Reciprocal of reluctance is

Question

Examoogle · Accepted Answer

Permeance

Explanation: Reluctance ($S$ or $\mathcal{R}$) is the opposition offered by a magnetic circuit to the establishment of magnetic flux. Permeance ($P$) is defined as the reciprocal of reluctance and represents the ease with which magnetic flux can be established in a magnetic circuit, analogous to conductance in an electric circuit.

Working Principle: In a magnetic circuit, the magnetic flux $\Phi$ is given by $\Phi = \frac{MMF}{\mathcal{R}}$, where $MMF$ is the Magnetomotive Force. Since $\mathcal{R} = \frac{1}{P}$, the relationship can be expressed as $\Phi = MMF 	imes P$. This shows that permeance acts as a measure of the magnetic conductivity of the flux path.

Key Formulas: $\mathcal{R} = \frac{l}{\mu A}$ — Formula for Reluctance; $P = \frac{1}{\mathcal{R}} = \frac{\mu A}{l}$ — Formula for Permeance

Key Points: Reluctance is analogous to electrical resistance.; Permeance is analogous to electrical conductance.; SI unit of Reluctance is $AT/Wb$ (Ampere-turns per Weber).; SI unit of Permeance is $H$ (Henry) or $Wb/AT$.

Advantages: Simplifies calculation of magnetic flux in series-parallel magnetic circuits.; Allows use of electrical network theorems (like superposition) for magnetic circuits.

Disadvantages: Requires knowledge of permeability ($\mu$), which varies with magnetic flux density due to saturation.; Linear assumption often fails in highly non-linear ferromagnetic materials.

Applications: Design of electric motors and generators.; Modeling of transformer magnetic cores.; Magnetic circuit analysis in relays and actuators.

Additional Info: Reluctivity is the reciprocal of permeability ($\nu = 1/\mu$).. Susceptibility ($\chi_m$) measures the degree of magnetization of a material in response to an applied magnetic field.. Permeability ($\mu$) represents the capability of a material to support the formation of a magnetic field.

Answer: C is correct — Permeance is the reciprocal of reluctance, representing the ease of magnetic flux flow.

Exam Tip: Always remember the duality: Resistance corresponds to Reluctance, and Conductance corresponds to Permeance.

Related Questions

Discussion (0)