We Buy All Cars, Running or Not!

How an Automobile’s Alternator Works? – Here’s What You Need To Know

Battery light

 Everyone has had the misfortune of going out to their car, turning the key in the ignition, and hearing nothing but a click. You may try and try to start the car before it finally catches and fires. When this situation comes up, you may notice certain things starting to happen in the car. the radio may go on and off and the dash lights may dim. 

⚠️ If It's Broken, Don't Fix It - Get Paid Cash for Your Vehicle ⚠️

These problems are caused by a bad alternator. If you don’t replace an alternator that is broken, , the radio and the heater will completely stop working. Your headlights may dim considerably and this can be deadly.­ 

The mechanics of alternators are easier to understand than you might think. There are a few ways to diagnose problems with alternators.

How Does a Charging system work?

A charging system in an automobile is made up of three basic parts: the battery, the voltage regulator, and an alternator. The alternator operates in concert with the battery to make power for the electrical components in a car.  An alternator makes sure the vehicle has alternating current.

Alternators tend to be housed towards the front of the engine. Alternators are operated by a crankshaft. The crankshaft causes the up-and-down movement of the pistons to change into circular movement. 

Most alternators are mounted by brackets that are bolted to a set point on the engine. There are two brackets. One of them is usually stationary and the other is adjustable. It must be adjustable in case the drive belt needs to be tightened. The electricity created by the alternator is channeled into the battery, this makes enough voltage to operate the electrical systems in the automobile. 

Alternators are about the same size as a honeydew melon. They generally have aluminum outer housing, and a non-magnetic metal must be used. 

Alternators have vents on both the front and backside so that heat can escape them. A drive pulley attaches to the rotor shaft on the front of the alternator. When the engine is turned on, the crankshaft rotates the drive belt, which in the cranks the pulley on the rotor shaft. An alternator transmits mechanical energy from the engine into electrical power.

On the backside of the alternator, you'll see many connection points. Each one should say what it is for.


It is very important that an alternator is allowed to cool down and they actually have cooling systems in them. 

When you open the alternator, you will see a large cylinder that has finger poles configured in a triangular shape. This is the rotor. A basic alternator is constructed of a series of finger-sized pole pieces. These small polls are placed around coil wires called field windings. They wrap around an iron core on the rotor shaft.  The rotor assembly is inserted inside the stator. They have to be set far enough away from one another so that the rotator can spin at a fast rate without coming in contact with the stator wall. There is a brush and a slip ring on each end of the shafts. 

The finger poles around the rotor are set up, so the north and south poles that surround the wire rotor field windings alternate. This alternating pattern creates the magnetic field that in turn induces a voltage into the stator. 

How the Alternator Produces Power

Alternating current is something that is very important in today’s vehicles. Car batteries produce DC power, so they are unable to use AC power. Hence the alternator's power output is sent through diodes. A diode is a device or component that allows current to flow in one direction. The AC power the alternator generates is turned into DC power. 


The rotor and the stator create power in a three-phase current. When the alternator pulley is rotated by the engine, the rotor spins past three wire coils that surrond a fixed iron core. 

The coil windings must be evenly separated at intervals of 120 degrees. They surround an iron shaft. The alternating magnetic field from the rotor makes an alternating current in the stator. 

This AC current travels through the stator into a pair of diodes. There are a pair of diodes connect to every stator. The diodes help to regulate the current. The diodes will only allow current to travel in one direction.

Single-phase alternators produce a single-phase of AC current. They are not as effective as three-phase alternators. Three-phase alternators are more effective because they have three sets of windings. 

Once the AC/DC conversion has taken place, the voltage will be used in the battery. If the battery receives too much or too little voltage. It can hurt the battery and the electronic system of the car. a voltage regulator figures out the amount of voltage that is needed in the battery. 

There are several components working to create the amount of electricity required in our vehicles. Alternators are critical. It is important to know when they are failing and what to do about it.

When Alternators go Bad

Like so many other parts of an engine, alternators go bad because of dirt and corrosion. They can also be affected by extreme weather. 


It is not uncommon fo ran alternator to fail due to bad bearings. There is a needle bearing that lets the rotor spin uninterrupted inside the stator. The bearing can break down dirt and heat. When the bearing becomes weak, the rotor cannot spin as it should and may freeze up.


