An alternator converts the engine’s mechanical energy into electrical energy and supplies the vehicle’s entire electrical system while the engine is running. It also recharges the battery.
How does an alternator work?
Driven by the engine via a belt and pulley, the spinning rotor induces three-phase AC in the stator windings. The rectifier (diode bridge) converts it to DC, and the voltage regulator keeps output at around 13.8–14.6 V.
Main parts
- Rotor and stator
- Rectifier (diode bridge)
- Voltage regulator
- Brushes and brush holder
- Bearings and pulley (solid or overrunning)
Signs of alternator failure
- Battery/charge warning light on
- Dim or flickering lights
- Battery repeatedly going flat
- Whining or bearing noise, burning smell
- Below 13 V or above 15 V at the battery with the engine running
Vural Otomotiv is the Türkiye partner of AS-PL, one of Europe’s leading manufacturers of alternators, starters and their components.
Frequently asked questions
What voltage should an alternator charge at?
Typically 13.8–14.6 V at the battery with the engine running; smart charging systems may vary between 12.5 and 15 V.
Can an alternator be repaired?
Yes, by replacing brushes, regulator, bearings or the rectifier. Winding or housing damage usually makes a new or remanufactured unit more economical.