Motional emf and Magnetic Damping

Motional emf and Magnetic Damping

By Rachel Wampler

Motional emf

Motional emf

Motional emf

• It takes force to move the rod.

• Once the electrons are moving in the rod, there is another force. The moving electrons in a B-field create a magnetic force on the rod itself.

• According to the RHR, the force is opposite the motion of the rod. If there were no force pushing the rod, it would stop.​

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Magnetic Damping

• When a conductor moves into (or out of) a magnetic field, an eddy current is created in the conductor.

• As the conductor moves into the B-field, the flux increases.

• This produces a current by Faraday's Law and is directed in way that opposes change in flux.

• This current's B-field causes a force on the conductor.

• The direction of the force will be opposite the motion ​of the conductor.

Magnetic Damping

Applications of Magnetic Damping

• Stopping a balance from moving.

• Brakes in a train/rollercoaster

  • No actual sliding parts, not effected by rain, smoother stopping

  • Since based on speed, need conventional brakes to bring to a full stop.

• Sorting recyclables

  • Metallic objects move slower down ramp​

Applications of Magnetic Damping

• Metal detectors

  • Primary coil has AC current

  • This induces current in metal

  • The induced current creates a B-field

  • This induced B-field creates current in secondary coil which sends signal to user.