Reluctance

Magnetic reluctance is the resistance of a material to a magnetic field. It is defined as the ratio of magnetomotive force to magnetic flux. The term was coined in May 1888 by Oliver Heaviside.

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The definition can be expressed as:

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:S=rac{F}{Phi}

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where

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:S is the reluctance in ampere-turns per weber (a unit that is equivalent to turns per henry)

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:F is the magnetomotive force in ampere-turns

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:Φ is the magnetic flux in weber

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The reluctance of a uniform magnetic circuit can be calculated as:

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:S = rac{l}{mu_0 mu_r A}

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where

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:l is the length of the circuit in metres

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:mu_0 is the permeability of free space, equal to 4 pi imes 10^{-7} henry per metre

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:mu_r is the relative magnetic permeability of the material (dimensionless)

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:A is the cross-sectional area of the circuit in square metres

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The inverse of reluctance is called permeance.

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Magnetic field: :For other senses of this term, see magnetic field (disambiguation)....

Magnetomotive force: In physics, the magnetomotive force produces magnetic flux. It is measured in units of ampere-turns....

Magnetic flux: Magnetic flux, is a measure of quantity of magnetism, taking account of the strength and the extent of a magnetic field. The flux through an element of area perpendicular to the direction of magnetic field is given by the product of the magnetic field density and the area element. More generally, ma...

Reluctance related Images and Photos (experimental)

Lady Jane Greys Reluctance to Accept the Crown Pictured Here with Lord Guildford Dudley Her Husband