Among the pieces that make up a vehicle we can find the alternator , a fundamental piece that is responsible for providing power energy on a continuous and no alternates to each and every one of the pieces that are part of the electrical circuit of the same. Alternators can be found in cars and in industry and are very important to ensure proper operation of the same.

What is an alternator?

An alternator is a mechanism by which mechanical energy can be transformed into alternating electrical energy . It is one of the most important parts that exist for a vehicle’s electronic circuit to function properly .

  • Alternator Characteristics
  • Types
  • Parts of an alternator
  • How does it work
  • What is it for
  • Breakdowns
  • Alternator Maintenance
  • Importance

Alternator Characteristics

Among the main characteristics of an alternator we find the following

  • It is an element that is part of the electrical circuit that a vehicle has.
  • It transforms mechanical energy into electrical energy .
  • It is made up of two parts considered essential, the inductor or the coil and the armature .
  • It generates and at the same time supplies electrical current to be able to make the circuits work.
  • It serves to keep the battery charged
  • For its operation it is based on electromagnetic induction .


Different types of alternators can be found depending on their characteristics and the type of vehicle in which they can be used. In this way, we find the following types of alternator:

Compact first and second generation alternators

This type of alternators are made up of 12 poles and have been designed to work in vehicles that have a high demand for energy . In them you can find liquid coolants for the engine and they have greater power, in addition, they generate less noise because they have a better cooling system.


This type of alternator is similar to the compact but allows a higher rotation speed .

Interleaved Pole Alternators

It has a series of slip rings , it is the best known type of alternator and the magnetic poles that the rotor has have a claw shape , in addition, they are interspersed .

Of individual poles

They also have slip rings and are used when the power needs to be higher as there is a higher current consumption .

Alternators with guide rotor without slip ring

In this case, fewer parts are used and they have less wear, since only the bearings are the ones that suffer from this wear. It is a type of alternator used in means of transport that make very long distances or in vehicles that must produce great efforts.

Parts of an alternator

The parts that make up an alternator are mentioned below:

  • Pulley : the pulley is the one that is responsible for receiving all the mechanical force that comes from the combustion engine and does so by means of a belt which is in turn attached to the alternator shaft, moving the internal rotor and the fan.
  • Rotor : it is also known by the name of inductor and it is the moving part that is inside the alternator. It is composed of an electromagnet that is responsible for receiving the current that comes from the regulator through a series of rings on the shaft.
  • Electromagnet : it has the function of being able to generate a magnetic field so that the stator coils can react, thus generating the electric current.
  • Stator : this piece is in a fixed position and the three-phase winding is located on it. It can be shaped like a star or a triangle.
  • Diode rectifier bridge : this is an element whose function is to be able to rectify the alternator current in order to convert it into a direct current .
  • Bearings : they are a series of mechanical parts that make the correct movement of the alternator parts possible. They have balls inside that make movement possible while reducing friction.

How does it work

The alternator works by producing a type of alternating current which is obtained by means of a drive mechanism which is driven thanks to the combustion engine that it has, in other words, it can work because it is connected to the rotation that the engine gives. combustion by means of a belt .

When the vehicle starts operating, the rotor coil that has the alternator is immediately fed by the current and, when the turns start to happen (when the engine starts), the energy begins to be produced . After starting the engine, the regulator can be self-powered by the energy produced by the alternator and when this process occurs, then the light that is produced in the instrument panel of the vehicle turns off automatically.

If this light does not go out after starting the car, it is an indication that the alternator current is not being adequately output and when this happens, then the vehicle will only have electricity while the battery is depleted.

What is it for

The alternator is a very important device that is used to supply , in an adequate way, the energy to a vehicle . It is an element that is responsible for transforming the mechanical energy of the car into electrical energy so that in this way it is possible to create and provide a constant and stable supply of electricity to the vehicle while it is in motion.


The increasing use of electrical energy every day due to technological innovations in vehicles today considerably shortens the useful life of alternators. Among the most frequent breakdowns that can be observed in a car’s alternator are the following:

  • Errors and failures in electrical accessories : when the alternator does not work properly, the battery cannot be charged optimally and this causes, for example, a series of faults in the vehicle’s lights and that the electrical devices decrease their performance .
  • Noises : when the alternator belt is damaged or has some kind of defect, you can begin to hear a series of notable noises that are easy to recognize as some of the moving parts of the alternator are detached.
  • Low Battery – Damage to the alternator can cause the battery charge to drop significantly.

Alternator Maintenance

The alternator is considered to be the heart of the entire electrical system of a vehicle and for this reason it is of the utmost importance to provide it with proper maintenance to prevent it from failing. In this regard, it is important to mention that its proper functioning as well as its duration will always depend on the use and mileage given to the vehicle. All parts of the alternator must be checked individually and cleaning them is essential to keep the alternator free of dirt .

The brushes or coals should be checked using an ammeter to find unusual reactions or breaks it. The bridge rectifier will also be evaluated using this aforementioned apparatus to determine if it has sufficient resistance for proper operation. Rotor maintenance is done by periodically checking the coils and the collector , looking for possible leaks .


It can be said that the alternator is the most important part of the vehicle because through it the electrical components have the ability to function properly . It is essential to avoid accidents and to be able to start a car when it is needed.

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