com·​mu·​ta·​tor ˈkäm-yə-ˌtā-tər How to pronounce commutator (audio)
: a series of bars or segments connected to the armature coils (see armature sense 2b) of a generator or motor so that rotation of the armature will in conjunction with a set of fixed brushes (see brush entry 2 sense 3) convert alternating current into direct current

Note: In a generator, a commutator results in an output of direct current. In a motor, the commutator converts incoming alternating current into direct current before using it to generate motion.

: an element of a mathematical group that when used to multiply the product of two given elements either on the right side or on the left side but not necessarily on both sides yields the product of the two given elements in reverse order

Examples of commutator in a Sentence

Recent Examples on the Web The commutator and wires inside the fuel pump may be fused incorrectly, potentially causing the fuel pump to fail. USA TODAY, 11 Feb. 2022 Instead of brushes and a commutator, a small circuit board coordinates the energy delivery to the windings. Doug Mahoney, Popular Mechanics, 14 June 2021 Before Tesla, inventors had always designed electric motors so that the magnetic field of the stator was kept constant and the magnetic field in the rotor was changed by means of a commutator. National Geographic, 27 Sep. 2019 While watching how a DC motor sparked during a demonstration in his physics class, Tesla suggested that the commutator (the rotating switch feeding electricity to the rotor in the motor) should be eliminated. National Geographic, 27 Sep. 2019

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'commutator.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1880, in the meaning defined at sense 1

Time Traveler
The first known use of commutator was in 1880

Dictionary Entries Near commutator

Cite this Entry

“Commutator.” Dictionary, Merriam-Webster, Accessed 24 Apr. 2024.

Kids Definition


com·​mu·​ta·​tor ˈkäm-yə-ˌtāt-ər How to pronounce commutator (audio)
: a device for reversing the direction of an electric current so that the alternating currents made in a dynamo are changed to direct current

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