Re: Test Coil, bi-dir RSG2

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Malcolm Watts" <m.j.watts@xxxxxxxxxxxx>

Hi Chris,

On 12 Jul 2005, at 14:41, Tesla list wrote:

> Original poster: "Chris Rutherford" <chris1@xxxxxxxxxxxxxxxxxxx>
>
> Hi All,
>
> I've now got a variable speed RSG, its made of bidirectional rotating
> disks powered by a pair of DC radio control car motors, it looks nice
> and sparkly :-)
>
> www.hackinghardware.com/rsg2.jpg
> www.hackinghardware.com/sparkoids.avi
>
> It has a rotational speed range of 0 to about 3000bps (8*8*RPM/60),
> and I've not yet fried my NST (now 2 in parallel giving 500VA).
>
> I've taken 2 photos of my scope, one is where I get no breakout on my
> secondary, and one where I do (at different speeds).  As you can see
> on the first photo, it looks like the 3rd node is dumping all the
> power back in to the primary where it is 'disapearing'.  The second is
> where I get breakout, and it looks to be operating in the 2nd node
> area, can anyone confirm this? Is it possible to get a first node
> system, or is it too hard to do using spark gaps?

It is not something that you specifically engineer for. It is one of
those things that just happens if the output arc optimally loads the
system. I think you are speaking of what is known as first notch
quenching? Optimal loading occurs when the arc is (a) attached to
some object with significant coupling to ground and (b) is close
enough to give a bright arc channel but no closer. You can perform a
simple expt to see for yourself. Move a ground rod in towards the
terminal from afar and scope the waveforms as you go. Note also the
change in brilliance of the primary gap discharge! If the rod is too
far away, the gap discharge will be bright showing prolonged energy
trades (and more energy dissipated in the gap). If the rod is too
close, energy no longer gets into the secondary easily (gets
reflected back to the primary) and once again the gap discharge
brightens. Under optimal loading conditions, the gap discharge is
dimmest and the output wil be dissipating the lion's share of the
primary energy.

Malcolm