In this topic, you study Magnetic Reluctance – Definition & Theory.
Reluctance is the resistance offered by the material to the passage of magnetic flux through it and corresponds to resistance in the electric circuit.
Reluctance is directly proportional to the length of the magnetic circuit (l) and inversely proportional to its cross-sectional area (a) and the relative permeability (gr). It is given by the expression:
Reluctance, S
amperes / weber
where ‘l’ is in metres and ‘a’ is in square metres. From the Equation (416), it is obvious that
M.M.F.
Reluctance, S —
Since m.m.f. is measured in amperes and flux in webers, the unit for reluctance is ampere per weber (A / Wb).
What are the factors which effects the magnetic reluctance?
The magnetic reluctance depends upon the following factors:
(i) The reluctance is directly proportional to the length of the flux path.
(ii) The reluctance is inversely proportional to the area of a crosssection of the flux path.
Here constant of proportionality, i.e.,
Permeability for free space and
relative permeability of any medium.
