Experiment investigation on triggered vacuum arc under the different contact materials

In order to improve the breaking capacity of contacts, it is very important to find a better contact material. In this paper, the triggering experiments of plate contact with different material are studied to investigate the characteristics of vacuum arc. The current range is from 1kA to 9kA (rms). The gap distance is 3mm and 5mm. The arc appearance and the behavior of cathode spots are captured by high-speed camera with an exposure time of 2 μs. The arc current and arc voltage are measured at the same time by Rogowski coil and high-voltage probe. The diameter of the contact is 25mm. There are five kinds of materials (CuCr10, WCu, CuW-WC, CuCr25 and CuCr30) conducted in this paper. Compared with the experiment results, for WCu, the arc speed is slowest, the arc distribution is most uniform and the cathode spot is brightest with a large angle of the ejected particles. The arc appearance of CuW-WC is changed fastest with noise of voltage. CuCr alloy's melting resistance property is poor. With the increase of Cr density, the erosion degree slows down gradually. The arc shape of the small gap distance hardly changes, and the burned area is more fixed.