Switching performance and capability of multiple breaks within electromechanical relays used for power backup application

The increase of break numbers is traditionally taken as one of effective arc interruption measures for any electrical apparatus switching the high-power load. Different from the single break case, the asynchronous mechanical separation of contact pairs in series makes the arc interruption behavior more complex. In this paper, the contact voltage and contact current waveforms of double breaks are analyzed with variable contact gaps in DC load type. Effect of asynchronous separation of each individual break on the switching performance and capability is analyzed explicitly. Further, the distinctive arc interruption process of quadruple breaks is recorded and the contact welding failure mechanisms of two contact bridges in the electrical endurance experiments are presented.