Understanding Generators: Types, Working Principles, and Their Functions

Understanding Generator – In everyday life, of course, we are familiar with electric generators. Usually, this tool is then needed in buildings that require a constant source of electricity, such as sewage treatment plants, hotels, airports, and hospitals. With a generator, it is able to prevent discontinuity and interruption of business operations. An electric generator is a device that produces electrical energy from a mechanical energy source, usually by means of electromagnetic induction.

Simply put, a generator is a machine with motion (mechanical) energy that is capable of converting it into electrical (electrical) energy. There are various sources of motion energy from generators. For example, in a wind power plant , this generator can move because of the wind that drives the wheel to rotate. So, what are the functions of the generator and how does it work? Check out the full review below:

Definition of Generators

An electric generator is a machine used to generate electrical energy from mechanical energy sources. The working principle of an electric generator is electromagnetic induction. Based on the type of electric current, generators are then divided into direct current generators and alternating current generators.

The difference between the two is in the use of a commutator in direct current generators and slip rings in alternating current generators. The working process of an electric generator is also known as a power plant. An electric generator also has much in common with an electric motor, but an electric motor is a device that converts electrical energy into mechanical energy.

In addition, the generator also encourages electric charge to be able to move through an external electric circuit, but the generator does not create electricity that is already in the windings of the coils. This is analogous to a water pump, which then creates a flow of water but does not create any water in it.

The source of mechanical energy can then be a reciprocating or turbine steam engine, water falling through a turbine or waterwheel, internal combustion engines, wind turbines, hand cranks, solar energy as well as the sun, compressed air, or whatever source of mechanical energy is passing through it. .

Generator Type

1. Direct Current Generator

The working basis of the direct current generator is the occurrence of electromagnetic induction events. Direct current generators can also produce induced failures in one direction by changing the shape of their terminal rings. The terminal ring in this form is also known as a split ring or commutator.

A direct current generator will only use a single ring commutator that is split in half, thereby producing direct current, while an alternating current generator has two separate rings.

When an electromotive force arises, the contact with the load circuit then switches terminals, so that the output voltage has only one sign and produces a direct current. The addition of the number of coils which are then connected to the commutator with a commutator ring consisting of several segments, is also able to reduce the ripple in the direct current voltage.

2. Alternating Current Generator

The first alternating current system was made by William Stanley in Great Barrington, Massachusetts. The project for making this system itself was funded by Westinghouse. At the same time, the alternating current system was traded by Nikola Tesla.

The use of alternating current continued to increase after CS Bradley made a 3-phase alternating current generator in 1887. This three-phase alternating current generator has high efficiency, so it has been used as a general power generator in the world since 1900 AD.

This alternating current generator consists of a coil and a coil of wire which is rotated in a magnetic field. The inside of the alternating current generator is also known as the armature. The contents of the armature are iron cylinders that are used as a place for coils of wire to be wound.

In addition, the generator terminal also has two rotating rings which are connected to the electrical load by means of soft copper bushings. The magnetic field is then formed by permanent magnets or electromagnets. The energy to rotate the armature can be in the form of human power, combustion, or the potential energy of water

Generator Working Principle

In a journal published by the Sriwijaya State Polytechnic, it is explained that the basic principle of a generator is alternating current. The principle of the generator also uses Faraday’s law which states that if a conductor is in a changing magnetic field, an electromotive force will form on this conductor. The magnitude of the generator voltage will then depend on:

  • Rotation speed(N)
  • The number of wires in the coil that cut the flux (Z)
  • The amount of magnetic flux which is then generated by the magnetic field (f)
  • Generator Construction

It was also explained that the number of poles of this alternating current generator depends on the speed of the rotor and the frequency of the generated EMF. This relationship can be determined by the following equation: F = pn/120 Description: f = voltage frequency (Hz) p = number of poles on the rotor n = rotor speed (rpm).

As we know that an electric generator is a device that converts mechanical energy into electrical energy, the generator does not create electrical energy, but only uses the supplied mechanical energy to drive electric charges.

In addition, the working principle of the synchronous generator is also based on electromagnetic induction, after the rotor is rotated by the prime mover, the poles on the rotor will rotate automatically. If the pole coil is supplied by direct voltage, a rotating magnetic field will arise on the surface of the pole.

Meanwhile, modern generators work based on the principle of electromagnetic induction which was first discovered by Michael Faraday in 1831. Faraday also discovered that electricity can be induced by moving an electric conductor, such as a wire containing an electric charge, into a magnetic field.

Therefore, this movement can create a voltage difference between the two ends of the cable or the electric conductor, which in turn causes electric charges to flow and produce an electric current.

Generator Function

The main function of the generator is to produce electrical energy by changing the force of motion in it. In addition, the number of electronic equipment today also makes generators have many functions. The functions of generators in everyday life include the following:

1. Power Plant

The generator is the main component that can generate electricity. The sources of energy used are various, such as water, sun, natural gas, ocean waves, wind, and so on. Thus, the function of the generator is to make us not easily run out of electrical energy.

2. As a Power Backup

As we know, there are lots of public places that use generators. Of course, it is used as a backup power supply. Some places, such as supermarkets, hotels, and hospitals, use generators in the form of generators to store electricity in them.

With a generator, this backup electricity can then help with daily activities. That way, you don’t have to worry anymore in the event of a power outage.

Generator Development

Before the relationship between magnetism and electricity was discovered, generators used electrostatic principles. The Wimshurst machine also uses electrostatic induction or “influence”. A Van de Graaff generator that uses one of two mechanisms:

  • Transfer of charge from high-voltage electrodes
  • The charge created by the triboelectric effect by means of the separation of two insulators

1. Faraday

Soundproof 3-phase generator made circa 1831-1832 Michael Faraday later discovered that a potential difference is produced between the ends of an electrical conductor which moves perpendicular to a magnetic field. He also built the first electromagnetic generator based on this effect by using a copper disc rotating between the poles of a horseshoe magnet.

This process also generates a small direct current. In addition, the design of the device, dubbed the ‘Faraday disk’, is inefficient due to the flow of electric current in the opposite direction to the part of the disk that is not affected by the magnetic field. The current induced directly under the magnet will flow back to the disk outside of the influence of the magnetic field.

The reverse current also limits the power delivered to the conducting wires and induces the heat generated by the copper discs. The homopolar generator which was later developed was able to solve this problem by using a number of magnets arranged around the edge of the disc to be able to maintain a stable magnetic field effect.

Another weakness of the development of this generator is the small voltage generated by this tool. This can occur due to a single current path through the magnetic flux.

2. Dynamo

The dynamo was the first electric generator capable of delivering power to industry, and is still the most important generator used in the 21st century. Dinamo also uses the principle of electromagnetism to be able to convert mechanical rotation into alternating current electricity.

The first dynamo based on Faraday’s principle was built in 1832 by Hippolyte Pixii, a French instrument maker. This tool also uses a permanent magnet that is rotated by a “crank”.

This rotating magnet is positioned so that its north and south poles pass through a piece of iron wrapped in wire. Pixii also discovered that magnets rotate by producing a pulse of current in the wire each time a pole passes through the coil.

Furthermore, the magnetic north and south poles induce currents in opposite directions. By adding a commutator, Pixii will convert alternating current into direct current.


From all the discussion above, it can be said that a generator is a machine that has the function of producing electrical energy and also providing electricity reserves. Therefore, these generators are usually owned by hospitals, supermarkets, and so on. Generators that function to provide electrical energy reserves are usually known as generators.

Thus the discussion about generators, starting from their understanding, functions, to their working principles. Hopefully all the discussion above can provide benefits as well as add to your insight.