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Re: [TCML] Q
I didn't think it did include the streamer length, but wanted to confirm it.
I also wanted to mention that I have used JAVATC for a lot of coils over the
past 2 years, and I always have to multiply the spark output by 70% to get
the accurate spark length value. You might consider adding this just before
it prints the output in the spark length section. I would make it immensely
more accurate.
The tuning seems to be very accurate, usually within 1/4 turn on every app I
have run.
Regards,
DC
On Wed, May 28, 2008 at 8:33 PM, bartb <bartb@xxxxxxxxxxxxxxxx> wrote:
> Hi DC,
>
> Streamer capacitance is not part of the top load object geometry. I tried
> to do this in the past (in various ways), but was unable to match a streamer
> load with the existing top load objects available. When it comes to streamer
> loading, this is where "tuning" a coil is in the hands of the experimenter.
> I run high on primary inductance myself. I suspect most do. Javatc will give
> you the tuning as based on everything except the streamers. For some coils,
> the effect is small and negligible. For moderately higher powered coils, the
> effect can be significant. Transformer power has everything to do with this.
>
> There was a time (a year or two ago) that I realized Javatc was one step
> away from tuning the coil based on the predicted streamer lengths. But what
> hindered my ability to add this was the fact that Javatc's core LC engine is
> Geotc of which I do not have control of nor do I have the programming skills
> to build upon it. All top load objects are dimensioned center to the coil.
> What really needs to happen to incorporate this is to have the ability to
> insert a top load object (rod representing a streamer arc) that issues from
> edge of toroid out to some length as proposed by the system max power or
> whatever. I can make all that happen, but the the Geotc portion I can't.
>
> I tried using the existing objects to accomplish this but I was never
> satisfied with the results. For example, half a streamer on both sides of a
> toroid is "not' linear to a single streamer on one side. Once I realized
> this, I knew I needed Paul Nicholson. I wrote an email to Paul for the
> implementation of this into Geotc, but at the time he wasn't getting my
> emails (lost in cyberspace I think). Paul also hates JavaScript more than I
> do (no, I don't think so!), so likely this can't be done unless I can figure
> a method to use existing objects. I have only at my disposal toroids,
> spheres, cylinders, and discs. All of these I can configure into a "rod"
> shape, however, they all implement out on both sides from the center of the
> coil and that is my problem. I couldn't find my happy spot and eventually
> got busy with other things never to resolve this situation. I still long to
> do it.
>
> For now, tuning is a close ballpark (and closer for lower powered coils
> than larger powered coils which have longer spark lengths). But even this is
> not linear. Coil geometry is part of how much the streamers will affect
> tuning. Some very little, others more.
>
> Thanks for asking this question DC! There are actually many of these type
> of issues very few even think about which I've already considered and tried.
> In the end, I have to ensure Javatc performs as needed, and in areas that I
> just can't control, I'm hindered to implement. I don't like to rely on
> theory for Javatc. For example, SecQ and Sec Rac. It's not theoretical
> output but a large number of various coil configurations (real coils) and
> top of the line measurements which enabled this output to become active. If
> it wasn't for the large number of empirical data which Malcolm Watts
> provided me, I would not have included it. But since Malcolm did give
> excellent top of the line measurement data, and because I was also able to
> include other coilers various measurements into the mix, the data was really
> excellent. I did have to perform some factors into the low hd coils (1:1,
> 1.5:1, etc.) to follow the curve, but this was needed. Q basic calculation
> was based on Fraga, Padros, and Chen "Practical Method and Calculation of AC
> Resistance of Long Solenoids", IEEE Transactions on Magnetics, Vol. 34, No.
> 1, January, 1998, pp. 205-212. They did not include low h/d coils. So, curve
> fitting was needed for those small h/d's. In the end, the measurement
> comparison to Javatc is graphed here:
> http://www.classictesla.com/temp/RAC-Q2.gif
>
> In the area of Q, Javatc did very well considering these were "measured"
> comparisons. Thus, I decided to include it into Javatc following evaluation.
> It certainly got you in the ballpark of Q, and even the low h/d areas did
> well. Thus, I was able to provide a somewhat decent prediction of Q for a
> decent range of coil h/d's. This has never been done before in any program,
> so it was a good enhancement for Javatc and the TCML. Not sure they all
> realize the work involved, but it's available now regardless.
>
> I hope someday we can include spark loading. I'll keep working on it.
>
> Take care,
> Bart
>
>
>
>
>
> DC Cox wrote:
>
>> Which brings to mind a question.
