The English name of the frequency converter is VFD or VVVF. It is an electrical device that uses a variant circuit to change the 50Hz power frequency power supply into an AC power supply with adjustable frequency and voltage to drive a three-phase AC asynchronous motor.

As the frequency converter is composed of microelectronic technology and power electronic modules, its electrical performance will change greatly in practical application, affected by the surrounding ambient temperature, air humidity, mechanical vibration, dust and corrosive gases. If it is operated for a long time without maintenance, the electronic components inside the frequency converter will age.

In particular, dust and moist air, if not eliminated in time, will lead to serious heating of electronic components in the frequency converter, which will cause failure or reduce the service life of the frequency converter. Therefore, it is necessary to carry out daily and regular maintenance and repair of the frequency converter.

Daily inspection items of frequency converter: ① whether the sound of the motor changes abnormally during operation, including whether the motor vibrates during operation. ② Whether the installation environment of the frequency converter has changed. Whether the ambient temperature is normal, the working temperature of the frequency converter is generally required to be within the range of -10 ℃ ~+40 ℃, preferably about 25 ℃. ③ Whether the frequency converter cooling fan works normally, including whether the frequency converter cooling channel is unblocked. Whether the current, voltage, frequency and other data output by the frequency converter on the display panel are normal. Whether the characters on the display panel are clear and whether there are missing strokes. ④ Whether the frequency converter is overheated. The infrared thermometer can be used to detect whether the radiator of the frequency converter is overheated or whether there is peculiar smell. Check whether there is fault alarm display during the operation of the frequency converter. ⑤ Clean the filter screen of the air inlet duct inside the electrical control cabinet regularly. Always keep the control cabinet and frequency converter in a good clean state. Effectively remove the dust on the surface of the frequency converter to prevent the dust from entering the inside of the frequency converter. Especially metal dust. Effectively remove the oil stain from the inverter cooling fan. ⑥ Use the annual overhaul time to turn on the frequency converter and focus the inspection on the interior that cannot be seen during daily operation for cleaning. Use a brush or vacuum cleaner to clean the circuit board of the frequency converter and the internal rectifier module, IGBT module, DC filter electrolytic capacitor, input and output reactor, etc. Replace unqualified electronic components (Note: the filter electrolytic capacitor inside the frequency converter generally needs to be replaced in 4-5 years). ⑦ Check the electric cooling fan. The electric cooling fan is a component that is easy to be damaged. Its life is limited by the bearing (it is an axial flow fan). According to the operation of the frequency converter, the fan or fan bearing is generally replaced once every 2-3 years.