Take the integral proportional adjustment type of electric actuator as an example:

1) After the electric actuator receives the opening and closing signals from the control system, the motor can rotate normally, but there is no valve position feedback. The possible reasons are:

a. The potentiometer of the position sensor and the travel control mechanism cannot be rotated in the same axis. Check whether the connection part is damaged;

b. The potentiometer is damaged or its performance deteriorates, and the resistance value does not change with the rotation;

c. Check whether the connecting wires between the potentiometer of the position sensor and the amplifier board are normal;

d. Check whether the PM amplifier board is damaged and whether the feedback signal is sent out.

2) After the electric actuator receives the opening and closing signals from the control system, the motor can rotate normally, but the valve position feedback is always a fixed value, which does not change with the opening and closing of the valve. The possible reasons are:

a. The resistance value of conductive plastic potentiometer is a constant value, which does not change with rotation. Repair and replace the potentiometer;

b. Check and handle abnormalities in relevant parts of the magnifying plate.

3) After the actuator receives the switch signal from the control system, the motor does not rotate and buzzes. The reasons may be:

a. The planetary gear of the reducer is jammed, damaged or deformed;

b. The helical gear transmission part of the reducer is deformed or excessively worn or damaged;

c. The transmission part of the turbine worm or screw nut of the reducer is deformed, damaged or jammed;

d. The overall mechanical part is not well matched and flexible, so it needs to be adjusted and refueled.

4) After the electric actuator receives the opening and closing signals from the control system, the motor does not rotate and there is no buzz. Possible causes are:

a. There is no AC power supply or the power supply cannot be added to the motor or position positioner of the actuator;

b. PM amplifier board does not work normally and cannot send corresponding control signal; The solid state relay is partially damaged and cannot convert the weak signal sent by the amplifier board into the strong current signal required by the motor;

c. The motor thermal protection switch is damaged; The torque limit switch is damaged; The travel limit switch is damaged; Manual/automatic switch position is wrong or the switch is damaged; The motor is damaged.

d. After the electric actuator receives the on/off signal sent by the control system, the motor does not rotate and there is a buzzing sound. The possible causes are: the starting capacitor of the motor is damaged; Slight interturn short circuit of motor coil; The power supply voltage is not enough.

5) After the electric actuator receives the opening and closing signals sent by the control system, the motor shakes and gurgles, which may be caused by:

a. The output signal of the PM amplifier board is insufficient to make the solid state relay fully connected, resulting in insufficient load voltage of the motor;

b. The performance of solid state relay deteriorates, resulting in incomplete conduction of its output terminal.