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Re: More real experiments

Tesla List wrote:
> 
> >From hullr-at-whitlock-dot-comTue Nov 12 22:35:46 1996
> Date: Tue, 12 Nov 1996 16:45:50 -0800
> From: Richard Hull <hullr-at-whitlock-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: More real experiments
> 
> Well gang,
> 
> I have been busy over the weekend with my Pearson current monitor and
> capacitive HV voltage divider.  I physically measured the voltge across
> the gap and current through it while the coil was in operation.  In an
> effort to find the power consumed by the gap in operation.
> 
<SNIP>

> Due to my using a variac and only allowing the AC line voltage to reach
> 28 volts in to the neon's primary, I measured a peak voltage out from the
> transformeers secondary of 2640 volts.
> 
> This showed up as the max voltage across the non-firing gap.  Firings at
> the gap showed a rather immediate fall to ~200 volts.  The  current
> transformer indicated a peak current in the system at this point of ~80
> amps.  Thus under the optimal conditions the gap had a lowest possible
> resisitance of 2.5 ohms. (The gaps were hardly making any noise!) For the
> instant of max turn on, the gap consumed 16,000 watts of peak energy.
> The peak tank energy in our little 15VA system would have been on the
> order of 160,000 watts. based on a 2KV firing point and 80 amp tank
> current.  10% losses figured this way.
> 
> The scope was set up to yeild a mathed third trace as A X B  yielding
> volt amps.  This was intergrated by hand with time to yield a total sine
> consuption of energy on the order of 1.6VA.  With the power factor
> corrected primary hooked to a watt meter we read 15.1 VA while the system
> was on (auto integrating).  This shows that we lost about 10% of the
> input energy in the gap on average.  Another cross confirmation.
> 
> Caveats:
> 
> The gap shunted the transformer out to such a degree that the transformer
> voltage followed that of the gap!  There is good news and bad news.
> (ain't that the way!)  The good news is that the power drain on the
> primary side was not nearly as bad as if a non-shunted transformer had
> been used.  This allows for a simple watt meter to be used with little
> error due to non-upset of the input voltage. (no odd waveshapes or
> spiking)
> 
> The bad news is that the high impedance of the secondary also caused the
> voltage to stay low for a protracted period (as much as 3ms-.003sec!!!).
>  This was due to cap shorting of the secondaary as it continued to bring
> the little transformer to its knees while it charged.  The charge time
> reflected the RC time constant of the high impedance secondary.  With a
> .008ufd capacitor this indicated a TC of about 600us  (.003s/5).  Thus, a
> rough idea of the charging impedance was on the order of 75,000 ohms!!
> This effect also aided in quenching the gap very well.  I detected only 5
> cycles in the current ring extending over only 10us! Again, peak current
> in the primary tank was on the order of 80 amps.
> 
> The gap consisted of 6 series static gaps (tungsten).  The operation is
> so quiet as to be virtually inaudible. (to these old grizzled ears.)
> Spark output at this level to a grounded rod is under 4".  At not time
> during measurement was a spark taken to ground.
> 
> I am sure that had a non-shunted transformer been used the voltage would
> not have hung around the zero axis so long after gap quench.  The
> capacitor TC would have improved, the quench might have actually
> worsened, system power consumption at the same peak cap voltage would
> increase due to increased gap losses and additional firings per half
> cycle (cap could come back on line more rapidly than in shunted system).
> 
> Basically, I got about 4 pops per cycle.  It varied wildly too, from 3
> per cycle to 5 per cycle. (~240BPS).
> 
> Experimenting will continue to obtain real data.  Note, I would not read
> a whole hell of a lot into this crap!!  These results are for one system
> with very specific size, frequency, gapping, top loading, operator skill,
> etc.
> 
> The neat thing is that it showed the old venerble neon transformer to be
> a good quenchin' thing, helping us out a bit and limiting the number of
> pops per cycle.  It further points up the old maxim I coined a few years
> back.  "Rotary gaps on a neon system are valuless"!  In general, they
> just are not needed nor desired in most any scenario involving one or two
> neon transformer systems.
> 
> Richard Hull,  TCBOR
> 
> P.S. good to get away from the theoretical bullshit once in a while.
> Back to some good ole "rolled up sleeve" engineering!


Richard,

Great information, with great equipment! Any idea what the total gap
length was?? 6 gaps and 200 Volts implies about 33 volts/gap, and about
0.4 Ohm/gap - NOT BAD performance at all! What's the faceplate current
rating on your little neon?

-- Bert --