Research on the influence of contact gap on AC arc duration of electromagnetic relay

AC arc generated during the electromagnetic relay (EMR) operates under AC load will cause the contact erosion and shorten the life time of relay. The increasing of contact gap is favorable for extinguishment of the AC arc, but it will also result in the increasing of magnetic gap, which may further influence the electromagnetic force and the dynamic features of the relay. In this paper, a certain type of AC loaded EMR is studied. Firstly, the relationship between contact gap and AC arc duration is analyzed, which can provide the theoretical basis for the optimization of contact gap. The next, by considering the limitation factors such as actual product dimension and actual manufacturing process, the convex hull is selected for changing the contact gap, and arc experiments of different contact gap are carried out. Then, simulation method is applied to obtain the final optimization solution. In the end, the optimization results for the relay are verified by the real product complete-period life test.