High-speed observations of arc modes on RMF- and AMF- contacts

Vacuum interrupter especially with high short-circuit interruption ability are mostly equipped with contact systems based on two different principles. One of them is the widely used radial magnetic field contact (RMF), while the other is the axial magnetic field (AMF) contact system. By using a high speed CMOS digital video camera, different contact systems could be observed during arcing under short-circuit conditions. The investigation was concentrated on arc modes development with different contact systems and different arcing times, and focused on three contact systems such as one improved RMF and two different AMF systems. In case of the AMF systems both an unipolar and a quadrupolar contact system was considered.