NOUFERROUS METALLURGICAL EQUIPMENT

With the rapid development of Chinese electrolytic aluminum industry and the continuous progress of automation and automatic control technology, frequency converters have been widely applied in electrolytic units. In a decade of application, many users have reported that during equipment operation, the damage of the frequency converter causes failure of single-phase grounding or the cable between the frequency converter and the motor, resulting in single-phase grounding on the output side of the frequency converter and eventually simultaneous burning of multiple frequency converters, and no reasonable solution has been found. This paper conducts a detailed theoretical analysis on the problems raised, and introduces the working principle of the frequency converter and the special technology of the electrolytic unit related to the fault. Combined with the field situation, the reason for the centralized burning of the frequency converter is found, based on which a solution is provided through voltage monitoring in the design. And the solution is proved by field test and long-term operation, showing good results.