Why Use Silicon Steel Sheets

Suppose that the magnetic induction strength in an iron core is B, the induced potential generated by Faraday's induction law is E, and the eddy current loss generated is, where R is the resistance of the iron core.

If according to the following figure, in the direction of the vertical magnetic field, the iron core is divided into N pieces, and the electrical insulation is carried out between each piece, then the area of each piece is 1 / N, and the induced potential generated is E/N. Along the eddy current direction, the cross-sectional area of each piece of iron core is reduced to 1 / N of the original, so according to the resistance formula, the resistance of each piece increases to N times of the original (ignoring the change in length).

Then the eddy current loss per piece of core is:

The total loss of N core is:

Therefore, the thinner the core is divided, the more the number of pieces, the more obvious the suppression effect of eddy current loss.

Of course, affected by the manufacturing process, the thickness of the silicon steel sheet cannot be infinitely thinner.