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Re: Jonathon's 6" Coil (fwd)



---------- Forwarded message ----------
Date: Thu, 28 Jun 2007 16:12:35 -0400
From: Scott Bogard <teslas-intern@xxxxxxxxxxx>
To: tesla@xxxxxxxxxx
Subject: Re: Jonathon's 6" Coil (fwd)

Jonathon
     46 inches is actually very decent for a 12/60 NST.  According to that 
formula 1.7*(P)^1/2 you are getting slightly better output than expected 
(assuming 720 watts for P).  Of course, I have questions as to how accurate 
that formula actually is (where did it come from anyway?).  Anyway, I would 
use the 6" duct, but don't stretch it around a pizza pan yet, start with it 
as small and compact as you can, and slowly enlarge it (by stretching it 
around a bigger center).  The reason I say this, is from my own top load 
woes, if you are going for maximum spark length, you want as big of a top 
load as possible, but not too big (I once made myself a huge top load, only 
to find it was a hair too big, and wouldn't spark (luckily I only spent 
about 20 dollars on the thing) I have since made one ever so slightly 
smaller, and I am now getting longer sparks than ever (61 inches from a 6" 
coil, which is better than yourself, but considering my power level (4 MOTS, 
probably 1500 Watts or double your power), it is way less efficient than 
your coil, making yours superior, so feel free to brag about that!).  
Anyway, given your power level, I think you can easily get away with the 6" 
duct.  As for your SRSG, Do as I did, open the gaps wider, put it in a test 
rig (If you don't have a "junk" NST or OBIT, slap together a few MOTS, but 
it shouldn't be too awful hard to find a 8/30 NST or something for little 
money), remove the safety gaps, find the sweet spot, clamp the electrodes 
back down, re-install in your coil (with the safety gaps back in place!!), 
and sit confidently with the knowledge that your SRSG is perfectly phased 
and needs no adjusting.  Granted, phase adjusters would be nice, but they 
are simply not necessary if you can rotate the motor by hand.  Good luck!
Scott Bogard.


>From: "Tesla list" <tesla@xxxxxxxxxx>
>To: tesla@xxxxxxxxxx
>Subject: Re: Jonathon's 6" Coil (fwd)
>Date: Thu, 28 Jun 2007 08:02:11 -0600 (MDT)
>
>
>---------- Forwarded message ----------
>Date: Wed, 27 Jun 2007 21:42:40 -0400
>From: Jonathon Reinhart <jonathon.reinhart@xxxxxxxxx>
>To: Tesla list <tesla@xxxxxxxxxx>
>Subject: Re: Jonathon's 6" Coil (fwd)
>
>Quick stats:    12/60 NST       .034uf MMC      120 BPS SRSG   (I
>think....1800RPM, 4 electrodes...  1800/60=30*4=120).
>
>I had a Terry Filter.  But for one reason or another, I believe one of the
>MOVs shorted out, and was thus robbing a ton of power from my coil.  When I
>added the 2nd half of my MMC, it took the spot where my terry filter was.
>So I think I'll have to forget it, or find a new place for it....  I still
>have the power resistors in place tho.
>
>I think I may also build John Freau's phase adjuster.      and what do you
>all think about my thoughts on my topload?
>
>Jonathon
>
>
>On 6/27/07, Tesla list <tesla@xxxxxxxxxx> wrote:
> >
> >
> > ---------- Forwarded message ----------
> > Date: Wed, 27 Jun 2007 18:04:30 EDT
> > From: FutureT@xxxxxxx
> > To: tesla@xxxxxxxxxx
> > Subject: Re: Jonathon's 6" Coil (fwd)
> >
> > In a message dated 6/27/2007 4:32:06 P.M. US Eastern Standard Time,
> > tesla@xxxxxxxxxx writes:
> >
> > Jonathon,
> > I find it odd that you can get  different results by adjusting the phase
> > of your spark gap.  The  reason I say this is because my SRSG will ONLY
> > fire,
> > when it is perfectly  in phase (I have about 2 degrees of play, between 
>a
> > roaring gap (making a  musical tone somewhere between B and B flat), and
> > an
> > occasional random  crackle, take it out another 2 degrees and I have
> > nothing).  What is  the approximate spacing of your gaps, mine are set
> > kind
> > of wide, at about  1/8 in (which is not really ideal).
> > Scott,
> >
> > That is the key.  Your rotary gaps are set rather wide which is
> > not  really
> > good
> > for the system. But if you have a Terry filter and run LTR, you can
> > get  away
> > with it.  Small NST systems should have a rotary gap spacing of
> > only  about
> > 1/16" or so.  This depends on how many series gaps are used, and
> > the  voltage,
> > etc.  If you're using tungsten then you have to be very careful of  
>course
> > because
> > it's brittle and can snap off if the electrodes hit each other.  This
> > presents a
> > danger to viewers unless a good safety shield is used around the gap.   
>I
> > run
> > the rotary gaps almost touching on my TT-42 coil.  I can do that  
>because
> > the gaps are copper and steel and I round the ends of the copper.  So  
>if
> > the
> > electrodes hit (which they've done at times during testing), they
> > just  glide
> > past each other anyway, and nothing gets damaged.  It just makes
> > a  ticking
> > sound (which is how I know they're hitting.  The rounded electrode  ends
> > might
> > reduce the tendency to *prefire*, and reduces the mechanical dwell time.
> > I actually leave the center of the end of the electrodes flat, but I 
>round
> > off the
> > edges.  In any case, once the electrodes are set to run closely, they  a
> > rather
> > large phase range will work.  An advantage of your set up though is
> > it  makes
> > it easy to find the best spot, since there is only one spot that  works
> > :)
> >
> > John
> >
> >
> >
> >
> > Are you  using 120 or
> > 240 BPS, (or are you not from the states, and using 100 or  200 BPS).  A
> > tip
> > of advice, to phase my gap, I built a test rig out  of a mason jar (beer
> > bottle) cap, and a copper coil primary, with a junk  OBIT I had laying
> > around
> > (that way if something got fried, it didn't  matter a whole lot), just
> > make
> > sure you put some form of primary (and  ideally a secondary) in there so
> > you
> > don't fry your junk transformer  (don't use expensive capacitors, make
> > one).
> > If phasing is still  difficult to tell, widen your gaps until you set 
>the
> > motor is in it's  sweet spot (loudest, most steady noise), and then 
>narrow
> > the gaps back  down to decrease you gap losses.  In my test rig I have 
>no
> > safety  gaps.  What is your power level?  46 inches isn't too shabby!
> > Good
> > luck.
> > Scott Bogard.
> >
> >
> >
> >
> >
> >
> >
> > ************************************** See what's free at
> > http://www.aol.com.
> >
> >
> >
>
>

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