Properties of Vacuum Arc Influenced by Electrode Diameter and Material in TMF Contact Based on Forced Current Zero

With the increase in electrical equipment in More/All Electric Aircraft, 270 V dc power supply systems will be needed. One method for DC interruption is forced current zero (FCZ). Based on FCZ technology with transverse-magnetic-field (TMF) contact, the spiral-type contacts are designed. Experiments with different currents are carried out with contact diameters being 30 mm, 40 mm, and 50 mm, and arcing surface materials Cu-W80 alloy and Cu-Cr50 alloy respectively. It is indicated by the experimental results that breaking capacity of vacuum interrupter and vacuum arc appearance are closely related to the electrode diameter and material. For the same size of electrode diameter, the breaking capacity in Cu-Cr50 is better than that in Cu-W80. With increasing electrode diameter, arc column expansion velocity and diameter increase gradually. Breaking capacity is increasing with larger contact diameter.