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Re: Continued Problems (fwd)



---------- Forwarded message ----------
Date: Fri, 1 May 1998 19:34:50 -0700 (PDT)
From: gweaver <gweaver-at-earthlink-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Continued Problems (fwd)

At 12:39 PM 4/29/98 -0600, you wrote:
>
>
>---------- Forwarded message ----------
>Date: Wed, 29 Apr 1998 12:52:12 EDT
>From: Esondrmn <Esondrmn-at-aol-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: Continued Problems
>
>Sorry, this is going to be a long one.
>
>I fired up my 6" coil last night for the first time this year.  I am still
>having problems.
>
>Quick overview: Secondary 6" dia, 991 turns of #22 awg, 29.1 mh.  Primary 3/8"
>copper tubing wound in a 30 degree saucer shape, 3/8" spacing between turns,
>I.D. 8", O.D. 26",  5.25" tall, 14 turns total, 88 uh.  Secondary is mounted
>so the lowest turn is  3.5" up from the first turn of the primary - right at
>about turn 7 or 8.  Mark Rzeszotarski (sure hope I got that right Mark)
>calculated the coupling to be about .167, so I wouldn't think it is coupled
>too tightly.  Best tune is at turn 11.75 with a 5" x 40" toroid.
>
>Capacitor is a .025 uf, 15 kv Condenser Products unit with a spark gap mounted
>directly across it made of #10 solid copper wire with 1.0" dia loops on the
>ends.  Gap is set to 5/8".  Power is from a 5 kva 14.4 kv pole pig and is
>supplied across the spark gap which consists of a rotary with a static gap in
>series with it.  Current is limited to the pole pig via a Miller Thunderbolt
>welder with an adjustable resistor stack in series with the welder.
>
>I built this coil about two years ago and scaled things up gradually from neon
>sign transformer to the pole pig.  I was quite happy with the performance,
>getting nice white hot bolts up to 80" long at about 8 kva input.  Then the
>first C. P. cap blew up.  I replaced it and within not too long, lost the
>second one.  Several folks on this list suggested I install a spark gap across
>the cap unless I have lots of money - which I don't so I did.  Now, I can't
>input much power without firing the cap safety gap.  Last fall, last time I
>had this coil fired up, Malcolm, Dr. Cox and a few other helpful folks
>suggested I had a bad case of 60 hz resonance.  I have to ask a question here
>- are there systems out there that can be run at say 10 kva with 15 kv in and
>not fire a .25" safety gap across the cap?


I had the same problem.  My .25" safety gap would fire all the time. With
safety gaps and my output dropped to about half.  I increased the spacing of
the safety gaps and my output got better each time I increased the safety
gaps spacing.  I tried several different types of chokes, fried a few,
several arces along the sides, and finally I found something that worked.  I
then removed the safety gaps completely and rely entirely on the chokes.  I
have a choke design that works very well. I get white hot 76" discharge
sparks from my 6" TC on 3200 watts.  I tried series resistors on the neons
and later removed them too.  I blew 7 neons in the learning process.  I
don't have a rotor but I get excellent output with my variable speed RQ
vacuum spark gap, 8 gaps .25" each.  I used a Lincoln arc welder as current
limiting on my 18KW transformer.  

Gary Weaver