Magnetic Reluctance

What is Magnetic Reluctance ?

What is Reluctance?

Reluactance Term used in Magnetic circuit and It is defined as the ratio of magnetomotive force (mmf) to magnetic flux. it represnts oppostion in a magnetic circuit to the prodcution/induced of magnetic flux. In other terms we can say it is the property of material that opposses the creation of magnetic flux in the magnetic circuit.

Magnetic Reluctance

Difference Between Reluctance and Resistance .

In an electrical circuit, the resistance opposes the flow of current in the circuit and it dissipates the electric energy. The magnetic reluctance in a magnetic circuit is analogous to the resistance in an electric circuit as it opposes the production of magnetic flux in a magnetic circuit but it does not give rise to the dissipation of energy rather it stores magnetic energy.

Reluctance is directly proportional to length of magnetic circuit and inversely proportional to to the area of cross section of magnetic path.

Reluctance formula

Reluctanc is scator quantity and it is donated by symble “S”. and measured in AT/weber (Henry).

Formula can be termed as

\begin{align*} S = \frac {l}{\mu_0 \mu_r A} \end{align*}



l = length of the magnetic path in meters

\mu_0 = permeability of free space (vacuum) = 4 \pi * 10^-^7 Henry/meter

\mu_r = relative permeability of a magnetic material

“Now Understand the terms used”

What is Permeability?

The permeability or magnetic permeability is defined as the ability of a material to allow the magnetic lines of force to pass through it. It helps the development of the magnetic field in a magnetic circuit.

Relative Permeability

Relative Permeability is defined as the degree to which the material is a better conductor of magnetic flux as compared to free space.

A = Cross sectional area in square meters (m^2)

When mmf and magnetic flux in the circuit

If mmf (NI) produced and magnetic flux (Φ) flowing in the magnetic circuit are the known quantities, then the reluctance of the magnetic circuit can be given as,

\begin{align*} Relectance (S) = \frac {m.m.f}{flux} NI = \frac {F}{\phi} \end{align*}


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