Re: RSG and NST's

["Tesla list" <tesla@xxxxxxxxxx>]

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
>
>
>