The Intrinsic Nature of the Alternator

The winter brings cold temperatures, snow, and other winter maladies. Before the temperature takes a nosedive, you should have a bumper-to-bumper inspection that would include the alternator. People are often confused about what the alternator is, what function it serves, and how to maintain it. If you do not take care of your alternator, you may find yourself sitting on the side of the road waiting for AAA to tow your car to a mechanic.

The What of It

The alternator is the power source for the electrical system in your car. This part works in tandem with the battery and the voltage regulator to create the entire charging system. It also keeps the battery charged. It provides power for the headlights, interior lights, windshield wipers, and other components used. Alternating current is produced through the process of electromagnetism inside the aluminum outer casing. Most modern alternators have vents on the front and back of the unit to allow heat to dissipate. Older models will have external fan blades on the rotor shaft behind the pulley, but newer models have cooling fans inside the unit. The back of the unit will have five terminals; each connecting point refers to a specific electrical function for the car.  

The Why of It

The alternator produces AC current, but the battery uses DC current. So how does this work? The alternator output must be converted from AC to DC. Diodes located inside the housing convert the AC power that is generated when the rotor spins past three wire coils called stator windings. These coils are spaced evenly around an iron core, which is the stator. As the rotor spins, it creates a magnetic field that produces AC electricity in the stator. The AC current travels through stator leads that are connected to a set of diodes that control the current flow. The diodes change the output from AC to DC before sending it to the battery, and they block the flow of electricity from the battery to the alternator.                                          

The Care and Repair of It

To make sure that your alternator is going to give you reliable service through the winter, you should take your car in to have the alternator output checked by a professional. Some mechanics charge a nominal fee and others will do it for free. If you notice that your headlights are dim, or the lights on your dashboard are not as bright as they should be, your alternator might be going bad. Check your owner’s manual for the recommended voltage that you should have and replace it if it is going out. Since cars are able to run devices such as mp3 players, cell phones, and other additional electrical products that add extra strain on your electrical systems, you should ask your mechanic if you would benefit from upgrading to an alternator with a higher level of voltage. If you are installing a new part, take the old one back to the auto parts store and trade it in for the new one. If you do not trade in the old one, most stores will charge a core charge. You can get the charge refunded if you return the old one with the receipt for the new one. If you have your mechanic change the alternator for you, they will take care of the trade-in for you.