Question

An electromagnet is constructed of 4% Silicon-iron as shown in Figure 6. current 1 cross sectional area of yoke, S N turns sample: cross sectional area,S thickness, t -effective path length, L Figure 5: Electromagnet Sensing Yoke It has magnetic path length L and yoke cross-sectional area S, in order to apply a magnetic field to a sample of a linear magnetic material with a relative permeability, μ, , of 100, The sample is also of area S and fits precisely between the poles of the electromagnet which have separation t. The B-H curve for Silicon-Iron is provided as an excel file. 1. 2. If L = 200 mm, t = 10 mm, N 500 and I = 0.1 A, what is the magnetic flux density in the 3. How will the inductance of the coil vary if the area of the yoke and sample is doubled? Explain what is meant by fringing associated with the poles of an electromagnet, and indicate qualitatively how it varies with S, t, and u, as defined above. sample? You may assume zero fringing, but state any other approximations made. Also sketch approximately what happens to the inductance of the coil as the d.c. current I is varied between 0 and 1 A. MagWeb Page Electrical-Steel-GO-35ZH135 (2) DC 2.008 0960 8000 B104 0138 036 Fully age inchmm Annealing Electrical Sheel G0 Brand H Am B Tesla Mur Mud ธ160 8160 0010 0171 0171 020 10523 15112 035 13073 19368 0066 16455 23281 0 099 18910 20953 0148 21609 30239 203 23820 33537 263 26728 44411 0 324 29624 55093 10 0485 37329 78900 11 0.540 39531 81602 11 0580 41480 89129 12 0.643 43457 92800 12 0682 44807 91770 35ZH135 60000 2.0 000o 40000 Mu-H Curve 30000 1.0 20000 0784 47893 8824 0.5 15 0 951 51534 80342 15 1.002 52204 68752 16 1062 52854 66878 10000 17 1.164 53241 57604 0.0 10 100 10000 18 1220 53003 48444 18 1271 5189S 34678 21 1.316 51067 35243 22 1370 45807 23343 25 1427 45864 18020 3844 14937 Magnetic Field Intensity, H Alm 40054 11656 34 1552 36369 8818 4 1.608 31420 6532 88 1.706 20481 3067 83 1754 15086 1428 154 1803 ได301637 257 1.842 5484 276 499 1.86 3009 149 52 1.925 1610 70 1944 1 965 8052 440 1 909 358 11 721 2.008 164

Answer 1

Sblution: Given that: net tans 77 Samph cros Sectional area thrckrm t n the Jiven qure an aur neath pok ard the bottow Sufoa like a South) Sct curved Colind卡irgirg effect obviously the effet+ ณุ tnging will be moti ir the air gap apmciabb the. g mor e alr gap in shor t e make nsi fy in end over an avea uhith great,than the CoTe sethra asca (s)

paci'cal magrthic eacuit, t ththneu ave much Small, ffect Given that kue knouw: l) 500 x D-) g 825 x 10 2246, 288 952 mm

T A rcct alro varj (doubled) from gro