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Re: ScanTesla - Tesla's Colorado Springs Coil



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

Hi Terry,
          It's great to see you pushing this data through your
optimizing engine and most interesting to see the results!

On 27 Jun 2005, at 22:43, Tesla list wrote:

> Original poster: Terry Fritz <teslalist@xxxxxxxxxxxxxxxxxxxxxxx>
>
> Hi All,
>
> I have incorporated Antonio's new TRSSTC calculation engine into
> ScanTesla-7.40:
>
> http://drsstc.com/~terrell/modeling/ScanTesla-TRSSTC-740.ZIP
>
> I found with MandK, that the K13 coupling was 0.0292 and the K23
> coupling was 0.0532.  The new coupling made a significant difference
> and it appears that K13 should be a negative coupling.  The negative
> coupling is not significant since it depends on how the model defines
> current flow.  It appears that Tesla should have wound all three coils
> in the same way and direction.
>
> At first, the model did not like to tune well.  It liked an enormous
> output capacitance of about 350pF!  But "I think" Tesla's third coil
> may have been connected to that 140+ foot tower with the ball on top.
> I ran that through E-Tesla and came up with 331.75pF!  So that is what
> I used:

The tower would indeed have added enormously to the extra coil's
capacitance (apologies to the Corums who probably abhor the notion of
capacitance but it is useful and works!).

> http://hot-streamer.com/temp/TeslaCSthridCapacitance.gif
>
> I got most of the number from Dave's data that Richard Hull figured
> out:
>
> http://hot-streamer.com/temp/CScoilInfo.txt
>
> And MandK and E-Tesla6 Modeling.
>
> http://hot-streamer.com/TeslaCoils/Programs/Programs.htm
>
> The numbers all seem to fairly well agree with each other.  The R1, R2
> and R3 losses are questionable, but I went light on them so the coil
> would have the best output.  Csecondary is questionable too since that
> coil was a giant in a small close building.  I did not change it since
> I assumed the wood was really dry ;-)
>
> The transformer was rewound for 25kV so we will assume the firing
> voltage was 1.414X or ~35.3kV
>
> At Cprimary =138nF, the coil seems to tune for maximum voltage of
> 502kV.  The input power is 50kW  The primary frequency is 56.2kHz.
> The data is given at the end here.
>
> The output power seems low still at 7.6kW.  For a normal 50% efficient
> coil, that would be a streamer length of 17.5 feet.  To get 32 feet,
> he "should" need a streamer power of 25.5kW
>
> Using mode 2, the program can graph many things vs. Cprimary tuning:
>
> http://hot-streamer.com/temp/power.gif
>
> The 50kW power point is in the center where all the lines meet and the
> parameters are normalized.  If he raised the primary voltage to where
> the input greater and retuned,  He would gain more streamer power.  He
> would have had to raise the BPS some too get the power he needed for
> 32 foot streamers.  The power draw would have been enormous, but he
> did blow up the power plant at one point too ;-))  If he did this, he
> would have had to run in short bursts...

You are quite correct. Tesla did indeed run the coil in short bursts.
He was not overly optimistic about his gear's chances of survival
with 5 minute+ runs and who could blame him with saltwater caps and
gutta-percha insulation. He states in the Notes that the photos were
taken with "... many closures of the switch..." and these closures
were on the order of 1/2 to 1 second or so. The photos were all time
exposures as anyone who has photographed coils would recognize and in
the case of those where he was apparently sitting amid a shower of
sparks, double-exposures.

