Re: double wound secondary (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Thu, 4 Oct 2007 14:41:48 -0700 (PDT)
From: Yurtle Turtle <yurtle_t@xxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: double wound secondary (fwd)

If you check the original post, it states "By careful
arrangement of individual wire entrance and exit into
windings,", which I took to mean they were in fact
series. I assumed the top winding entered the coil
form, then ran to the bottom to start over. Maybe the
original poster can clarify.

Adam

--- Tesla list <tesla@xxxxxxxxxx> wrote:

> 
> ---------- Forwarded message ----------
> Date: Tue, 02 Oct 2007 23:56:40 -0700
> From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: double wound secondary (fwd)
> 
> Yes, I stand corrected and I know better. Not sure
> why I had parallel on 
> the brain. I was wondering who was going to point
> out my horrible 
> mistake after I re-read my own post tonight. Yes
> Gary, exactly correct 
> as you stated. Series will add and if it is tightly
> coupled, it might 
> approach 4X.
> 
>  From a high voltage mechanical standpoint, how does
> one wind a 2 layer 
> series connected Tesla Coil? Somethings not right. I
> think that's why I 
> stated parallel and inversed my inductance
> relationship. The Q threw me 
> as well down this same path.
> 
> Maybe Dave can help state if this is a series
> connected set of windings 
> or if they are two parallel connected windings. If
> they are parallel, 4X 
> is not possible. Should be near the same as a single
> winding.
> 
> Take care,
> Bart
> 
> Tesla list wrote:
> 
> >---------- Forwarded message ----------
> >Date: Wed, 3 Oct 2007 13:50:24 -0400
> >From: "Lau, Gary" <Gary.Lau@xxxxxx>
> >To: Tesla list <tesla@xxxxxxxxxx>
> >Subject: RE: double wound secondary (fwd)
> >
> >No!  Inductors in parallel do not add.  If they are
> tightly coupled and
> >identical in value, the net inductance approaches
> that of a single coil.
> >If the two identical tightly coupled coils are
> wired in SERIES, the net
> >value then approaches 4X the individual value.  If
> the series coils were
> >not coupled, the net value would be 2X.  See
>
>http://en.wikipedia.org/wiki/Series_and_parallel_circuits
> >
> >Gary Lau
> >MA, USA
> >
> >  
> >
> >>From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
> >>To: Tesla list <tesla@xxxxxxxxxx>
> >>Subject: Re: double wound secondary (fwd)
> >>
> >>Hi Dave,
> >>
> >>The Q isn't as neat (in my little book) as the
> inductance. The only
> >>    
> >>
> >way
> >  
> >
> >>possible I can account for this is if the two
> windings at the bottom
> >>    
> >>
> >and
> >  
> >
> >>top are in parallel and very close proximity. We
> know inductors in
> >>parallel add. But, when current is flowing and if
> the two inductors
> >>    
> >>
> >are
> >  
> >
> >>in "that" type of proximity (and position) winding
> for winding, then
> >>    
> >>
> >we
> >  
> >
> >>now have the currents in both inductors doubling
> up on the flux (the
> >>density is double on both windings). This would
> certainly result in a
> >>    
> >>
> >4x
> >  
> >
> >>(or about) inductance. I've never done that with a
> coil, but from an
> >>    
> >>
> >arm
> >  
> >
> >>chair physics view, it makes perfect sense that
> you would have 4X the
> >>    
> >>
> >L.
> >  
> >
> >>One of the goofy things not always realized with
> the multiturn coil
> >>formula's (air core or otherwise) is that that a
> series connection is
> >>assumed. You must have 2 parallel wires in this
> type of close
> >>    
> >>
> >proximity
> >  
> >
> >>to achieve this. Very cool!
> >>
> >>Take care,
> >>Bart
> >>
> >>    
> >>
> >>>---------- Forwarded message ----------
> >>>Date: Tue, 02 Oct 2007 01:32:13 +0000
> >>>From: sparktron01@xxxxxxxxxxx
> >>>To: Tesla list <tesla@xxxxxxxxxx>
> >>>Subject: RE: double wound secondary (fwd)
> >>>
> >>>Antonio
> >>>
> >>>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).
> >>>
> >>>Band pass testing with two winding coil revealed
> a bandpass so
> >>>      
> >>>
> >narrow, I
> >  
> >
> >>>could not fine tune VFO to maximum response, it
> would "jump" either
> >>>      
> >>>
> >side of
> >  
> >
> >>>response peak.  Gary noticed large improvement
> with two windings in
> >>>parallel, less improvement from 2 to 3 layers in
> parallel.
> >>>
> >>>My coil was used on a VTTC powering a CO2 laser.
> >>>
> >>>Regards
> >>>Dave Sharpe, TCBOR/HEAS
> >>>Chesterfield, VA. USA
> >>>      
> >>>
> >
> >
> >
> >
> >
> >
> >  
> >
> 
> 
> 



       
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