When it was first invented, the alternator was actually called a “generator”. Today the cars alternator turns energy into AC or alternating current from the electrical energy that is created by the mechanical energy it generates while turning.
The internal combustion engine requires a battery to start an engine but it is the cars alternator that keeps the car running and recharging the power used by the battery while driving the vehicle.
So how does an alternator work? Car alternators use a rotating magnet inside the conductor that generates electricity. It then collects the electricity that is generated by the alternator from the magnetic field around a conductor within the alternator.
Conductors have an iron base with coils wound around that also allow the voltage of the current generated to be controlled, thanks to a voltage regulator. The alternators rotor is set in motion by mechanical rotation from the drive belt which also spins the radiator fan and water pump.
Alternator’s running efficiency usually depends on the size of the alternator and when problems arise it because of problems in the bearings or by not enough airflow from the internal fan. On rare occasions it can even be linked to iron and copper loss.
Today’s alternators operate at about 55% efficiency. This comes from the conversion of mechanical energy in into electrical energy.
In the past, the alternator only task was to make sure the car had enough power to turn on the lights and a horn, today we have internal computers, electrical components, heating, radios and GPS systems that require a lot of power.
The big difference in today’s high-amp alternators is that they are made from far better materials mostly utilizing high-quality magnets, bearings and winding's. Even though many parts of the car now have become very high-tech, the alternator still remains a fairly simple piece of equipment and is relatively easy to replace.
How do you know when it is time to replace your cars alternator? Well without testing it regularly, clear signs of a failing alternator are a dead battery. Although a battery can become bad, fail to retain a charge or even start to leak a dead battery is the main identifier to you finding out that it has not been getting charged from the alternator.
A quick test is to try to charge your battery from an external source such as a battery charger, or most auto parts stores such as autozone will test your battery for free. If your bearings start to go you will hear a loud grinding noise coming from the alternator.
If your headlights and internal lights are dimming but, brighten up once you press down the accelerator your belts might have loosened up and would need to be tighten up, otherwise this could also lead to a dead battery, and a bad day.
Finally, you may want to purchase a voltmeter an inexpensive tool used to the voltage generated from the alternator.