DC motor brush life

This paper looks at brush life, why brushes wear, and what can be done to achieve longer brush life. It is meant to provide an understanding of the factors and conditions that contribute to brush wear in order that problem areas can be avoided and existing problems identified and resolved. This, however, is not an instruction manual on how to fix problems. The motor manufacturer should be contacted for help in resolving brush and commutation problems. The following applies to medium- and large-horsepower industrial DC motors and generators.