Experimental investigation of vacuum arc characteristics subject to axial magnetic field contacts with different ratios of diameter to gap distance

Abstract

In this study, to investigate vacuum arc characteristics under different diameter-to-gap distance ratios ( D/ g), experiments are conducted on axial magnetic field (AMF) contacts with varying D/ g. The peak current value ranges from 15 to 35 kA. The experimental results show that the ability of AMF contacts to control the arc decreases with D/ g. Furthermore, the 2/3 coil contact can control the arc under long gap distances, whereas the cup-shaped contact cannot effectively control the arc under long gap distances. The arc energy and noisy period duration decrease with increasing D/ g. The arc voltage of the 2/3 coil contact at the peak moment is always the lowest compared to the cup-shaped contact and the 1/2 coil contact, and the arc voltage of the 2/3 coil contact at the peak moment has an approximate power function relation with D/ g. The simulation results show that the AMF distribution changes from saddle shape to bell shape with decreasing D/ g. The 2/3 coil contact is more suitable for high-voltage vacuum interrupters (VIs), while the cup-shaped contact is more suitable for medium-voltage VIs.