Self-Attracting Contact Systems for High-Current Contactors

When electrical current flows from one seemingly flat body to another, it is constricted to a small area where contact actually takes place. This results in a repulsive force that tries to separate these two bodies. In contactors that are subjected to a short circuit fault current, this force is likely to be higher than the holding force of the actuator, leading to contact lifting and severe damage to the device. This paper analyzes three different contact systems, in which an additional attraction force acts on the moving contacts and counteracts the separation force. If designed properly, this attraction force can avoid contact lifting and damages in case of a short circuit fault.