1, overcurrent fault Overcurrent fault can generally be divided into acceleration, deceleration and constant speed overcurrent.

The main reasons are too short starting acceleration time, sudden increase of load, short circuit of inverter output, uneven load distribution, mismatch between inverter and motor capacity, damage of internal rectifier or inverter components, out-of-phase power supply, output disconnection, internal fault of motor, grounding fault, etc.

The maintenance method is as follows: when checking the fault, disconnect the load first and check the frequency converter.

If the overcurrent fault still exists after the load is disconnected, it means that the internal components of the inverter have failed and need further inspection and maintenance.

Take corresponding measures:

Extend the acceleration time, design the load distribution, check the line, prevent interference and mechanical vibration, and reduce the sudden change of load.

2. Overvoltage fault Inverter overvoltage fault refers to the overvoltage trip of the inverter when the DC bus voltage of the unit exceeds.

The main causes of unit overvoltage fault are:

First, the high-voltage power supply at the input side exceeds the maximum allowable value;

Second, the inverter is over-voltage tripped during deceleration. Inverter overvoltage faults include overvoltage when compensation capacitor is put into operation, lightning overvoltage, overvoltage when braking or deceleration time is too short, power overvoltage, etc.

On the premise of confirming the stability of the input power supply voltage, an absorber is added at the input side of the power supply to reduce the possibility of overvoltage caused by overvoltage factors such as impulse overvoltage and lightning overvoltage at the input side, and the overvoltage caused by the compensation capacitor during closing or opening can be solved by using a parallel surge absorber or a series reactor at the input side. Overvoltage fault usually occurs in the process of parking, which is related to intermediate circuit and braking link. The main reason is that the braking resistor is damaged or the deceleration time is too short.

Therefore, the solution is to increase the deceleration time parameter or braking resistance (braking unit).

3. Undervoltage fault Inverter undervoltage fault refers to the low voltage of the main circuit, such as 220v series is lower than 180v, and 380v series is lower than 300v.

Generally, it is due to the lack of phase of power supply, simultaneous operation or over-starting of frequency converters, damage of DC loop current limiting resistor or thyristor short-circuit current limiting resistor in frequency converters, external interference and other reasons, or between frequency converters.

The treatment measures are to check the input part of the inverter, check whether the contacts of the air switch or contactor of the inverter power supply are in good contact, whether the contact resistance is too large, and whether the output voltage of the transformer is normal. Minimize the number of times that the inverter starts or works at the same time, and improve the anti-interference ability of the inverter.

4, overload fault overload fault, first check whether the motor is hot. If the temperature rise of the motor is not high, first check whether the thermal protection function setting of the inverter is reasonable. If the inverter has any margin, please loosen the preset value. If the output voltage of inverter is balanced, the problem lies in the circuit from inverter to motor;

Finally, check whether there is any wrong operation. Under light load or no load, measure the output current of the inverter with an ammeter and compare it with the running current value displayed on the display screen to check whether there is a big error between the displayed value and the actual value. If yes, it means that the trip is misoperation.

Extended data:

Inverter fault monitor: 1, state fault monitor: DC overvoltage/long voltage, DC overcurrent, AC overcurrent, excessive speed deviation, ground fault, inequality.

2. Hardware fault detection: current board fault, trigger board fault, IGBT fault, pulse generator fault, etc.

3. System fault monitoring: watchdog fault, abnormal system parameters, clock fault, etc. 4. Communication fault monitoring: timeout, overrun, etc.

5. Power failure monitoring: alarm when the control power supply is too high/too low.