Study on arc characteristics and influencing factors of cup-shaped axial magnetic field contact at different gap distances

Abstract

The cup-shaped axial magnetic field (AMF) contact, integral to high-voltage vacuum interrupters, undergoes innovation by enhancing the slotting rotation angle of the cup wall. This adjustment significantly amplifies the gap magnetic field, promising breakthroughs in handling long-gap arcs within high-voltage vacuum interrupters. Comprehensive vacuum arc experiments were conducted on cup-shaped AMF contacts with varying slotting rotation angles at different gap distances. The research meticulously analysed the evolution of vacuum arc characteristics under diverse breaking currents. Scanning electron microscope (SEM) images of the cathode surface unveiled three distinctive microscopic morphologies: particle gullies, pore platforms, and particle platforms. Notably, the chromium content corresponding to these morphologies exhibited a progressive increase. Integrating the surface distribution of copper and chromium, the study proposed a plausible cathodic erosion mechanism. Extending the investigation, the research delved into the influence of the iron core, contact diameter, and slot number on vacuum arc characteristics, which expected to provide reference for the application of the cup-shaped AMF contact in high voltage vacuum interrupters.