RE: Got my 6-incher going!

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Lau, Gary" <Gary.Lau@xxxxxx>

Hi Ben:

That's a nice, neat coil layout your have - I tip my top-load to you ;-)

My comments and suggestions are:

1) On the NST protection circuit, replace the RF chokes with large,
ceramic-cased wire-wound resistors, 500-2000 Ohms, 50+ Watts.  It has
been shown that L-C filters as you have actually make matters worse,
creating their own resonances.  I suspect that's why you saw the
flashovers on the caps.  I know - they won't fit into the footprint of
your chokes :-(

2) Your doorknob tank capacitor uF value sounds good, but as you said,
their 20kV rating sounds too low to be safely used with a 15kV NST.  I
see that you found them to get warm after use.  Do you have a
capacitance meter to see if their value drifts when warm?

3) If you're using a 15/60 or 15/90 NST, you should be able to use a
much larger top load than a mixing bowl.  Could it be that you just
didn't have enough primary turns to tune a larger top load?

Regards, Gary Lau
MA, USA

> Original poster: Ben Buxton <bb@xxxxxxxxxx>
>
>
> After much research, list archive browsing and many many weeks of hard
> work, my first coil is up and running! So far I've only managed 80cm
> (~31 inch) arcs from the 15kv/90mA supply, but I would guess that it
can
> be improved either with a sucker gap or closer pri-sec coupling (now
> 4cm)...? Otherwise my TCT shows good resonance at 180KHz.
>
> Details, photos and vids at http://bb.cactii.net/archives/000176.php
>
> Ben
>