ABSTRACT
This chapter explains sliding contacts with graphite type lubrication. An electrographitic brush has a voltage drop of about 1 V with variations of about 0.2 V as shown on oscilloscope traces. Sliding contacts are widely used to transfer electric power and/or signals between stationary devices and moving devices. In order to realize high reliability and long lifetime, various components must be considered in working with sliding contacts. Another basic difference between stationary and sliding contacts is friction. Friction has two effects. First is the heat generated by sliding that adds to the heat generated electrically in determining the temperature. The second friction effect is concerned with friction-excited vibration. Finite Element Analysis and other simulation methods are used to examine phenomena of sliding contacts from electric, thermal and mechanical aspects. In the case of a brush-ring sliding system, a voltage increase is observed just after the ring starts moving.
