Re: Draco Specifications

[FutureT-at-aol-dot-com (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

In a message dated 8/29/00 7:18:41 AM Pacific Daylight Time, tesla-at-pupman-dot-com 
writes:

> But besides that, is this a good design? I'm looking for 
>  someone to point me in the right direction. But of course, I haven't yet 
>  obtained any parts, so, as I said last time, I can 'drift' on my design 
> quite 
>  a bit. By the way, have I forgotten anything necessary? (I designed this 
>  using WinTesla 3.2 if anyone is curious.)
>  
>  Thanks,
>  - Joshua

Joshua,

Basically good.
I don't think that 4" is too wide for the coil form, but I would make it
taller, at about 26" tall, if you have room in the area.  This will permit
you to use more turns on the form.  I've found the best results using
a lot of turns, such as 1500 to 1600 turns.  This lets you use more
turns on the primary, and reduces the gap losses and increases
the spark length.  You should gain 10% using this method.  This
is a method that is not well known on this mailing list since it has
been tested (with great success) by only a few people as far as
I know.  My coil which uses this approach, gives 42" sparks from
a 12/30 NST.  The coil can be seen at:

  http://hometown.aol-dot-com/futuret/page 3.html
 
Click on spark gaps tc's.

If you use more turns on the secondary, then you'll also need more
primary turns, so I would use 1/8" copper refrigeration tubing rather
than 1/4" tubing.  This will make the coil a lot more compact over-all
also.  

The only other change I would make is to use a capacitor of twice
the nF value so it's an LTR sized cap which will stress the NST
less.

I should mention that the coil will work fine using your design.  It's
just a matter of 10% more spark length that may be gained by
using the methods I mentioned.  My webpage goes a little more 
into what I call the Six Keys for Efficiency.  Using a sync gap, or
air blast gap, you may get 37" sparks depending on the toroid
size and smoothness, etc.

One other thing I should mention.  Using an LTR sized cap
reduces the tank impedance, and makes it even more important
to use more sec. turns to keep the tank Z high.  If you stay with
the design you have now (reso-charge), you might not need
so many turns, but the NST will be stressed more (or you'll 
have to deliberately throttle back on the output to protect the
NST).   Details.... details.....   

John Freau