Re: RSG and NST's

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Dr. Resonance" <resonance@xxxxxxxxxx>


We run them around 380 bks/sec without problems.  I do agree, the lower
break rates might cause problems especially if the xmfr is not protected
with a safety gap.

Dr. Resonance

Resonance Research Corporation
E11870 Shadylane Rd.
Baraboo   WI   53913
>
> I don't agree that the hazard associated with async RSG's and NST's is
> due to excessively high break rates.  With an NST, as an RSG's break
> rate increases, the bang voltage will go down, making it LESS stressful
> to everything.  The same effect may be achieved by reducing the spacing
> of a static gap - lower bang voltage and higher bang rate - and I think
> all agree that narrow static gaps are the least stressful.  Even if bang
> voltages did not diminish with increasing BPS, I still don't see how the
> NST would be any more stressed at higher BPS.
>
> On the other hand, it's easy to demonstrate via simulation the
> consequence of having a too-slow BPS, resulting in mains resonant-rise.
>
> I'll be the first to admit that my opinions are based solely upon theory
> and simulations, and I have not personally attempted an async RSG and
> seen an NST fail. If you have experience demonstrating that high BPS is
> in fact more stressful, I would enjoy hearing it, as well as your theory
> as to the actual stress mechanism that increases with BPS.
>
> Regards, Gary Lau
> MA, USA
>
>  > -----Original Message-----
>  > From: Tesla list [mailto:tesla@xxxxxxxxxx]
>  > Sent: Friday, November 26, 2004 8:07 PM
>  > To: tesla@xxxxxxxxxx
>  > Subject: Re: RSG and NST's
>  >
>  > Original poster: "Dr. Resonance" <resonance@xxxxxxxxxx>
>  >
>  >
>  > Technically, a NST is designed to provide an ignition voltage for a
> plasma
>  > tube, ie, 9-15 kV to quickly ignite the gas in the tube, and then the
> xmfr
>  > voltage drops back considerably, usually down to 400-600 VAC to
> sustain the
>  > plasma.  At this point it becomes a current source to keep the plasma
>  > bright.
>  >
>  > In short, a NST is not designed to provide a continuous source of HV.
> They
>  > do, and they work well with TCs firing 120 bks/sec.  They will also
> work at
>  > higher break rates but one must be very very careful to provide
> excellent
>  > filtering to prevent ANY high freq transients from getting back into
> xmfr
>  > windings.  A "Terry Filter", named in honor of its inventor, Terry
> Fritz, is
>  > commonly employed to provide this high level of filtering.  Perhaps
> Terry
>  > could post this location in his extensive archives collection.
>  >
>  > http://hot-streamer.com/TeslaCoils/Misc/NSTFilt.jpg
>  >
>  > The other area, that must be carefully monitored, is the total spark
> gap
>  > setting when running a NST.  Usually 0.220 to 0.250 is the absolute
> MAXIMUM
>  > total spark gap setting that should be used with a NST.  Larger gaps
> invite
>  > problems and failures on the NSTs.  It's always advisable to keep your
> total
>  > gap setting at the maximum size (or less) that provides the
> performance you
>  > want.
>  >
>  > RSGs can run asynchro IF you use a good filter with safety spark gaps
> and
>  > total gap settings in the recommended range.  Not using all these
> cautions
>  > invites trouble.  I would suggest less than 400 bks/sec as a max for
> NSTs.
>  >
>  > I've been working for quite some time now for a reliable replacement
> for the
>  > NST especially since the 60 mA units seem to be disappearing rapidly
> from
>  > local suppliers.  Our unit contains two separate 8 kV coils and a LOT
> of
>  > mylar under both coils so they can be either operated as a CT ground
> unit
>  > (like NSTs) or, the coils may be connected in series, for a 16 kV to
> ground
>  > unit.  These units are designed to be operated in oil so that the
> final
>  > product should be quite robust.  A standard "Tupperware" type plastic
>  > container will serve as a suitable xmfr tank.  For greater mobility,
> we
>  > intend to offer a steel tank with a phenolic top that is sealed with a
>  > gasket.
>  >
>  > There has been a lot of delays.  We finally received the two sets of
> test
>  > coils and are awaiting the laser cut cores from Magnetic Metals.  We
> hope to
>  > have them in our lab and tests completed prior to Dec. 20th.
>  >
>  > After that, we can start ordering production quantities which will
> determine
>  > final pricing of these units.
>  >
>  > Dr. Resonance
>  >
>  >  >
>  >  > Several posts lately are discussing the use of rotary spark gaps
> with
>  > NST's.
>  >  > I was under the impression that a RSG was not for use with NST's as
> they
>  >  > cause them to fail.  Is this not right?
>  >  >
>  >  > randyaz
>  >  >
>  >  >
>  >  >
>  >
>
>
>