Analytical Model for the Electrodynamical Forces inside Electrical Contacts of Commutation Devices

This paper aims to present a new analytical model for the contact area of all switching devices, at all voltage and current levels. It was proposed in order to recalculate all the computational formulas related to the electrodynamical forces which inevitably appear in a mostly symmetric contact, with a different shape, other than a sharpen or pointed one. When applying this model, the very simplifying hypothesis of the constant current density on equipotential stiction surfaces for the crossing current is completely abandoned. These new expressions could experimentally be verified by means of a simple device. By using this model, we can study the “attraction”, electrodynamical forces that may appear in an electrical contact belonging to any switching device used in electrical and power engineering technique. This research could improve both design and maintenance of new and existing switching equipment like contactors, low voltage switches, oil submersed switches or even SF6high voltage ones.