2. Input voltage is not within the 160V~250V range, the carbon brush is at its limit position, and the unit can no longer adjust. If the input voltage is out of range, adjust the external input voltage.

3. Wiring error (neutral wire not connected). Three-phase voltage stabilizers use a three-phase four-wire system for wiring, and the input must include a neutral wire. (If the neutral wire is not connected for three-phase 1.5kVA～4.5kVA products, the output voltage may show line voltages of over 400V or over 300V.)

4. Inaccurate sampling voltage on the circuit board. Adjust the potentiometer on the circuit board (turn clockwise to increase voltage, counterclockwise to decrease voltage).

5. Excessive dust accumulation causing the carbon brush to jam. Clean the dust inside the product, polish the coil contact surface to ensure it is smooth.

6. Circuit board failure. Replace the circuit board.

7. Motor short circuit or jammed, motor not rotating. Replace the motor.

8. Load is frequently started inductive or capacitive load. Change the load starting method, increase the capacity of the voltage stabilizer or power supply.

9. Compensation coil neutral wire has a cold solder joint (loose wire). Resolder the neutral wire.

II. AC voltage stabilizer has no voltage output.

1. No output due to overvoltage or undervoltage. Input voltage is not within the range, relevant indicator lights on the panel are lit. Adjust the external input voltage.

2. For three-phase products, input neutral wire not connected or phase missing, output contactor not engaged, no voltage output, carbon brush on the coil rotates irregularly, carbon brush limit switch makes noise, may show irregular lighting of overvoltage or undervoltage indicators. Strictly follow the three-phase four-wire system wiring method.