Re: Calorimeter response #1

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

Original poster: "R.E.Burnett by way of Terry Fritz <twftesla-at-uswest-dot-net>" <R.E.Burnett-at-newcastle.ac.uk>


Hi Gary, Paul, all,

Thankyou Gary, for another very interesting post about resonator
behaviour.

I have also noticed this drop in Q,  (and increase in base impedance) of
my SSTC resonator in damp foggy weather.  The usual climate here in UK :(
This was accompanied by a noticeable reduction in current draw,  and spark
length.  (My secondary is 3.25"x13" cardboard form.)

> Original poster: "Gary Johnson by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <gjohnson-at-ksu.edu>
> 
> like the resistance of a linear RLC model ought to act. Above breakout,
> however, the coil changes from constant impedance to constant current. If I
> get a 3 inch plume at 300 V and 1 A input, then at 400 V input the plume is
> somewhat longer, but the input current is still 1 A. And no, the phase
> between voltage and current has not changed. I am still thinking about a
> good explanation for that. If anyone has a good explanation, I would
> appreciate hearing it.

It seems to me that once breakout is reached,  the resulting corona
"clamps" the terminal voltage at (or just below) the breakout
voltage.  The impedance inversion property of the 1\4 wave resonator
seems to make this appear as a constant current at the base.

In my tests the resonator impedance increased steadily with spark length,
but input current,  and toroid voltage remained essentially constant as
described in Gary's old paper.  Available for download here:

http://hot-streamer-dot-com/TeslaCoils/OtherPapers/GaryJohnson/*.jpg

Paul,  have you seen this paper ?

I also saw a drop in resonant frequency as the corona grew.  My tests were
quite rough so I haven't presented any results on the list,  but will try
to quantify the impedance and detuning at a range of powers above
breakout if I can.

It seems that we are now in a position to understand resonator behaviour
far better,  thanks to the great work being done by list members.

						Cheers,

						-Richie,