Alternator & Its Importance

What Is Alternator?

An alternator is an electrical generator which would convert the mechanical energy to electrical energy which would be in the form of alternating current. Because of the reasons of cost as well as simplicity, there are many alternators which would utilize the rotating magnetic field with a stationary armature.

Types of Alternators

Are you searching for the different types of alternator? Then don’t worry! All you have to do is to have a look below and then all your doubts regarding its types would be cleared.


The five different types of alternators include:


  • Automotive alternators – which are utilized in latest automobiles.
  • Diesel-electric locomotive alternators – which would be used in diesel electric multiple units.
  • Marine alternators – they are used in marine applications.
  • Brushless alternators – these types of alternators would be utilized in electrical power generation plants as the main source of power.
  • Radio alternators - utilized for low band radio frequency transmission.

Important Features of Alternators

Do you want to know the essential features of alternator? Then you have arrived at the right place. Have a look below to know the important features of alternator:


  • It should have great deliverable ampere capacity.
  • There should be output current characteristic with respect to varying rpm.
  • There should be an in-built safety in design against reverse polarity and against “load dump “effect.

How Do Alternators Work?

Are you searching how do the alternator actually work? Then all you have to do is to have a look below and then you will be able to understand everything.


  • There are a lot of people who might start thinking that it is the battery which would power the electrics in your car, but that is not the case. The electricity which is required for the starter motor to start the car is provided by the car battery. Now when the car would be running, then the energy would be generated by the alternator to feed the electrical system as well as charge the battery. Earlier the alternator was known as a generator and it works in the same way. Now in this case, the car internal combustion engine would spin the pulleys under the bonnet, which would then turn the pulley on the alternator and then the energy would be created.
  • It is the alternator which would work together with the car battery so that the power can be supplied to the electrical components of the vehicle. The output of the alternator is known as the direct current (DC). When there would be a rotation of the alternator pulley, alternating current (AC) would pass through a magnetic field and then there would be a generation of the electrical current. It would be then converted to DC via the rectifier.
  • With the advancement in technology, the alternators have changed a lot in the last 50 years. Earlier the alternators were only utilized to generate current which was controlled by an external regulator. In the 1990s, the built-in regulator was introduced which utilized the warning light to excite the alternator and then begin the charging process.
  • A load request type charging system is adopted by the latest automobiles with the introduction of smart charge systems and CANBUS systems which are now utilized widely. It is the engine control unit (ECU) which controls these systems. If more load would be demanded by the vehicle, then a signal would be sent to the alternator by the ECU requesting it to start charging. The alternator would have to cope up with the different electrical loads and its charge rate is adjusted accordingly.

Symptoms of Bad Alternator

There are a few things which might cause your alternator to malfunction. Watch for the following symptoms if you suspect a bad alternator:


  • You might have to jump start the automobile on a regular basis.
  • Some issues related to the dim lights.
  • The battery light might start flashing.

Tools Needed for Alternator

Are you thinking of repairing your alternator on your own? Then there is one thing which you must have, that is the right tools needed for repairing your alternator It is essential to make sure that you are outfitted with the right tools to get the work done properly. Have a look at some tools which you might need to get started with your repair work: -


Top Brands for Alternator

When it comes to vehicle owner’s choice, the brands really matter a lot. You might pay a premium for a specific car part brand, over time, as it has created a perception of quality, stability as well as trust. There are some leading car parts brands which are more than just products or services as they give rise to memories and emotions related with the quality. So have a look at some top brands for alternator.

Wilson Alternator

Armature DNS Alternator

Remy Alternator

Mr. Gasket Alternator

Related Parts of Alternator

It is very important to arm yourself with information before you shop any auto part. We are here to help you dive deep into the names of the alternator related parts.


Total Costs & Repair Times, Effort for Alternator

Alternator replacement cost can differ wildly depending on application, the brand of the alternator as well as who does the work. All you have to do is to replace your faulty alternator with us online and then you can leave your car to the mechanic and pick it up a few days later. Just be sure that the car mechanic is highly skilled and has a good reputation. Sometimes the additional service level might cost you more than what you have expected. We also recommend you to take pictures of your car before you leave it with them so that you are sure that later on it is returned back to you in an unharmed condition. The average cost for an alternator replacement is between $562 and $758. Labor costs are estimated between $121 and $154 while parts are priced between $441 and $604. Estimate does not include taxes and fees.

How to Change Alternator?

How to Change Alternator?

Do you want to change your alternator on your own? Then have a look at the steps of changing the alternator below:


First of all, the alternator should be disconnected.


  • The car should then be parked on an even level surface. Just keep in mind that safety is very important whenever you would plan to work on your automobile. There might be a need to jack the vehicle up, so just make sure that it should be parked on a surface which would be suitable for the work. It should be paved evenly and at the same time it should be flat.
  • It would be easy to work on an even surface even if you don’t have the jack the car up.
  • Just ensure that the vehicle is parked properly or it has a parking brake engaged.
  • The battery should then be disconnected. The correct socket should be found to loosen the bolt which would keep the cable on the negative terminal tight. It is the terminal of the battery with a visible (-) sign. Now once it is loose, the cable should be slid off the terminal so that the battery can be disconnected. Make sure that you do not work in the engine bay of the automobile without first disconnecting the battery for safety.
  • If you will keep on working on the alternator without disconnecting the battery, then it would result in getting shocked and at the same time the vehicle would be damaged.
  • The positive cable should be left attached.
  • The vehicle should then be jacked up as per the requirements. The serpentine or accessory belts should be followed to locate the alternator in your engine bay.
  • Just be sure that the parking brake should be on and the wheels should be blocked before it is jacked up.
  • The jack stands should be inserted beneath the vehicle for safety once it has been jacked up.
  • The main power cable should then be removed from the alternator. The main power cable would be a thick cable which would be attached to the alternator which would run from the car battery.
  • Standard size sockets for wrenches would be needed by the bolts in the American made vehicles.
  • The only other cable which would be running to the alternator would connect to a harness, so that it would be very easy to identify it.
  • The bolt should then be set aside someplace safe until new alternator has been installed.
  • The safety clip should be released which would connect the wiring harness. The control harness is the only other wiring heading into the alternator. A finger or a flat head screwdriver should be used to release the clip holding the harness together and then it should be slid apart.
  • Just be careful whenever a screwdriver would be utilized to get to hard to reach clips so that the plastic is not broken.
  • The loose wire should be tucked aside so that the alternator is not snagged with it would be removed. 

