Common faults and maintenance methods of frequency converters

The common faults and maintenance methods of frequency converters are as follows:

1. Parameter setting fault. Whether commonly used frequency converters can meet the requirements of the transmission system during use, the parameter settings of the frequency converter are very important. If the parameter settings are not correct, it will lead to the frequency converter not working properly.

Maintenance method: Once a parameter setting fault occurs, the frequency converter cannot operate normally. Generally, the parameters can be modified according to the manual. If the above does not work, it is best to restore all parameters to their factory values and then reset them according to the above steps. The parameter recovery method for each company's frequency converter is also different.

2. Overvoltage type faults. The overvoltage of the frequency converter is concentrated on the branch voltage of the DC bus.

Repair method: Under normal circumstances, the DC power of the frequency converter is the average value after three-phase full wave rectification. If calculated based on 380V line voltage, the average DC voltage Ud=1.35U line=513V. When overvoltage occurs, the energy storage capacitor of the DC bus will be charged. When the voltage reaches around 760V, the inverter overvoltage protection will activate.

3. Overcurrent fault. Overcurrent faults can be divided into acceleration, deceleration, and constant speed overcurrent. Acceleration and deceleration overcurrent are caused by factors such as short acceleration and deceleration time settings of the frequency converter, sudden load changes, uneven load distribution, and output short circuits.

Maintenance method: At this time, it is generally possible to extend the acceleration and deceleration time, reduce sudden changes in load, add energy consuming braking components, design load distribution, and inspect the circuit. If the load inverter is disconnected and there is still an overcurrent fault, it indicates that the inverter circuit of the inverter is closed and needs to be replaced.

4. Overload fault. Inverter overload includes its own overload and motor overload. Inverter overload is caused by a short acceleration and deceleration time (forming a brief overload) and excessive DC braking.

Repair method: By changing its internal parameters and extending the braking time. Motor overload caused by low grid voltage, heavy load, and other reasons. Repair: Check if the power grid and voltage load are too heavy. The selected motor and frequency converter cannot drive the load, or it may be due to poor mechanical lubrication (excessive resistance).

5. The undervoltage temperature is too high. There is a problem with the power input part of the frequency converter, which needs to be checked before it can be operated.

Maintenance method: If the motor has a temperature detection device, check the heat dissipation of the motor; The temperature of the frequency converter is too high. Check the ventilation of the frequency converter.

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