17:
588:, the required volume of magnet to achieve a target flux density in the air gap is minimized. This expression assumes that the permeability in the core that is connecting the magnetic material to the air gap is infinite, so unlike the equation might imply, you cannot get arbitrarily large flux density in the air gap by decreasing the gap distance. A real core will eventually saturate.
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Equivalently, it can be graphically defined as the area of the largest rectangle that can be drawn between the origin and the saturation demagnetization B-H curve (see figure).
542:{\displaystyle E_{\rm {gap}}={\frac {1}{2\mu _{0}}}(B_{\rm {gap}})^{2}{\rm {Vol}}_{\rm {gap}}=-{\frac {1}{2}}B_{\rm {mag}}H_{\rm {mag}}{\rm {Vol}}_{\rm {mag}}=-E_{\rm {mag}},}
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108:); these quantities are also determined from the saturation loop and are related to the maximum energy product, though not directly.
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During the 20th century, the maximum energy product of commercially available magnetic materials rose from around 1 MGOe (e.g. in
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thus in order to achieve the desired magnetic field in the gap, the required volume of magnet can be minimized by maximizing
618:"What is Maximum Energy Product / BHmax and How Does It Correspond to Magnet Grade? | Dura Magnetics USA"
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in the gap (volume-integrated magnetic energy density) is directly equal to half the volume-integrated
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is that the volume of magnet necessary for any given application tends to be inversely proportional to
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can be graphically defined as the area of the largest rectangle that can drawn in the second
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Historical trends in the maximum energy product of permanent magnets (MGOe units).
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fields are in opposition. It is defined as the maximal value of the product of
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eFunda: Glossary: Units: Energy
Density Units: Megagauss-Oersted (MG⋅Oe)
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along this curve (actually, the maximum of the negative of the product,
243:{\displaystyle (BH)_{\rm {max}}\equiv \operatorname {max} (-B\cdot H).}
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in the magnet. By choosing a magnetic material with a high
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51:(kilojoules per cubic meter, in SI electromagnetism) or
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is an important figure-of-merit for the strength of a
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690:Umans, Stephen D. (2014). "1.5 Permanent Magnets".
138:The maximum energy product is defined based on the
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674:"COBALT: Essential to High Performance Magnetics"
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150:curve), in the demagnetizing portion where the
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278:. This is illustrated by considering a simple
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309:in the gap. In such a situation, the total
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696:(7th ed.). McGraw-Hill. p. 33.
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646:. Retrieved
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622:. Retrieved
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598:Tetrataenite
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577:is equal to
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718:Categories
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624:2020-01-20
604:References
97:coercivity
729:Magnetism
516:−
436:−
362:μ
229:⋅
223:−
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211:≡
84:remanence
26:magnetics
592:See also
132:quadrant
76:KS Steel
61:oersted
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55:(mega-
28:, the
677:(PDF)
63:, in
57:gauss
698:ISBN
162:and
154:and
53:MGOe
49:kJ/m
585:max
567:max
306:gap
293:gap
291:Vol
286:mag
284:Vol
275:max
264:max
214:max
127:max
44:max
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