Then the old alternator should be removed.


  • The tension on the belt should be relieved with the auto-tensioner. Alternator is utilized by some automobiles so that tension can be applied to the serpentine or accessory belt, but others utilize an auto tensioner pulley. The square drive should be inserted from a breaker bar into the hole in the auto-tensioner pulley and then the pressure should be applied in the clockwise direction to relieve tension on the belt.
  • One can easily tell if the automobile utilizes an auto-tensioner by looking at the alternator mounting bracket: if the bolts would slide from side to side in the bracket, it would not have an auto-tensioner.
  • The belt should be slid off the alternator pulley before the auto-tensioner has been released.
  • There might be some cars where you will require a friend to relieve the tension while the belt would be removed.
  • The bolts on the alternator should be loosened up if there was no auto-tensioner. In the automobiles which would not have the auto-tensioner pulley, the tension can be relieved on the belt simply by loosening the two bolts which would secure the alternator to the car engine. They would many a times need a 14mm or 1/2-inch socket, though you might need to try others as well.
  • Now as the bolts would be loosened up, the bracket would be slid by the alternator under the tension of the belt.
  • There is no need to remove the serpentine or accessory belt if it would not be damaged.
  • The serpentine belt should then be inspected for any faults. The signs of glossing or glazing should be looked on the edges and underside of the belt. Both the top as well as underside should be inspected for signs of cracking as well. If there would be any of such issues, then there would be a need to restore it.
  • The alternator should then be removed from the engine bay. Now when the belt would be pulled off of the alternator pulley and the wires would be disconnected, then the alternator should come out very easily.
  • There might be a need to wiggle the alternator around some things so that it can be removed.
  • Just keep a track of how the alternator should worm out of the engine bay so that the new one can be squeezed.
  • The new alternator should then be compared to the new one. Now before you install the new alternator, it should be set down on the table next to the old one you just removed. Just be sure that the mounting holes and wire connectors are in a similar place and then those two parts are of similar size.
  • This step is really very essential to make sure that the correct part has been provided to you.
  • You can always return the new alternator is they would not match so that you can get the right replacement. 

The new alternator should then be installed.


  • The new alternator should be slid into place. There might be a need to wiggle the alternator around so that it can be squeezed back into place in a crowded engine bay. Just be sure that you should hold the loose wires as well as the serpentine belt out of the way as you get it into place.
  • No wiring should be trapped behind the alternator as it would be slid into place.
  • The serpentine belt should be watched out as the alternator would be slid into the place to be sure that it is not damaged.
  • The mounting bolts should then be inserted. The mounting bolts should be slid through the alternator as well as into the mounting bracket. They should be tightened by hand until they would be snug. The automobiles which would have an auto-tensioner pulley, the bolts should be fully tightened at this point or else you should keep the bolts loose.
  • There would be a need to tighten the belt by utilizing the alternator later if there would be no auto-tensioner.
  • Just make sure that the bolts should be snug enough so that the alternator can be held in place, but should be loose enough to slide side to side in the bracket.
  • The belt should be run over the new alternator pulley. You can always install a new belt or run the old belt back through all of the correct pullets.
  • If there would be no diagram stuck in the engine bay, then you might have to find the diagram in your automobile’s owner’s manual.
  • The diagram can also be found on the manufacturer’s website.
  • Tension should be applied to the alternator with a pry bar as per the requirements. If there would be no auto-tensioner pulley in your vehicle, then the pressure should be applied to the alternator by utilizing a large screwdriver or pry bar until the belt would be tight. The pry bar should be placed between the alternator as well as engine, and then the alternator should be pushed out away from the car engine.
  • Just be careful that you should not pinch or cut any wires by using a screwdriver or pry bar.
  • The pressure should be applied in a continuous manner until the bolts would be tightened.
  • The bolts and belt should then be tightened up. The tension on the belt would be applied via the alternator and pry bar, then utilize the appropriate socket and a ratchet so that two mounting bolts can be tightened up the rest of the way. It would then allow the alternator to keep the tension on the belt.
  • Just be sure that the serpentine belt should have less than an inch of play back as well as forth once it has been installed.
  • Now if the belt would be a little loose, then the bolts should be loosened up and then pressure should be applied once again by using the pray bar when it would be tightened up.
  • The power cable and monitor harness should then be connected. The wire harness should then be reconnected and then the bolt should be inserted which would secure the main power cable to the alternator in the same order they were removed.
  • The primary power cable should be tightened firmly onto the new alternator.
  • Just be sure that you are able to hear an audible “click” from the wiring harness so that it is seated snugly.
  • The battery should then be reconnected. When the new alternator would be in place, then you would be left to reconnect the negative lead to the car battery. It should be tightened firmly so that it is not shake loose while driving.
  • If the car battery would be dead, then there would be a need to jump start it.
  • Now if the automobile would be jacked up, then the jack stands should be removed and then lower it.