I read in sci.electronics.design that Keith R. Williams wrote (in ) about 'Help winding my own inductor?', on Sun, 21 Dec 2003:
The name 'Litzendraht' might just be a clue that the original patent is German? And I guess that 1932 is about 30 years too late. Those huge spark and alternator transmitters used very thick wires for their inductors.
Perhaps. I was simply doing a search in the Delphion database and filtered it back as far as the patent I referenced above. That pretty much covered the interesting issues of such cable. If there is a prior claim, I can't find it. A German name isn't evidence of German origins.
I have seen the definition of inductance as flux times area per current (1 henry =3D (1 tesla * meter^2)/amp)) but this gives my mind a snag. Perhaps you can straighten me out.
Lets say you have a large toroid core of infinite permeability with a small air gap sawed through it, and 1 turn through the hole. I measure the inductance and find x henries. So at 1 ampere, I have 1/2 x joules stored in the inductor and in the magnetic field in the air volume of that gap. I then saw the gap to twice as wide and wind a second turn through the hole, and get the same flux passing through this thicker but same area air gap, and still measure x henries. So by 1/2L*I^2 I still have the same energy stored in the inductor and in the air volume in that gap, but there is now twice the original volume of air stressed with the original flux. How can that be the same total amount of magnetic energy?
N^2 has gone up 4 times and l has gone up 4 times, so the energy remains the same. H, B and [phi] doubled due to the two turns, but dropped by a factor of 4 due to the longer air-gap, giving a net halving.
I read in sci.electronics.design that YD wrote (in ) about 'Help winding my own inductor?', on Mon, 22 Dec 2003:
Bunched (untwisted) and purely twisted wires are offered by some suppliers with the incorrect description 'Litz'. At least one supplier, found by Google, lists these as "litz" wires.
I read in sci.electronics.design that R.Legg wrote (in ) about 'Help winding my own inductor?', on Mon, 22 Dec 2003:
There is wave winding and there is progressive wave winding, which is a development of wave winding to make coils which are very long compared with the diameter.
Progressive wave winding works by effectively mounting the waver wire guide on a stock driven by a lead screw, so that the wave slowly creeps along the former. When the desired length is reached, the lead screw rotation reverses.
I didn't find any hits on Google, but I think I know who invented it. If so, there should be a UK and a US patent dated in the early 1950s, probably. Certainly, we had the machine in our model shop in 1958.
Let's stop playing "I'm righer". It's obvious who's got the wisdom that comes from years of experience. You've made your statements. Let the jury of your peers (and we beginners, too) retire in peace to ponder the evidence.
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