alternator
n. B2 Upper Intermediate US //ˈɔɫtɝˌneɪtɝ// UK //ˈɔltənˌeɪtɐ// al·ter·na·tor
n. a machine that changes electricity from a direct current to an alternating current. It is usually found in a car to keep the battery charged while the engine runs.
n. a device that converts direct current (DC) to alternating current (AC). In automotive contexts, it refers to the component that generates electrical power for the vehicle's systems and recharges the battery.
The car's battery died because the alternator was broken.
The mechanic checked the alternator to see if it was providing enough power to the car's electrical system.
Modern vehicles rely on a high-efficiency alternator to supply the necessary electrical energy for both the internal combustion engine and the various electronic components of the vehicle.
From alternate + -or.