What Is Electric Generator
The electric generator is a machine for producing electric current or electricity. The electric generator convert mechanical energy into electrical energy.
Principle of working of an electric generator:
Electric generator is an application of electromagnetic induction.
Electric generator works on the principle that when a straight conductor is moved in a magnetic field, then current is induced in the conductor
In an electric generator a rectangular coil is made to rotate rapidly in the magnetic field between the poles of a horseshoe type magnet. When the coil rotates it cut the magnetic field lines due to which current is produced in the coil .
As a matter of fact, the principle of AC generator is the same to direct-current generator. The basic principle of a generator is to convert motion into electricity. Providing this motion requires that either a magnetic field is generated and a wire coil is rotated within it, or a magnetic field is rotated within a stationary coil. The turning of a coil in a magnetic field produces motional emfs in both sides of the coil which add. Since the component of the velocity perpendicular to the magnetic field changes sinusoidally with the rotation, the generated voltage is sinusoidal or AC.
Electric generators are of two types:
Alternating current generator(A.C generator)
A.C. generators or alternators (as they are usually called) operate on the same fundamental principles of electromagnetic induction as D.C. generators.
Alternating voltage may be generated by rotating a coil in the magnetic field or by rotating a magnetic field within a stationary coil. The value of the voltage generated depends on-
the number of turns in the coil.
strength of the field.
the speed at which the coil or magnetic field rotates.
Direct current generator (D.C generator)
It is based on the principle of production of dynamically (or motionally) 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 and A conductor or conductors which can so move as to cut the flux.
Construction :
A single-turn rectangular copper coil abcd moving about its own axis in a magnetic field provided by either permanent magnets or electromagnets. The two ends of the coil are joined to two split-rings which are insulated from each other and from the central shaft. Two collecting brushes (of carbon or copper) press against the slip rings.