DC Generators

DC generators are machines which convert mechanical energy into electrical energy. They use a magnetic field and conductors to produce direct power. An AC generator can be converted into a DC generator in a number of ways: by using a commutator, a rectifier or with batteries. These machines produce a reliable and efficient energy supply although they tend to be more complicated than AC generators because of these extra parts and so need more maintenance. There are several types of DC generators. The first is the Separately Excited generator, which has its field coils energised by an independent external DC source. The second kind is the Self-excited generator whose coils are energised by current produced by the generator itself. These machines vary in type and can be series wound, shunt wound or compound wound. Like DC generators, they are available as standby (fixed) or portable and the amount of voltage they produce can vary. DC generators are also used to supply general lighting as well as small amounts of power supply. In machinery in general, they can provide excitation to alternators. In the industrial sector, DC generators can provide power for electrolytic processes, welding processes and variable speed motor drives.