Characterization of arc plasma during hybrid-switching using a DC-Hybrid model switch

The paper deals with further results of the investigation of the plasma of a DC hybrid-switching discharge between metallic contacts combining electrical and optical methods. The setup consists of a model switch using a linear motor as mechanical drive and a semiconductor parallel to the contacts to commutate the current forcing arc extinguishing after a defined arcing-time. Firstly, the current flow remains initially through the contact path due to lower resistance of the closed contacts. During contact opening, the resistance rises due to reduced contact force, finally ending up with a single metal bridge that will be heated until explosion, leading thus to a metal-dominated discharge plasma. High-speed imaging and spatially and time resolved spectroscopy was used to capture the radiation during arcing and during post-arc. Spatially solved spectroscopy delivered the characteristics of radiation during arcing. Intensity lines of the elements of the electrodes indicate a predominately arc in metal vapor. Combining a secondary high voltage DC source it was possible to characterize the behavior of the resistance of the gap during arc and in the post-arc phase also.