Electrical Engineering ⇒ Topic : Series Magnetic Circuits

Series Magnetic Circuits

In a series magnetic circuit, the same flux (Φ) flows through each part of the circuit. It can just be compared to a series electric circuit which carries the same current throughout.

Consider a *composite series magnetic circuit consisting of three different magnetic materials of different relative permeabilities along with an air gap as shown in Fig.(a). Each part of this series magnetic circuit will offer reluctance to the magnetic flux (Φ). The reluctance offered by each part will depend upon dimensions and μ_r of that part. Since the different parts of the circuit are in series, the total reluctance is equal to the sum of reluctances of individual parts, i.e.

                                                                   figure (a)

Hence the total ampere-turns required for a series magnetic circuit can be found as under :

(1) Find H for each part of the series magnetic circuit. For air, H = B/μ₀ whereas for magnetic material, H = B/μ₀μ_r

(2) Find the mean length (l) of magnetic path for each part of the circuit.

(3) Find AT required for each part of the magnetic circuit using the relation, AT = H x I.

(4) The total AT required for the entire series circuit is equal to the sum of AT for various parts.