Change in Electric Contact Resistance of Low-Voltage Relays Affected by Fault Current

Andrzej Ksiazkiewicz; Grzegorz Dombek; Karol Nowak

doi:10.3390/ma12132166

Change in Electric Contact Resistance of Low-Voltage Relays Affected by Fault Current

Materials (Basel). 2019 Jul 5;12(13):2166. doi: 10.3390/ma12132166.

Authors

Andrzej Ksiazkiewicz¹, Grzegorz Dombek², Karol Nowak¹

Affiliations

¹ Institute of Electric Power Engineering, Poznan University of Technology, Piotrowo 3A, 60965 Poznan, Poland.
² Institute of Electric Power Engineering, Poznan University of Technology, Piotrowo 3A, 60965 Poznan, Poland. grzegorz.dombek@put.poznan.pl.

Abstract

Contact resistance is an important maintenance parameter for electromagnetic switches, including low-voltage relays. The flow of significant current through electric contacts may influence the contact surface and thus the value of the electric contact resistance (ECR). The change in ECR is influenced not only by the value of current but also by the current phase. Therefore, the impact of the switching short-circuit current's phase on the ECR was analyzed in this paper. Significant changes in the resistance after each switching cycle were observed. The ECR decreased significantly after each make operation, and a correlation with current amplitude, total let-through energy, and short-circuit time was not observed.

Keywords: contact materials; contact welding; electric contact resistance; relays.