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Electric generators and motors

An electric current flowing in a wire produces a magnetic field around the wire. Electricity and magnetism are so closely linked that one can produce the other. An electric current flowing in a cable produces a magnetic field around the cable. A magnetic field moving near a wire causes electricity to flow along the wire. Electromagnetism is the basis of how both generators and electric motors work.



├śrsted demonstrates his discovery that a magnetic compass needle is deflected by an electric current flowing through a wire.

Electromagnetism

In 1820, the Danish scientist Hans Christian Ørsted (1777–1851) observed that when he passed an electric current through a wire, a magnetic compass needle nearby was slightly deflected. He realised that the electric current had produced magnetism: he had discovered electromagnetism.

To work out the direction of motion in an electric motor, use Fleming's left hand rule. Raise your left thumb, point straight ahead with your first finger (index finger) while using your second finger to point at right angles to that. The thuMb indicates Motion; the First finger indicates the direction of the magnetic Field; the seCond finger indicates the direction of the electrical Current.  

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