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Quenching & ring-down time

Subject:  Quenching & ring-down time
  Date:   Wed, 16 Apr 1997 20:07:47 -0700
  From:   "DR.RESONANCE" <DR.RESONANCE-at-next-wave-dot-net>
    To:   "Tesla List" <tesla-at-pupman-dot-com>


Hello John:

Noted your excellent research on quenching.  Was wondering if you noted
any correlations between ring down time and dwell time as calculated by:

 d / v     where d = electrode dia and v = electrode speed (in/sec)

also if this data has any direct correlation with actual quench time.

The difficult part in using d as defined above is that we don't always
know exactly where the spark will strike as the electrode approaches and
also where it stops.  This is a complex function as it relates to the
effects of air turbulence in the vicinity of the electrodes.  This
changes dramatically with changes in the design of the rotor and
electrode configuration.  Best we can do is hope for data that applies
to one specific design and perhaps extrapolate some key ideas to other
designs.

DR.RESONANCE-at-next-wave-dot-net

> All,
> 
> In todays tests, I first tightened the coupling, then went back and
> re-checked the quench at lower power.
> 
> At k = .11, I had been obtaining 1st notch quench at 2640VA.  >Tightening to about k = .13, still obtained 1st notch quench.  >Tightened further to about k = .16, but the quench moved to the >second notch, and racing sparks destroyed the secondary by burning >through in two places.  Small incremental changes in sec. height >were unable to bring about 1st notch quenching at these tighter
> couplings.  Quality of quench seems extremely dependent on tightness of k value, magic k values seem to provide a small benefit in quenching. 
> Good tuning is is a prerequisite for good quenching.  By changing >the tune point by one turn, the quench moved from the 1st notch to >the 2nd notch and stayed there when a streamer hit a ground.  With >proper tune point, quench moves to the 2nd notch only when spark >hits a ground.
> 
> Next I patched up the secondary and changed the system back to >360VA to see if the recent sync-gap modification would improve the >quench at low power.
>  Originally, the electrodes were less than 1/8" in dia, now they >are over 1/8" in dia.  The quench has now improved from the 2nd >notch to the 1st notch.  In addition, the gap originally had 12 >series gaps, now it has 8, but the benefit of the wider electrodes >has overwhelmed this change.  Wider electrodes for better cooling >and quenching were recommended by Dr. Resonance,  by Bert H. and >probably others.  I do not know if using even wider electrodes would >improve the quench at these power levels, it seems there would be a >point of diminishing returns.  Free ringdown time is now about 120uS >due to the higher frequency which results from this smaller
> (4" x 17") toroid.  Basically, I did not see any change in spark >length (still 37"> to 39") for 1st notch versus 2nd notch quenching. >I think this is because even when the gap quenched on the 2nd notch, >very very little energy was left in the second energy packet, so it >just didn't make much difference.  I lowered the secondary to 5/8" >above the primary (about k = .16), still quenched (mostly) on 1st >notch, and another streamer started to form. 
> My next test will be to tighten the coupling even more, and see >what happens.
> 
> After that, I may go to a non-sync system to compare small-cap, >high break-rate operation with my previous (above) results.  I will >be looking at overall efficiency, and ease of quenching.
> 
> Comments welcomed,
> 
> John Freau