What is the Difference Between an Alternator and a Generator?

The difference between an alternator and a generator is that an alternator can only generate alternating current AC, while a generator can generate both alternating current AC and direct current DC.

Alternators and generators are crucial components of any engine system. They can power the battery and other electrical systems.

With the help of this article, we will clear all your confusion in differentiating between a generator and an alternator. Read the full blog for better understanding.

What is an Alternator?

What Is An Alternator

The power production industry’s powertrain is the alternator. It can produce AC power at a given frequency.

It also goes by the name “synchronous generator.”

When two or more alternators connect parallelly to supply electrical energy to load, the generators are now called synchronous generators.

Electromagnetic induction generates electricity in alternators.

An Alternator consists of an armature and a rotor. A starter generator powers the rotor.

When the rotor rotates, it induces an emf in the armature windings. The voltage regulator of an alternator directly controls its output.

Alternators are highly effective. They produce more than generators do. They can conserve more energy and only use the power needed.

The alternator is basically a component of an alternator.

Working Of an Alternator

By converting mechanical energy into electrical energy, the alternator operates.

When the engine runs, it powers a drive belt attached to an alternator pulley.

The alternator’s pulley rotates the rotor shaft, which spins a series of magnets around a coil. Around the coil, these rotating magnets produce AC (alternating current).

Main Components of An Alternator

Main Components Of An Alternator

 Following are the main components of an alternator:

  1. Rotar
  2. Stator
  3. Brush
  4. Rectifier

1. Rotar

A component that turns the pulley inside the alternator is called the rotor. It functions as an electromagnet that spins.

2. Stator

An iron ring called a stator has multiple wire coils twisted around it.

The stator’s component acts as the alternator’s core, generating an electrical current whenever a magnetic field is created.

3. Brush

 The alternator brushes are mounted on slip rings to create a sliding electrical connection.

4. Rectifier

Throughout most of the charging process, the rectifier is utilized to convert DC produced by an alternator to DC.

What is a Generator?

What Is A Generator

Generators are practical devices that provide electricity during a power failure, reducing the stoppage of daily activities or company operations.

The generator transforms mechanical energy into power or electrical energy.

The generator operates according to the Faraday rules of electromagnetic induction, which state that whenever conductors are severed, an EMF is induced.

Working Of Generator

According to Faraday’s law of electromagnetic induction, the fundamental working principle of a generator is that.

When a conductor is rotated in relation to a magnet or magnetic field, an emf is produced in the circuit or system when the circuit is closed.

When wires are put on a stator, a rotating component called the rotor rotates around it.

As a result of this relative motion, an emf is generated and is successively sent to the circuit via the appropriate connections.

So, all we need to do to generate electricity is rotate the rotor. For that, we can either employ thermally induced superheated steam.

Main Components of a Generator

Main Components Of A Generator

 Following are the main components of a generator:

  1. Engine
  2. Fuel System
  3. Alternator
  4. Regulator
  5. Lubricating System
  6. Battery

1. Engine

The engine generates mechanical energy that the generator will then convert into electrical energy using its fuel supply, which may be gasoline, diesel, natural gas, or hydrogen.

Each generator engine is built to provide the most electrical current possible while using a particular fuel or other power source.

2. Fuel System

 Fuel-powered generators have a mechanism that stores and delivers the right fuel to the engine. A generator might run for the same hours on the fuel that is kept in the tank.

 3. Alternator

It is mainly the element in charge of producing electrical output.

The alternator converts the diesel engine’s mechanical energy into electrical energy, which drives the rotor to move a magnetic field around the stator.

4. Regulator

The voltage regulator controls the output voltage. It guarantees a constant voltage of electricity production from the generator.

Without it, you would experience significant swings based on how quickly the engine is operating.

5. Lubrication System

To reduce the effects of metal-on-metal contact, it flows oil through the engine.

It also absorbs a lot of heat produced in order to ensure smooth performance.

6. Battery

The battery serves as a container for the energy that battery chargers provide.

It retains this energy by converting electrical energy to chemical energy and then back to electrical energy. It fuels the cranking engine, which turns the machine on.

Difference Between an Alternator and a Generator

Alternators and generators are used everywhere. They are electromechanical regulators in vehicles. They help in power backups and many other ways.

The alternator produces voltage when needed, and the generator always produces voltage.

Both generators and alternators can produce electricity. One variety of generators is the alternator.

While a generator generates AC and DC current, an alternator only produces AC current.

Another key difference between a generator and an alternator is that an alternator generates electricity when a magnetic field rotates within the stator coil.

On the other hand, a generator’s armature winding of wire turns within a constant magnetic field to produce electricity.

The generator output is lower compared to that of an alternator.

Dead batteries cannot be charged with an alternator because they could burn out. A dead battery can be recharged using a generator.

Alternators can generate more amps for the same size device and are more built. In addition, they can charge efficiently at lower generator revolutions per minute.

The main difference between an alternator and a generator is that a generator basically consists of a spinning set of coils that produce both DC and AC and a static magnetic field via a commutator.

On the other hand, an alternator contains a spinning magnetic field and a static collection of coils that use rectifiers to produce DC current.

Alternators are better because commutators have trouble with very high currents and quick rotation. So, alternators can spin faster, giving more current at lower revolutions.

Comparison Between Alternator Vs. Generator

Highlighting the comparison between an alternator and a generator in the following table:

An alternator only produces alternating current.A generator produces both alternating and direct currents.
The efficiency of alternators is high.The efficiency of generators is viewed as lower.
Compared to generators, alternators offer better output.The output of generators is inferior.
Alternators are more energy-efficient.Generator preserves less energy.
An alternator’s armature is immovable.Generators have revolving armatures.


The main difference between a generator and an alternator is that the generator generates both AC and DC electricity, the alternator only produces AC. Alternating current from the generator is transformed into direct current (DC) with the aid of the commutator. The generator needs a lot of space. However, the alternator is smaller and takes up less.

Read more: What is the Difference Between Bacteria and Fungi?

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