Generator

One of the most important practical applications of generators is in the production of large amounts of electrical energy for industrial and residential use. The two most common prime movers used in operating AC generators are water and steam. Both of these prime movers have the ability to drive generators at the very high rotational speeds at which they operate most efficiently, usually no less than 1,500 revolutions per minute.

Hydroelectric power (the power provided by running water, as in large rivers) is an especially attractive power source since it costs nothing to produce. It has the disadvantage, however, that fairly substantial superstructures must be constructed in order to harness the mechanical energy of moving water and use it to drive a generator.

The intermediary device needed in the generation of hydroelectric power is a turbine. A turbine consists of a large central shaft on which are mounted a series of fan-like vanes. As moving water strikes the vanes, it causes the central shaft to rotate. If the central shaft is then attached to a very large magnet, it causes the magnet to rotate around a central armature, generating electricity that can then be transmitted for industrial and residential applications.

Electrical generating plants also are commonly run with steam power. In such plants, the burning of coal, oil, or natural gas or the energy derived from a nuclear reactor is used to boil water. The steam thus produced is then used to drive a turbine which, in turn, propels a generator.