# Transformer frequency contradiction on induction heating

The Skin Effect is when the current flows preferentially on the outside of a conductor, due to the fact that the current flows more easily on a smooth surface.

TL;DR Summary
Help solve tangled transformer freq contradiction over induction heating
As a transformer freq bet higher, inside induction get more efficient i.e. less loss:

1. Hysteresis loss = η * Bmax^n * f * V.
2. Eddy current loss( proportional to B2mf2Bm2f2 )

Now it seems that losses increases with increase in efficiency...
But the above equations are valid when max flux density Bmax remains constant.

The gist is that when increasing the frequency flux density does not remain constant, it actually decreases with increase in frequency, as

V = 4.44 . Bmax . A . f . Tp

Now how is it on Induction_heating, as it's read more, the more contradiction is to above

Yeah, seems counter intuitive doesn't it?

But it sounds like the Skin Effect is the important missing element here.

For DC and a solid conductor, current flow is evenly distributed throughout the cross section.

For AC, the current tends to concentrate towards the outer surface of the conductor. The higher the frequency, the thinner this conductive layer is, and the thinner the layer the higher the resistance.

For more details see:
https://en.wikipedia.org/wiki/Induction_heating

Cheers,
Tom

TL;DR Summary: Help solve tangled transformer freq contradiction over induction heating

As a transformer freq bet higher, inside induction get more efficient i.e. less loss:

1. Hysteresis loss = η * Bmax^n * f * V.
2. Eddy current loss( proportional to B2mf2Bm2f2 )

Now it seems that losses increases with increase in efficiency...
But the above equations are valid when max flux density Bmax remains constant.
Can you please post a reference for your equations? And the 2nd equation is pretty unreadable, IMO. Please learn to post equations using LaTeX (see the LaTeX Guide link below the Edit box). Thank you.