve upward or downward action. During the movement, observe the valve position opening gauge on the electric operator, and when the desired valve position opening is controlled, immediately release the switch.

3. Automatic adjustment method

When the electric operator switch is placed in the "automatic" position, it is in the automatic adjustment state, and its control process is as follows:

When the input signal I λ When 1=0 (or 4mA DC), the feedback current I of the position transmitter is reversed to 0 (or 4mADC). At this time, the servo amplifier has no output voltage, the motor stops rotating, and the output shaft of the actuator stabilizes at the pre-selected zero position;

When the input signal I λ When 1>0 (or 4mA DC), this input signal is compared with the position feedback current of the system itself for magnetic potential in the front-end magnetic amplifier of the servo amplifier. Due to the unequal size and opposite polarity of these two signals, there is an error magnetic potential, which allows the servo amplifier to have sufficient output power to drive the motor. The output shaft of the actuator moves in the direction of reducing this error magnetic potential, Until the input signal and position feedback signal are equal, the output shaft is stable at the corresponding position of the input signal.

What are the precautions for selecting an electric actuator?

1、 Pay attention to checking for loose screws between valves

Because the tightness of the screws during the operation of the machine greatly affects its quality of use, it is necessary to pay attention to checking the screws of the valve in advance. If the screws become loose, the operation must be stopped and the parts must be disassembled to change the installation sequence, ensuring that the entire connecting screw can be tightly and firmly fixed on the machine body.

2、 Please note that manual testing and confirmation of the agency is required

Due to the fact that machine parts are prone to errors during installation on the assembly line, without manual inspection and detailed adjustments, it is easy to cause problems in the produced products. Therefore, it is important to pay attention to manual inspection, which can better make accurate judgments on machine manufacturing and prevent machine parts from getting stuck.

3、 Pay attention to the accuracy of positioning and use tools to confirm

Because in order to ensure the installation position of the machine during installation, it is necessary to do a good job in positioning. Therefore, when selecting, it is necessary to pay more attention to the accuracy of the locator. If there is a deviation in the position, it may cause a decrease in efficiency in the subsequent use process. Therefore, the accuracy of positioning should be ensured through tools or other methods of the oneself.