702 / 2017-09-13 21:22:38

Study on Factors Influencing the Characteristics of Arc in DC Contactors

Arc voltage, arc shape, DC, hydrogen arc, influencing factors

The characteristics of arc in DC contactors are a major factor affecting the breaking performance of small-sized contactors. Based on the magneto hydrodynamics (MHD) model, this paper obtains the temporal and spatial distribution of arc temperature by taking DC arc as its research objective and H2, N2 and He as arc extinguishing media. A removable arc chamber was adopted to build up a DC experimental circuit, in which a double-contact structure made of pure copper was selected, with a contact diameter of 10mm and a contact spacing of 2mm, to measure the influence of magnetic field, pressure and breaking speed on the characteristics of DC arc. The simulation and experimental results suggest that H2 has a stronger arc extinguishing capability than N2 and He when used as an arc extinguishing medium for switches; the increase in pressure contributes to the reduction in arcing time but the reduction is not monotonic, and a pressure of 3-4atm is desirable; the increase in magnetic flux density and breaking speed can effectively shorten the arcing time, and a breaking speed of 0.5m/s and magnetic flux density of 50mt are desirable.