At the contact point of current collector of railway, it is difficult to investigate the relation between the wear and the electric current because of many influence factors and the sliding conditions. Therefore we need to show this relation by means of smaller current conditions than railway to see the effects of electric current on friction and wear.
Experimental device is pin-on-wire type, which we improve pin-on-disk type sliding system into. It is set in a direct-current circuit and the pin rubs wires under an electric current. At this point, there is not only the mechanical phenomenon by adhesive wear, but also the electric phenomena including fusion caused by the heat from constriction resistance and the arc discharge caused by the contact loss during sliding test. To examine the effects on the wear of contact materials by them, we investigate the details classifying contact loss, which has a great influence on the wear of contact materials, to two kinds of contact loss, arc contact loss and complete contact loss. As a result of it, we can show the relations between the power supply voltage and the outbreak number, the outbreak ratio of two types of contact loss, and relations between the wear and the power supply voltage, materials by means of the former two relations. And we can see the effects of fusion and arc discharge on the sliding surface by optical microscope.