Experimental study on relationship between electromagnetic noise and surface profile from arc discharge of Cu-C contact

The authors observed the correlation between electromagnetic noise and discharge traces on electrode surfaces for opening Cu-C contacts. In the case of Cu(anode)-C(cathode), the number of sporadic burst noise generated by discharge is equal to that of traces of discharge on the cathode surface. The period of burst noise corresponds to fluctuations in arc voltage waveform. The authors showed a correlation between static arc and circular discharge trace as well as between the arc with large fluctuation and melted area. In the case of C(anode)-Cu(cathode), continuous burst noise was observed in the period of arc discharge. The level of noise becomes high in the period of fluctuation of arc voltage in the beginning of the arc and in the latter half of the arc. Patterns of arc voltage waveform and change of electrode surface for various circuit conditions are classified into four categories, and the boundaries of the four categories showed fine coincidence. Patterns of noise are classified into four types and correspond to patterns of arc voltage waveform and change of electrode surface. By these results, a correlation between arc voltage, change of electrode surface, and electromagnetic noise was shown.