RE: troubleshooting tesla coil, continued (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Thu, 13 Sep 2007 22:30:03 -0400
From: "Lau, Gary" <Gary.Lau@xxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: RE: troubleshooting tesla coil, continued (fwd)

I think you meant to say that your cap should be about 7nF (not pF).  I
can't tell how it is constructed, but it doesn't look nearly large
enough to be 7nF.  JavaTC  suggests an optimum value of 20nF for best
results, though you can certainly expect some reasonable sparks at 7nF.

Once you get your cap construction right, I'd suggest going for a larger
topload (a toroid is better than a sphere).  Also I strongly recommend a
better spark gap.  Two nails or screws arcing on a small surface with no
airflow is about as bad as it gets.  You really want to spread the
arcing surface out so no point gets too hot - parallel copper pipes.
And any forced airflow through the gap helps (you don't need heroic
measures; a small, focused fan is OK).  Both of these improvements
should bring considerable performance gains, after the tuning is
straightened out.  

Regards, Gary Lau
MA, USA

> From: Marko Ruban <Marko@xxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: troubleshooting tesla coil, continued
> 
> Hello guys, I'm back from a long summer vacation.  As per previous
> suggestions I have acquired an old NST transformer (12kV, 60Hz, 60mA
> output).  And the spark gap does run now with capacitor/primary in
> circuit.  However, there's no visible effect on the topload, still.
> Could it be that badly un-tuned?
> 
> Please see the photo of my simple setup and make any suggestions...
> http://marko.dppl.com/TC_setup.jpg
> 
> The flat rectangular thing in front, is the capacitor, which should be
> about 7pF.  Can't make a more specific measurement since my new
> multimeter is still in the mail.  Spark gap is on top of the NST, and
> consists of two screws facing each other (about 0.2" adjustable
> spacing).  Wire running in the back to the right is the ground.
> 
> Also, here's a dump of JavaTC for my coil...
> http://marko.dppl.com/coil.txt
> 
> Thanks in advance for any assistance.
> 
>