AC generator and Faraday_s law 12 Grade.pptx

Physics Magnetism and Electricity - Faraday's Law

1. AC generators basics

2. Flemings Right Hand Rule The generator effect describes what happens when a conductor is moved in a magnetic field. A emf is induced across the ends of the conductor. If the circuit is completed, an induced current flows in it.

3. The AC Generator An electric generator converts mechanical energy into electric energy. The three main components are: - a field magnet - an armature - slip rings with brushes If the armature is rotating with a constant angular velocity in a constant magnetic field, the magnitude of the induced emf and current varies sinusoidally with respect to time.

4. Cutting magnetic flux Describe the induced emf at each stage

5. Sinusoidal Output

6. Induced Voltage: CRO

7. Quiz: Name the parts of an AC generator Describe the slip rings and their functions Describe carbon brushes and their functions

8. Faraday’s Law and AC Faraday’s Law: Moving a conductor through magnetic flux lines causes an emf to be induced in the conductor. Relative motion between a conductor and a magnetic field induces an emf in the conductor. The direction of the induced emf depends on the direction of motion of the conductor with respect to the field. The magnitude of the emf is directly proportional to the rate at which magnetic flux lines are cut by the conductor. The magnitude of the emf is directly proportional to the number of turns of the conductor crossing the flux lines.

9. Lenz’s Laws Lenz’s Law states that an induced current is always produced in a direction such that the magnetic field resulting from the induced current opposes the change in the magnetic field that is causing the induced current