DC motors require carbon brushes to run on the armature’s commutator to supply electrical current to the armature windings. If the commutator surface is not smooth and concentric, the carbon brushes will wear out quickly and even the armature winding could fail resulting in a costly repair. Here we are clean cutting the armature’s commutator so that it is a smooth surface for the brushes and it is at least one thousandths of an inch in run out in comparison to the bearing journals.
A commutator is made up of individual copper bars that are welded or soldered to individual coils in your armature. These bars have to be electrically separated from each other. So after the commutator is turned down, we undercut and clean any burrs to electrically separate each bar.
Shown here is a dc motor being test run and it’s repaired commutator with its brushes working seamlessly together.
