Re: Toroid Recommendations?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Mark W. Stolz by way of Terry Fritz <twftesla-at-qwest-dot-net>" <mark_w_stolz-at-hotmail-dot-com>

Shad,

Thanks for the input.  So you're thinking towards an 8-9" minor diameter?  
Now that I've heard 4,6, and 8-9" I'm getting confused again.  Probably just 
a case of analysis paralysis. :-)

I don't have a SRSG yet, I'm using a static at present.  I have a total of 
40nF -at- 30kVDC worth of Geek caps available so LTR isn't a problem and I'm 
set when I do find more power.

I burned up my 2.5" coil that which was where the 4 x 15.5" toroid came 
from.  It was throwing about 39" streamers.  Of  course I was pushing almost 
4kVA through the poor little guy at the time. :-p

For those that are interested, here are links to the 2.5"  that cooked and 
the new 9" secondary.
http://users2.ev1-dot-net/~nmyreality/tesla/J010910/index.html
http://users2.ev1-dot-net/~nmyreality/tesla/other/9inch.html

Mark Stolz
Houston, TX


>Original poster: "sundog by way of Terry Fritz <twftesla-at-qwest-dot-net>" 
><sundog-at-timeship-dot-net>
>
>Hi All,
>
>Usually, I don't base my toroid sizes on aesthetics, though I generally
>make the minor diameter about the same size as the form diameter, and the
>major diameter about 1/2 to 3/4 of the coil's height.
>
>    When I get "sophisticated", I choose a tune point about 3/4 of the way
>in on the primary, pick an LTR cap for the power supply, and size the minor
>diameter so that it's just below what would hold off the spark, then adjust
>the major diameter so that Fres of the coil is just above what the tank
>circuit is tuned at.  Example,
>
>   For my 2.5" coil I wanted to tune it at ~7 turns on a 10 turn primary,
>and use an LTR 12/30 NST tank supply, on a 120bps sync gap.  So I figured
>the resonant size cap, make it 1.5x larger, and figured what freq the
>primary would oscillate at.  The secondary's Fres is 1.2mhz-ish, so I
>figured a 3" minor diameter, and increased major diameter till I got it
>where I wanted it.  That was too freakishly huge, so I added a 1.5x6"
>toroid underneath it, and re-sized the big topload appropriately.  Works
>for me, but be prepared, the toploads can get big like that.  With a
>different tank cap, the 2.5" coil was using the 1.5x6 toroid and a 3x17"
>toroid on a 9/60 NST, and threw constant 30" sparks, and I got a few hits
>out to 35" or so. Not too shabby.
>
>Hope it helps!
>
>Shad G3-1203
>
>At 09:49 AM 4/11/02, you wrote:
> >Original poster: "Barton B. Anderson by way of Terry Fritz
> ><twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>
> >
> >Hi ALL,
> >
> >I know everyone is busy with one thread or another, but could some of you
> >reply to Marks request for
> >toroid recommendations (see below for coil specs). I asked Mark to ask 
>the
> >List so he could get an idea of
> >what sizes some of you are using, but haven't seen any replys come 
>through
> >yet.
> >
> >Thanks,
> >Bart
> >
> >Tesla list wrote:
> >
> > > Original poster: "Mark W. Stolz by way of Terry Fritz
> ><twftesla-at-qwest-dot-net>" <mark_w_stolz-at-hotmail-dot-com>
> > >
> > > Hi All!
> > >
> > > I'm working on my new coil and wanted to get some input regarding the
> > > toroid.  Here's the specs:
> > >
> > > Primary
> > > 19 turn 20 degree inverse cone
> > > 3/8" tubing, 3/8" turn to turn spacing.
> > >
> > > Seconday
> > > 9" diameter 38" winding length 22 AWG single build
> > >
> > > Tank
> > > 15/60 NST, 7 segment RQ/TCBOR fan cooled static gap, 20 nF MMC
> > >
> > > I was think about using my existing 4" x 15.5" toroid from my previous
> > coil,
> > > except that ETesla 6 indicates a drop in the free space capacitance 
>from
> > > 17.2 pF to 5.2 pF.  I'm now thinking more towards a 4" x 30".
> > >
> > > What are your recommendations for minor/major diameters and why (i.e.
> > > testing, taste, experience)?
> > >
> > > Thanks in advance,
> > >
> > > Mark Stolz
> > > Houston, TX
> > >
>
>-----------------------------------------------------------------------
>Shad (Sundog)
>G-3 #1203
>"Ever stop to think, and forget to start again?"
>-----------------------------------------------------------------------
>
>
>