When you’re listening to your car’s radio, using your headlights, or relying on any of your vehicle’s other electronic components, you might assume that the battery is doing all the work. Well, it is, but the job of actually keeping everything powered on and running is done by the alternator.
But what does an alternator do? How does an alternator work? Continue reading to learn why your alternator is so important, and how to spot potential car alternator issues before it becomes a larger car care problem.
What Is a Car Alternator?
The alternator is one of three parts to your vehicle’s electric charging system (together with the battery and voltage regulator). The alternator tends to look like a small cylindrical generator and is usually found bolted to the engine.
What Does an Alternator Do?
You need a battery to start the vehicle when it’s off but what does an alternator do in a car? The alternator supplies electricity to the battery and the electrical system to keep your car running when the engine is running.
When driving or idling, they alternator powers other key components such as headlights, dashboard lights, power windows, the radio, air conditioning, and any other electrical bells and whistles options you might have.
The alternator is also responsible for recharging the car battery when driving. The alternator ensures your battery is ready to start at the next starting attempt.
How does a car alternator work?
Even though your car’s alternator produces electricity, it works by taking mechanical energy from the engine and converting it to electricity.
When the engine runs, it spins a belt connected to the alternator, which turns the rotor inside. It is that alternating motion, which produces alternating current (AC) electricity, that is converted to direct current (DC) electricity for use in the car.
Common alternator components
The alternator contains several parts that work together simultaneously to provide electricity generation. Let’s look at what these parts are:
1. Pulley:
The alternator has a pulley that spins by a drive or serpentine belt powered by the engine’s crankshaft. That movement provides power to the alternator by providing mechanical movement that the alternator can turn into electrical movement.
2. Rotor:
Inside the alternator, sits a rotor, which is cylindrical in shape, has windings around it, and magnetic poles at triangular distances separating north and south. When the rotor spins, it turns into an electromagnet.
3. Stator:
The stator surrounds the spinning rotor and contains three windings made of copper wire. The spinning rotor produces alternating current (AC) inside the copper wire windings in the stator.
4. Voltage Regulator:
The voltage regulator controls the electrical input to the rotor so that too much electrical output from the stator does not burn up your car battery or other electronics, it controls how much electricity powers the rotor to make the electricity produced by the alternator what is needed.
5. Rectifier:
Car batteries run on direct current (DC), while the stator produces an alternating current (AC) charge. A battery cannot accept an AC charge, so the rectifier takes the AC charging and rectifies it into a DC charge so that it is “battery compatible.”
How Long Will an Alternator Last?
In most cases, an alternator can last for the duration of your vehicle’s life, creating a dependable source of electricity for your car’s electrical system.
If damaged for wear and tear, heat, too much electrical output, water, defective equipment, or worn-out or broken connections and wires, your alternator will break before your car reaches the end of its life. You just need to watch for the signs of a bad alternator.
How to Prolong the Life of Your Alternator
Just like any vehicle component, good maintenance and habits will help prolong the life of your alternator and minimize costly failures. Here are a few ways you can help your alternator stay in good condition:
- Relieve Electrical Strain: Running multiple electrical accessories all at once, especially while the vehicle is idling, is stressful for your electrical system. Tuning off systems, like heated seats when not needed, will relieve the load on your alternator.
- Check the Drive Belt: A drive belt that is worn, loose, or damaged is sure to put more stress on your alternator than required, shortening it’s life expectancy. Get the condition and tension of the drive belt checked regularly so that it is aligned and performing properly.
- Keep Connections Clean and Tightly Secured: Corrosion on battery terminals or looseness in the alternator connections can cause charging disruptions. If your connections are corroded, your alternator will have to work in overdrive. Also, inspect your connections and cables to ensure a good flow of electricity through the wires.
- Care for the Battery: Your battery and alternator work together. A failing battery or weak battery will mean an overworked alternator. Have your battery tested regularly and replace it as needed.
Warning Signs of a Faulty Alternator
If an alternator dies, your car might not start at all, or it might only run for a few minutes infinitely so, but a lot of times, these signs of a bad alternator are misdiagnosed as poor battery performance, or something else that exhibits similar symptoms.
In other words, if you have only one of these problems, then your alternator might be dead:
- Dim or overly bright lights
- Dead battery
- Accessories slow or do not work or malfunction
- Slow cranking or stall while trying to start
- Growling or whining noises
- Burning wires or rubber smell
- Battery warning light is lit on dashboard
Even though these warning signs can be clues to a potential problem with the battery, an alternator or other problems with your vehicle as a whole electrical system, these warning signs can tell you when to drive the car into your local mechanic’s shop so that your local mechanic can have a look at the electrical system and find out what is wrong.