Commutator design and manufacturing techniques

A commutator is an arrangement of insulated copper bars that are connected to coils of an electric motor to provide a reversal of current into the coils of the motor. Commutation is the reversing of current direction. The purpose of this paper is to provide basic information on the different styles of commutators and the various internal locking designs. There are barrel shaped commutators and flat face commutators. Barrel commutators are cylinder shaped with the copper bars parallel to the bore. There are three basic styles of barrel commutators-steel and mica, mica molded, and molded shell. The flat face commutator looks like a pie with copper bars shaped in pie sections perpendicular to the bore. We review these basic designs to better understand their differences. The manufacturing process is also outlined, along with comparative cost factors. This information is useful in deciding which commutator style to select for a particular application.