Model for temperature estimation of dc-contactors with double-break main contacts

The double-break arrangement of dc-contactors is advantageous for electrical arc quenching, so the most important disadvantage of the double-break, the higher temperature rise during current carrying operation, is acceptable. However, overheating can be a serious problem. In this paper, a mathematical model is proposed for the steady-state temperature difference distribution of double-break dc-contactors and an experimental verification of the theoretical results attempted. The influence of different dc-contactors’ parameters on the temperature distribution is investigated, and it is convincingly shown that the heat generated is dissipated mainly by the conductors, and that this dominates the optimisation of the dc-contactor temperature rise.