The cast iron of Figure 12-49 measures 1cm x 1.5cm, lg=0.3mm, the air-gap flux density is 0.426T, and N=600 turns. The end pieces are half circle. Taking into account fringing, find current I.
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magnetic circuit?
2016-08-06 2:22 pm
回答 (1)
2016-08-08 8:07 am
✔ 最佳答案
Magnetic field strength (H) in air gap = 0.426/(uo) A/mwhere uo is the permeability of free space (= 4.pi x 10^-7 H/m)
hence, H = 3.39 x 10^5 A/m
Total magnetic path
= (3.2 + pi x 2) x 2 cm = 9.483 cm = 0.09483 m
Because H is the same in the air gap and in the iron core, by Ampere's law,
H.(0.09483) = 600(I)
where I is the current in the coil.
Thus, I = (3.39 x 10^5) x (0.09483)/600 A = 53.6 A
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