Re: More THOR Expts

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

Original poster: "mercurus2000" <mercurus2000-at-cox-dot-net> 

This is off topic, but I'm assuming that to get the stringy, thin sparks you
need a high break rate? Are there any other factors to increase the
"stringyness"?
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, July 30, 2004 10:50 AM
Subject: Re: More THOR Expts


 > Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com>
 >
 >
 >
 > We should also be asking "what is the best break rate to generate the best
 > spark appearance"?
 >
 > The long "stringy" spark appearance generated by a high break rate on a
 > classic design coil don't have as much character is sparks produced by a
 > synchro RSG.
 >
 > Unfortunately, the tradeoff requires Cres * 3.2 for a synchro system.
This
 > requires more capacitance and hence more $$$ spent.
 >
 > A non-synchro system, kept at a reasonable break rate in the 375-450 pps
 > range produces nice thick sparks without the "stringly" appearance.  A
 > synchro system produces nice bushy appearing sparks at 120 pps but usually
 > they are not as long as a higher charge pumping system in the 375-450 pps.
 > We prefer to run around 400-450 pps for most of our systems operating in
the
 > 5-15 kVA range.  Slightly longer sparks than synchro with a nice
appearance
 > before going "stringy".
 >
 > The beauty aspect of the pps should also be considered when searching for
 > the best looking sparks with a good length.
 >
 > This range seems to work well for both medium, and large coil systems.
With
 > small systems we usually run a stationary 2 or 3 gap sparkgap.  Using 1/2
 > dia. tungsten electrodes and 1/2 dia brass rod fitted to 1.25 x 1.25 inch
 > square brass blocks as a heatsink, good quenching and efficient operation
is
 > the result with nice looking spark on the output.  A mistake many small
 > coilers make is not using a large enough dia. heatsink and electrodes for
 > good cooling and quenching.  Even carriage bolt heads are an improvement
 > over small 1/8th and 1/16th inch dia. tunsten rod.  It works but the
 > electrode ends quickly heat to near red hot and the output spark
diminishes
 > as a result of poor quenching.
 >
 > Dr. Resonance
 >
 > Resonance Research Corporation
 > E11870 Shadylane Rd.
 > Baraboo   WI   53913
 >
 >
 >  >                 A question that needs to be answered is "what
 >  > determines what the useful maximum breakrate is?", "useful" being
 >  > defined as the breakrate beyond which no further increase in spark
 >  > length results. Some thought led to the hypothesis that the useful
 >  > breakrate will scale with secondary charge storage (i.e. capacitance).
 >  > I devised some expts which will hopefully prove or disprove this.
 >  > There is weak evidence already that supports this hypothesis, mainly
 >  > the results obtained by Richard Hull in his extensive work. My own
 >  > observations with a range of coil sizes also suggests this might be
 >  > true.
 >  >
 >  > Noting the highest useful breakrate for the current THOR
 >  > configuration:
 >  >
 >  > #1 - increase Ctop while maintaining the same ROC, and maintain the
 >  > same theoretical Vout by suitably increasing Cp or Vp (i.e. Ep). An
 >  > increased useful BPS would indicate a charge-available dependence.
 >  >
 >  > #2 - decrease Ctop while maintaining the same ROC and same Vout
 >  > (reducing Ep to maintain this). If the useful BPS increases, that
 >  > would throw my hypothesis out. If useful BPS decreases, there is
 >  > supporting evidence for the hypothesis.
 >  >
 >  > #3 - decrease Ctop while maintaining Ep to increase Vout (at this
 >  > point, I am not sure whether increasing or maintaining the same ROC
 >  > is the way to go - for completeness' sake it would be worth doing
 >  > both). Does the useful BPS change and if so, higher or lower?
 >  > If higher, it again negates the hypothesis.
 >  >
 >  > #4 - increase Ctop while maintaining Ep to reduce Vout (ROC may have
 >  > to be reduced to allow breakout). If useful BPS remains the same, it
 >  > would provide more support for the hypothesis.
 >  >
 >  > This list is by no means complete but should be a useful guide to
 >  > devising a complete set of tests. Some of these questions may already
 >  > have been answered but what I would like to see is the full gamut of
 >  > tests and results presented all at once. A key question I would like
 >  > to see answered is the degree to which sparklength depends on output
 >  > voltage and, separately, charge availability. My guess is that there
 >  > is a dependence on both but that charge availability is the more
 >  > dominant of the two. The enormous discharge from the 5MV Russian Marx
 >  > bank plus the behaviour of lightning seems to indicate this also.
 >  >
 >  >      The purpose of all this is to refine the design criteria for a
 >  > spark-producing coil, a goal I'm sure we'd all welcome being reached.
 >  > The general approach at present seems to be equivalent to grabbing
 >  > whatever components one has available and building something that
 >  > works. In the engineering world however, one does as much as is
 >  > needed to fulfil a design goal and no more (safety margins
 >  > nothwithstanding), size, weight and economics being the arbiters.
 >  >      This is also what I'd consider to be a rigorous (scientific if
 >  > you like) approach to coil building. Why throw a 20 x 5" toroid on
 >  > top of a coil just because it happens to be lying around if it makes
 >  > the finished product bulkier and heavier without actually
 >  > contributing to the performance? I think anyone building coils for
 >  > commercial gain (I am NOT one of them) would appreciate this way of
 >  > doing things.
 >  >
 >  > Malcolm
 >  >
 >  >
 >  >
 >  >
 >  >
 >  >
 >
 >