DISCOVER

# How does a generator work?

Updated February 21, 2017

An electric generator is a device or machine that is used to convert mechanical energy into electrical energy. It is based on the principle of electromagnetic induction, a scientific law that was discovered by British scientist Michael Faraday and American scientist Joseph Henry in 1831. The principle states that when an electric conductor, such as a copper wire, is moved through a magnetic field, electric current will flow through the conductor. The mechanical energy of the moving wire is converted into the electric energy. Faraday and Henry found that when you move a magnet in a coil of wire, electric current is generated.

## Electric Generator History

An electric generator is a device or machine that is used to convert mechanical energy into electrical energy. It is based on the principle of electromagnetic induction, a scientific law that was discovered by British scientist Michael Faraday and American scientist Joseph Henry in 1831. The principle states that when an electric conductor, such as a copper wire, is moved through a magnetic field, electric current will flow through the conductor. The mechanical energy of the moving wire is converted into the electric energy. Faraday and Henry found that when you move a magnet in a coil of wire, electric current is generated.

Faraday's law of induction shows that a moving magnetic field will cause electrons to move. Generators create electron movement in the copper wire coils contained within by moving them through a magnetic field. Faraday built the first electromagnetic generator, called the Faraday disc, which was a simple copper disc rotating between the poles of a horseshoe magnet. It produced a small DC voltage and large amounts of current that was inefficient, but a good start for future generators.

## Generator Magnets

Generator magnets apply pressure to the electrons to push them and create a flow or current of electricity. The number of moving electrons is called the amperage or the current and is measured in amps. The pressure pushing the electrons is called the voltage and is measured in volts.

## Electromagnets

A generator is basically created by a mechanical force that turns a conductive wire or bar within a magnetic field. The force used to spin the conductive object can be provided by many sources, such as moving water, steam, wind, gas engine or even hand-cranked levers. The electricity then flows into an electric motor or other electric-powered device, which reverses the process and the electricity makes it move. Small generators create a magnetic field with permanent magnets. Larger generators create a magnetic field with a set of metal coils with electric current flowing through them; this is an electromagnet.

## Types of Generators

There are many types of generators. Each is based on the method it uses to either spin a conductor through a magnetic field or a magnet through a conductor. Some include the following generators and devices using generators. Magnetohydrodynamic generators creates electric power from hot gases moving through a magnetic field. Pre-1960s vehicles used DC generators with electromechanical regulators but have been replaced with alternators, which are cheaper, to recharge the batteries. An alternator is a type of generator that creates a magnetic field that rotates and passes through coils to create an electric current. Engine generators are the combination of electrical generators and engines that are used in piston engines or gas turbines, such as small portable gas-powered units to large turbines. Hydroelectric power plants use falling water to turn a turbine, which provide the mechanical energy to turn the generator and create electricity. The electricity is then sent through transmission lines to deliver electricity to homes or buildings. Some sail boats use water or wind-powered generators to charge the batteries through the use of small propellers, wind turbine or impeller. Human-powered electrical generators are used in devices such as portable radios or flashlights with a crank. Small generators are used in bicycle lights and powered by riders.