Effects of Cr content on the interruption ability of CuCr contactmaterials

摘要

The effects of Cr content in CuCr contact materials, especially onhigh current interruption, have so far mostly been examined inexperimental chambers rather than in actual vacuum interrupters (VIs).Possible interactions of the contacts with their surroundings, bothelectromechanical and gaseous, may require commercial VIs for a morerealistic test determination of the effects of Cr content on the overallperformance. In this work, the Cr content in CuCr contacts is variedfrom 5 to 75 wt% and tested in their 38 kV axial magnetic field typeVIs. The material properties of electrical conductivity, hardness andtotal VI resistance are measured as a function of the Cr content. AC andimpulse voltage withstand capabilities are tested before and aftershort-circuit current interruption tests. Contact erosion behavior isexamined with VIs subjected to only a half cycle arcing duty