What Are the Functions of an Alternator?

Recharging the Battery

An alternator's main function is to generate electricity to recharge the battery. A standard car battery does not have the power or capacity to start and run a car on its own for very long. Without a properly functioning alternator, a new car battery might last about 20 to 30 minutes, depending on the terrain and whether you are using any other electricity draining functions, such as headlights or a radio. The alternator recharges the battery while the car is being used, ensuring that your battery is good for a much longer period of time.

Converting Mechanical Energy to Electrical Energy

Gasoline is taken from the gas tank into the pistons in the crank shaft, where combustion takes place. The crank shaft transmits the explosive energy from the combustion to a serpentine belt, which is connected to the alternator. As the pulley on the alternator spins, it generates electricity by powering a magnet and copper wire coil, which converts mechanical energy into electrical energy. Having a mechanic check the tension on your alternator belt will help keep the alternator at peak performance.

Powering Accessories

Nearly every part of the electrical system is mostly powered by the alternator, although some electricity may be taken directly from the battery. Your car's electrical components include engine cooling fans, fuel injection system components, ignition coils, radio, power steering, power windows, headlights and wipers. If you suspect that your alternator is not working properly, then using the least amount of electricity will help you get where you are going until your alternator can be fixed.