Thermal deformation in brushes for current passage through a steadily moving patch

Abstract

The development of a numerical analysis is outlined for an electrical brush treated as a thin half-disk with a small contact patch near the center of its straight edge. The brush material is treated as passing relative to the contact at a fixed speed. A steady electric field is assumed to act in the brush, giving rise to a distributed heat source. The relative displacements of the center and of each end of the patch are calculated. The patch is assumed to be held at ambient temperature by the passage of the cool conductive slip ring. The final result is a measure of bulge and tilt which may be added to similar effects resulting from frictional heating to provide an interpretation of the relative roles of current and friction on contact behavior.