Re: Capacitor Help

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Original poster: "James Zimmerschied" <zimtesla@xxxxxxx>

Malcomb,
the spark gap makes all the difference. On my small coil I went from 
a 10-12" spark eventually to a 30-30" spark. My Cp is 0.011mF and my 
gap is a stacked washer gap.

Rotary gaps (synchronous are best for NST) can boost output further. 
Google on John Freau's website or the archives for a lot of good info 
on that aspect.
Jim
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Sent: Tuesday, December 20, 2005 10:56 AM
Subject: Re: Capacitor Help

Original poster: "MalcolmTesla" 
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Sent: Tuesday, December 20, 2005 12:42 AM


 > Original poster: "James Zimmerschied" 
<<mailto:zimtesla@xxxxxxx>zimtesla@xxxxxxx>
 >
 > Malcomb,
 > I suggest you try a multiple main gap. Five or six copper cylinder
 > gaps in a line with a total gap spacing less than 1/4". Use your fan
 > to help quench.

I sure will.  I made one last night using 4" PVC and some copper tubes cut
to 1 1/2" in length stacked side by side with pennies for spacing.  I super
glued them down.  I'll let you know how this goes.

 > The only two pole gap that I used on a system your size that worked
 > well was a sucker gap - see Gary Lau's web site. I am now using a six
 > gap design using washers stacked up with rubber spacers. This gap was
 > designed by Bob Svangren and currently gives me 30-32" streamers with
 > a 12 kV x 30 mA NST. This may be too much of a project for you right
 > now but Terry posted some photos
(<<http://hot-streamer.com/temp/z-1>http://hot-streamer.com/temp/z-1>http://hot-streamer.com/temp/z-1>http://hot-streamer.com/temp/z-1
 > thru z-4.jpg) if you are interested.

That looks interesting.  I take it the spark gap is very important with
regards to output.

 > Another fine point, it looks like you are taking the top wind of the
 > secondary inside the tube then up to the toroid. If that is the case
 > you may get a burn down the tube like I reported in a previous post.
 > If you have baffles this would help in your current configuration. I
 > have found it best to wind the last few turns in increasing spacing
 > until it gets above the top of the tube then air line it to the
 > bottom of the toroid center disc. There are a lot of ways people do
 > this, however so there is no only way. My experience has been to keep
 > the hot wire out of the tube to avoid carbon arcs inside it.

Interesting you should mention that.  It came to mind and we didn't have
anything handy right here at work to put inside the secondary so we stuffed
some wal-mart bags in there to form a dielectric between the top and bottom.
I don't think arcing down the tube was my problem though as my output was
pretty mild it wouldn't have even made it all the way down.  Definitely
something to look at in the future though.

I got to thinking... what about a rotary powered spark gap?  I see people
building all kinds of disks etc. to make this work but why not just grab an
old spark plug distributor from a car and attach an electric motor to it?
With a rotary spark gap do you just set the motor to a certain speed?  It
seems like there would be a timing issue too?  What if the caps are still
busy charging and the distributor lines up the terminals and discharges it?
I don't know, maybe I'm just thinking to hard about it :)

Thanks
Malcolm - KC