Abstract:

In order to solve the problem that the fuse breaks in advance in the preheating stage or takes a long time to break in the full-voltage circuit due to the inaccurate judgment of the preheating transition time during the fuse breaking capability test using the existing fuse overload breaking test system in the laboratory, the fusing process of the fuse and the changing trend of the port voltage are analyzed. A testing method using the voltage slope of the fuse port as the criterion is proposed. The voltage fitting formula and control program are designed and verified by the simulation and experiment. The simulation and testing results show that the curve fitted by the formula is perfectly consistent with the actual testing waveform. The control program determines the preheating conversion time and performs the preheating conversion operation. After switching to the full voltage loop, the flow passing time is controlled within 3 seconds, and the ideal testing results are obtained. The testing system and control method mentioned are suitable for different types and voltage levels of fuses, and have high application value.

Key words: fuse, overload breaking, preheating conversion, voltage slope, fitting curve