AC generator- SINGLE PHASE&THREE PHASE

                             AC GENERATOR 

AC generator is a device used to convert mechanical energy to electrical energy 

CONSTRUCTION & OPERATION

Main parts of a AC generator is Field magnet , Armature coil ,Slip rings ,Graphite brush

WORKING

Armature is an insulated copper wire wound on a soft iron core .When it rotate inside the field magnet.it cuts the magnetic lines.By electromagnetic induction an emf is produced in the coil.During each half rotation the direction of current in the out put changes.So it is an AC current

Simple method of experiment

Take a round magnet magnet from loud speaker and split it in to two pieces,it is taken as field magnet.A hard plastic sheet (if soft iron is used we can increse current in the output)is cut in the shape of a square with a neck.Cut another small square in side. Wind insulated copper wire on the plastic sheet.Connect the two ends to a metallic ring.The whole arrangement is rotated in side magnetic field. Out put is taken from the metallic ring
There are two types of AC generators
Single Phase generator and Three Phase Generator

Single Phase Generator

 In this generator there is one Armature for a pair of magnets.So there is only one phase line out put. The most important parts of a generator are Field magnet and Armature. The rotating part is called rotar and stationary part is called stator.

Three phase generator
In three phase generator there are three identical armature coils at an angle of 120'. with one another against each pair  of magnetic poles. Electric current in three different phases are obtained from such generators. Ends of each armature coil connected to a point called neutral. It is a zero potential wire.
There are three phase line out puts . If we take one phase line and a neutral line it is 230v. If we connect two phase line to a device we will get 400v