Comparison of vacuum arc behaviors for slot type axial magnetic field contacts with and without iron plates

We experimentally compared vacuum arc behaviors of slot type axial magnetic field (AMF) contact with and without iron plates. W e compared 3 contact diameters - 48 mm, 58 mm, 66 mm and 2 contact gaps - 8 mm and 14 mm. The AMF contacts were fixed in a demountable vacuum chamber and the vacuum arcs were initiated by a trigger. We compared vacuum arc behaviors at 8 current peak values from 2.5 kA to 21.8 kA and the vacuum arc appearances were recorded by a high-speed charge-coupled device (CCD) video. Experimental results suggest that slot type AMF contacts with iron plates are suitable for high contact diameter case for a better vacuum arc control, where the vacuum arcs arc controlled in diffuse mode until higher current level.