Re: double wound secondary (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

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Date: Tue, 02 Oct 2007 07:32:25 -0700
From: Ed Phillips <evp@xxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: double wound secondary (fwd)

Gary Weaver has posted several times (and I have built)
a "multiple layer" coil that is not specifically a bifilar wound
coil.  Wind one layer _close wound_ then wind another
layer on top of and in "groves" between adjacent turns
of lower winding layer.

By careful arrangement of individual wire entrance and
exit into windings, maximum winding error of only ± 1 turn
(much less is practical) will occur.

I have wound such a coil with two layers, and have noticed
a MUCH higher Q then a typical "bifilar" wound coil. 
Inductance is ~4X higher to boot.  In this case, it is equivalent
of two coils close wound in parallel, R would approach
R/2 (proximity effects will make it larger, but still significantly
less R then a single winding coil). "

	A problem I can see with this method [beside the extra difficulty in winding] is that there is more contact between adjacent turms with resulting problem of sparking between them.  Same effect as getting two turns "crossed over" in a single layer winding.  Sorry but the 4X inductance CAN'T be true if the two windings are IN PARALLEL.  True and only true if they were in SERIES. 

Ed