n.
A measure of the ability of a magnetic circuit to conduct magnetic flux; the reciprocal of reluctance.
[From Latin permeāre, to penetrate. See permeate.]
permeance
| Dictionary: per·me·ance |
(pûr'mē-əns)
n.
A measure of the ability of a magnetic circuit to conduct magnetic flux; the reciprocal of reluctance.
n.
A measure of the ability of a magnetic circuit to conduct magnetic flux; the reciprocal of reluctance.
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| Architecture: permeance |
A measure of a material’s resistance to water-vapor transmission, expressed in perms. Equal to the ratio of (a) the rate of water vapor transmission through a material or assembly between its two parallel surfaces to (b) the vapor pressure differential between the surfaces.
| Wikipedia: Permeance |
Permeance, in general, is the degree to which a material admits a flow of matter or energy.
Contents |
Electromagnetism
In Electromagnetic theory, permeance is the inverse of reluctance. Permeance is a measure of the quantity of flux for a number of current-turns in magnetic circuit. A magnetic circuit almost acts as though the flux is 'conducted', therefore permeance is larger for large cross sections of a material and smaller for longer lengths. This concept is analogous to that of electrical conductance.
Measuring Permeance
The equation for permeance is definitely:
Where:
Λ=Permeance
Φ=Flux
NI=Current-turns (current x number of coils)
Alternatively, similar to the equation for electric conductance:
Where:
Λ=Permeance
μ=Permeability of Material
A=Cross Sectional Area
l=Length of Circuit
Units of Permeance
The SI unit of permeance is 'webers per ampere-turn' given as Wb A-1.
Materials science
In Materials science, permeance is the degree to which a material transmits another substance.
See also
External articles and references
- Electromagnetism
- Properties of Magnetic Materials (units of magnetic permeance)
- Material science
- Bombaru, D., Jutras, R., and Patenaude, A., "Air Permeance of Building Materials". Summary report prepared by, AIR-INS Inc. for Canada Mortgage and Housing Corporation, Ottawa, 1988.
- Don Mills, "The Details of Air Barrier Systems for Houses". Ontario New Home Warranty Program, 1993.
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 | Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved. Read more |
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| Architecture. McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc. All rights reserved. Read more |
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| Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Permeance". Read more |
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Answer these
- What is air permeance?
- Which of the following best describes permeance?
- Why does permeance and inductance hav the same unit henry?
Mentioned in
- vapor resistance
- permeability
- perm
- henry (electromagnetic inductance, magnetic permeance)
- Air conditioning (mechanical engineering)
- Perm (unit)
- Perm (disambiguation)
- Magnetic capacitivity
- Oxygen transmission rate
- Magnetic reluctance
- Inductance
- Greek letters used in mathematics, science, and engineering
