Numerical analysis of DC arc evolution process of two parallel contacts model

The movable contact of conventional air circuit breaker (ACB) includes multiple parallel contacts. The arc motion process directly affects the breaker capacity of ACB. Therefore, it is important to study the arc motion process of multiple parallel contacts model. A three-dimensional (3D) magneto-hydro-dynamic (MHD) model of air arc plasma is built to investigate the arc motion process. The anode of this model consists of two parallel contacts. The potential vector approach is adopted to calculate the electromagnetic field. The thin sheaths surrounding the electrodes are also employed to represent the voltage drop of electrodes. Based on this model, the evolutions of arc voltage, temperature, and current density are obtained. It is noted that the anode arc root form on two parallel contacts with the arc evolution, and the cathode root is the only one. The arc column is merged together due to their attraction.