Influence of Slot Number on the Vacuum Arc Characteristics Between Spiral-Type Transverse Magnetic Field Contacts

摘要

The transverse magnetic field (TMF) contacts can generate a transverse magnetic field driving the arc to rotate on the contact surface, which is beneficial to avoid severe ablation of contacts and improve the breaking performance. The contact structural parameters have an effect on the magnetic field distribution and vacuum arc characteristics. In this paper, the 3-D finite element models of spiral-type contacts with different number of slots were established, and the magnetic induction intensity distribution between contacts and the electromagnetic force of arc column were calculated. It was found that increasing the number of slots could effectively enlarge current density, and enhance the control of arc motion, but it would continually cause an arc motion to cross slots. Therefore, it was necessary to comprehensively consider the influence of the two aspects in the design of contact structure. The inductor-capacitor (LC) oscillation circuit was used to establish the experimental system. The vacuum arc appearances of 3-slot contacts and 4-slot contact were recorded by highspeed video camera, and the comparative analysis of vacuum arc and arc voltage characteristics were carried out. It could be observed that the 4-slot contacts had a higher concentration degree of arc column and a longer duration of arc voltage noise during the arc motion stage, in the meanwhile, the arc motion was more obvious.