Question

An iron core shaped as a tore number of turns mean `R = 250 mm`. The supports a winding with the total number of turns `N = 1000`. The core has a cross-cut of width `b = 1.00 mm`. With a current `I = 0.85` A flowing through the winding, the magnetic induction in the gap is equal to `B = 0.75 T`. Assuming the scarttering of the magnetic flux at the grap edges to be negligible, find the permeaiility of iron under these conditions.

Answer 1

Here, `oint vec(H).d.vec(l) = N I` or, `H(2pi R) + (Bb)/(mu_(0)) = N I`, so, `H = (N I mu_(0) - Bb)/(2pi R mu_(0))`
Hence, `mu = (B)/(mu_(0) H) = (2pi R B)/(mu_(0) N I - B b) = 3700`