A brushed DC motor has a set of rotating windings wound on an armature mounted on a rotating shaft. The shaft also carries the commutator a long-lasting rotary electrical switch that periodically reverses the flow of current in the rotor windings as the rotor bar rotates. Thus, every brushed DC motor has AC flowing through its rotating windings. Current flows through one or more pairs of brushes that bear on the commutator; the brushes connect an external source of electric power to the rotating armature.
The rotating armature consists of one or more coils of wire wound around a ferromagnetic core. Current from the brushes flows through the commutator and one winding of the armature, making it a temporary magnet. The magnets field produced by the armature interacts with a stationary magnetic field produced by either permanent magnets or another winding armature coil, as part of the motor frame. The force between the two magnetic fields tends to rotate the motor shaft. The commutator switches power to the armature coils as the rotor turns, keeping the magnetic poles of the rotor from ever fully aligning with the magnetic poles of the stator field, so that the rotor never stops (like a compass needle does), but rather keeps rotating as long as power is applied.
YNF Engineering produces and replaces worn armature coils and V-rings.