Drum or barrel commutator for electrical machines - has commutator bars with grooves having associated reduced diameter bore-holes filled with surface coating material in one piece

摘要

The drum commutator includes commutator bars (11) electrically separated by axial slots, each having a surface coating (12) of carbon material. Each commutator bar has at least one depression (16, 17) in the underside which lies on the insulating material barrel (10). The depressions have at least a radial bore hole (18, 19) which has reduced dimensions w.r.t. the depression. The carbon material of the surface coating fills the bore-hole and depression in one piece. USE/ADVANTAGE - For electric motors in vehicle fuel pumps. Provides tight fit of coating material in all directions, reducing commutator sensitivity to e.g. voltages occurring due to temp. changes, and improves long term behaviour.