Megmeet inverter - the fault handling method of low-voltage inverter

Before using the inverter, the inverter parameters should be carried out from the following aspects:

First, confirm the motor parameters, the inverter sets the power, current, voltage, speed, and maximum frequency of the motor in the parameters, and these parameters can be directly obtained from the motor nameplate.

Second, the control mode adopted by the inverter, that is, speed control, rotation control, PID control or other methods.

Third, set the starting mode of the inverter.

Fourth, the choice of a given signal.

Once the parameter setting class failure occurs, the inverter can not operate normally, and the parameters can generally be modified according to the instructions. If the above fails, it is best to restore all the parameters to factory value, and then re-set them according to the above steps, and the parameter recovery method is different for each company's inverter.

The overvoltage of the inverter is concentrated in the tributary voltage of the DC bus. Under normal circumstances, the direct current of the inverter is the average value after three-phase full-wave rectification. Therefore, the inverter has a normal operating voltage range, and when the voltage exceeds this range, it is likely to damage the inverter.

The input voltage exceeds the normal range, which generally occurs when the load is light, the voltage rises or decreases and the line fails, so it is best to disconnect the power supply, check and deal with it.

The fault that occurs higher is mainly that the synchronous speed of the motor is higher than the actual speed, so that the motor is in the state of power generation, and the inverter is not installed with the braking unit again, and there are two situations that can cause this fault.

First, when the inverter drags the large inertia load, its deceleration time is set relatively small, in the deceleration process, the speed of the inverter output is relatively fast, and the load decelerates relatively slowly by its own resistance, so that the speed of the load dragging the motor is higher than the speed corresponding to the frequency of the inverter output, the motor is in the state of power generation, and the inverter does not have an energy feedback unit, so the voltage of the DC circuit of the inverter tributary rises, exceeds the protection value, and the fault occurs, and the paper machine often occurs in the dry part, To deal with this fault, you can add a regenerative braking unit, or modify the parameters of the inverter to set the inverter deceleration time longer.

Second, this failure can also occur when multiple electric vehicles apply the same load, mainly due to the absence of load distribution. Take two motors dragging a load as an example, when the actual speed of one motor is greater than the synchronous speed of another motor, then the motor with high speed is equivalent to the prime mover, and the low speed is in the state of power, causing failure. In the paper machine, it often takes place in the press section and the net section, and the load distribution control needs to be added during processing. The characteristics of the inverter at the branch of the paper machine speed chain can be adjusted softer.

Overcurrent faults can be divided into acceleration, deceleration, and constant speed overcurrent. It may be caused by the acceleration and deceleration time of the inverter is too short, the load is abruptly changed, the load is unevenly distributed, and the output is short-circuited. In this case, it is generally possible to extend the acceleration and deceleration time, reduce the sudden change of load, add energy consumption braking elements, carry out load distribution design, and check the line. If the load inverter is disconnected or the overcurrent fault is faulty, it means that the inverter circuit of the inverter is looped and the inverter needs to be replaced.

Overload faults include variable frequency overload and electrical machine overload. It may be caused by the acceleration time is too short, the DC braking amount is too large, the grid voltage is too low, the load is too heavy, etc. Generally, it is possible to extend the acceleration time, extend the braking time, check the grid voltage, etc. The load is too heavy and the selected motor and inverter cannot drag the load, or it may be caused by poor mechanical lubrication. If the former is the case, the high-power motor and inverter must be replaced; In the case of the latter, the production machinery should be overhauled.

If the inverter is undervoltaged. It means that there is a problem with the power input part of the inverter, and it needs to be checked before it can be operated. If the temperature of the inverter is too high. If the motor has a temperature detection device, check the heat dissipation of the motor; If the temperature of the inverter is too high, check the ventilation of the inverter. For other situations, such as hardware failure, communication failure, etc., you can contact the supplier.

Fault phenomenon: a frequency converter suddenly trips in operation, the operator immediately resets, and makes the frequency converter run again, about 5min after running, tripping, reset, running many times, touch the panel are displayed as FL code. Fault analysis: Since the touch panel is displayed as FL code, it is obvious that the main device self-protection is working, and the main device self-protection diagnosis content is short circuit, grounding, overcurrent, heat sink overheating, etc. Therefore, we used a megohmmeter to detect the load side, and there was no short circuit or grounding. Check that the sound and vibration of the unit are normal, and the operation is flexible, and there is no stuckness. Under constant process conditions, no overload is caused and therefore no overcurrent is possible. After queuing the above faults, the rest may be overheating faults. Upon closer inspection of the internal cooling fan, it was found that the top one was no longer running. Special attention should be paid during the inspection, because the bottom cooling fan is running, the top fan may also be driven by the wind, so the operation of the top fan should be carefully analyzed and checked. The fan should be replaced at this point.

Megmeet inverter - the fault handling method of low-voltage inverter

Megmeet inverter - the fault handling method of low-voltage inverter

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