Re: NST power rating -- another perspective

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

Original poster: "Malcolm Watts" <m.j.watts-at-massey.ac.nz> 

Hi Gerry,

On 8 Oct 2003, at 18:11, Tesla list wrote:

 > Original poster: "Gerry Reynolds" <gerryreynolds-at-earthlink-dot-net>
 >
 > John
 >
 > I absolutely agree with you.  Power transfer is NOT a simple match the NST
 > output impedance I think some have questioned.  This simple matching, I
 > believe,
 > does work for linear loads for the case where you match the load resistance
 > to the transformers equivalent resistance and operate at resonance.  Clearly
 > would stress the transformer.  If you disagree with this, I would be
 > interested in your reasons.

Being pedantic, how does a transformer with a matching resistive load
resonate or am I missing something?

<snip>
 > My current experiment is the real problem I want to focus on.  I want to
 > verify Terry's pi/2 * Cres derivation (at least to my satisfaction) in a
 > real TC system.  The experiment is to vary Cp and measure spark length in a
 > controlled way.  The safety SG is set to fire at predetermined value and is
 > left unchanged during the measurements.  At the Cp being tested, the main
 > gap is wided until the safety SG fires occasionally.  The spark gap voltage
 > and quench time is measured with a scope.  The secondary streamer lenght to
 > free space, distance between topload and grounded rod when corona begins to
 > occur from the rod, and distance between rod and topload when a power arc
 > occurs are measured.  I don't have a good way of measureing BPS so i can't
 > even infer the power being delivered.  I don't have a watt meter so I can't
 > measure the wall power.  I'm trying to make the best use of the resources I
 > do have.

You can see gap firings as transient spikes on a scope fitted with an
aerial probe and positioned some distance away. You'll find as Cp is
increased that streamers increase in length until gap firing becomes
irregular and  unreliable with a resultant decrease in streamer
length to the point where it fails to fire altogether. Loaded Q for
the system remains relatively high for the streamer-to-air case and
will result in multiple energy trades and subsequently increased gap
loss. Best power transfer efficiency results with attached output
sparks as does best quench with lowest primary gap loss with the
qualification that the longest attached streamers are best to meet
this ideal.

Malcolm