Experimental Investigation of the Cumulative Arc Erosion Phenomena Occurred in Low-voltage DC Electrical Apparatus

In this work, the electrical endurance experiments were conducted on silver tin-oxide contacts under DC 28 V/8.5 A condition. The electrical characteristic parameters and the 3D height point cloud datasets of the contact surfaces were recorded in-situ using a designed model switch. The experimental results indicate that the surface roughness of the contacts increases with the operation cycle. The contact material exhibits a pronounced directional mass transfer characteristic, with the cathode undergoing continuous material loss and the anode experiencing a volume increase, although the total volume of both contacts shows a continuous decrease trend. The mechanical interlocking caused by the concave-convex morphology on the contact surfaces leads to breaking bounce, which significantly aggravates the erosion degree and causes the volume change rate of contacts to show an initial increase followed by a subsequent decrease.