Vacuum Arc and Characteristics of Arc Voltage in Curved Surface Contact

In this paper, we proposed two novel contact structures for vacuum interrupter. The sine surface contacts (sin-ruled surface contact and sin-revolution surface contact) were experimental studied in the condition of 3mm opening gap. Experiments were carried out in the oscillating circuit with the contact diameter being 40mm, the anode contact material being CuW80 alloy and cathode contact being CuCr25. The vacuum arc appearance and voltage characteristics of butt contact, sine-ruled surface contact and sine-revolution surface contact were analyzed contrastively. Experimental results showed that the diffusion path of cathode spots was along the curved surface. The movement of cathode spots did not be inhibited by the curved surface. Compared to butt contact, arc voltage and voltage noise of curved surface contacts were relatively low. The losing of plasmas was a main reason why voltage noise generated. In arc stability and diffusion stage, plasmas and metal vapor were mainly absorbed by curved surface between contacts but a few of plasmas spread outside of arc gap, for which the service life of the vacuum interrupter chamber was effectively improved.