Novel Design of 3-D Microstructure Contact Material Generating Autoexcitation Magnetic Field

The development of vacuum circuit breaker (VCB) toward large current and high voltage is extremely limited with contact material. Herein, a new type of VCB contact model including microstructure is proposed. Emerging contact material achieves the breakthrough from external applying to self-excited magnetic field, besides strong magnetic strength and low temperature rise. Three-dimensional finite-element simulations, which contain microcoil, unit groups, and coupled contacts, were implemented. And the influence factors involve eddy current losses, iron core diameter, units' spacing, and copper-chromium layer thickness. Simulation results indicate that the magnetic field is the most efficient when the distance between the coupled coils is 1.65 mm and the thickness of the Cu-Cr layer is 3 mm. Moreover, the relative practical models and measures were carried out to verify the distribution of magnetic field, and the results were in good agreement with theoretical predictions. Therefore, the theoretical data can guide the design of practical contact models and support the optimization of structural parameters, applied to vacuum interrupter.