Brush Wear During Commutation

Abstract

This paper compares the influence of the brush wear on commutators exerted by arcs with the influence of transient high contact voltages, here called flashes. The wear per kilometer travel is expressed as a function of the mechanical load on the brush, the current, the voltage flashes, and the charge transported by arcs. It is important to note that the flashes cause more wear than the arcs. However, strong arcing is accompanied by strong flashes and thus indicates general high brush wear.