Center limb: [ \mathcalR_c = \frac0.1(4\pi\times 10^-7)(1000)(6\times 10^-4) \approx 132.6 \ \textkA-t/Wb ] Each outer limb: [ \mathcalR_o = \frac0.2(4\pi\times 10^-7)(1000)(3\times 10^-4) \approx 530.5 \ \textkA-t/Wb ] Yoke (each, two yokes in series effectively for each flux path): [ \mathcalR y = \frac0.05(4\pi\times 10^-7)(1000)(6\times 10^-4) \approx 66.3 \ \textkA-t/Wb ] Total for one outer path (center → yoke → outer limb → yoke → center): [ \mathcalR outer, total = \mathcalR_c + 2\mathcalR_y + \mathcalR_o ] [ = 132.6 + 2(66.3) + 530.5 = 795.7 \ \textkA-t/Wb ] But careful: The two outer paths are after the center limb.
Let’s find gap length that gives (\mathcalR total = 312.5\ \textkA-t/Wb): [ \mathcalR g = \mathcalR total - \mathcalR iron = 312.5 - 497.4 = -184.9 \ \text(negative → impossible) ] Conclusion: The core is saturating or the permeability has dropped. A better problem would give (\Phi_healthy) first. magnetic circuits problems and solutions pdf
Given: Core length (l_c = 0.15 \ \textm), area (A = 4 \ \textcm^2), (\mu_r = 600) (still valid). What is the effective air gap length that explains the reduced flux? (Ignore fringing first, then discuss if fringing would make the gap larger or smaller.) 3. Complete Solutions Solution 1 – Toroidal Core (a) Reluctance of core: [ \mathcalR_c = \fracl_c\mu_0 \mu_r A = \frac0.4(4\pi \times 10^-7)(800)(5\times 10^-4) ] [ \mathcalR_c = \frac0.4(1.0053 \times 10^-3) \approx 398 \ \textkA-turns/Wb ] Center limb: [ \mathcalR_c = \frac0