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RE: E-Teala6 Program
Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>
Hi John,
That coil had a Tektronix 5100 High-voltage RF probe hooked to the top. Paul
modeled it with the probe in place and his models still work when he added to
3.1pF of probe loading. So it was not really a "bare" coil in this case. The
note is below.
-------------
The top voltage measurement requires a probe connection directly to the top of
the coil, which introduces some additional capacitance and load resistance. The
predicted values are obtained from a model in which the probe capacitance is
adjusted to make the predicted f1 match the observed f1, after having first
ensured that the resonance of the unprobed coil is modeled correctly.
Terry Fritz measured his small coil to obtain the comparisons
measured modeled error
tfsm1p: probed d=0.108m h/d=6.14 sr=0.91 b/h=0.01 turns=1176
f1: 310.9 kHz 310.9 kHz 0.0% Ctop adjusted to match: 3.145 pF
f3: 847.8 kHz 828.4 kHz -2.3%
Zft: 34450 ohms 34874 ohms +1.2%
Les: 17.64 mH 17.85 mH +1.2%
-----------------------------------
The 17.64mH is "Les" which Paul defines as the equivalent series inductance.
That is the AC inductance at resonance with is about 20% less than the measured
DC inductance. I did some tests and Paul figured out Les, but the details
escape me at the moment.
Cheers,
Terry
At 02:51 PM 3/21/2001 -0800, you wrote:
>
>Terry -
>
>In one of Paul's tables that you mention below your coil shows as 4.25" dia,
>26.1" lg, 1176 turns, 17.64 mh, 310.9 Khz.
>
>Did you measure the 17.64 mh with a meter? This is 21.4% less than what the
>Wheeler equation shows. Also did you measure the 310.9 Khz with a meter? The
>Wheeler/Medhurst equations give 349.86 Khz.
>
>Paul's web sites are a marvel of detailed Tesla coil information. However, I
>am finding it difficult to understand some of the data.
>
>John Couture
>
>-----------------------------
>
>
>-----Original Message-----
>From: Tesla list [mailto:tesla-at-pupman-dot-com]
>Sent: Sunday, March 18, 2001 7:53 PM
>To: tesla-at-pupman-dot-com
>Subject: Re: E-Teala6 Program
>
>
>Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>
>
>Hi John,
>
>E-Tesla6 is verified against a wide array of known tested coils. That data
>is
>included in the zip file as "data.txt". Comparing the program to the known
>data is the only way I could keep such a complex program on the true track.
>
>I know exactly where we differ. You find the frequency with Lsec and Csec.
>That seems right, however, the actual effective secondary inductance at AC
>resonant is LESS than the DC inductance. Paul Nicholson's research finally
>figured that one out. E-Tesla6 consistently showed something was wrong and
>the
>early versions fudged it. However Paul's work finally found the correct
>numbers and why. The secondary does not have uniform current through it and
>thus it losses inductance at resonance (10-20%).
>
>http://www.abelian.demon.co.uk/tssp/
>http://www.abelian.demon.co.uk/tssp/pn2511.pdf.zip
>http://www.abelian.demon.co.uk/tssp/pn1710/
>
>I can't begin to explain all Paul's work in a single E-mail here, but the
>relevant cut and past from
>http://www.abelian.demon.co.uk/tssp/formulae.html
>follows...
>
>==========================
>The inductance of a solenoid effective at its lowest self-resonant frequency
>differs from the low frequency (Nagaoka) inductance due to the non-uniform
>current distribution at resonance. The following two formulae may be used to
>calculate the effective series inductance,
>Bare coil:
> Les = Ldc * pow( 8.0724 + 4.5129 * h/d, -0.8016) *
> pow( 0.0079 + 1.384 * b/h, 0.2623) *
> pow( 338.89 + 18.9111 * awg, 0.1493) *
> pow( 0.346 + 4.23 * h, 0.0232) *
> pow( 115.768 + 7.1 * sr, 0.0241) + 0.658311
>
> average error = 1.3%, peak error = 2.8%
>Toroided:
> Les = Ldc * pow( 4.6675 + 5.5509 * h/d, -0.5983) *
> pow( -0.0147 + 0.9557 * b/h, 0.131) *
> pow( 5.2204 + 0.145 * awg, 0.0703) *
> pow( 3.94 + 0.9199 * h, 0.0487) *
> pow( 5.41 + 80.798 * sr, 0.0114) *
> pow( -4.1441 + 14.3397 * td/h, 0.1537) *
> pow( 0.312 + 0.58 * tb/h, 0.088) + 0.686997
>
> average error = 1.6%, peak error = 4.5%
>where
> h = length of secondary winding, metres;
> d = diameter of secondary - metres;
> b = height of winding start above ground - metres;
> awg = wire gauge, AWG;
> wd = 7.348e-3/pow(1.122932, awg-1) (wire diameter - metres)
> sr = spacing ratio = turns * wd/h
> td = toroid outer diameter, metres.
> tb = height of toroid plane above the top of the winding, metres.
>===============================
>
>Perhaps you could incorporate the above data into your program. I still am
>using an older method and will change E-Tesla to the above latest and
>greatest
>formula when I get a chance... Paul also has a data base of 13500 coil
>configurations at:
>
>http://www.abelian.demon.co.uk/tssp/vsd/
>
>In fact, one could write a whole new Tesla coil program using this new data
>that whould probably be the most accurate program yet!! Hmmmmm..... There
>is
>a ton of data on Paul's site that will take years to fully digest...
>
>Cheers,
>
> Terry
>
>
>
>At 06:44 PM 3/18/2001 -0800, you wrote:
>>
>>Terry -
>>
>>I checked your E-Tesla6 program outputs with the JHCTES program and
>obtained
>>the following results.
>>
>>Entered in the JHCTES Ver 3.2 for the Secondary circuit.
>>
>> Sec Rad 5.13
>> Turns 1000
>> Turns per inch 33.3
>> Sec Term pf 36.0
>>
>>Outputs - JHCTES E-Tesla6
>>
>> Oper Freq Khz 81.05 87.66
>> Coil Lgt 30.05 30.0
>> Sec coil Ind mh 75.96 75.4
>> Tot Sec Cap - pf 50.77 50.75
>>
>>How does E-Tesla calc the 87.66 from the above data?
>>Have you ever tested the operating frequency of this coil?
>>It appears your program and the Toroid/Sphere graph in my Tesla Coil
>>Notebook are in close agreement. The graph shows 33 pf for the Sec Term.
>>
>>John Couture
>>
>>------------------------------
>