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Re: Another First Light! (fwd)





---------- Forwarded message ----------
Date: Wed, 20 May 1998 22:26:25 -0600
From: "D.C. Cox" <DR.RESONANCE-at-next-wave-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Another First Light! (fwd)

to: Pat

If you are in Madison you are only approx 40 miles south of our lab.  Stop
by someday for a chat if you are in the area.  We are two miles east of the
International Crane Foundation (ICF) in Baraboo - Dells area.

DR.RESONANCE-at-next-wave-dot-net

----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Another First Light! (fwd)
> Date: Tuesday, May 19, 1998 9:46 PM
> 
> 
> 
> ---------- Forwarded message ----------
> Date: Tue, 19 May 1998 18:27:02 -0600
> From: "Patrick J. Gustafson" <gustafpj-at-uwec.edu>
> To: Tesla List <tesla-at-pupman-dot-com>
> Subject: Re: Another First Light! (fwd)
> 
> Gary:
> 
> For tuning the coil, I did put a tack on the toroid, and I was still
getting
> secondary streamers shooting for my garage door.  I would like to build a
> larger toroid, or just stack them for that matter, but this a coil that I
built
> for the physics department here at the university and I probably won't
see it
> much longer (I'm moving on the 30th of May to Madison).  My first coil
and I
> already have to leave it (sigh).  I did also have the 1K resistors coming
off
> of the NST's like you mentioned, but they were only rated to about 5W (I
know
> they should be around 30W but I had to give them a try), needless to say,
they
> got smoked.  I can't tell any difference without them.  Thanks for the
bypass
> cap info, never knew about that.  You are correct about my secondary
being as
> low as I can get, I'm not getting an racing sparks at all.  Is there
anywhere
> that I can post pictures of my coil?
> 
> Thanks to Jeff Corr for his excellent advice in getting my coil running.
> 
> Patrick Gustafson,
> Leaving his First coil behind, in Eau Claire Wisconsin
> 
> Tesla List wrote:
> 
> > ---------- Forwarded message ----------
> > Date: Tue, 19 May 98 08:54:25 EDT
> > From: Gary Lau  19-May-1998 0811 <lau-at-hdecad.ENET.dec-dot-com>
> > To: tesla-at-pupman-dot-com
> > Subject: Re: Another First Light! (fwd)
> >
> > Damn good for a first try!  My thoughts:
> >
> > Each time your main gap fires, your safety (bypass) discharges it's
> > charge and this energy dissipates in non-productive (and possibly
> > destructive) ways.  If your main cap is .01 uF and your safety cap is
> > .001 uF, this means that .001/(.001+.01) * 100% = 9.1% of your
> > transformer's power is going to no-good.  You might want to use a
> > smaller value bypass cap.  You also must use series damping resistors
> > (1K or so) when using chokes to dissipate all that power.  Even so, use
> > of chokes is controversial.
> >
> > I started out with a flat primary with my 4" secondary, and the single
> > greatest improvement I made was converting to a 15 degree conical (also
> > with a 15Kv/60mA NST).  I'll bet your secondary is as low as you can
get
> > it and you still don't see any racing sparks to indicate overcoupling.
> >
> > Re. your gap, if there is a single gap segment that is .225", I think
> > this be the weak point that affects quenching.  The total gap length
> > seems right but it shouldn't be lumped like that.  Build another RQ gap
> > in series.  You do have a fan on it, right?
> >
> > Re. your toroid, if you put a nail on it and you still get multiple
> > streamers, you might try going to a 6" cross section X 24" (and
re-tuning).
> > While I think the multiple streamers look nicer, when trying to measure
> > your longest arc as a goal, a single streamer is necessary.
> >
> > Let me know how your 6" secondary works out.  Using #28 may be kinda
> > small though, and the inductance with that many turns may be too high
for
> > your primary to tune.  I'm still using the 4.25"x23", #22, w/ 42"
sparks.
> >
> > Regards and congrats,
> > Gary Lau
> > Waltham, MA USA
> >
> > >Date: Mon, 18 May 1998 22:26:13 -0600
> > >From: "Patrick J. Gustafson" <gustafpj-at-uwec.edu>
> > >To: Tesla List <tesla-at-pupman-dot-com>
> > >Subject: Another First Light!
> > >
> > >Hello All:
> > >
> > >With schoolwork, and finals week here I haven't much time to work on
my
> > >first coil, but I did nonetheless complete it and give it some initial
> > >runs. The specs are as follows:
> > >
> > >primary - flat pancake with .25" copper tubing (15 turns)
> > >power supply - (2) 15kV 30mA NST's paralleled
> > >chokes - 100 mH on each leg of the NST's
> > >spark gap - RQ type (6 section (.1" combined) plus adjustable brass
> > >gap(.225")) set at .325
> > >capacitor - .0125 micro farad rolled polyethylene (.062"), filled with
> > >transformer oil
> > >safety cap - .001 micro farad, filled with transformer oil
> > >safety gaps across the NST's and main cap
> > >twin variacs rated at 17 Amps
> > >toroid - 4" cross section x 25" diameter
> > >grounding - 8' x 1/2" dia copper ground rod
> > >secondary - see below
> > >
> > >I had a two layer 6"dia x 22" length secondary wound with #28 magnet
> > >wire, but I had a problem with the inner winding being shorted out
> > >somehow, so I replaced it with an alternate secondary that I had wound
> > >(4"dia x 20" with #22 magnet wire).  The tuning took quite awhile,
> > >beginning with zero spark length, and now properly tuned I'm pulling
> > >around the 30-35" mark (loud as %&*-at-)  Not bad for my first coil eh?
> > >And plus I'm using the lower inductance secondary.  Can't wait to
> > >re-wire the 6" and see what I get.
> > >
> > >Patrick Gustafson, Ozone plentiful in Eau Claire, Wisconsin
> 
>