Re: troubleshooting tesla coil, continued (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Fri, 14 Sep 2007 18:17:24 -0700
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: troubleshooting tesla coil, continued (fwd)

Hi Marko,

Your inserting 0.007uF into Javatc so the frequency's do match as they 
should at that capacitance. However, your "saying" 7pF and that is way 
off from both Javatc and what the plate cap really is. Judging by your 
plate cap configuration, it is about 0.7nF (not 7nF) if your using glass 
as an insulator. If air is your insulator, then it's down to 0.1nF.

So you are way out of tune. The fix is the cap. For a plate cap using 
glass with about 0.2" spacing, you would need a plate surface area of 
900 square inches (30" x 30").


If your going to use a plate cap, you might want to consider Castor oil 
which has a high dielectric of 5. About 15 plates (8" x 11") with a 0.2" 
spacing between plates would yield near 7nF (which is 0.007uF). Plate 
caps are fun to play with, but when you start building to a capacitance 
such as this, it can get bulky and messy. I of course recommend an MMC 
for performance.

Take care,
Bart

Tesla list wrote:

>---------- Forwarded message ----------
>Date: Thu, 13 Sep 2007 19:19:45 -0400
>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.
>
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