Online optical observation of air arc ablation in silver-based contacts

Abstract In low-voltage power systems, silver-based contact materials serve as critical components in various switching devices, playing a vital role in interrupting currents. The performance of these materials in terms of electrical and mechanical properties significantly impacts the safety, reliability, and lifespan of electrical systems. To investigate the performance differences of various silver-based contact materials under different DC breaking conditions, we designed an online optical observation platform and analysis method specifically for air arc erosion. Using three silver-based contact materials commonly employed in low-voltage circuit breakers, this study systematically examined the effects of different contact materials, arc current, and breaking speed on ablation, material transfer, and postarc dielectric recovery properties. This was achieved through a combination of online ablation video analysis, offline weight measurement, and scanning electron microscopy. Finally, by summarizing and analyzing the experimental results, the mechanisms by which these factors influence the erosion of silver-based contact materials were identified. This provides an important reference for further enhancing the performance of existing silver-based contact materials and developing new contact materials.