Re: Grounding Problem???

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

Original poster: "Marry Krutsch by way of Terry Fritz <twftesla-at-qwest-dot-net>" <u236-at-earthlink-dot-net>

Hi Mr.Sonderman, All.

	Your specs are quite detailed, so I hope I can give enough info.  

	My secondary is 6.5" OD thick wall PVC wound for 28" with what appears
to be #25 AWG wire.  It has approx. 1350 turns on it.  The inductance is
65.6 mH, the Cself is 11.7 pF, and the self resonant freq. is 182 kHz. 
With my 6" by 20" toroid it runs at around 106 kHz.  It is coated with
3/32" to 1/8" of boat builder's epoxy (way too much).  I have a 3" by
12" corona ring at the top, and four 6.5" ID, 9" OD plexiglass washers
glued onto the top half of the coil.  They stop full-secondary arcing,
but arcing then just occurs on the lower half of the coil with nearly
the same intensity.

	The toroid is 6" by 20" dryer duct, Al tape covered.  I used to use my
8" by 22" toroid, but the racing sparks were worse.  When streamers
broke out, they were longer though.  Often I have extremely hot power
arcs leave the corona ring and connect to the strike ring.  They stay
there for a few seconds.

	My primary is 12 turns of 1/4" Cu tubing with an OD of 20" and an ID of
8" tapped at 7.25 turns for an inductance of 20.6 uH.  It is a flat
spiral, with a C-C turn spacing of 1/2"  Pri-Sec coupling is about
0.21.  It's a bit high, but even with lower coupling, racing sparks
remain.  The streamer length goes down though.  On a good run, I can get
a few 6 ft streamers.

	The capacitor is an MMC bank rated for 18 kV with a capacitance of 0.1
uF (currently).  I can change the capacitance to 0.066 or 0.033 uF.  It
has 90 caps in it.  30 units in series, and three 30 unit banks in
parallel.

	The power supply is two GE copier xfmrs with the secondaries in anti
series, and the primaries in anti parallel, the same as a dual MOT
supply (I hope I got that right).  They pull 1600 VA.  Output voltage is
6600 VAC -at- about 250 mA.  Resonant rise brings the voltage up to around
10 kV (I think).  The only protective device I use on them is a safety
gap.

	My sparkgap is a single static "sucker gap" with a spacing of around
3/32".  
	Tank wiring is 12 AWG THHN.

	RF ground is 8 Al stakes 18" into the ground with 12 AWG wire
connecting them together.  I use one 15 foot length of 12 AWG wire to
hook the coil up to it.  I hope I remembered everything.

	MISC---Racing sparks seem to occur much more on dry days, when it is
harder for the coil to break out.  Moist evenings give the best
performance, and the fewest racers  This thing runs best when there are
drops of condensation on the secondary.  Judging by this, it looks like
the coil is being overvolted, but since my toroid is small (breaks out
easily), I don't see how.  Should I try a larger toroid?  I was thinking
that a 6" by 30" or larger toroid might lower the developed voltage
enough to keep the coil from breaking down, while still allowing the
coil to break out.  BTW, nice site, and that coil looks great!


	If I'm getting annoying, or becoming a list hog, please let me know.
Thanks,
	Winston

Tesla list wrote:
> 
> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Esondrmn-at-aol-dot-com>
> 
> In a message dated 1/24/02 7:25:48 AM Pacific Standard Time, tesla-at-pupman-dot-com
> writes:
> 
> Winston,
> 
> You certainly are not overpowering your coil.  I run my 6" coil up to 7
kva.  I
> use no corona rings.  I do have a 33" x 6" toroid mounted on top of the
> secondary with another 40" x 6" toroid mounted above that.  The coil was
> finished with several coats of polyurethane after winding.  I don't
recall, is
> your primary flat - or inclined?
> You can see pictures of this coil at my web site:
> http://members.aol-dot-com/esondrmn/index.html
> How does your set up differ from mine?
> 
> Ed Sonderman