Assignment 4

Generator Designs and Application

Definition

An electrical Generator is a machine which converts mechanical energy into electrical energy.

Principle:

It is based on the principle of production of dynamically induced e.m.f (Electromotive Force). Whenever a conductor cuts magnetic flux, dynamically induced e.m.f. is produced in it according to Faraday's Laws of Electromagnetic Induction. This e.m.f. causes a current to flow if the conductor circuit is closed.

Hence, the basic essential parts of an electric generator are:

· A magnetic field

· A conductor or conductors which move as to cut the flux.

The Dynamo was the first electrical generator capable of delivering power for industry. The dynamo uses electromagnetic principles to convert mechanical rotation into a pulsing direct electric current through the use of a commutator.

Through a series of accidental discoveries, the dynamo became the source of many later inventions, including the DC electric motor, the AC alternator, the AC synchronous motor, and the rotary converter.

A dynamo machine consists of a stationary structure, which provides a constant magnetic field, and a set of rotating windings which turn within that field. On small machines the constant magnetic field may be provided by one or more permanent magnets; larger machines have the constant magnetic field provided by one or more electromagnets, which are usually called field coils.

blelow is a typical portable generator;

The two main parts of a generator or motor can be described in either mechanical or electrical terms:

Mechanical:

· Rotor: The rotating part of an alternator, generator, dynamo or motor.

· Stator: The stationary part of an alternator, generator, dynamo or motor.

Electrical:

· Armature:

The power-producing component of an alternator, generator, dynamo or motor. In a generator, alternator, or dynamo the armature windings generate the electrical current. The armature can be on either the rotor or the stator.

· Field:

The magnetic field component of an alternator, generator, dynamo or motor. The magnetic field of the dynamo or alternator can be provided by either electromagnets or permanent magnets mounted on either the rotor or the stator. (For a more technical discussion, refer to the Field coil article.)

Since power transferred into the field circuit is much less than in the armature circuit, AC generators nearly always have the field winding on the rotor and the stator as the armature winding. Only a small amount of field current must be transferred to the moving rotor, using slip rings. Direct current machines necessarily have the commutator on the rotating shaft, so the armature windin

Below is a simple illustration of the generator

conclusion

The generator is one of the most important electrical invention because it produces electricity. Generators over the years has found its way into our day today life; from the main generating stations to the back up generators at home.Generators have also changed in terms of size and form. now days you can get a generator that is convinient for your needs.