Breaking performance degradation mechanisms of high-power DC contactors

High-power DC contactors incorporating double-break contact bridge structures function as essential components in power systems for aviation, electric vehicles, and data centers. During load switching operations, arcing inevitably occurs, resulting in erosion-related damage to the contact bridge. Existing analytical methods remain inadequate in explaining the unbalanced corrosion observed in contact bridges during electrical endurance testing. To address this issue, this study introduces an in-situ diagnostic system that integrates three-dimensional laser scanning with synchronized electrical measurements, enabling real-time correlation between arc erosion behaviour and surface morphology. Detailed waveform analysis facilitates the investigation of asynchronous arc interruption phenomena under magnetic blow-out conditions. By extracting arc ignition locations and analyzing the arc voltage waveforms during circuit breaking, the study elucidates the mechanism underlying the uneven distribution of arc energy between the two contact interfaces. The resultant asymmetric arc erosion and its associated effects, induced by the ABA phenomenon, are subsequently interpreted.