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Electrodynamics

Generators, motors, alternating current

Electrodynamics

A generator converts mechanical energy to electrical energy using electromagnetic induction. A motor converts electrical to mechanical energy. AC alternates direction; DC flows in one direction. Eskom generators use the AC generator principle.
Example

Generators and Motors

AC generator: a coil rotates in a magnetic field, inducing alternating EMF. DC motor: current-carrying coil in a magnetic field experiences a force. A split-ring commutator reverses current each half-turn to maintain rotation.
Note

Exam Tip

Know differences between AC and DC generators (slip rings vs split-ring commutator). V_rms = V_max/sqrt(2). Average power: P = V_rms x I_rms.

Key Vocabulary

Electromagnetic inductionGenerating an EMF by changing magnetic flux through a conductor
GeneratorA device that converts mechanical energy to electrical energy
Alternating currentElectric current that periodically reverses direction

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Electromagnetic induction
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