magnetic loss due to metal nearby

Hi

When metal plate is brought near the inductor. there is magnetic loss and hence inductance value...

I am unable to understand how eddy current generated in metal plate will cause magnetic loss in coil....
Can you please elaborate this mechanism...

In this system there is 3 types of loss:

1. Eddy current loss
2. Hysteresis loss
3. Residual loss

The current circulating in the metal plate will cause joule heat loss and this is called eddy current loss.

The magnetic field inside the metal plate does not return to its original state. The internal field lags behind the external field. This behaviour results in a loss of energy called hysteresis loss.

The residual loss = Total loss - (Eddy current loss + Hysteresis loss)

But you might talk about the fact that the magnetic field produced by the eddy current in the metal plate will acts against the original magnetic field generate by the loop (Lenz's law). This results in a decrease of the overall magnetic field of the system (small cancellation) and thus in a change of the inductance value of the loop (L = Total flux through the loop/Current in the loop).