What Is an Alternator?


There are several important parts under the hood of a vehicle that help it run effectively. They include components that help provide electrical power to various systems. Among them is the alternator, which creates electrical energy from mechanical energy using alternating current (AC).

Knowing what an alternator does and how it operates is helpful when you own a vehicle, and necessary if you’re considering pursuing a career working on cars. Keep reading this guide to learn all about alternators and why they’re important!

How Does an Alternator Work?

The alternator is responsible for helping provide electrical power to different parts in a vehicle. It differs from a battery, which is a key component that helps start the engine. Once the battery does its job, the alternator takes over to help keep the car running.

So, what does an alternator do? As stated before, the alternator converts mechanical energy into electrical energy. The crankshaft in a vehicle utilizes a serpentine belt, or V-belt, to drive the alternator, which moves the rotor within the alternator at a high speed.

As this rotor spins, electricity is created. There are magnets inside the alternator that allow the AC to convert the mechanical energy generated into electricity. Power gets sent to a voltage regulator that distributes electricity to different parts of the car.

Parts powered by the alternator include a variety of electrical components, from headlights to electric steering and power windows. The alternator also has the task of charging the battery.

How Does an Alternator Charge a Battery?

Car batteries operate on direct current (DC) power, not the AC current that alternators produce. Before energy from the alternator can be sent to the battery, it needs to be converted.

Prior to going through a voltage regulator, power gets sent through a diode rectifier that turns it into DC that the battery can absorb. This allows it to recharge.

What Does an Alternator Look Like?



Warning Signs of a Failing Alternator

While most alternators are built to last a long time, there are parts in them that can wear out over time. Overuse, heat damage and general wear can diminish the health of an alternator. Without a working alternator, a vehicle can encounter a range of issues.

Here are some indications that your alternator may be starting to fail:

  • Weakened battery: Whenever you’re having battery issues, it’s good to also get the alternator checked out. It could be that the alternator is failing and unable to adequately charge your battery.
  • Dimming lights: Noticing dimming or flickering headlights? Alternator failure can cause inconsistent voltage, which can cause this to happen.
  • Problems with electronics: Another thing to pay attention to are the different accessories in your vehicle that are powered by your alternator. Power windows not working properly or trouble with the radio could mean that the alternator is on the fritz.
  • Abnormal noises: Whining or growling sounds coming from under the hood might indicate that the belt controlling the movement of your alternator is misaligned. Getting strange noises checked out is always a good idea.
  • Issues starting the vehicle: When you put your key in the ignition, you shouldn’t have any problems trying to get the engine going. If you hear clicking noises and the engine is cranking a lot before starting, your alternator might be the cause.

It’s a good idea to get your vehicle looked at whenever you’re experiencing anything out of the ordinary to ensure parts are working properly. The alternator is an important component in your vehicle’s electrical system that you want to keep in good condition!

Diagnose Alternator Issues as an Automotive Technician

A great way to improve your skills working on vehicles is to train to become an automotive technician. Not only could you learn how to maintain and work on your own vehicle, but you could work toward a hands-on career in a growing industry.

Total auto technician employment is expected to be 794,000 by 2032.47 Attending a trade school like Universal Technical Institute (UTI) is a great way to gain the education you need for an entry-level position in the industry.1

The Automotive Technology program offered at UTI can help give you the hands-on experience and training employers are looking for. Courses cover a range of topics, like the various electrical systems and parts in vehicles, including alternators.

Want to find out more? Request more information here, or call 800-834-7308.

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1 ) UTI is an educational institution and cannot guarantee employment or salary.
2 ) For program outcome information and other disclosures, visit www.uti.edu/disclosures.
47 ) The U.S. Bureau of Labor Statistics projects that total national employment for Automotive Service Technicians and Mechanics will be 795,000 by 2032. See Table 1.2 Employment by detailed occupation, 2022 and projected 2032, U.S. Bureau of Labor Statistics, www.bls.gov, viewed November 16, 2023. UTI is an educational institution and cannot guarantee employment or salary.

Universal Technical Institute of Illinois, Inc. is approved by the Division of Private Business and Vocational Schools of the Illinois Board of Higher Education.


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