Re: first coil built (but not working ;o)

Hi Jan,

	Your coil's dimensions and values seem to match up well.  The key to the
problem seems to be the caps won't charge.

I would try drawing a spark with ONLY your spark gap hooked to the neon
transformer.  Adjust the gap to were it has the maximum gap but still fires
evenly and reliably.  Then the gap will be set.  Your safety gap should be
set to were the gap just will not fire when connected across the neon
without anything else in the circuit.

Now add the primary cap and inductor to the circuit (the secondary should
be left off for this).  The gap should fire.  If not check all the wiring.
The inductor can't really go too wrong but check the beer bottles carefully
for shorting or miss - wiring.  Then listen for sizzling sounds that would
indicate shorts or high corona somewhere.  You may ohm across the cap
looking for shorts, but be sure to completely discharge the cap before hook
you meter across it.

	I would guess the caps are either miss wired or the high voltage is arcing
or has found a low resistance path that is draining the energy.  There is a
chance the transformer is defective too but this sounds like a cap problem.

Be careful working with all the high voltage and saltwater.

Hope this helps.

	Terry Fritz

At 12:06 PM 09/11/1999 +0300, you wrote:
>I've completed my first coil (a bit crappy, I guess ;). I've problems
>getting it to work. Here's some specs
>prim: PSU 8kV 50ma 400VA cos(phi)=0.55 - net voltage 220V 50Hz
>      cap is measured 9,7nF (+-5%-at-20nF) salt water caps, 12 brown glass
>      beer bottles
>      primary coil is ~5 turns 1/4" dia copper tube, inner 4cm dia, 
>      start to end is 7,5cm - i.e. outer dia 11,5 cm
>      spark gap is 0,5cm apart metal corner/edge plates (across NST)
>      safety gap is 1,5 cm apart metal springs    
>      everything wired up with 8kV neon sign cables (Litz wire)
>      no chokes or filter, only on the 220V side a RF filter
>      should be resonant as 763kHz
>sec:  secondary coil is 600something turns 0.335mm dia (about AWG#27)
>      dia 4,3cm height 23cm
>      toroid is 18cm center-to-center 8,5 cm dia, aluminium duct tape
>      self freq about 1,7MHz, with topload 763kHz
>The spark gap works, but it sems the cap never gets charged. There's no
>spark or anything when I try to discharge it...
>It would be great if someone could give me a few tips what could be wrong
>in the setup?
> Jan Florian Wagner
> jwagner-at-cc.hut.fi, petwag-at-kolumbus.fi
> http://www.dsh.edu.hel.fi