Development of arc-free DC300V/30A electro-mechanical devices using transient current switching circuits

Devices with electric contacts have simple structures and excellent isolation for DC current applications. However, the arc is easily ignited during current interruption. The authors have proposed a transient current switching circuit to suppress rapid rising of the contact voltage. The diode and the capacitor are connected with the contacts in parallel. This paper shows the arc free current-voltage characteristics and the observed residues on the electrode of arc free current interruption. By applying the method to an electromagnetic relay, a switch, and a fuse, arc-free current interruption was confirmed for 300V/33A.