Re: Jonathon's 6" Coil (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- 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.







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