Thermoelastic effects in brushes with high current and high sliding speeds

Experimental results in the literature indicate that electric brushes may deform thermally, leading to point contact with the slip ring at high current levels. The present work provides theoretical support for these observations and a quantitative statement showing how operating variables influence this behavior. The analysis is restricted to a two-dimensional model of the brush with isotropic and constant material properties. The most unexpected result is that for steady current flow cooling of the exterior of the brush increases the tendency to deform unfavorably.