Re: Streamer length vs. power delivery time...

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Steve,

At 04:42 PM 6/17/2005, you wrote:
> Hi Terry,
>
>
> > I wrote up a little blurb comparing my DRSSTC and Steve's.  It would appear
> > that the power delivery time is pretty critical:
> >
> > http://drsstc.com/~terrell/modeling/StreamerTime.pdf
>
> More to think about now.
>
> But there is one big detail that doesnt make sense.  That being, my
> bang energy *cant* be that small!  When i do a pspice simulation of my
> coil, i get the following energies per shot for the given cycles of
> operation:

The graph is showing commutative "streamer energy" not coil 
energy/bang.  The second to the last page lists your total bang energy at 
15.476 joules.  At 120 BPS, that is 1857 watts.


> Primary Cycles  / Streamer Energy
> 6       / 8.7
> 6.5     / 9.6
> 7       / 10.6
> 7.5     / 11.6
> 8       / 12.6
> 8.5     / 13.5
> 9       / 14.5
> 9.5     / 15.4
> 10      / 16.4
> 10.5    / 17.3
> 11      / 18.2
>
> The text didnt paste too nicely, but i think you can figure it out.
> To figure out the energy per shot, i just did the integral of the
> power through the streamer resistance: s(W(Rstreamer)) is what i used
> for pspice to do its math.  Is this a valid method?  When i integrate
> all of the energies in the tank circuit (including the losses) i end
> up with almost exactly the same energy that is in the streamer (which
> it should be).

Our numbers are a little different but pretty close.  But you say this is 
"streamer energy" into the 220k ohm load resistor?  I think you mean total 
bang energy.


> Im running 9-10 cycles right now which suggests ~15J, which agrees
> with the fact that i was slowly blowing 15A fuses when operating on a
> 120V line at 120bps.  The large filter capacitors explain why the 15A
> fuses are going.  Pspice says the line current would be 23ARMS in the
> case of 15J shots at 120bps, but i only modeled the line with .2ohms
> of resistance, while it might be higher, and i didnt try to figure in
> the inductance since its just 60hz.  Im not sure how much current is
> needed for a fuse to blow out slowly (these are just standard "speed"
> fuses, not slow blow or anything).
>
> Anyway, assuming 15J/shot, that would exactly match the spark length=
> 1.7 SQRT(bang energy X 120).
>
> So why does ScanTesla suggest im only running 6-7J per shot??

I am using "streamer energy" not "bang energy" in the graph.  Just a matter 
of which data column I picked up in the graph.  No rhyme nor reason that I 
did not pick total energy I guess that is what the program just happened to 
be set for...  But no problem, everything is ok.  I got 15.476 joules...



> >
> > I suppose we could pull the old coil data bases with a zillion coils
> > reported in it and actually try to find the function...  That would be the
> > Freau equation's constant for streamer length vs. power delivery time...  A
> > bit of a time consuming project but if we had about 20 data points, maybe
> > the line would be straight ;-)
>
> Hah, good luck!

Have to wait for a day when I am really board ;-))  But If I make the 
program just print this out, we will soon get new data anyway.  I think I 
can even print out the Freau number too since all the number should be 
available...  Have to think on that.  That number should probably be in the 
metric system too...  I think all the other numbers in the program are free 
of English vs metric system problems...  I think it needs a BPS number in 
there as well...


> >
> > Perhaps we should define a new "term" to describe "power delivery time" and
> > define it better.  Like the time it takes to deliver 90% of the bang 
> energy...
> >
> > Lets NOT use the term the Marx generator folks use :o))
>
> Yeah, "rise time" is not the best term here.  I cant think of a better
> term though...

What's wrong with "rise time"!!!  Just the plain old 10% to 90% rise time 
for streamer or bang energy...  QED...  That would be simple to add to the 
readout in the program.  I can mention"rise time" in front of groups of 
people too ;-)  I am going to call it a rise time...

I have not played with the model you sent me yet, but I will.

Cheers,

        Terry



> Steve
>
> >
> > Cheers,
> >
> >          Terry
> >
> >
> >