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



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

===================================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



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06/10/2005 09:43 PM
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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