CuCr触头材料小电流下阴极斑点与截流值研究

Cathode Spots and Chopping Current in Vacuum and at Low Current for CuCr Contact Materials

摘要:

研究了在峰值电流分别为10A和80A的小击穿电流下，CuCr25与CuCr50合金阴极斑点蚀坑形貌的差异。通过比较阴极斑点蚀坑的大小和分布，分析了CuCr触头材料显微组织中Cr相尺寸的大小对阴极斑点运动和蚀坑形貌的影响。采用示波器直接测量出截流值和电弧寿命，结合CuCr合金阴极斑点蚀坑形貌的分布，从现象和机理上解释了CuCr25合金截流值低于CuCr50合金的原因。这些结果对通过优化CuCr合金的显微组织以降低触头材料的截流值提供了有力的依据。

Abstract:

The discrimination between CuCr25 and CuCr50 alloys for the cathode spot craters with peak currents of 10 A and 80 A has been studied in this paper. The microstructure analysis showed that the CuCr alloys has an important effect on the discrimination, in which the size of Cr phase plays an main role in effecting the moving direction and distribution of cathode spot craters. It can well be explained why the chopping current of CuCr25 is less than CuCr50 by the direct measurements of chopping current and arc lifetime by oscillograph. All above useful conclusions will provide powerful supports on decreasing chopping current by minimizing the size of Cr phase for CuCr alloys.