Common Faults and Solutions of AC Automatic Voltage Stabilizer（AVR)

The overvoltage and undervoltage indicators of the voltage regulator light up at the same time, indicating that there is a problem with the detection circuit, because these two phenomena are contradictory; the voltage regulator is a device that stabilizes the output voltage. The voltage regulator is composed of voltage stabilization, constant voltage, control circuit, and servo motor.

When the input voltage or load changes, the control circuit samples, compares, and amplifies, and then drives the servo motor to rotate, so that the position of the voltage regulator carbon brush changes, and the output voltage is kept stable by automatically adjusting the coil turns ratio.

The circuit board is broken or the motor is broken. Replace the circuit board or motor.

No input power Check whether the input power is normal (whether the wiring is firm and whether there is a lack of equality).

Check whether the power cord of the motor driving the chain is in poor contact. Is there a short circuit outside the input power supply? Is the chain stuck? Is there a short circuit in the air switch?

If there is voltage increase but no voltage reduction or voltage reduction but no voltage increase, mainly check whether the travel switch is closed and whether the control relay under the control board is normal.

The voltage regulator starts normally but has no output: Check whether the wiring of the output AC contactor start coil is loose.

Possible reasons:

Has the phase sequence of the input power line been changed? The air switch in the machine is not turned on or broken

Handling:

1. Swap any two power supply wires or check whether the power supply line is normal
2. Close the switch or replace the switch

Possible reasons:

1. The limit switch fails or the limit switch connection line is disconnected
2. The boost and boost buttons fail and the contact is poor
3. The voltage stabilizer motor power supply contact is poor
4. The motor is broken
5. The brush plate is stuck
6. The transmission chain falls off or disconnects

Handling:

1. Replace the limit switch or check the connection line
2. Replace the button
3. Connect the voltage stabilizer power line
4. Replace the voltage stabilizer motor
5. Repair the brush plate
6. Repair chain

Possible reasons

1. Normally closed contact of stop button is open
2. Contact of voltage regulator button is broken
3. QA electric control switch on main circuit is broken

Handling:

Replace

Possible reasons:

1. Overvoltage value on control circuit board is not adjusted properly
2. Parameters of components on control circuit board change

Handling:

Readjust or repair

Possible reasons:

1. Brush defective
2. Poor contact between brush and voltage regulating coil
3. Is the load within the allowable range of voltage regulator
4. Main circuit fasteners are loose
5. Load lead is too long and too thin

Handling:

1. Replace brush
2. Adjust brush spring pressure and brush position
3. Reduce load
4. Tighten main circuit fasteners
5. Reduce the voltage drop of the wire, shorten the wire distance, and increase the wire cross-section

Possible reasons:

1. The sampling transformer of the voltage regulator is damaged
2. The control circuit board is broken
3. The motor is damaged
4. Mechanical system failure
5. Load feedback high-order harmonics

Handling:

1, 2, 3, 4 repair or replace;

5. The sampling power supply needs to be equipped with a filter

Possible reasons:

1. There is no response when adjusting the potentiometer RP1. RP1 is broken or the circuit board is broken
2. The input voltage exceeds the allowable range of the voltage regulator

Handling:

1. Replace the circuit board or potentiometer
2. The input voltage can work within the allowable range