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Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
Hi, I came across a formula for eddy current losses in thin sheets or wires, at [Strength of eddy currents]. They say the formula is simplified for no skin effect influence. When there is a skin effect, will the losses be lower or higher? Do you think I can multiply the answer by the DC to AC resistance ratio of the conductor, as calculated eg. by JAVATC to get closer to the real world value?
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
Hmm, but the current path no longer represents a conductor with its diameter equivalent to the skin depth, but rather a hollow tube where the currents can flow a larger diameter than the skin depth - if I get this right...
Registered Member #2099
Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1716
You can't really separate eddy currents from skin effect. As the Wikipedia artice cited in OP says: Self-induced eddy currents are responsible for the skin effect in conductors
[edit] Anyone here got time & inclination to study that formula in the Wiki article, "eddy current loss without skin effect", and figure how it is derived?
I will guess that in the case of, say, steel core laminations much thicker than the skin depth, the per-pound losses will be lower than those calculated by the f^2 formula. In fact will agree with Steve C, that they will (in the limit) go up as f^1.5.
Dr.DC: can you give us the specific application of interest? For more detailed, more distracting study? Note that skin effect theory seems to invariably use a linear model, while the magnetization of transformer steel is extremely nonlinear in ordinary operation.
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
klugesmith: It is for the calculation of eddy current losses in a Tesla coil secondary with single layer solenoid primary and secondary coils. The primary induces a high frequency magnetic field B, which induces eddy currents in the copper wire of the secondary winding. The purpose is to calculate the eddy losses per cm2 of the secondary winding with sufficient accuracy. This is just for the calculation of eddy current losses alone, not the IIR losses in the wire from the actual winding current passing through it.
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
Hmm. I think this is better analysed in terms of proximity effect and skin effect, than by using the eddy current loss formula. Could be a job for FEMM.
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The influence of skin effect on eddy current losses