> The system seems to "tune best" at Cp = ~85nF.  But it still does not
> seem, even with high BPS, that he could have gotten near a streamer
> power of 25kW.
>
> The Load Energy Rise Time is higher at lower Cp values.  He coil seems
> to have been in the ~250uS range which is not too bad for a coil that
> has a cycle time of 17uS or about 14 cycles  However, about 50% of the
> power is delivered within 25uS as shown:
>
> http://hot-streamer.com/temp/Voltage.gif
>
> The top voltage has a powerful start and a high peak.  This provides a
> very short powerful burst which is very good for LERT and high BPS
> operation.  Most of the burst is "over" in 100uS!!  It is not know how
> much that would help streamer length.  It may be dramatic!!
>
> We don't know what effect the very short LERT had on streamer length
> at this time.  Like all coil's, the streamer length is fairly directly
> proportional to firing voltage.  If Tesla used a higher voltage and
> higher power than we think (3.4X power 1.8X voltage), he would have
> had the bang energy to get to 32 feet.  It was probably a combination
> of using high voltage and the very short LERT that got the coil that
> far.  In the second file below, I ran a case where the firing voltage
> was 65kV with and efficient tuning and higher BPS.  The coil has 25kW
> of streamer power in this case which could easily hit 32 feet.  The
> input power is very high at 155kW!!  Tesla could probably easily raise
> the primary voltage and BPS rate until something blew up (the power
> plant?).  A short burst at 155kW would have been fairly easy.  He also
> would have had a fairly wide tuning range in this case of "throw a lot
> of power at it"...  He probably could have run 60nF to 200nF of Cp and
> still pushed 32 foot arcs.  A higher Cprimary would have driven the
> LERT down also which may have certainly given better performance
> overall...
>
> Take all this with a big grain of salt ;-))
>
> Cheers,
>
>  Terry

But not too far from the truth I would say. Interesting that the
second run below shows a combined secondary+extra voltage (had the
phasing been correct) was indeed approaching 1MV. Nice one!

Regards,
Malcolm

>
> Coil Output Data
> ----------------------
> ScanTesla V-TRSSTC-7.40 June 23, 2005 Terry Fritz
> ........
> Cprimary = 1.380000e-007
> Lprimary = 5.800000e-005
> Rprimary = 3.000000e+000
> K12 = 0.550000 K23 = 0.053200 K13 = -0.029200
> Csecondary = 1.500000e-009
> Lsecondary = 9.622000e-003
> Rsecondary = 6.100000e+000
> Ltertiary = 1.591100e-002
> Ctertiary = 3.317500e-010
> Rtertiary = 9.400000e+000
> Cload = 3.200000e-011
> Rload = 2.200000e+005
> BPS = 576.000000
> Dwell Time = 3.000000e-003
>
> Ilprimay Maximum = -1683.990371
> ICprimary RMS = 116.958365
> VCprimary Maximum = 35255.285148
> VCsecondary Maximum = -163863.037412
> VCtertiary Maximum = 501655.667015
> Coil Power = 49679.047138 Primary Bang Energy = 86.248346
> Load Power = 7616.217639 Load Bang Energy = 13.222600
> Primary F0 = 56255.707590
> Load Energy Rise Time (Sec) = 2.369537e-004
> Models Tested = 1
> --------------------
>
> Second case with higher input voltage and higher BPS
> -------------------------
> Cprimary = 8.500000e-008
> Lprimary = 5.800000e-005
> Rprimary = 3.000000e+000
> K12 = 0.550000 K23 = 0.053200 K13 = -0.029200
> Csecondary = 1.500000e-009
> Lsecondary = 9.622000e-003
> Rsecondary = 6.100000e+000
> Ltertiary = 1.591100e-002
> Ctertiary = 3.317500e-010
> Rtertiary = 9.400000e+000
> Cload = 3.200000e-011
> Rload = 2.200000e+005
> BPS = 863.000000
> Dwell Time = 3.000000e-003
>
> Ilprimay Maximum = -2559.496625
> ICprimary RMS = 205.505341
> VCprimary Maximum = 64816.393975
> VCsecondary Maximum = -241876.001888
> VCtertiary Maximum = 654553.421935
> Coil Power = 154962.437500 Primary Bang Energy = 179.562500
> Load Power = 24987.984775 Load Bang Energy = 28.954791
> Primary F0 = 71679.781368
> Load Energy Rise Time (Sec) = 2.689740e-004
> Models Tested = 1
> -----------------
>
>
>