How Does a Generator Work

Electrical generators are the devices which have driven our industrial revolution. Without electricity, no piece of technology can work. At a very basic level, a generator is a machine which converts mechanical energy to electrical energy. Every process on earth and every device is based on energy transformation of one kind or the other. In this article, I'll try to explain how does a generator work to produce electricity.

What is an Electrical Generator?

When you ask me how does a generator work, I assume that we are talking about electrical generators. An electrical generator supplies electricity by conversion of mechanical energy obtained from various sources. It uses an arrangement of magnets and rotors, to derive electricity from mechanical motion. More on that later. Depending on the source from which the mechanical energy is derived, there are various types of electrical generators.

If you are wondering how does diesel generator work, then answer is same as that of an electrical generator. The only difference is that the mechanical energy for this type of generator is derived from chemical energy released through combustion. A dynamo and a car alternator are two other types of generators that supply electricity to automobiles. Every type of generator which includes the big ones that are operational in power stations and the small ones like the car alternator, have the same principle of working which I will explain in the next section. The only thing which differs is the way in which the mechanical energy is derived.

Working Principle of a Generator - Electromagnetic Induction

To know the working of any machine, one must know the physical idea or principle on which it is based. Every machine built by man harnesses natural physical laws for its working. When you ask a question like how does a generator work to produce energy in the form of electricity, you must delve into basic electromagnetism for an answer.

Almost every single physical device and every single biochemical mechanism is driven by the electromagnetic force. In fact, it wouldn't be an understatement if I say that we live in an electromagnetic world. The working principle of an electrical generator is no exception to this. A generator works on the principle of electromagnetic induction. It states that a changing magnetic field creates a current through a conductor.

If I were explaining how does a generator work, for kids, I would illustrate the following experiment which demonstrates the principle of magnetic induction. If you have a workshop around, gather some metal shavings and spread them on a sheet of paper. Now get a small magnet and move it over that sheet. You will see that metal shavings cling to the magnet and move in synchronization to the movement of the magnet. If you place the magnet on the paper, they arrange themselves in a specific pattern around it. That is magnetic induction at work! The changing magnetic field around the metal shavings influences the electrons in orbit around atoms in them. The magnetic field change pushes the electrons around creating small electric currents in the metal shavings. Every magnetic field is created by an electric current. The magnetic field in magnets is the result of currents in the atoms of the material which makes magnets. In general, every electric current creates a magnetic field around it and every changing magnetic field creates an electric current! Let us see how does a generator work by harnessing this fundamental principle. Read more on

• What is a Portable Electrical Generator?
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How Does an Electrical Generator Work?

So, now we are finally in a position to answer the question of how does a generator work in principle. Every generator consists of two main components: stator (stationary part) and rotor (the moving part). In every generator, stator is a single or a set of magnets, while the rotor is a metal loop which rotates in it. When metal loop of a rotor, revolves between the magnets, the magnetic field associated with electrons in them changes and an electric current is generated in it. With every rotation, the changing magnetic field creates a current, which is then transported through a coil to an external electrical circuit. That is how electricity is supplied by the generator!

Generators may have an alternative arrangement, where the stator can be the metal loop, while rotor is the magnet. That is a magnet rotates around a stationary metal loop, generating current in it. The mechanical force required to turn the rotor is provided by various methods. In a diesel generator, it is driven by a motor which runs on diesel combustion. If you ask me about how does a generator work in a power station, the answer is same in principle. Only the generators in power stations have huge and more number of magnets in them and the rotors there are driven by various other sources like falling water (in a hydroelectric power station), steam generated by heat supplied through nuclear fission (nuclear power station), the movement of a crankshaft in a car (in an alternator) and more such mechanical sources of energy. There is an elaborate mechanism that supplies the electric power generated in power stations to our homes through electrical cables.

Hope this simple explanation has given you a rough idea of how does a generator work. There is a lot more complexity involved in the working of a generator, which works at a power station. I will not go into those details as I only intended to explain basic principles. Every machine like a generator is an extension of an idea or principle. Once you understand the idea or principle, understanding the working based on it is a simple job!