Explain the underline principle on which it works.
Answers
Answer:
In an electric generator, mechanical energy is used to rotate a conductor in a magnetic field to produce electricity. It is working on the principle of electromagnetic induction.
Working:
When the axle attached to the two rings is rotated such that the arm
AB
moves up (and the arm
CD
moves down) in the magnetic field produced by the permanent magnet. Let us say the coil
ABCD
is rotated clockwise in the arrangement. By applying Fleming’s right hand rule, the induced currents are set up in these arms along the directions
AB
and
CD
. Thus an induced current flows in the direction
ABCD
. If there are larger number of turns in the coil, the current generated in each turn adds up to give a large current through the coil. This means that the current in the external circuit flows from
B
2
and
B
1
.
After half a rotation, arm
CD
starts moving up and
AB
moving down. As a result, the directions of the induced currents in both the arms changes, giving rise to the net induced current in the direction
DCBA
. The current in the external circuit now flows from
B
1
to
B
2
. Thus after every half rotation the polarity of the current in the respective arms changes.
There are two brushes and in the electric generator, one brush is at all times in contact with the arm moving up in the field, while the other is in contact with the arm moving down. Because of these Brushes unidirectional current is produced.
Explanation:
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