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Brushes and Commutator

Brush: A brush or carbon brush is an electrical contact which conducts current between stationary wires and moving parts, most commonly in a rotating shaft. Typical applications include electric motors, alternators and electric generators. The lifespan of a carbon brush depends on how much the motor is used, and how much power is put through the motor.

Commutator: A commutator is a rotary electrical switch in certain types of electric motors and electrical generators that periodically reverses the current direction between the rotor and the external circuit. It consists of a cylinder composed of multiple metal contact segments on the rotating armature of the machine. Two Carbon Brushes press against the commutator, making sliding contact with successive segments of the commutator as it rotates. The winding  (coils of wire) on the armature are connected to the commutator segments.
A DC Motor Commutator
A pair of Carbon Brushes



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