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Re: 43" in first run

Hi Finn,

	It is truly amazing to see a first time coiler like yourself using state
of the art spark gaps, capacitors, homemade transformers, and doing other
very "advanced" things.  Further more, to hear of ones first coil getting
43 inch arcs is very impressive!  It sounds like your coil is built rock
solid!  Needless to say, your coil far surpasses most of our first
attempts!!!  

	Most of us didn't have much help at all when we started.  Our first
pitiful little coils (that, I at least, will never admit to have ever built
:-)) burned more than they ever arced.  However, we never turned back.  It
is a good measure of how far the hobby has come and how much the Internet
has helped this hobby of ours when we hear of such great first time success
stories.  Nice to know someone out there is listening to us :-))

	Great work and very nice to know that we all had a little hand in helping out.

	Terry

BTW - Don't worry about the small capacitance change.  High voltage caps
often gain a bit of capacitance after being used for the first time.  I
don't think the primary flash had anything to do with coupling.  You
coupling is right on target (it is very nice to see a first timer who
actually knows what the coupling is!).  A little water would certainly
explain the arc.  If it continues to be a problem, we all have many ideas...



At 11:52 PM 4/29/99 +0200, you wrote:
>Today I fired my coil for the first time, and this was also my debut as
>a coiler. Since I have changed my mind all the time, during
>construction, I will start to describe my system.
>400 volts trough a homemade variable choke that can "seduce" the 3kW
>20kV homemade pig into delivering from 10 to 400 mA into a short or
>jacob ladder.
>Sparkgap is a series sparkgap with 28 gaps 0.4 mm each, for a maximum
>total of 11,4 mm (1/2") This length can be altered, but this was what I
>used this time.Sparkgap is sucked fy a vacum cleaner run by a variac.
>
>Cap is a MMC with 600 philips 376, 0,022 µF/1600 V caps in 30 strings of
>20 caps, each paralled with Philips VR37 33mOhm resistors. 34nF total.
>
>primary is 14 tyrns of 8mm copper plumbing tube, spaced 8mm (8mm=4/16")
>
>Rf ground is 3 lengths of 2mm copperplate, 1 m long (3feet)and 10 cm
>wide(4"), hammered into the ground in a triangle, 2 meters apart(7´),
>and connected with 50 mm wide plate, 2 mm thick. all soldered together,
>and in one corner, there is one strap more soldered on, which connects
>to the strike ring, and the base of the :
>
>Secondary, 250 mm dia.(10") 820 mm long(32") with about 800 turns of
>0.95 mm wire(AWG 18.4)
>
>Anticorona ring is 85 mm dia (3,abit") by 350 mm center to center(about
>a foot). Main discharge terminal is a 320mm by 640 mm toroid (12" by
>24").
>I had measured the res. freq. of the secondary system to 105 kHz, and
>found a point on the  primary btwn, 11 and 12 turn.  that resulted in
>100kHz, thinking that I would make up for the rest with streamers.
>
>Furthermore, I measured the coupling to be 0,17 with the secondary in
>level with the primary, 0,15 raised one inch, and 0,13 raised 2 inches.
>I started the coil with K=0,17.
>It was a beatifull, almost windstill evening, and I set the sparkgap at
>4mm(0.16") for thefirst run, no breakout, but the neon tube did light
>up, so I threw a length of shield from a antenna caple on the toroid,
>and bent it out about 5 cm (2") to form a discharge point. This created
>a spark to the grounded rod 36 Cm (14").
>I opened the gap to 6.6 mm (0.26") and the discharge grew to 60 cm (24")
>Tapping in 1/32turn brought the discharge up to 85 cm (34")
>Then I opened the gap up to 7.2 mm (0.28") and got 110 cm (43").
>By then the safety gap, which I had set to fire at 20 kV started to kick
>in very regularly, and I got one interturn flashover on the primary,
>which I interpreted as the result of too high coupling, but what do you
>think? Perhaps a little dew was falling, anyway, I was at a point where
>I felt it was time to let the experience sink in. So I packed up, and
>called it a day.
>No doubt, there is more to be had, when I get the hang of tuning the
>coil properly. 
>Sparks to the ground rod were white, streamers were definately violet,
>and my son said he thought his dad is cool! :-)
>After the session, the cap measured 34,3 nF, whereever the last 0,3 came
>from is a mystery to me.
>I would like to extend my thanks to the members of the list: You guys
>sure know how to bring up coilers. Special thanks to Bert Hickman for
>patient tuition on current limiting, Terry fritz for having the manycap
>pictures on his site, and the german gang for talking the whole thing
>about MMC up.
>Maby it is true that a beginner should start small, surely a smaller
>coil is easier to handle, physically, but a man has to do his thing,
>right?
>
>Cheers, Finn Hammer