Investigation of vacuum arc root characteristics between transverse magnetic field contacts with slot structure

The magnetic field generated between the transverse magnetic field contacts drives the vacuum arc to move on the contact surface, thereby preventing localized overheating and mitigating contact erosion. Arc root characteristics play a crucial role in the arc morphological evolution and motion behavior. In this paper, the vacuum arc root behavior evolution and motion characteristics between different structures of transverse magnetic field contacts were investigated experimentally and simulated. The evolution patterns of arc root behavior under different contact configurations were obtained, and the dynamic characteristics of key parameters at the cathode and anode arc roots under constricted arc conditions were analyzed. The results indicated that abrupt variations in the arc root dynamics characteristic correspond to changes in arc motion modes or morphological transitions. The area ratio between the cathode and anode arc roots of the constricted arc remained dynamically stable within a certain range and was intrinsically linked to the arc constriction degree. Furthermore, a quantitative method was proposed for evaluating arc constriction by integrating the cathode-anode arc root area ratio with arc light grayscale values. The study also elucidated how various influencing factors affect the arc constriction behavior. This work provides a novel perspective and methodological framework for better understanding the arcing characteristics of the vacuum arc between transverse magnetic field contacts. It also offers valuable theoretical guidance and technical support for optimizing contact design and improving vacuum switch performance.