Statistical analysis of voltage from constriction to micro-arc values during aging by fretting

Abstract

In a previous work we observe that the vibration of contact interfaces is the main cause of contact voltage fluctuations due to the so called fretting corrosion phenomenon. In fact the process of generated particles by mechanical wear produce the increase of contact voltage frequently assimilated as high contact resistance. The main objective of this work is to examine conjointly contact voltage and the occurrence of arcs during the well-known three successive fretting phases. The arc voltage is measured during fretting with set oscilloscopes which plot the arc voltage histograms in real time. So, a histogram is built and arc duration is determined and the position on the track of fretting. We applied a voltage of 16V and a current of 3A. Samples extracted from commercial contact are used and fixed on vibration system (frequency 20Hz and relative displacement of 0.8 mm). The main results show that the arcs are observed during the first and final phase of fretting. We assume that after the initiation period of fretting, the wear is increased and induce the increase of the contact voltage and it reaches few hundred millivolts (melting and fritting voltage) and induce micro-arcs. In the second phase, it seems that number of arcs decreases. Finally in ultimate stage of degradation, intermittent arcing voltage is detected close 12V due to bounce on degraded surface filed wear debris.