DC vacuum arc lifetime of contact materials CuCr50 and CuCr25

摘要

The objective of this paper is to determine the lifetime of DC current vacuum arc in contact materials of CuCr50 and CuCr25. Commercial vacuum interrupters with contact materials of CuCr50 (50% Cr) and CuCr25 (25%Cr) were designed. A DC current vacuum arc lifetime circuit was set up. The vacuum arc was drawn by contact separation. The vacuum arc voltage duration indicated the DC vacuum arc lifetime. There were five levels of DC current, e.g. 2.2, 2.0, 1.8, 1.6 and 1.3 A. At each DC current level, the vacuum arc lifetime measurement repeated for 20 times. Thus the average DC vacuum arc lifetime were determined. The experimental results show that the average DC vacuum arc lifetime was proportional to the DC current level. For CuCr50, the average DC vacuum arc lifetimes were 3.92, 2.17, 2.08, 1.66 and 0.72 μs under the five current levels. For CuCr25, the average DC vacuum arc lifetimes were 3.01, 1.73, 1.29, 0.81 and 0.59 μs, respectively. At the same DC current level, the DC vacuum arc lifetime of CuCr50 was higher than that of CuCr25.