Eddy Currents

Eddy Currents

Suppose we replace the conducting loop of with a solid conducting plate. If we then move the plate out of the magnetic field ‘as we did the loop  the relative motion of the field and the conductor again induces a current in the  conductor. Thus, we again encounter an opposing force and must do work because of the induced current. With the plate, however, the conduction electrons making up the induced current do not follow one path as they do with the loop. Instead, the electrons swirl about within the plate as if they were caught in an eddy (or whirlpool) of water. Such a current is called an eddy current and can be represented as in   as if it followed a single path .As with the conducting loop of Fig 31-10, the current induced in the plate results in llIt.chanical energy being dissipated as thermal energy. The dissipation is
more apparent in the arrangement  a conducting plate, free to rotateabout a pivot, is allowed to swing down through a magnetic field like a pendulum. Each time the plate enters and leaves the field. a portion of its mechanical energy is
transferred y. After several swings, no mechanical energy remains and the warmed-up plate just hangs from its pivot.

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