Explain the underlying principle and working of an electric generator by drawing a labelled diagram. What is the function of brushes?

Dear student


Principle:An electric generator works on the principle of electromagnetic induction. When a coil is rotated between the magnet or when the magnet is rotated in and out of the coil the current is induced in the coil and the direction of current is given by Fleming’s right hand rule.

Working:As shown in the figure, when the axle attached to the two rings is rotated such that arm AB moves up and arm CD moves down in the magnetic field produced by the permanent magnet i.e. ABCD rotates clockwise. By Fleming’s right hand rule, the induced currents are set up in these arms and flows in the direction ABCD, which flows from B2 to B.
After half a rotation, arm CD starts moving up and AB moves down. As the directions of the induced currents in both the arms change current is induced in direction DCBA, which further flows from Bl to B2 externally. After every half rotation the polarity of the current in arms changes. Such current which changes direction after equal intervals of time is called an alternating current (AC).

Brushes:are used to transmit current induced externally from coil ABCD to the external circuit.


Thanks