Re: Coupling vs secondary voltage chart

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Steve Ward <steve.ward@xxxxxxxxx>

Terry!

On 6/16/05, Tesla list <tesla@xxxxxxxxxx> wrote:
> Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>
>
> Hi Steve,
>
> The program says that your coil should work better at k=0.18 !!

Program appears to be right!!

Just lowered the K to ~.18 according to JavaTC9.1.  I also arranged to
run the coil on my 240V line so i dont have to worry about the 15A
120V breaker ;-).  Solid 6 feet at about 80% input (out of 280VAC) and
only requiring 150uS burst lengths.  At full 85% input i got some 80"
strikes!  I didnt dare push to 100% yet.

The MMC is running very hot, and i saw a small flash on one of the
caps again.  So i gave it a break and tested the capacitance on my
meter, still 451nF dead on!  Fire it back up and it just spits out
those 6 footers plus some as i increase the BPS to 150 or so.

>
> There is more power delivered to the streamer and it is delivered faster!!
>
> I wrote a file explaining it (sort of quickly thrown together...) at:
>
> http://drsstc.com/~terrell/modeling/WardsCoil-18vs25.pdf

Cool, thanks.

I need to throw my current transformer on there to see if my waveforms
match the waveform shown there.  I notice im not tuning the primary
super low anymore but still at 13.3uH according to javaTC.  Thats a
little lower than what TeslaScan says should work (says 12.2uH).
Maybe i should tune it a little higher next time ;-).  But the
difference is like a 1/4 turn... so i'd say thats fairly good!

>
> The chart on page three shows the streamer energy (joules) as a function of
> time.  Blue is the K=0.18 case and read is the K=0.25 case.  The higher K
> is actually hurting the speed of the power delivery and apparently wasting
> more of the coil's energy.

Wow, that is very cool to see!  Looks like i get another .5-.6J per
shot in there.  It would be nice to know the actual power draw on the
240V line, but those darn filter caps mess up the current waveform so
much you cant get a good number.  7J per shot just seems small for 6
foot sparks, does it not?

>
> The delivered power to the load goes from 6.253J to 6.822J and the power is
> delivered about 20 to 50uS faster.

Yes, i noted that i was getting 6' at 2 cylces less than before (which
is about 20uS).

  The primary currents go down a tiny bit
> and the capacitor voltage goes up about 100V so not big deal
> there.  Primary frequency goes up a tiny bit.  Secondary peak voltage is a
> tiny bit lower.

I'm quite surprised to see the program says my cap voltage stays under
4kV.  Maybe that other capacitor got so hot that the plastic just lost
its dielectric strength?  I cant imagine how hot they are on the
inside when they feel uncomfortable to touch on the outside.

>
> If you get 72 inches now, changing the k to 0.18 might increase that to 72
> x SQRT( 6.822 / 6.253 ) = 75.2 inches.

Or better ;-).

>
>
> This is using the programs new "streamer power vs. time" function.  It
> shows the energy delivered to the streamer as a function of time.
>
> The latest program is here:
>
> http://drsstc.com/~terrell/modeling/ScanTesla620.ZIP

I should really download it an mess with it some more, try entering in
parameters for my other coils and see what it says will work better
;-).

>
> Sorry to keep updating the program all the time.  But I just keep adding
> new features as I want ;-))  I need to write general instructions for it
> too....

Yes, instructions please!  Especially for me, im not good at just
figuring out programs like this, but i shouldnt comment until i
actually look at it.

I surely hope this whole event wasn't some fluke and that the program
really is giving out good information.  It really does seem to right
so far!

Steve

>
> Cheers,
>
>          Terry
>
>
>
>
>
> At 12:41 PM 6/16/2005, you wrote:
> >Heh, thats pretty interesting that K=.25 is the peak output.
> >
> >Looks like i could even back off the K to .18 or so and still probably 
be ok.
> >
> >Its interesting to see that the graph looks smoother at the very low
> >K's.  If these predictions are in fact meaningful, i would be curious
> >to see you operate your big coil from a K of say .03 to .12 or so and
> >see if peak performance lies at the peak in your graph there.
> >
> >So i wonder what causes this difference in coupling preference, is it
> >the tank circuit or the secondary characteristics?
> >
> >Maybe you could try a different tank impedance on your big TC, say a
> >.5uF cap and whatever primary it would need to tune with then and see
> >what K it prefers?  Or maybe try my secondary specs with a .05uF tank
> >cap or something and the needed L to retune.  That seems like it might
> >cover most of what DRSSTC builders might come up with... the next
> >thing would be to put these results to the test.
> >
> >And, good work Terry!
> >
> >Steve
> >
> >On 6/16/05, Tesla list <tesla@xxxxxxxxxx> wrote:
> > > Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>
> > >
> > > Hi Steve,
> > >
> > > The graph is at:
> > >
> > > http://hot-streamer.com/temp/KvsVtop-SteveWard-DRSSTC.gif
> > >
> > > It would appear your K of 0.25 is perfect!  The first low K hump is 
there
> > > but far lower down for your coil.
> > >
> > > The graph of my other big coil at 140uS is at:
> > >
> > > http://hot-streamer.com/temp/KvsVtop-BigCoil-DRSSTC-140uS.gif
> > >
> > > Cheers,
> > >
> > >          Terry
> > >
> > >
> > > At 11:00 PM 6/15/2005, you wrote:
> > > >Hi Terry,
> > > >
> > > >Let me just enter my values right into the text below:
> > > >
> > > >On 6/15/05, Tesla list <tesla@xxxxxxxxxx> wrote:
> > > > > Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>
> > > > >
> > > > > Hi Steve,
> > > > >
> > > > > The model is running now at 140uS...
> > > >
> > > >Did it change the coupling vs Vsec graph?  OR when you say its
> > > >"running" do you mean its currently crunching numbers?
> > > >
> > > > >
> > > > > If you send me the following data on you coil I can run it.  My
> > coil might
> > > > > be substantially different than yours.  The coil I modeled was
> > never meant
> > > > > to be a DRSSTC.
> > > > >
> > > > > Lprimary =14uH (though it might be 2-3uH lower)
> > > > > CPrimary =450nF
> > > > > K =.25 (this is a changing parameter, right?)
> > > > > Lsecondary =130mH
> > > > > Csecondary =38pF
> > > > > Streamer length =72"
> > > > > Rail to rail buss voltage =400V
> > > > > T1 on time =175uS
> > > > > Current limit =850A
> > > > > BPS =120
> > > > > Max coil power =1800W (might be less... the killed the 
kill-a-watt with
> > > > my SGTC! arggg!!)
> > > > > If the coil is on your site, which one is it?
> > > >
> > > >The DRSSTC-1
> > > >
> > > >http://www.stevehv.4hv.org/DRSSTC1.htm
> > > >
> > > >I look forward to what your program spits out ;-).
> > > >
> > > >Steve
> > >
> > >
> > >
>
>
>