Hi, I have been trying to understand eddy current loss in transformer cores but seem to have run into a bit of a misunderstanding with one of the books I have read, and I was wondering if someone could just clarify if I have got this all right.(adsbygoogle = window.adsbygoogle || []).push({});

starting with the beginning, if the magnetic flux varies sinusoidal, then the flux at one instant would be;

∅ = ∅_{m}sin(ωt) (I have been told this should be done in degrees and not radians?)

value of induced emf in core at any time (t) =

[itex]\frac{d∅}{dt}[/itex] = ω∅_{m}cos(ωt)

Am I correct in saying that from this second equation, ωθ_{m}= E_{m}(Max induced EMF in core)?

If E_{s}= rms value of emf induced in core, this = [itex]\frac{1}{\sqrt{2}}[/itex]ω∅_{m}= [itex]\sqrt{2}[/itex]∏f∅_{m}= [itex]\sqrt{2}[/itex]∏f(AB_{m})

Eddy current Power Losses = [itex]\frac{E_{s}^{2}}{R_{s}}[/itex]

= [itex]\frac{2*∏^{2}*f^{2}*A^{2}*B_{m}^{2}}{R_{s}}[/itex]

The next bit is the section of the notes that seems to confuse me,

Eddy current Power Loss = P_{E}= K_{E}*f^{2}*B_{M}^{2}, where K_{E}= Constant = 2*∏^{2}*A^{2}/R_{s}.

The book then says 'hence eddy current losses = α (f^{2}*B_{M}^{2})

Does this mean that K_{E}is the same as α and eddy current power loss is the same as eddy current loss, or are these two different things? As far as I can see they appear the same but I just wanted to make sure from someone who has a bit more experience or knowledge of this.

thanks

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# Eddy current loss help please

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