Tips on setup/tuning for first coil

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

Original poster: "Resonance Research Corp. by way of Terry Fritz <teslalist-at-qwest-dot-net>" <resonance-at-jvlnet-dot-com>


Never start out with a "fixed" primary.  Always use (in this design) at
least 15-20 turns of scrap house wire (12 AWG) for a "test" primary.  After
tuning is established then you can revert to the correct number of turns for
your "finished" and beautiful copper tubing primary.  Keep spark gap spacing
very close, use a wire off the toroid and a ground wire so you can actually
measure the initial spark, and tune at lower power variac setting -- around
20 to 25% max.

For good electrostatic protection keep you toroid 1-2 inch above the last
turn of the sec. coil.  Also, space wind the last 3 turns of the sec.
winding to slow reduce distributed capacitance and prevent excessive voltage
buildup on the very last turn which "sees" less capacitance due to the fact
this turn is not "sandwiched" between adjacent turns.

It looks like a nice design.  Later, you might substitute a 9 kV 30 mA or 60
mA NST for more output.  Be sure to use a good protection circuit to protect
your NST.  Terry has several in the archives.

Hope you can make it up to Wis. Dells, WI, for our Teslathon next fall.

Dr. Resonance

Resonance Research Corp.
E11870 Shadylane Rd.
Baraboo,  WI  53913
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, January 26, 2003 12:37 PM
Subject: Questions on first coil...


 > Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>"
<CoolCorals-at-aol-dot-com>
 >
 > Hello, I have been watching this list and researching Tesla for about 8
 > months now.  I finally am building my first TC.  Of course, I have run
into
 > some questions in the process.  I have read quite a bit and have the
 > formula's from
 >
<http://home.earthlink-dot-net/~electronxlc/coilspecs.html>http://home.earthlink
-dot-net/~electronxlc/coilspecs.html
 > .  Also, I have the Tesla cad and Win Tesla program.  I have used these to
 > get the baseline for my coil.  After components are built I am confirming
 > each item (h/d, L, turns, Tpi, etc.).  This is where my questions come
 > about, but first  I'll give a quick run down of what I have so far.  The
 > Transformer and 28 gauge wire are what I had to start.
 >
 > Neon Supply:  Franceformer 6000v -at- 30 ma
 >
 > Secondary:   2.37" x 22.20" x 28ga x 781.15 turns. (win tesla L= 3.68mh &
 > SC=7.49pF & Fo= 505Khz)
 >
 > Torrid:  4.25" x 13.45" (win tesla C= 19.47pF)
 >
 > Primary:  4.37"d x 2"H x 7 turns x 6 ga (win tesla.159wire, .100 space, 7
 > turns L= .0117mH)
 >
 > Tank Cap:  My neon max is .0133uF, with this P/S combo win tesla says
 > .0085pF is required for Xl=Xc -at- 505khz.
 >
 >
 >       Now my questions.
 >       1.  Secondary is wrapped on PVC form because that is what I had is
 > that okay?  How much Loss is it compared to Acrylic?
 >       2.  My secondary when built had the same turns, turns per inch and
 > length that win tesla said, buy my Marconi RLC shows a 3.825mH inductance
 > whereas win tesla said 3.68mH,  why the difference?
 >       3.  I then went back into win tesla and forced the 3.825 by "showing
 > at 22.5" height and same torroid (it's built, home-brew ducting), is this
 > correct?
 >       4.  Now my big problem now.  I have just finished the primary and
 > tested it's inductance on my RLC.  Actual L= .005945mH  Win Tesla
 > .0117mH!!!!!!!  That's almost double the actual inductance!!! What's up
 > with that?  So, I cross checked with the old formula from the site
 > above.  Low and behold it says I will end up at.0054mH!  Now that's a lot
 > closer.  My question is why is Win tesla so high?  The only thing I can
 > think is that it adds the mutual inductance with it?  Please help
 > here.  Now that it's L is so low I have to have a .0171uF to meet Fo and
 > that exceeds my Transformer!  I was trying to keep below the max output,
 > but what the heck.
 >
 >       Anyway, if you can help it would be greatly appreciated.  I only
have
 > to get or make the cap and spark gap left.  I hope I don't have to make
any
 > stuff over again.
 >
 >       Thanks, Brad Kretzmeier
 >       Intraspek
 >       800 Main Street
 >       Lafayette, IN
 >
 >