Electrical Generator

An electrical generator is an electro-mechanical energy conversion device that converts mechanical energy into electrical energy. The machine with converts electrical to mechanical energy is called motor. It works on the principle of faraday's law of Electromagnetic Induction “whenever a conductor cuts magnetic lines

of force emf is induced in it”.  Faraday developed the first electrical generator.

An electric Generator

Generator can be classified into two types based on the nature of current:

1. DC Generators: produce direct current and has a commutator. The various types of DC generators depending on the type of excitation are separately excited DC generator, series generator, shunt generator and compound generator.
2. AC Generators: produce sinusoidally varying alternating current. These machines are called alternators. Synchronous machine is the mostly used electric generator in power generation. In wind turbines the induction generators too used for power generation

In the initial stages of power generation the DC generators are only means of generation. After the adoption of AC which has the ability of easy transformation DC generators are rarely used.

Equivalent Circuit of Electrical Generator

The simplified approximate equivalent circuit of a generator is shown in following figure.

Equivalent Circuit of Electrical Generator

It is represented as a Voltage source which represents the voltage generated in the machine, in series with its internal resistance which is the winding resistance. The exact equivalent circuit may vary considerably.

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Transformer