Domestic inverter repair and maintenance methods

Because the domestic frequency converter can adapt to the various requirements of the production process, especially in the industrial automation control application, the AC frequency conversion speed regulation technology has risen to the mainstream of industrial automation control. The performance of the AC speed control system can already compete with the DC speed control system, and can even exceed the DC system. It uses an all-digital control method to greatly enhance information processing capabilities. At the same time, it has continuously integrated practical experience and skills into software functions. Complex control that cannot be realized by analog control has become possible today, and the reliability, usability and maintainability of the inverter are enriched. Because the frequency converter has good speed regulation performance, wide speed regulation range and high operating efficiency, convenient operation and use, and is suitable for interface with other equipment, the application is more and more extensive. Over the years, we have been learning in practical production applications and have accumulated experience in the maintenance and repair of some inverters.

Due to the rapid development of power electronics technology and microelectronic technology, the speed of inverter modification is also relatively fast, and new products are continuously introduced, and the performance is continuously improved, and the functions are continuously enriched and enhanced. At present, there are many inverter brands sold in the domestic market, such as Danfoss, ABB, SIEMENS, GE, Schneider, etc. There are many domestic inverter brands. Although there are many kinds, the functions and usage are basically similar. In general, the methods of use, maintenance and troubleshooting are basically the same. In practical applications, the frequency converter is affected by environmental conditions such as ambient temperature, humidity, vibration, dust, corrosive gas, etc., and its performance will have some changes. If used properly and properly maintained, it will extend the service life and reduce production losses caused by sudden failures. If the maintenance is not used properly, the maintenance work will not be able to keep up, there will be operational failures, resulting in the inverter not working properly, or even causing premature damage of the inverter, which will affect the normal operation of the production equipment. Therefore, routine maintenance and regular inspections are essential.

Routine maintenance and inspection

For continuously operating drives, the operating status can be checked visually from the outside. Regularly inspect the inverter for inspection and check if there is any abnormality when the inverter is running. Usually the following checks should be made:

(1) Whether the ambient temperature is normal or not, it is required to be in the range of -10 °C to +40 °C, preferably around 25 °C;

(2) Whether the various data such as output current, voltage and frequency displayed by the inverter on the display panel are normal;

(3) Whether the characters displayed on the display panel are clear and whether characters are missing;

(4) Use a temperature measuring instrument to detect whether the inverter is overheated and whether there is any odor;

(5) Whether the inverter fan is running normally, whether there is any abnormality, and whether the cooling air duct is unobstructed;

(6) Whether there is a fault alarm display during the operation of the inverter;

(7) Check if the AC input voltage of the inverter exceeds the maximum value. The limit is 418V (380V × 1.1). If the input voltage of the main circuit exceeds the limit, even if the inverter is not running, it will cause damage to the inverter circuit board.