alternator

American  

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

noun

Electricity.

1. a generator of alternating current.

---

alternator British  

/ ˈɔːltəˌneɪtə /

noun

1. an electrical machine that generates an alternating current

---

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

You don’t replace the whole robot any more than you replace your car when the alternator dies.

From MarketWatch • Nov. 14, 2025

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

He can change a transmission, replace an alternator, diagnose the weird sounds and, in his free time, he is restoring a 1938 Packard Six initially purchased brand new by his great-grandparents.

From Seattle Times • Aug. 4, 2021

There was some back and forth about the sickly alternator, and then Peter Derry, 28, offered a solution.

From Washington Post • Dec. 29, 2018

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