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RE: gap spacing



Comments interspersed:

>Original Poster: "Christopher Boden" <chrisboden-at-hotmail-dot-com> 
>
>Gap:
>
>12 1" solid brass spheres tapped to 1/4"-20 bolted to a piece of G-10
>
>Question:
>
>How far apart should I set the balls? They will not be moveable and we are 
>machineing the G-10 on a CNC mill so we want them EXACT :)
>
>I have seen everything from .020 to .050 and was wondering the perfect 
>setting.

There are two issues in determining the answer to your spacing question.

The total of all gaps will determine the capacitor charging voltage.  A
wider total spacing will stress your cap and NST more, and will also deliver
greater performance, a tough choice!  I use a single 0.34" gap with my 15/60
NST, I'm not sure if the sum of multiple gaps can be added linearly to
compare with a single gap space.

The other issue is the number of gaps.  You indicated that you wish to use
12  balls yielding 11 gaps, so this part perhaps is resolved.  However, be
aware that there is again a tradeoff.  A single or low number of series gaps
gives lower gap losses, but a high number of series gaps yields superior
quenching (and is less stressful on caps too).  So, if you are going for the
12 ball configuration, I would start with 0.34/11= .031" per gap.

Whichever way you go, just be sure to direct air flow through the gaps.

>Also, FYI: 12 Corona bottles will *just* fit into a 5Gal HDPE bucket and
use 
>a LOT less water/oil then an Aquarium (less space between bottles).For the 
>same capacitance of .0125uF Will having the bottles so closely spaced cause
>any problems?

No problem that I can see.  In fact, if the outer foil from adjacent bottles
presses firmly against each other, that only serves to make the parallel
connection between bottles all the better.

Gary Lau
Waltham, MA USA