Commutator

A rotary electrical switch that reverses current in a motor’s armature at appropriate points in its rotation. In a brushed DC motor, it works with brushes to keep torque turning in one direction.

Brush (electric): A stationary conductive contact that transfers current between an external circuit and a rotating electrical machine. It presses against the commutator to carry current into and out of the rotating armature.
Electric motor: A device that converts electrical energy into mechanical motion. The commutator is a component of certain motors, not a motor by itself.
Universal motor: A series-wound motor designed to operate on either alternating or direct current. Its commutator enables operation on AC as well as DC, despite the supply’s changing polarity.
Hippolyte Pixii: A French instrument maker who built an early alternating-current generator in 1832. Pixii’s generator used a mechanical commutator to produce a unidirectional output.
Armature (electrical): The winding or magnetic assembly in an electrical machine where voltage is induced or current produces force. The commutator reverses current in its windings as they pass through successive positions.
Rotor (electric): The rotating part of an electric motor or generator. The commutator is mounted on the rotor and turns with it.
Brushed DC motor: A DC motor that uses brushes and a mechanical commutator to switch armature current. This is the characteristic motor design built around a commutator.
William Sturgeon: An English physicist and inventor who built an early practical electromagnet and electrical machines. His early motor experiments contributed to the development of commutated electric machinery.
Back electromotive force: A voltage induced in a motor that opposes the applied voltage driving its current. Current switching occurs while the coil’s induced voltage affects how quickly its current reverses.
Lorentz force: The force exerted on an electric charge by electric and magnetic fields. Magnetic force on current-carrying armature conductors creates torque whose direction commutation sustains.

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