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InterviewSolution
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A core with the shape and dimensions in millimeters shown in Fig. 30.14 has been manufactured of a ferromagnetic material whose magnetization curve is shown in Fig. 29.9a (p. 76). One layer of wire of 0.6 mm diameter (including insulation) was closely wound on the core. Find the inductance of the coil for a current of 200 mA flowing in it. Find the energy of the magnetic field and the energy density. |
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Answer» `w piD//d=80pi//0.6=420` The magnetic FIELD strength is `H=(iw)/(l)-(iw)/(PI D_(m))=(I D)/(dD_(m))` where `D_(m)=120nm` is twice the distance from cho axis of revolution of the torus to the centro of tbo gonorating circle. Knowing the magnetic field strength and making use of the graph of Fig. 20.9a, we find the induction of the field. Applying the FORMULA `w_(m)= BH//2 ` we find the energy density, and multiplying this by the VOLUME of the core we find the total onergy of the magnetic field. The INDUCTANCE is found using the formula `W_(m)-Li^2//2` |
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