Dalingshan Southern Inverter Maintenance Hotline

Dalingshan Southern Inverter Maintenance Hotline

Dongguan Changping Juyou ElectromechanicalEquipment Maintenance Department specializes in repairing Mitsubishi servo drives, Panasonic servo drives, Yaskawa servo drives, Dongrong servo drives, Sanyo servo drives, Fuji servo drives, Delta servo drives, Omron servo drives, Fanuc servo drives, etc; MitsubishiPLCPanasonicPLCSiemensPLCOmronPLCWait; Various touch screens, frequency converters, industrial circuit boards, etc.

Provide on-site service near the company,Bringing you convenience. We have the advantages of short maintenance cycle, high repair rate, reasonable price, and no need for circuit diagrams, We have also repaired different types of circuit boards for multiple companies. Customers from outside the province can send the servo to be repaired to our company, and we will conduct testing on the day of receiving the goods and arrange for repairs as soon as possible. If the customer's machine is severely damaged and cannot be repaired, our company will not charge any fees. Welcome to consult and cooperate!

Dalingshan Southern Inverter Maintenance Hotline

Common Fault Case Analysis and Maintenance Methods of Southern Frequency Converter

Overcurrent fault (OC)‌

‌fault phenomenon‌：

• Frequent OC alarm jumping during acceleration/deceleration, accompanied by abnormal noise13；

• Sudden overcurrent shutdown during operation, significant motor vibration68.
  ‌Cause investigation‌：

1. ‌Abnormal loadMotor winding short circuit (phase to phase/ground), mechanical jamming or overload operation13；

2. ‌Hardware damage‌：

• IGBT module breakdown (caused by poor heat dissipation)11；

• Driver optocoupler damage causing output short circuit (such as A3120 model)311；

3. ‌Parameter Settings: Short acceleration time or high torque boost value67.
   ‌Maintenance steps‌：

4. Disconnect the motor load and conduct a no-load test to distinguish between frequency converter/load faults18；

5. Detect the static voltage of the drive circuit (normal value: upper bridge+10~15V, lower bridge -5~-10V), replace the abnormal optocoupler or voltage regulator tube311；

6. Extend acceleration and deceleration time, reduce torque compensation value in heavy load scenarios7.

Overvoltage/undervoltage fault (OV/UV)‌

‌typical scenario‌：

• Deceleration and shutdown report OV alarm (regenerative energy accumulation)36；

• Telegram UV fault, DC bus voltage below threshold610.
  ‌key reason‌：

• ‌OV malfunctionBrake resistor failure or short deceleration time313；

• ‌UV malfunction‌：

• Input phase loss or rectifier bridge damage (insufficient DC bus voltage)610；

• Abnormal voltage detection circuit (sampling resistance variation)8.
  ‌solution‌：

• OV: Extend deceleration time, replace braking resistor (high inertia load)13；

• UV: Check the phase sequence of the power input and the on/off of the rectifier bridge, replace damaged components610.

Module explosion (IGBT damage)‌

‌Typical Case‌：

• Module explosion in humid environment (circuit board carbonization leading to driver misoperation)1213；

• Repeated OV and forced operation caused a short circuit and explosion of the machine13.
  ‌Safety maintenance process‌：

1. Clean the carbonized PCB and test the balance of the driving waveform with low voltage (24V DC) before replacing the module1112；

2. Connect 40W bulbs in series for current limiting protection, confirm no short circuit before operating at full voltage412；

3. Install dust covers for dust scenes such as textiles and ceramics, and regularly clean the heat dissipation ducts1314.

Overheating fault (oH)‌

‌trigger conditionInternal temperature>85 ℃1314.
‌root cause‌：

• Cooling fan stops running (dust clogging bearings or coil aging)1314；

• The dust accumulation rate of the heat sink is greater than 50%, and the airflow in the air duct is obstructed514.
  ‌Treatment measures‌：

• Replace the fan with the same specifications (pay attention to voltage matching: AC220V/DC24V)14；

• Installation spacing ≥ 10cm, control cabinet equipped with ventilation fan to improve heat dissipation environment1314.

Frequency anomaly fault‌

‌Phenomenon and Handling‌：

• ‌Frequency fluctuationCheck the V/F curve setting (select linear type for constant torque load)7Calibrate current detection Hall sensor4；

• ‌The frequency cannot increaseRestore factory parameters (long press the 'STOP' button), reset frequency gain value (default 100%)7.

Environmental adaptability failure‌

• Dewing on circuit boards during rainy season → installation of moisture-proof heating plates13；

• Cotton wool clogging the heat sink in the textile factory → Clean the air duct filter every month1314.

‌Quick Reference Table for Fault Codes‌

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