What does an electric generator do?

Originally called an electric dynamo, the electric generator converts mechanical energy into electric energy. It does this by rotating a magnet inside a tightly bound group of wires. As the magnet spins it dislodges electrons from the wiring (normally made of copper) and the electrons flow along the wire. Depending on how many wires surround the magnet dictates the total amount of voltage that is produced.

The first electric generator was invented by Michael Faraday and Joseph Henry separately in 1832. This discovery made the possibility of harnessing the properties of electrical power, but was unable the explain how it worked. In 1873 the Scottish physicist James Clerk Maxwell submitted his treatise on electro-magnetism, it described the relationship between magnetism and electric current and how to calculate their potential. The impact of these two events would resound throughout history.

The first electric generators were Direct Current, or DC generators. This means that the electron flow would only go in one direction, i.e. directly to the load. However, due to James Clerk Maxwell's treatise, a young inventor, Nikola Tesla, developed the first alternating current or AC generator in 1892. The AC generator operates similar to a DC generator, but the magnetic rotation shifts poles. The polar reversal allows the electrons to have a positive (+) and negative (-) charge. By flip-flopping the magnetic rotation (rotor) inside the stationary wires (stator) the output would be constant without the voltage loss that was common with DC generators.

This development allowed for longer transmission of electric power and the introduction of power generation stations. It also allowed for underdeveloped portions of the country to have the availability of electricity without the interruptions and voltage drops that were common for DC electricity.

Currently, electric companies use the same concept on a much grander scale. Normally, utility companies use hydro-mechanical energy to convert into electric energy. A good example of this would be the Hoover Dam near Las Vegas, Nevada. The Hoover Dam constricts the flow of water and forces it past a turbine, the turbine spins the large magnetic coils inside the dam housing, producing the electricity for the city of Las Vegas.

There are multiple types of electric generators. Some use water (as in the case above), and some use wind, coal, natural gas, oil, gasoline and lastly steam. The original electric generators used nothing more than human energy to spin a rotor with a magnet inside a stator of copper wires. Whatever the kind of electric generator there is, the intention remains the same, to convert mechanical energy into electric energy.