If you hear loud grinding noise when you are driving the car, there is a good chance that one of the car’s bearings is bad. 


How to Figure Out if Your Alternator is Bad

Most cars have dashboards that light up when the ignition of the car is on. There will be a light that is in the shape of a battery. When it illuminates, there may not only be a problem with the battery but with the alternator as well.


Before checking for trouble with the alternator itself, you may want to check the serpentine belt for damaged. A worn serpentine belt can cause an alternator to fail. If it is worn down, you can try replacing it. They only cost about $20. If the problem is not due to a worn belt, you will want to check the voltage on your alternator.


The vast majority of cars these days have three-phase alternators that are able to operate with only one of the stator windings. You can test if the stator windings have gone bad by using a voltmeter. 


You will want to use the voltmeter to do a load test. Simply set the voltmeter to DC rather than AC. Attach the red wire to the positive terminal and the black wire to the negative terminal. With no accessories on, start the engine and increase the RPM to around 1,000. The voltage should stay at 14 volts. It should never be less than 12. 


Turn on everything in the car that uses electricity and rev the engine. Check the voltmeter because the voltage should still be at 14 volts. If you have a bad alternator, the voltage will be less than 14 volts. You will know you need a new alternator.


How much does an alternator cost to replace?


A new alternator can run from about $500 to $1000. You can get a remanufactured alternator for about $300. There are some vehicles that have alternators that are very easy to replace. These components can be changed out in your garage in a couple of hours. There are other alternators that require a skilled hand to remove.


Before deciding to do the work yourself, you will want to consult your owner’s manual. You can also find tutorials for replacing the alternator on your particular kind of car on YouTube. 


If you decide you would rather have a professional work on your car, you will have a couple of options for having the work done.


Take Your Vehicle to an Auto Body Shop

Auto body shops are the most popular option for car repair in the United States. You will have direct contact with the mechanic who will work on your car. They are also considerably less expensive than a dealership. Many chain autobody shops will have loyalty clubs that provide their members with discounts on various jobs.


When you are looking for a mechanic, you should check the AAAs website. They maintain a list of the best auto body shops in the country. You should ask the mechanic for references and find out if they are certified in the make of your car. Ask if they have the appropriate parts available. If they do not have the parts on hand, ask how long the parts will take to come in. Try to get a time and cost estimate for the job.


Taking Your Vehicle to a Dealership

An auto dealership will charge you much more than an auto body shop will. You will not get to talk to the mechanic directly. However, the technician who works on your vehicle will be specifically trained in your make and model of vehicle. They will charge you by the job rather than the hour so at least you will know the total cost before you have to pay. The dealership will almost always have the parts on hand so you should get your car back soon. You may not have to rent a car or figure out the bus schedule. 


Alternator replacements are not cheap and if the cost of the repair supersedes the value of the car, you may want to think about selling it and getting a new vehicle. If you decide to get a new car, you will have a few options for getting rid of the old one.


Where to Sell Your Car

Many people choose to sell their junk cars online. There are several car sales websites that will allow you to list your car for a monthly fee. If you do this, you will be in competition with hundreds of other sellers. 


If you do get an interested buyer, you will have to meet them and show them the car. You may have to show the car to many people before you sell it. Some people will only be interested in certain parts of your car and you may be left with the body of a parted out car on your property. 


Selling your car online can also be dangerous. Identity thieves and violent criminals have found their victims online.


You can use your old vehicle as a trade-in for a discount on your new car. Most dealerships will not give you what your car is really worth. They will rely on your being too lazy to explore your options for making money on your old ride.


Sell Your Car to Us

Cash Cars Buyers is the best option for getting rid of an old car. Simply fill out our form and wait for us to get back to you with an offer. Our form asks for your name, email address, and phone number. We ask for basic information about the car. We will want the car’s VIN number, year make, and model. We will call you right back.


If you accept our offer, we will make an appointment with you to pick up your car. We will pay you in cash and tow your old automobile away for free. We often pay as much as $500 for junk cars and we usually do not need the title. Contact us today.

© 2022 Cash Cars Buyer. All Rights Reserved. Terms & Conditions | Privacy Policy | Sitemap