Re: Calorimeter response #1

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

Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>

Hi Paul and All,

At 03:28 PM 1/18/2001 +0000, you wrote:
snip...
>> 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.
>
>Yes, we have yourself, Gary, Terry, and a recent posting by John
>Freau on a closely related observation - John, I'm still pondering
>the latter. It's good to see the interest in making loss and load
>measurements, but somehow the efforts are disparate.

Indeed, the work so far has been sort of a demonstration that measurements
in this area simply "can" be made with the equipment we have.  In my case,
I was just trying to see if all the test equipment would work with little
regard as to the results and what they may mean.

>
>Guys, there's a problem here. We have to specify what we're looking
>for. Me - I want to know what the effective impedance of the breakout
>loading is, as a function of frequency, top voltage, and resonator
>geometry - a tall order. By looking at the view from the coil base,
>the picture is somewhat complicated by the effect of resonator losses,
>which is a minefield of traps for the unwary. Now I'm as interested in
>resonator losses as anyone, but for the present the breakout loading
>seems to be the issue we ought to focus on (+). In which case, I think
>the approach used by Terry and partially described in his notes at
>
> http://hot-streamer-dot-com/TeslaCoils/MyCoils/CWCoil/CWImpedance.txt
>
>has a lot going for it. Simultaneous measurements of coil top voltage
>and top load current allow us to gauge the breakout loading directly,
>without concern for what's going on in the coil beneath.

I can measure forward power, reflected power, and at a fixed frequency (the
power supply strictly controls frequency).  I can also see input voltage
and current.  I can see streamer current and get darn close to measuring
the top voltage.  All in real time, phase accurate, and DSO recordable.  So
I have all the tools.  I have placed pretty high priority on getting my CW
coil going again this week.

>
>Richie, I agree, the constant current at the base is a reflection of
>a constant voltage characteristic at the top. The thing is it won't
>be quite constant voltage - and to assume so throws the baby out with
>the bathwater. What needs to be looked at is just how the load voltage
>and current vary in the approximately constant voltage regime above
>breakout. Somewhere within that non-linear regime is an equilibrium
>point - a condition of optimum coupling to the load, which I would
>like to be able to model and calculate. The essential experimental
>data from which this would come doesn't appear to exist in the Tesla
>community and the tentative results so far put forward by
>experimenters such as Terry and Gary are mere forays into the topic
>compared with the concerted effort that would be required to make real
>progress.  So my request to the experimenters on this list is to stop
>giving us tantalising snippets and to join heads in a coordinated
>effort to map out the characteristics of load impedance.

Yes!  Start thinking about the type of tests you want run.

>
>On the subject of humidity effect - Gary's observations are a real
>eye opener and may go some way to accounting for the apparent day to
>day variability of Q measurements. We've given Gary a heap of
>suggestions to follow up and I hope the he can find a way to discern
>just what the humidity loss mechanism is.
>
>(+) The reason being that for impulsed coils, the secondary Q appears
>to be of little consequence - performance being determined by the 
>primary gap losses, and the ability of the secondary resonator to
>couple effectively to the breakout loading. If we ever want to say 
>what the optimum design of a secondary is, for a given power level, we
>must try to get some kind of handle on the load impedance.

I think CW coils are the next step.  They are well behaved and consistent.
They can also be far more easily probed and studied by many people.
Disruptive coils have many variables and that data would just be too messy
to deal with at this point IMHO.  The staccato coils are also a new area
that needs looking at.  They have very good performance and would be easy
to study.  My generator has a 0-10V input that controls either forward or
delivered power.  I am pretty sure it has the bandwidth required for such
studies.  I don't have an arbitrary waveform generator but that would be a
valuable tool for this study.  I will be interested in the circuit that was
mentioned earlier for this task.

So tons of work to do in this area.  I think this will be my focus in the
near future.

Cheers,

	Terry


>
>Regards All,
>--
>Paul Nicholson,
>Manchester, UK.
>--
>