Measuring the permeability of metallic objects


by daudaudaudau
Tags: measuring, metallic, objects, permeability
daudaudaudau
daudaudaudau is offline
#1
Jan7-13, 10:31 AM
P: 296
Hello everyone. I'm working on a project where I have to do a finite element simulation of low frequency magnetic coupling. But my problem is that I don't know the permeability of all the objects involved. Can anyone suggest a good way to measure the permeability of these objects ? The objects are quite irregularly shaped, i.e. not spheres or boxes or cylinders.

I have one idea myself. I could make a coil of sufficient size and then put the object inside this coil, and measure the inductance. Then I could set up an identical finite element simulation and then adjust the permeability of the object until I get the same results as in the measurement.
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Simon Bridge
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#2
Jan7-13, 06:12 PM
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That is pretty much what you do all right. That way the geometry considerations should take care of themselves.
http://www.physicsforums.com/showthread.php?t=596013
Enthalpy
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#3
Jan11-13, 12:38 PM
P: 660
Permeability of materials is normally measured on purposely-made toroidal cores, to get sensible values.

In normal life, if these objects are undesired, they have unit of infinite permeability. Often accurate enough, because air gaps rather than metals determine the flux. Or take 1000, then 10000, and observe no difference.

If the field is intense enough, saturation can be more important than permeability. Uncommon with separated objects.


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