Magnetische demping

Consider a metallic plate fixed to one end swinging freely about its mean position, placed between two electromagnets.

When there is no magnetic field, the plate keeps oscillating. Once the electromagnets are turned on, the plate slows down and stops quickly.

This reduction in motion without any physical contact is called magnetic damping, caused by the opposing nature of eddy currents.

Now swing the plate again to understand this mechanism.

When the plate enters the magnetic field, the magnetic flux on the plate changes.

As per Faraday's law, eddy currents are induced in the plate, and according to Lenz's law, their direction is anticlockwise. So, the plate experiences a magnetic force that opposes its motion.

Similarly, when the plate goes out of the magnetic field, magnetic flux decreases, and eddy currents are induced in the clockwise direction.

As a result, the plate again experiences a magnetic force that opposes its exit from the magnetic field.

So, as a combined effect, the oscillations of the metallic plate are quickly damped.