The Influence of TMF and AMF Components on Arc Movement Characteristics in Spiral-Slot Contacts

Spiral-slot contacts produce an axial magnetic field (AMF) and the transverse magnetic field (TMF). The magnetic field between TMF contacts will affect the breaking performance of vacuum interrupters. In order to study the effect of TMF and AMF on arcing process and movement characteristics, five contacts with different TMF and AMF, but the same ratio of TMF to AMF, were designed and experimentally investigated in a demountable vacuum chamber. The arc movement phenomenon under different TMF and AMF was obtained. It was found that increasing TMF and AMF could reduce the arc jets to the outer electrode, and arc stagnation was more likely to occur in the later stage of the movement. The influence of TMF and AMF on arc movement characteristics and the utilization of contact surfaces was investigated. With the increase in TMF and AMF, the number of arc rotations increased, and the range of arc movement and the utilization of contact surface increased first and then decreased. Simulations were performed to analyze that the influence mechanism of TMF and AMF on arc movement characteristics was investigated. With the increase in TMF and AMF, the tangential force of the concentrated arc was increased, and the radial force was reduced.