Basic knowledge of inverter maintenance

After repairing a large number of inverters, we feel that if people can avoid some misunderstandings and clear out some wrong concepts in the use and maintenance of inverters, it will be of great benefit to the use and maintenance of inverters.

1. Do not install the inverter on equipment with vibration, because the main circuit connection screws in the inverter are easy to loosen, and many inverters are damaged due to this reason.

2. Wiring problem: The value of the protection current of an air switch connected to the input terminal of the inverter should not be too large, so as to prevent the burnout in the event of a short circuit. The "N" terminal must not be grounded. Try not to make the control line too long. Because this makes the control board easy to be interfered by electromagnetic waves and cause malfunctions, it will also cause damage to the control board. Use shielded wires over 2 meters in length. Do not install a contactor with high current and frequent action next to the inverter, because it has a great interference to the inverter and often causes the inverter to malfunction (display various faults).

3. Don't rely on the inverter to brake the inverter that often needs to stop urgently. Instead, add a brake voltage or use a mechanical brake. Otherwise, the inverter will often be impacted by the motor's back electromotive force, and the failure rate will be greatly increased.

4. If the inverter often runs at low speed below 15HZ, the motor should be equipped with a cooling fan!

5. Dust and humidity belong to the inverter. Install the inverter in an air-conditioned room or in an electric cabinet with a dust filter. Clean the dust on the circuit board and radiator regularly; if the inverter has been stopped for a period of time, blow the circuit board with a hair dryer before turning on the power.

6. When the cooling fan of certain brands of inverters is broken, it will not provide overheat protection until the inverter is damaged. Therefore, when the fan makes a noise, it should be replaced.

7. In some factories, the power supply is generators, and the voltage is unstable, and the frequency converter is often damaged. The generators are equipped with voltage stabilization or overvoltage protection devices, and the effect is very good.

8. Lightning protection is also very important. Although it rarely happens, when the inverter is struck by lightning, it will be severely damaged. The frequency converter of constant pressure water supply is easily struck by lightning because it has a lightning pipe that extends to the sky.

9. In order to prevent electromagnetic interference, use shielded wires for the input, output, and control wires of the inverter. The shielding layer wiring method cannot be wrong, otherwise the effect is opposite. It is possible to use iron pipes to cover them, install filters, and lower the carrier frequency. We found that if the switch tube of the inverter's switching power supply is a field effect tube (such as K series), its interference will be larger.

10. When the inverter is broken, do not hand it over to someone without maintenance experience! Otherwise, the more repaired, the worse! Sometimes the fuse is about to fuse, you must check whether there is a problem. Some electricians are inexperienced and immediately install a good fast fuse (definitely not replace with copper wire). As a result, the inverter will burn more severely. According to our experience, if the module is fast blown, there are mostly problems with the module, but the fast blow of the module is indeterminate. Many inverter power modules and rectifier modules are interchangeable.

11. In the process of repairing the inverter, we often encountered some inverters that were blown up after repairs by the factory itself, and the damage was more serious than the original and more difficult to repair. After inspection, it turns out that they used a repaired module. It is difficult to detect the repaired module with a meter. The parameters are completely normal. However, due to the rough internal wiring, the transistor’s sealing silicone grease cannot be sealed after opening. Some such modules can be used for several months, and some can be turned on. Just blow up.