Re: ScanTesla program - Lowering the coupling may be better...

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Malcolm Watts" <m.j.watts@xxxxxxxxxxxx>

Hi Terry,

On 14 Jun 2005, at 13:15, Tesla list wrote:

> Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>
>
> Hi Daniel,
>
> I tried the following two runs which were looking for the maximum top
> voltage and then the maximum streamer power.  It scanned about 800,000
> combinations (DRSSTC case) varying:
>
> L1 = 10uH to 200uH step 0.5uH
> C1 = 10nF to 50nF setp 1nF
> K = 0.01 to 0.20 step 0.01
>
> L2 = 100mH
> C2 = 25pF
> Load = 4pF+220k
>
> In both cases, the optimal coupling came out to 0.04!  The other
> values were pretty much the same.
>
> The program tended to like high Cp values which also gave a fairly low
> peak primary cap voltage.  The primary current was only about 300
> amps.
>
> It is interesting that the two cases gave pretty understandable
> answers but the very low coupling seems to always pop up in the
> models.  I don't know what it means yet, but maybe something cool
> happens with very low coupling...
>
> Cheers,
>
>          Terry

I think your use of a fixed secondary load when trying to compute top
voltage is highly suspect (unless determining that voltage under load
is what you are wishing to do) and may be the reason that you are
getting the same result for streamer power. I have to wonder about
the low coupling too. I don't recall seeing stunning results from any
coil I've built when experimenting with k's that low. Lowering k
amounts to increasing the feed impedance to the secondary which is
probably a reasonable thing to do when it is loaded. About time to
put the results to the test I would say.

