Fw: 15/120 NST Coil Static Gap Performance Problems

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Original poster: "claude masetto" <claudmas-at-optusnet-dot-com.au> 


----- Original Message -----
From: "Ian McLean" <ianmm-at-optusnet-dot-com.au>
To: "Claude Masetto (E-mail)" <claudmas-at-optusnet-dot-com.au>
Sent: Monday, February 16, 2004 3:52 AM
Subject: 15/120 NST Coil Static Gap Performance Problems


 > Hi all,
 >
 > I having a difficult time trying to understand this problem, so it's going
 > to take a bit to explain, so sorry all in advance for the long post :) :)
 >
 > Tuned my 6" coil last Saturday afternoon with the help of Claude.  I don't
 > have a decent static gap, so Claude kindly brought along his sucker gap,
 > control box which has a current meter, and an extra variac to help tune
the
 > SRSG and to control the suction to the suction gap - BTW: thanks for
 > Saturday Claude :-)
 >
 > Firstly, we got some good streamers on Saturday :)  Especially with my
SRSG
 > and the 62.5nF tank cap.  Some nice bright power arcs to the colourbond
 > roofing and overhead metal pipe.  Some out to 5 foot.  One power arc to
 > ground, through a vice mounted on my workbench.  The 5 footers at the end
of
 > the day, when both Claude and I think we just about got it right, wanted
to
 > go further.  A couple of streamers arced through a metal jerry can on a
 > shelf, through the half inch thick wooden shelf above it (directly
through,
 > it was no barrier at all) and upwards to the furthest point on the corner
of
 > the ceiling 5 foot away - so I am getting very close now to predicted
 > output.  It was definately limited by the roofing.  I am now getting
 > prepared for an early evening full power outdoor test.
 >
 > I learnt a few things on the day.  Don't use GTO-15 for tank cable -
 > dramatic drop in output.  This was the first thing changed, for some thick
 > multi-strand copper cable, and the output instantly improved.  This was
 > unshielded - so I am going to get some even thicker copper multi-strand
and
 > shield it myself.  I learnt not to let this unshielded copper touch the
 > varnished wood of the primary base (it caught on fire :-0).
 >
 > And now the mystery.  My coil didn't respond too well to the sucker gap.
 > Streamers about 4 foot max.  But that's not the mystery.  No matter the
 > tuning, tweaking, adjusting of coil coupling, gap size,  cap size (LTR
 > static -at- 37.5nF or LTR rotary -at- 62.5nF, or sucker suction velocity, the
 > output did not improve beyond this, and the gap seemed to sputter, and
 > seemed to be at a low break rate (slower than SRSG at 100bps, you could
 > easily tell the difference between the two).  Now neither Claude nor I
could
 > understand the reason for this, so if anyone can shed some light as to why
 > ????  Is my 15/120 NST bank not getting the caps charged enough ?  Current
 > draw with sucker gap was 15A average, tuned, from 240VAC mains (Australian
 > supply).  With SRSG, tuned, that dropped to about 10A average.  This
sucker
 > gap performs much better on it's owner's (Claude's) coil.  On his coil, it
 > roars like a chainsaw on heat, and the gap spark is much brighter.  On my
 > coil, it is loud, but not as loud, and the spark brightness is sputtery
and
 > not quite as intense (although still very very bright).
 >
 > My coil instantly performed well on the SRSG, once tuning and SRSG
alignment
 > had been tweaked.  5 footers wanting to be longer.  Nice bright power
arcs.
 > Clean 100bps break rate.  Very loud but even sounding.  Very smooth.  I
like
 > the way the streamers seem to "snake out" of the toroid, and fork more, on
 > the SRSG.  Noticed this on Claudes coil as well.  Even breakout over the
top
 > toroid, with some arcs and streamers moving around the toroid.
 >
 > Wish I could have taken pictures.  My sister will be at my place on
 > Wednesday, with her digital camera, so I'll do an outdoor SRSG run in the
 > early evening and get her to take some pictures of it all for me :)
Hoping
 > for 6 footers.  Wish me luck :-)  I'll get some photo's up on a Web page
 > somewhere.
 >
 > Any help with the sucker gap performance problems would be greatly
 > appreciated.  I want to build one.  I like the more random and thicker,
 > brushier output (albiet shorter) it gives as well.
 >
 > Rgs
 > Ian
 >
 >
 >
 >