Re: Rotary Spark Gap and NST ? ? ?

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <FutureT-at-aol-dot-com>

In a message dated 7/21/02 12:00:51 AM Eastern Daylight Time, tesla-at-pupman-dot-com
writes:

Jonathon,

ARSG's have certain benefits in certain situations.  For example
if an experimental coil is built, and one does not know the best
break rate, an ARSG can be run at various break rates to find
the best rate.  Also, in a DC coil, an ARSG is excellent for
varying the power to the coil, and the spark length.  Also,
at high breakrates, it makes much less difference if a rotary
is SRSG or ARSG, so the ARSG makes for a simpler design.
A good transformer can easily withstand any erratic firing
aspects of an ARSG.  Even at lower breakrates, an ARSG
can give excellent results with a good transformer, and the
the transformer will not be damaged.  Most of
the problems with using ARSG's with NST's is because the
NST output is so feeble, that firings may be skipped at certain
calculated breakrates, or at very low breakrates, letting the voltage
go extra high, or causing kickback.  This is less likely to occur with 
a more powerful transformer.  Whether the capacitor charges fully for
its position on the sine wave has much to do with the value of 
the capacitor, and the transformer current, not only on the breakrate.
With an ARSG system, components can simply be chosen to
withstand whatever voltages are present.

Another thing to consider is that most of the conclusions about the
use of ARSG with NST's date back to an earlier day, when 
safety gaps and protective filters were not always used.  This made
NST failures much more likely, and may have caused incorrect
conclusions to be drawn.  Another important factor is that matched
(resonant) value caps were used in those days, which made NST
failure with ARSG's much more likely.  The modern advent of 
LTR mode systems makes failure much less likely in *any* NST
TC system.  Still another factor that may have led to the failure
of many NST's in the old days was the use of protective chokes,
which often contributed to NST destruction (via resonant effects),
rather than its protection.

Cheers,
John


>
> This brings up the question: WHY? use ARSGs? Is it THAT hard to convert to
> SRSG? The cap would charge fully, and there is less chance of over-volting
> components...
> ---------------------------------------
> Jonathon Reinhart