- Jan 1, 1970
You can of course apply the Litz trick to foil, but you don't have any
free lunch; the geometry reduction is still required whether putting
together a bunch of strips or strands. Ten strips woven together will
have less resistance than a single strip of the same width and
thickness, but higher than 1/10th of an isolated strip that size. I
know of at least one company that claims to have some sort of foil
technology that reduces Rac like Litz, presumably doing some kind of
weave. Tempting to buy a bigass custom part from them just to take it
apart and look, see how they put the stuff together. I can't imagine
it's all that easy to make, considering there are only two US companies
making the round stuff as is.
Somewhere there is an IEEE paper [I think] showing how multistranded cable
is a 'poor' man's Litz wire. The better performance of multistrand versus
solid is attributed to the poor 'cross-conductivity' between strands. It
seems the stranding vectorizes the conductivity. From memory they
presented data comparing losses between solid and stranded with the same
copper cross section.
Very interesting article, because I had always thought that solid versus
stranded didn't matter much. But, the paper is good news since it's easier
to wrap 10 strands of 18 Awg than a single strand of 8Awg. The only
'overhead' appears to be similar to stacking factor - in that you can't
completely fill the winding area.