Basic knowledge of Chinese frequency converter maintenance

- Aug 21, 2019-

After the maintenance of a large number of frequency converters, we feel that if people in the use and maintenance of frequency converters can pay attention to avoid some mistakes, clear some wrong ideas, then the use and maintenance of frequency converters will be of great benefit.

1. The frequency converter should not be installed on the equipment with vibration, because it is easy to loosen the connection screw of the main circuit inside the frequency converter, many frequency converters are damaged because of this reason.

2. Wiring problems: inverter input end had better be connected with an air switch protection current value is not too large, in order to prevent short circuit burning will not be too serious.The "N" end must not be grounded.Control lines should not be too long.Because this makes control board easy to be disturbed by electromagnetic wave and produce wrong action, also can cause control board damage, more than 2 meters long had better use shielding line.Frequency converter side do not install large current and frequent action of the contactor, because of its frequency converter interference is very big, often make the frequency converter error operation

3. Often need to stop the frequency converter had better not rely on the frequency converter itself brake, but also add brake electrical or mechanical brake, otherwise frequency converter often by the motor back emf impact, failure rate will be greatly improved.

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

5. Dust and moisture is the frequency converter of the most deadly killer had better be able to install the frequency converter in the air conditioning room, or installed in the electric cabinet with dust net, to regularly clean circuit board and radiator on the dust;The frequency converter shut down for a period of time is better to blow the circuit board with a hairdryer before power.

6. When the cooling fan of some brand inverter is broken, it will not issue overheating protection until the inverter is damaged, so when the fan has a sound should be replaced.

7. Some factories supply electricity is the generator generation, the voltage is not stable, the frequency converter often damages, the generator installs the stable voltage or the overvoltage protection device, the effect is very good.

8. Lightning protection is also very important.Although rarely occur, but when the frequency converter is struck by lightning, will be severely damaged.The frequency converter with constant pressure water supply is the most vulnerable to lightning strike, because it has a lightning pipe reaching into the sky.

9. In order to prevent electromagnetic wave interference, frequency converter input, output, control line had better use shielding line, shielding layer wiring method can not be wrong, otherwise the effect is opposite, it is possible to use iron tube sleeve, add filter, reduce the carrier frequency.We find that if the inverter switching power supply is the field effect tube (such as K series), its interference will be greater.

10. Ten, after the frequency converter is broken, do not give to the person who has no maintenance experience to repair!Otherwise it might get worse and worse!Sometimes fast fusing, must check whether there is a problem, some electricians have no experience, immediately install a good fast fusing (absolutely can't replace with copper wire), the result is the frequency converter burned more severe.According to our experience, if the module fuses quickly, then most of the modules have problems.Many inverter power modules and rectifier modules are interchangeable.

11. We in the maintenance of frequency converter process, often come across some factories after their own maintenance and blow up the frequency converter, and damage than the original more serious, more difficult to repair.After inspection, it turned out that they used repaired modules.It is very difficult to detect the module with the instrument, and all the parameters are completely normal. However, due to the rough internal wiring, the sealed silicon grease of the transistor cannot be sealed after opening. Some such modules can be used for several months, and some will blow up as soon as they are turned on.