alternator

IPA/ˈɔːltəneɪtə(r)/
KK[ˈɔltɚnˌetɚ]IPA/ˈɔːltərneɪtər/

alternator — noun

  • alternatorsingular
  • alternatorsplural

1. a piece of equipment in a vehicle that turns the engine's mechanical energy into

1.nounB2
Definition

a piece of equipment in a vehicle that turns the engine's mechanical energy into electricity, keeping the battery charged and running the lights, radio, and other electrical parts

Example

Mei's mechanic said the alternator was failing and would need to be replaced soon.

collocation: alternator + fail / replace

Sofia's alternator stopped working, so the dashboard battery light glowed red.

Common collocations
  • broken alternator
  • faulty alternator
  • failed alternator
  • replace the alternator
  • alternator belt
  • alternator failure
Synonyms
  • generator

    broader term; an alternator is a type of generator that produces alternating current

  • dynamo

    older term for a DC generator; not interchangeable with alternator in modern usage

Usage Note

Frequently modified by broken, faulty, failed, or bad when describing mechanical problems. In vehicle contexts, alternator often appears with battery (the alternator charges the battery) and belt (the alternator is driven by a belt connected to the engine).

Common Mistakes

My car's generator needs replacing.
My car's alternator needs replacing.
Most modern cars use an alternator (AC), not a generator (DC), though the terms are sometimes confused in casual speech.

Word family

Synonym discussion

Sense: noun/1

Alternator, generator, and dynamo all refer to machines that produce electricity, but they are not interchangeable. An alternator produces alternating current (AC) and is the standard device in modern cars — it is lighter, more efficient, and keeps the battery charged at idle speeds. A generator, in strict technical terms, produces direct current (DC); it was common in older vehicles (pre-1960s) but is now found mainly in industrial power plants. A dynamo is an older term for a DC generator that uses a commutator; outside of historical or British English contexts, it is rarely used for car parts today. In everyday speech, some mechanics still say 'generator' when they mean 'alternator,' but a learner should use 'alternator' for the car part to be accurate. For example: 'The mechanic replaced the alternator on my Toyota,' not '…the generator.'

alternator ↗generator ↗dynamo ↗

Common collocations

Nouns

  • car alternator
  • alternator belt
  • alternator failure

Etymology

LatinEnglish

Coined in the 1880s from 'alternate' (from Latin alternare, meaning 'to do by turns') and the suffix '-or' (indicating a thing that performs an action). The name refers to the fact that an alternator produces alternating current, which changes direction back and forth.