Back-Commutation And Sticking Reduction Methods In Dc Contactor

Abstract

The back-commutation and sticking are phenomena which cause an increase in time delaybetween arc ignition and arc reaching the arc chute. These effects cause increase in total switchingtime and contact and arc runner wear. This paper gives a comparison of several approaches to reductionof these effects in a medium voltage contactor for traction usage. The three chosen approacheswere: changes of the shape of the arcrunners, changes of the pole plates of the magnetic circuit andincrease of the ventilation cross section. Metrics on how to compare the performance of these differentalterations were given, based on switching times. From the three tested methods the ventilationincrease yielded the best results as it both reduced the switching time and time delay caused by theback-commutation and reduced the variation of these characteristics.