Current-limiting switching by squeezing arcs into narrow insulating slots

Abstract

For low-voltage circuit breakers, arc breaking by squeezing the arc in a narrow insulating slot is an interesting alternative to the conventional technique of using arc chutes with steel plates. The performance of a switching device based on this principle was experimentally investigated. The influence of slot dimension, switching speed, insulating material, and other test parameters on the arc breaking characteristics was determined. The results show that the arc voltage in the slot chambers depends mostly on the arc length (moving speed of the plate) and the cross-sectional area of the slot, while the influence of the insulating material and the shape of the slot plays only a minor role. By using a simplified ar model the curves of arc voltage and arc current can be simulated. There is a good agreement between the experimental and the calculated results.<>