On 8/25/16 8:12 PM, Bill Metzenthen wrote:
On 26/08/16 08:14, Hal Murray wrote:
billm...@gmail.com said:
If the conductor also has magnetic properties (e.g. if iron were
used) then
magnetic saturation could be an issue.
Ah... Sorry I wasn't clear. How about
Is skin depth an interesting concept if you are using materials
commonly used
for magnetic shielding, for example mu-metal?
The electrical conduction is poor so the normal skin depth reasoning
probably
won't be useful in practical examples.
For skin depth, the lower conductivity of mu-metal is more than
compensated for by its higher permeability. At 50 Hz its skin depth is
calculated to be around 0.3 mm assuming that the conductivity and
permeability are real (as distinct from complex) and everything is
linear. I haven't needed to consider what happens when these
assumptions aren't valid so I could only guess how rapidly the skin
depth increases when a magnetic material such as mu-metal is pushed past
its linear region.
The usual skin depth calculation is based upon assumptions about the
form of the electromagnetic field and the conductor, which might not
apply to the situation in which one is interested. Despite this, it is
often used to get an estimate which is useful in a range of applications.
it's all about sqrt( rho/mu)... good conductivity and high mu are what
you want. soft iron works well... heck, steel works well for a lot of
applications.
Mu metal (which as others have noted has all sorts of handling and
fabrication issues) is for the more exotic cases..
But, could you not run a differential pair of fibers, and both would be
affected, but with opposite signs....
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