Re: Best RSG ever?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Luc by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ludev-at-videotron.ca>

Hi Gregory,

Why not trying it it should help, but if we want to resume here
the "natural" way for quenching a gap; first you want your coil
to produce a spark as fast as possible this way the secondary
stop to return energy to the cap by the primary and second you
need a cap the right size to the current of your power supply.
What cause the gap to quench is the fact that the cap represent a
lower resistance to the PS than the gap. If the cap is to small
it never empty and is resistance stay higher than the gap or if
your coil could not transform the energy in streamer fast enough
the cap again stay partly charge preventing the quench. Past a
certain amount of energy the coil is able to process the extra
energy will only make your gap harder to quench. Many way could
help a gap to quench most are design to eliminate the ions as
fast as possible some make the current low for a short period of
time after the bang ( inductor ).

Cheers,

Luc Benard
 

Tesla list wrote:
> 
> Original poster: "Mr Gregory Peters by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <s371034-at-student.uq.edu.au>
> 
> Last night, I was thinking about my airblast/RSG arrangement, and came
> up with an idea that may or may not be original, but which I think has
> great potential. Firstly, let's discuss the role of an RSG in a Tesla
> coil. I'm no expert on this subject, and I'm no electrical engineer.
> But I have read lots of books and have had practical experience. Think
> of the following as me "thinking out loud". I may be barking up the
> wrong tree here.
> 
> Now, in low power systems, an RSG with no static gaps is fine. It will
> quench the spark quite well by itself. The role of the RSG is to
> control the "switching"  rate of the primary capacitor. This has two
> aspects. Firstly the breaks per second, which we all can appreciate the
> importance of, and secondly the dwell time, or time that the electrodes
> are within a close enough proximity to allow arcing to occur. It is
> well known that, up to a point, the smaller the dwell time the better.
> A problem that arises in high power coils is that the switching
> efficiency of a sole rotary gap decreases. The arcs tend to "follow
> `round", or continue to occur for a short distance after the rotating
> electrode has passed the stationary electrode. This effectively
> increases the dwell time and lets primary voltages drop significantly.
> This effect is similar to an air blast static gap running without the
> air blast - the arc just won't go out, the caps don't charge well, and
> the coil output is reduced as the gap is over powered.
> 
> Traditionally, to combat this, the clearance in the rotary gap is set
> as small as possible. A static gap is placed in series. In this
> arrangement, the static gap (air blast or similar) takes care of the
> quenching, and the rotary is used purely as a device to control the
> BPS. The result is better performance and longer RSG electrode life.
> 
> Now, last night I thought "why not combine the two gap types in the one
> unit?" My idea is to pass, say, 150 psi of air through the CENTRE of
> the stationary RSG electrodes. This has several advantages. Firstly,
> follow `round is reduced and quenching is improved. So coil performance
> is better. Secondly the rotary and stationary electrodes won't get as
> hot. So maybe we can forget about using tungsten electrodes, and use
> cheaper disc materials that don't need high temperature abilities.
> 
> One way I have thought of doing this is to make the stationary
> electrodes from copper pipe. You could hammer the end of the pipe until
> it is almost flat. If you align the flat pipe perpendicular to the
> rotating electrodes, the width will be less than 1/4", so the dwell
> time will still be quite small. You would then blow air through this
> pipe. The air would spread out, like a garden hose nozzle. It would
> quench the arc and would also cool the stationary and rotating
> electrodes and also the RSG rotor in the immediate vicinity of the
> rotating electrodes. This would help prevent melting of the rotor and
> would increase the life of the electrodes. What do you think?
> 
> Cheers,
> 
> Greg Peters
> Department of Earth Sciences,
> University of Queensland, Australia
> Phone: 0402 841 677
> http://www.geocities-dot-com/gregjpeters