Question

Describe working and construction ogf ac generator

Answer 1

he working principle of an alternator or AC generator is similar to the basic working principle of a DC generator. Above figure helps you understanding how an alternator or AC generator works. ... Let the conductor coil ABCD is placed in a magnetic field. The direction of magnetic flux will be form N pole to S pole.

Answer 2

$\huge \bf{ \red{answer}}$

$\bf{\: principal}$

It is based on the principle of electromagnetic induction . when a coil is rotated about an axis perpendicular to the direction of uniform magnetic field, an indused emf produced across it.

$\bf{construction}$

The AC generator consists of the following parts :

$\sf{1. \: armature}$

A rectangular coil ABCD consisting of a large number of turns wound over a soft iron core is called armature. the soft iron core is used to increase the magnetic flux.

$\sf{2. \: field \: magnet}$

it is a strong magnet having concave poles. the armature is rotated between the two poles of this magnet so that axis of armature is perpendicular to magnetic field lines. in a small AC generator the magnet is the permanent magnet but in Big AC generators it is an electromagnet.

$\sf{3. \: slip \: rings}$

the leads from the arms of armature AC connected to two slip rings S, which rotate with the loop .

$\sf{4. \: brushes}$

the rings slide against stationery contacts called brushes . these brushes are made up of carbon. these brushes are connected to the output terminals p and q.

$\bf{working}$

the working of AC generator can be understood with the help of various positions of the armature .

suppose at time 't' =0 , the plane of the loop is perpendicular to B . as the loop rotate from position t=0 to position t=T/2 , induced EMF changes from zero to maximum value and then becomes zero again, hence induced EMF is zero. as the loop moves from position t =T /2 to position t=T , the EMF again changes from zero to maximum value and then again becomes zero .

Thus the output of the AC generator varries sinusoidally with time . The induced EMF does not depend upon the shape of the loop but depends only upon area of the loop..