alternator

American  

[awl-ter-ney-ter, al-] / ˈɔl tərˌneɪ tər, ˈæl- /

noun

Electricity.

1. a generator of alternating current.

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alternator British  

/ ˈɔːltəˌneɪtə /

noun

1. an electrical machine that generates an alternating current

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Etymology

Origin of alternator

First recorded in 1890–95; alternate + -or ²

Explanation

An alternator is a generator that powers a running vehicle's electrical components and maintains the battery's charge. If your car won't start, you might need to replace the battery — or you may have a broken alternator. Alternators are devices that convert mechanical energy, usually rotational force from an engine or turbine, into electrical energy. Alternators get their name from the alternating current (A/C) that they create. They are an essential part of any car, keeping the battery charged and powering the headlights, stereo, and heated seats. Large power generators, yachts, and some trains also rely on alternators to keep their electrical systems running.

Example Sentences

I’ve had to pay $1,000 for a new alternator for my 2007 Lexus.

From MarketWatch • Mar. 17, 2026

My van was fitted with a 180W solar panel that fed power to a 95Ah battery that also received charge from the VW’s alternator when driving.

From The Verge • Jul. 15, 2022

If the battery is new, thick engine oil, a bad starter or alternator, faulty spark plugs or frozen fuel lines might cause the car not to start.

From Seattle Times • Feb. 14, 2022

The lengthy stops to change the battery and the alternator belt saved his race and staved off his own startling flirtation with an early playoff exit.

From Washington Post • Oct. 10, 2021

The Susan Marie had gone dead in the water—the bolt shook loose in her alternator pulley bracket—on the night of September 15.

From "Snow Falling on Cedars: A Novel" by David Guterson