ALTERNATOR:

                            These days 3-phase system is being extensively used for generation,transmission and distribution of power. The machine which produces 3-phase power from mechanical power is called an ALTERNATOR or SYNCHRONOUS GENERATOR.

These are the primary sources of all the electrical energy we consume.These machines are the largest energy converters found in the world.They convert mechanical energy into a.c energy.

An ALTERNATOR operates on the same fundamental principle of electromagnetic inductio as a dc.generator i.e.,when the flux linking a conductor changes,an emf is induced in the conductor.

                                                 

OPERATION OF ALTERNATOR

The rotor winding is energized from the d.c exciter and alternate N and S poles are developed an the rotor.When the rotor is rotated in anticlockwise direction by a prime mover,the stator or armature conductors are cut by the magnetic flux of rotor poles.Consequently e.m.f is induced in the armature conductors due to electromagnetic induction.The induced e.m.f is alternating since N and S poles of rotor alternately pass the armature conductors.

TYPES OF ALTERNATORS:

According to the machines the alternator are classified into:

1.       Automotive type - used in modern automobile.

2.       Diesel electric locomotive type - used in diesel electric multiple unit.

3.       Marine type - used in marine.

4.       Brush less type - used in electrical power generation plant as main source of power.

5.       Radio alternators - used for low brand radio frequency transmission.