Abstract : Due to their high efficiency, energy saving and automation performance, frequency converters are widely used in industrial production. However, frequency converter tripping caused by overcurrent and overload is very common during their operation. Solving such problems is very beneficial for practical operation. The difference between frequency converter overcurrent protection and overload protection is that the protection limit of the current is different. The protection object of overcurrent is the frequency converter itself. The basic characteristic is that the working current exceeds the rated current of the frequency converter. Secondly, overcurrent protection adds a detection position. Since the cause of overcurrent is not only abnormal operation of the output side, it may also be caused by abnormality inside the frequency converter. Therefore, in addition to the output current, the input current must also be detected at the same time to judge the overcurrent. Furthermore, the processing methods of frequency converters are different. Overload protection is based on inverse time characteristic, while overcurrent protection is handled according to different situations: (1) If an overcurrent occurs during acceleration, deceleration or operation, but has not exceeded the overload capacity of the frequency converter, it can be handled by the "anti-trip function". (2) When the current exceeds the overload capacity of the frequency converter, it must trip immediately. Analysis and Solutions for Overcurrent Tripping Overcurrent tripping in frequency converters can be categorized into short-circuit faults, tripping during operation, and tripping during acceleration/deceleration. [b]1. Short-circuit fault (1) Fault characteristics[/b] 1) Insulation breakdown between phases or between each phase and ground of the motor and motor cable causes short circuits between turns or between phases and ground, resulting in overcurrent. The first trip may occur during operation, but if reset and restarted, it often trips immediately upon acceleration. 2) It has a large inrush current, but most frequency converters are capable of protective tripping without damage. Because the protective tripping is very rapid, it is difficult to observe the magnitude of the current. [b][align=center]For more details, please click: Causes and solutions for overcurrent and overload in frequency converters[/align][/b]