Malcolm

> ===================================h
> ScanTesla  V-5.11  June 13, 2005  Terry Fritz
> C1 1.000000e-008 0.500000e-007 1.000000e-009
> R1 5.000000e-001 5.000000e-001 1.000000e-001
> L1 1.000000e-005 2.000000e-004 0.500000e-006
> L2 1.000000e-001 1.000000e-001 5.000000e-003
> K12 1.000000e-002 2.500000e-001 1.000000e-002
> R2 3.000000e+002 3.000000e+002 1.000000e+000
> C2 2.500000e-011 2.500000e-011 1.000000e-012
> C3 0.400000e-011 0.400000e-011 1.000000e-012
> R3 2.200000e+005 2.200000e+005 1.000000e+003
> T1 0.000000e+000 1.000000e-003 -1.000000e-007
> Vrail 3.400000e+002
> VCpri_init 0.000000e+000
> DwellTime 0.300000e-003
> Current_Limit 5.000000e+002
> Goal Type 0
>
> NEW HIGH!! Goal = 2.904387e+005
> Time = 0.001000
> Model Number = 357964
> Goal Number = 407
>
> Cprimary = 4.900000e-008
> Lprimary = 5.750000e-005
> Rprimary = 5.000000e-001
> Coupling = 4.000000e-002
> Csecondary = 2.500000e-011
> Lsecondary = 1.000000e-001
> Rsecondary = 3.000000e+002
> Cload = 0.400000e-011
> Rload = 2.210000e+005
>
> Ilprimay Maximum = 329.200146
> VCprimary Maximum = 11283.824426
> VCsecondary Maximum = 290438.692352
> Bang Energy = 16.971438
> Load Energy = 9.520373
> Primary F0 = 94817.427723   Secondary F0 = 100658.424209
> )
> ========================
> ScanTesla  V-5.11  June 13, 2005  Terry Fritz
> C1 1.000000e-008 0.500000e-007 1.000000e-009
> R1 5.000000e-001 5.000000e-001 1.000000e-001
> L1 1.000000e-005 2.000000e-004 0.500000e-006
> L2 1.000000e-001 1.000000e-001 5.000000e-003
> K12 1.000000e-002 2.500000e-001 1.000000e-002
> R2 3.000000e+002 3.000000e+002 1.000000e+000
> C2 2.500000e-011 2.500000e-011 1.000000e-012
> C3 0.400000e-011 0.400000e-011 1.000000e-012
> R3 2.200000e+005 2.200000e+005 1.000000e+003
> T1 0.000000e+000 1.000000e-003 -1.000000e-007
> Vrail 3.400000e+002
> VCpri_init 0.000000e+000
> DwellTime 0.300000e-003
> Current_Limit 5.000000e+002
> Goal Type 1
>
> NEW HIGH!! Goal = 9.012762e+000
> Time = 0.001000
> Model Number = 294580
> Goal Number = 6
>
> Cprimary = 4.200000e-008
> Lprimary = 6.700000e-005
> Rprimary = 5.000000e-001
> Coupling = 4.000000e-002
> Csecondary = 2.500000e-011
> Lsecondary = 1.000000e-001
> Rsecondary = 3.000000e+002
> Cload = 0.400000e-011
> Rload = 2.210000e+005
>
> Ilprimay Maximum = -297.192069
> VCprimary Maximum = 11886.983325
> VCsecondary Maximum = -283162.020606
> Bang Energy = 15.164977
> Load Energy = 9.012762
> Primary F0 = 94876.375461   Secondary F0 = 100658.424209
> )
> =================================
>
>
>
> At 10:26 AM 6/13/2005, you wrote:
>
> >Terry;
> >
> >Re; your comment,
> >
> >"But it suggests that "very low" coupling may be a good thing....
> >Like a coupling of 0.03!!!"
> >
> >I noticed something just this past weekend which seems to support the
> >idea that lower coupling might be better. About a year ago I built a
> >SRSG for my coil and designed the motor to fit in to a cradle so that
> >it could be rotated to provide a means to advance or retard the
> >firing angle. I used a stepper motor assembly to rotate the motor in
> >its cradle but never got around to building the stepper motor
> >controller. So in the meantime I just adjusted the motor manually in
> >a trial-and-error fashion until I got (what I believed was) the best
> >output. This past weekend I finally completed the controller and for
> >the first time was able to adjust the SRSG on the fly and some things
> >became readily apparent.
> >
> >For one thing it turns out that my original static setting was too
> >advanced and as I began to retard the setting and it came in to tune,
> >the sparks got longer, brighter, it got louder (goodness) but I also
> >began to develop racing sparks along the secondary and for the first
> >time, the cap safety gap started to fire. I tried to gently push it a
> >few times and the racing sparks and cap S-G firing were consistent
> >and proportional to the degree that I retarded the SRSG. Even at
> >lower power settings on the variac where I wasn't getting the racing
> >sparks the cap safety gap went ballistic! Could the firing angle of
> >the RSG have any bearing on resonance between C1 and the NST
> >secondary? (my C1 is an mmc @ .049 uf and the NST is a 15,000 x .120)
> >Or put another way; perhaps the angle of the RSG has no bearing on
> >the resonance between C1 and the NST but running it so far advanced
> >attenuated any naturally occurring resonance?
> >
> >Years ago, I set the coupling of this coil to one of the magic K
> >values of .18 using the suicide cord method. (applying 120 VAC to the
> >secondary and measuring the induced voltage in the primary, then
> >computing the value of K and adjusting the coil height to the desired
> >value. .18 was as tight as I could go since any setting higher
> >introduced severe racing sparks in this coil.  I was disappointed
> >that I could not achieve a higher coupling but wrote it off to the
> >physical dimensions/parameters of the secondary, that had provided a
> >ceiling which prevented me from going to a tighter coupling. But it
> >never occurred to me that perhaps a LOWER  K value might allow me to
> >retard the SRSG to a close-to-max position sans the racing sparks!
> >
> >I'll whup out my suicide cord later this week and readjust to the
> >next lower magic K value (or maybe several steps down) and post the
> >results soon. BTW, I attached a scale and pointer to the body of the
> >gap motor so I can reference how far I've rotated it and in which
> >direction. The scale is really handy because, if I ever get totally
> >out of tune the scale allows me to quickly return to my starting
> >point.
> >
> >Daniel Hess
> >
> >
> >
> >"Tesla list" <tesla@xxxxxxxxxx>
> >
> >06/10/2005 09:43 PM
> >To
> >tesla@xxxxxxxxxx
> >cc
> >Subject
> >Re: ScanTesla program - basically working!!
> >
> >
> >
> >
> >Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>
> >
> >Hi All,
> >
> >I note that the ScanTesla program is repeating something the MicroSim
> >modeling suggested months back, but I ignored...
> >
> >The MicroSim model took all day to work by "hand"...  ScanTesla took
> >35 seconds while I "watched" ;-)))
> >
> >But it suggests that "very low" coupling may be a good thing....
> >Like a coupling of 0.03!!!   I am guessing that this would ring the
> >primary to "very high" voltages and give very high secondary voltages
> >(and probably good sparks ;-))...  The model suggest that this is a
> >fairly "optimal" power transfer (and significantly better!) situation
> >for getting really high top terminal voltages even with a significant
> >streamer load...  Lp is pretty much set for the Fo frequency since
> >the coupling is so low...
> >
> >Much much to ponder.......
> >
> >Cheers,
> >
> >Terry
> >
> >
>
>
>