This paper focuses on the research of a new high-speed DC switch repulsion mechanism with experimental and simulation methods. Multi-physical equations reflecting the transient electromagnetic field, electric circuit, mechanical motion and material deformation are coupled in the calculation. For the reason of accuracy, skin effect and the proximity effect caused by the current in the coil are also taken into account. According to the simulation results, which indicate several key parameters severely affecting the mechanism speed, a high-speed DC switch repulsion mechanism is developed. By the test of mechanism motion, its average speed can be up to 8.4 m/s and its mechanism response time is 250 µs, which verifies the simulation results. Furthermore, during high speed motion the stress on the metal plate and moving contact is also discussed. It is noticed that the influence of the material deformation on the mechanical motion is very important.

This paper focuses on the numerical and experimental investigations of the influence of two polymers (PA6 and POM) on the arc behavior during arc motion process. The mathematical model of 3-dimentional air arc plasma considering the ablation of lateral walls is built based on magnetic hydro-dynamics (MHD). By adopting the commercial computational fluid dynamics (CFD) package based on control-volume method, the above MHD model is solved and the distribution of temperature field, concentration field, flow field and electrical potential field in the arc chamber are calculated. The simulation results indicate that the vapor concentration behind the arc column is higher than that in front of the arc column because of the existence of "double vortices" in the arc chamber. The use of polymers causes the maximal arc voltage increase 16.2% with POM and 18.9% with PA6 in this case and causes the average arc velocity increase 15.8% with POM and 21.1% with PA6 in this case. The experiments are also carried out to study the influence of polymers on arc voltage and arc root position in the arc chamber during arc motion. The experimental results prove the validity of the numerical investigation.

This paper proposes the P-1 radiation model for the calculation of low voltage arc plasma. The influence of both emission and self-absorption are taken into account in this model. Based on the couple of electric field, magnetic field, flow field and thermal field, a three-dimensional arc chamber model is constructed and its radiation energy is calculated by the P-1 model with the spectrum divided into six bands. From the obtained distributions of temperature, incident radiation intensity, plasma velocity and current density by P-1 model, it is observed that temperature is obviously different from the result by net emission coefficient (NEC) method in the low temperature region. Arc column edges near the arc root also absorb radiation energy. Furthermore, compared with the result by NEC method, the arc column voltage calculated by P-1 model is lower and more close to the experimental result.