FIGURE 1 Representative hysteresis loops for (a) low-loss material and (b) high-loss material.

Eddy currents are generated within a conducing material whenever the magnetic field changes, as implied by the relation for J in equations (1-3). For design purposes, the power Pe lost due to cyclic eddy-current variations in a flat plate may be estimated from

(1-11)

where δ represents the plate thickness, ƒ is the frequency of the cyclic variation, k is the specific resistance of the material, and C is a dimensional constant.