After a lot of maintenance practice, we find that some faults can not be solved if the general maintenance theory and method of frequency converter are used blindly. In fact, the general user can handle, that is to ensure that the input voltage is normal, the motor connection line is normal, the motor insulation is no problem, the motor three-phase balance, and then adjust the acceleration and deceleration time, and so on.

1. Not shown. This kind of situation is quite common. Generally, under the normal condition of external three-phase power supply, the switch power supply of the frequency converter is burnt out. You can measure the 24 V power supply on the output board of the frequency converter terminal. If not, this is the problem. In this case, the switch tube burn ratio is more, and you can simply replace it. If not, it is recommended to find the manufacturer or professional frequency converter maintenance Repair company.

2. Output three-phase imbalance. If the unbalance rate is more than plus or minus 15%, it can't be used. You can measure whether the voltage is balanced through the voltage range of the multimeter. If possible, use the clamp meter to measure the current. In the case of three-phase output imbalance, you need to disconnect the connecting wire between the frequency converter and the motor. Use the multimeter alone to simply measure whether the resistance between the three phases of the motor is close, such as If there is a problem with the motor, it needs to be repaired. If the motor is normal, the IGBT is broken in this case, and the drive circuit is generally faulty.

3. The speed is not stable. Try to avoid the frequency converter working at low frequency. Generally, the frequency converter should be set above 8Hz. If the high frequency is still unstable, the V / F ratio can be reduced. If the vector control mode is used for a long time, the parameters of the motor may change and cause parameter mismatch. You can re match the parameters between the frequency converter and the motor, and then save them.

4. Motor sound is too loud, motor temperature is high. The carrier frequency can be properly increased, and the output waveform of the frequency converter will be ideal. If the frequency converter interferes with other equipment during operation, the carrier frequency can be reduced a little.

5. The newly installed frequency converter cannot be started. Many frequency converters are set as panel operation mode by factory, that is, they are started by the panel start button, and the frequency is given by the panel key, so if you use the external terminal control of the frequency converter, of course, it can not be used directly. You can find the frequency source and the given signal source in the parameters, and set them as the corresponding external control mode.

6. The converter has been used for a long time and the current is too large. You can check the fan at the air outlet of the converter to see if there is a lot of dust or something stuck on the fan blade, or there is a lot of dirt in the main circuit of the converter. At this time, dismantle it, clean it up as a whole, and blow it several times with dry compressed air. Generally, the problem can be solved.