explain the construction , working and principal of ac generator
Answers
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.
The AC generator consists of the following parts :
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.
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.
the leads from the arms of armature AC connected to two slip rings S, which rotate with the loop .
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.
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..
The AC generator consists of the following parts :
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.
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.
the leads from the arms of armature AC connected to two slip rings S, which rotate with the loop .
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.
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..