When voltage jumps from the brush to the commutator (or from one surface to another) due to poor or corroded contact between the two components Arcing will cause excessive heat, resulting in premature brush and commutator wear
Band of sparks formed when an electrical discharge form a conductor jumps to another conductor
the action of turning the wrist or elbow at the end of each pass of paint while doing blends or panel repair This causes a lighter application of paint at each end of the pattern