# commutator

[kom-yuh-tey-ter] /ˈkɒm yəˌteɪ tər/
noun
1.
Electricity.
1. a device for reversing the direction of a current.
2. (in a DC motor or generator) a cylindrical ring or disk assembly of conducting members, individually insulated in a supporting structure with an exposed surface for contact with current-collecting brushes and mounted on the armature shaft, for changing the frequency or direction of the current in the armature windings.
2.
Mathematics. the element equal to the product of two given elements in a group multiplied on the right by the product of the inverses of the elements.
Origin of commutator
1830-1840
1830-40; commutate + -or2
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2016.
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Examples from the Web for commutator
Historical Examples
• The commutator part of the motor should be enclosed so that there may be no possibility of a spark igniting the film.

Henry C. Horstmann
• A commutator, B, permits of establishing or interrupting the current at will.

• As in the other cases, the commutator revolves while the collector remains stationary.

Thomas Commerford Martin
• To these arms the brushes are attached, so that their spring ends engage with the commutator .

J. S. Zerbe
• As armature, commutator, and shaft rotate, the brushes connect first with one segment of the commutator and then with the other.

Bertha M. Clark
• The commutator is in two parts, which must be insulated from each other.

Thomas M. (Thomas Matthew) St. John
• The armature winding is not to be put on the core until the commutator has been constructed and mounted on the shaft.

Various
• The slots in the commutator must be under the center of the yoke, 14.

Thomas M. (Thomas Matthew) St. John
• The armature is marked A, the shaft B, and the commutator C.

• In a direct current motor this reversal is brought about by the commutator.

Willis Eugene Tower
British Dictionary definitions for commutator

## commutator

/ˈkɒmjʊˌteɪtə/
noun
1.
a device used to reverse the direction of flow of an electric current
2.
the segmented metal cylinder or disc mounted on the armature shaft of an electric motor, generator, etc, used to make electrical contact with the rotating coils and ensure unidirectional current flow
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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Word Origin and History for commutator
n.

1839, agent noun in Latin form from Latin commutare (see commute (v.)).

Online Etymology Dictionary, © 2010 Douglas Harper
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commutator in Science
 commutator   (kŏm'yə-tā'tər)    The arrangement of contact points in an electric motor connecting an external direct current power supply and the rotating electric coils that use the power, used to generate the AC voltages needed by the coils. The commutator is located at the rotating shaft of the motor, where two power contacts are swept underneath two metal brushes, supplying positive and negative voltage to the coils. When the motor has rotated 180 degrees, the power contacts are each moving under the opposite brush, reversing the polarity of the voltage supplied to the coils.In a group or an algebra, an element of the form ghg-1h-1 where g and h are elements of the group or algebra. If g and h commute, the commutator is the identity element. The commutator is often written [g, h].
The American Heritage® Science Dictionary
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### Difficulty index for commutator

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### Word Value for commutator

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