Arc motion and pressure formation in low voltage switchgear

To understand the complex nature of arc motion in current limiting low-voltage switchgear detailed information about the interaction between pressure distribution, arc movement and plasma flow are necessary. One of the major factors concerning these interactions is the geometry of the arc chamber. Systematic experimental investigations have been carried out to study the influence of the gap between the arc runners and the insulating side walls of the arc chamber in combination with different outlets at the top of the chamber. A high time resolution optoelectronic measuring device for the observation of arc motion, and pressure transducers at different positions of the chamber give a good impression of each stage of arc movement and the corresponding pressure development. Significant differences depending on the geometry of arc chambers can be shown. The findings are explained quantitatively and qualitatively.