AC Generator - Electromagnetic Induction, Physics Video Lecture - Class 12

AC generator do you know that most of
our electrical energy comes due to the
spinning of rotors in the AC generator
of power stations like nuclear power
stations thermal power stations and
hydroelectric power stations and so on
what is an AC generator an AC generator
is a device which converts mechanical
energy into electrical energy AC
generator was originally designed by
Nikola Tesla
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what is within listed here are the
contents of this module
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the working of an AC generator is based
on electromagnetic induction that is
whenever the flux passing through a
circuit changes and EMF is induced in it
and a current begins to flow the
direction of induced EMF is given by
Fleming's right-hand rule or Lenz's law
Fleming's right-hand rule stretch the
forefinger the middle finger and the
thumb of the right hand such that they
are mutually perpendicular to each other
if forefinger indicates the direction of
the magnetic field Thumba indicates the
direction of motion of the conductor
then the middle finger indicates the
direction of the induced current in the
conductor
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Lenz's law it states that the direction
of induced current is such as to oppose
the very cause producing it
components of an AC generator an AC
generator consists of a magnet with
concave cylindrical poles an armature
and a current collecting arrangement the
current collecting arrangement consists
of slip rings and brushes
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armature is a soft iron core on which a
coil having a large number of turns of
insulated copper wire is wound
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magnetic poles are concave and
cylindrical the concave poles produce a
radial magnetic field
slip rings the ends of the armature are
connected to two slip rings they rotate
along with the coil the slip rings are
made of metal and are insulated from
each other
brushes there are two brushes b1 and b2
made of carbon one end of each brush is
in contact with the rotating slip rings
and the other end is connected to an
external circuit here the brushes are
connected to a galvanometer observe that
the brushes do not rotate with the coil
working as he armature rotates about an
axis perpendicular to the magnetic field
it keeps on changing its relative
orientation with respect to the field
thus the flux keeps on changing
continuously with time this change in
magnetic flux induces an EMF if the
outer terminals of the armature are
connected to an external circuit an
electric current flows through it the
deflection of the galvanometer needle
indicates that an EMF is induced
graphical representation observe the
plot and the movement of the coil to
understand the sinusoidal nature of the
induced EMF
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time to explore explore and learn the
workings of an AC generator play around
with the frequency and the direction
observe the deflection of the
galvanometer needle and the change in
the nature of the graph this will help
you understand the workings of an AC
generator
assessment here is an exercise to assess
your comprehension the questions will
appear one at a time on the screen to
keep your score valid refrain as far as
possible from wild guessing
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