Electrodynamics

Generators
Background - Electromagnetic Induction

1. If a wire is moved in a magnetic field, a current is induced (created) in the wire.

2. The current exists in the wire only as long as there is relative motion between the wire and the magnet.

3. What happens is that the flux lines linking the conductor with the magnet, changes.
This changing flux is what induces the current in the wire.
3.1. In open circuit, only voltage is induced.
3.2. In a closed circuit, both voltage and current is induced.

4. The rate of change of flux linkage produces an emf(electromagnetic force) in the wire.

5. Faradays Law
Faradays Law states that “the emf produced is directly proportional to the rate of change of flux”.
In simpler terms, faster movement of the wires creates more current in the wire.

6. Maximum emf is induced when the wire is at right angles to the magnetic field of the magnet.
No current is induced when the wire is parallel to the magnetic field.

7. The direction of the current that is induced can be determined by using Flemings Right Hand Dynamo Rule.

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