Characteristics of Carbon Flat Commutator with Condenser for Arc Quenching

In an automotive fuel pump system, a small DC motor is widely used to drive the pump. The motor is installed in a gasoline tank, so that the current is commutated in gasoline, and arc voltage and duration differ from that in air. In this research, we use carbon brush and carbon flat commutator. Under high commutation current and high inductance, arc duration is long and black parts damaged by arcing on commutator rapidly invade from the edge of segments. Unstable sliding or abnormal wear occurs when a black part width reaches a brush width. To decrease arc discharge, the condenser is connected between commutator segments. The arcing decrease when the condenser which capacity is micro-farad order is connected, and as a result, it is possible to drive longer time. And, it can be clear that the effect of condenser for suppress arc discharge.