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Tetsuya KITAJIMA Junya SEKIKAWA Mitsuru TAKEUCHI Takayoshi KUBONO
The purpose of this study is to examine the impact of the opening speed on a breaking arc. The opening speeds are 10, 20 and 30 mm/s. The breaking arc is generated in a D.C. 42 V/10.5 A circuit, and the arc voltage, the arc current, the gap length and the arc spectrum intensity are measured. Arc temperature is calculated by using a Boltzmann plot. Even if the opening speed is changed, the arc temperature starts from a high temperature, and falls gradually to 4650-4750 K with time. Namely, the opening speed has no influence on the arc temperature.
Junya SEKIKAWA Tetsuya KITAJIMA Takayoshi ENDO Takayoshi KUBONO
The motion of arc spots of breaking arc is investigated for Ag electrical contacts in DC 42 V/10 A resistive circuit using a high-speed camera. Also, the eroded contact surfaces are observed with a microscope after each breaking operation. As results, some kinds of different films and eroded regions are distinguished. Diameters of these regions are corresponding to the widths of the cathode and anode spot regions that are obtained by using the high-speed camera. It is found that the films and eroded regions on the electrical contacts are generated at different stages of the breaking arc.