Differences Between A Generator And An Alternator

A generator and an alternator are both electrical machines that generate some kind of power. However, they are very different in their functionality.

So here, I am going to tell you the difference between a generator and an alternator.

 A generator is more similar to a starter engine, so it produces an AC current; the difference with these types of generators is that a lot of the mechanical aspects are done by wiring and metal gears rather than by rotating machinery parts.

The rotor turns at speed ratios determined by the machine’s manufacturer and this spinning motion causes electrodynamic induction to propel electromagnets within the rotor which then generates electricity.

Let us clear some basic things first:

What is a Generator?

In order to understand what a generator is, you need to know the basics of electricity. Electricity is a form of energy which is being transferred through conductors—this transfer occurs by means of electromagnetic induction.

The conductors that carry the electricity are made of materials with free electrons (i.e., metals or semiconductors) and this makes the conductors able to sustain an electric field through their surfaces.

Now, the electromagnetic induction we are talking about here is the generation of an electric field. An electric field is a specific electromagnetic wave that is created by moving electric charges in a certain direction.

What Is A Generator?

The movement of those charges generates a magnetic field which pushes the ions and electrons from one side to another side.

Those ions and electrons are what we call as electrical charges. Now, since every charge has an opposite charge (either positive or negative), the movement creates an imbalance in those charges which means that something wants to restore equilibrium.

To restore the equilibrium, the charges of opposite kind come together. This creates a certain amount of force which then pushes back all those forces. These pushing forces combine to create a powerful electrical field that can be used as a source of electric power—this is how electricity is produced.

What is an Alternator?

What Is An Alternator?

An alternator is a type of electrical generator that produces alternating current (AC).

Despite the difference in their appearance, generators and alternators usually share the same basic functionalities. They perform similar functions, like converting mechanical energy into electricity.

What is Electricity?

What Is Electricity?

Electricity is a phenomenon that occurs in nature, but not in its original form—it is a product of human work. Electricity originates from the transfer of thermal energy through conductors with free electrons. In order to understand the basic principles of electricity, you need to know what are free electrons and how they are created.

There are two completely different types of electrical current: Direct current (DC) and Alternating Current (AC).

Direct Current (DC)

In the context of physics, Direct Current (DC) refers to a type of current which is always directed in the same direction and does not return on itself.

Alternating Current (AC)

In the context of physics, Alternating Current (AC) refers to a type of current that has an alternating direction and that returns to its initial position after each complete cycle.

Difference between a generator and an alternator

Difference Between A Generator And An Alternator

When we talk about a generator, we usually mean an electrical machine that produces electricity. In fact, the word generator is the common term used to refer to any device that produces electric energy. On the other hand, when we talk about an alternator, we usually mean a device that converts mechanical energy into electricity in alternating AC (alternating current).

They are both similar machines that convert mechanical energy into electricity; however, they are completely different from each other. The purpose of this article is to explain the difference and similarities between them in a simple way so you can understand them better and then decide for yourself which machine is right for you.

How does a generator work?

Generators use rotating machinery parts to produce electricity. These rotating parts are called the rotor and the stationary parts are called as the stator. The rotor moves at high speed with the help of mechanical rotation and depending on their rotational speed, they generate electricity in different ways.

How Does A Generator Work?

The alternator works differently from a generator because it doesn’t have any moving parts. Instead, it uses electrical charges to maintain an electrical field in its surroundings which then produces AC current.

Methods to produce electricity

A generator can use two different methods to produce electricity:

The first method is called as Induction, and is used by machines like the starter engine in a car. In this method, electromagnetic induction causes a current to flow through a wire loop located inside the rotor—electromagnetic induction occurs when the magnetic field surrounding an electrical conductor causes a nearby conductor to move.

This movement induces an electric current in the nearby conductor. The second method is called as “excitation” and it is only used by machines like large power plants; in this method, the high-voltage AC supply powers rotating coils that are embedded into the rotor shaft of an alternator. These rotating coils help in creating strong magnetic fields near the stator windings which in turn, produces AC voltage.

Methods To Produce Electricity

The alternator uses two different methods to produce electricity:

Commutators are used by machines like large power plants, and the brushes are used by machines like large motors. In this method, a direct current is supplied to a set of rotating coils that are embedded into the rotor shaft of an alternator.

These rotating coils help in creating strong magnetic fields near the stator windings which in turn, produces an AC voltage.

Comparing both types of machines, you can see that while generators use electromagnets to produce electricity, alternators use electrical induction instead — this is the main difference between them. It’s easy to see that the generator works according to electromagnetic induction, but the alternator works according to electrical induction.

Advantage of Alternator vs generator

Advantage Of Alternator Vs Generator

They both produce electricity using mechanical energy, but they are different from each other. Although the two machines use different methods, they both have their own advantages.

A generator can be used to produce electrical power in smaller quantities as compared to an alternator. A generator is a widely used machine that is used as an emergency backup in many homes and offices.

Alternators are also used in many places, but mostly for industrial purposes. People usually get confused when it comes to the difference between these two machines; however, they are completely different machines with different working principles and uses.


The main difference between an alternator and a generator is the type of coil that is used. Alternators use induced coils, whereas generators use electromagnetic coils.

Both the machines are used to generate electricity, but they have different working principles and uses. Although these two machines are electrically the same, they produce electricity in completely different ways.

Alternators are mostly used for industrial purposes and generators are widely used by individuals for their homes as well as offices.

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