Influences on the length and severity of intermittences in electrical contacts

This paper deals with short-duration high contact voltage-drops in static electrical contacts during fretting experiments on tin-plated terminals. The focus lies on the rate of high voltage-drop events over the fretting cycle, the maximum level of voltage-drops, the influence of current and the influence of the direction of relative movement. The parameters used for measuring the contact voltage-drop are an open circuit voltage of 14 V, a nominal current of 9 mA, 29 mA, 54 mA and 92 mA, an amplitude of fretting motion of 0.2 mm and a maximum velocity of relative movement between the contact partners of 100 /spl mu/m/s. The contact force is 500 mN+50 mN. It is shown that high voltage-drop events occur in clusters, not as isolated events. The nominal current through the contact as well as the open circuit voltage have an influence on the occurrence of these events. Two different shapes of events have been identified, suggesting different conduction mechanisms.