>>
>> Bart --- do you account for streamer length in JAVATC, ie, do you add some
>> topload capacitance to give the best pri configuration based on added
>> streamer capacitance, or does it just do distributed capacitance and
>> topload
>> capacitance in the calc?
>>
>> Dr. Resonance
>>
>>
>>
>>
>> On Tue, May 27, 2008 at 12:11 PM, b alex pettit jr <a_pettit_jr@xxxxxxxxx
>> >
>> wrote:
>>
>>
>>
>>> Continuing with this project ....
>>>
>>> I just ran several tests measuring the F_res of this 4.5" dia x 21" 940
>>> turn coil.
>>>
>>> I drove the primary ( without cap) via sig.gen and measured the coil's
>>> response
>>> on a freq.counter and scope. It was quite evident the coils F_ res was
>>> 268.98 KHz.
>>> Half Power points at 268.3 KHz and 269.5 KHz = a Q of 224 and well
>>> correlated
>>> to JAVATC's Q calc of 285. (The Primary and lower end of the Secondary
>>> were tied
>>> to my in-ground copper stakes)
>>>
>>> With slight tweaks in ground plane and adding a turn or two to the Sec
>>> parameters,
>>> JAVATC calculated a F_res = 268.86 KHz ( as close as I felt needed to
>>> match 268.98 KHz).
>>>
>>> The Rest of The Story:
>>> That F_res via JAVATC tunes the Primary at 6.797 turns, a HalfPower
>>> point
>>> at 6.777.
>>> With a 45" circumference of the Primary at turn 7, this equates to +-
>>> 3/4"
>>> from resonance
>>> to half power point frequencies.
>>>
>>> BUT,
>>> I added a 'StreamerLoad " wire of 36" , it detuned the F_res by 30 (
>>> thirty ) Hz !
>>>
>>> This changes the Primary tuning point to 7.751 turns ...a full turn !
>>>
>>> How does one actually Tune a Tesla Coil ?
>>>
>>> I am considering a banjo type coil element equal to 1/3rd turn of the
>>> main primary to
>>> use for experimentation.
>>>
>>> Or, how precise IS the tuning of Pri to Sec ?
>>>
>>> I know that in lightly damped mechanical structures, the frequency of
>>> the
>>> excitation is
>>> extremely critical for full excitation.
>>>
>>> This is becoming a tail chasing dog senario... am sure also changes in
>>> coupling factor
>>> detune the system ...
>>>
>>> good news,
>>> multigap spark gap is working and streamers are exceeding 24 inches...
>>>
>>> Thanks,
>>> Alex P
>>>
>>> ********************************************************************
>>> J A V A T C version 11.8 - CONSOLIDATED OUTPUT
>>> Tuesday, May 27, 2008 2:32:20 PM
>>> Units = Inches
>>> Ambient Temp = 68°F
>>> ----------------------------------------------------
>>> Surrounding Inputs:
>>> ----------------------------------------------------
>>> 38 = Ground Plane Radius
>>> 100 = Wall Radius
>>> 100 = Ceiling Height
>>> ----------------------------------------------------
>>> Secondary Coil Inputs:
>>> ----------------------------------------------------
>>> Current Profile = G.PROFILE_LOADED
>>> 2.26 = Radius 1
>>> 2.26 = Radius 2
>>> 2.3 = Height 1
>>> 23.3 = Height 2
>>> 943 = Turns
>>> 24 = Wire Awg
>>> ----------------------------------------------------
>>> Primary Coil Inputs:
>>> ----------------------------------------------------
>>> 4.25 = Radius 1
>>> 7.647 = Radius 2
>>> 3.3 = Height 1
>>> 3.3 = Height 2
>>> 6.793 = Turns
>>> 0.25 = Wire Diameter
>>> 0.0187 = Primary Cap (uF)
>>> 0 = Total Lead Length
>>> 0 = Lead Diameter
>>> ----------------------------------------------------
>>> Top Load Inputs:
>>> ----------------------------------------------------
>>> Toroid #1: minor=3, major=12, height=30, topload
>>> ----------------------------------------------------
>>> Secondary Outputs:
>>> ----------------------------------------------------
>>> 268.86 kHz = Secondary Resonant Frequency
>>> 90 deg° = Angle of Secondary
>>> 21 inch = Length of Winding
>>> 44.9 inch = Turns Per Unit
>>> 0.00217 inch = Space Between Turns (edge to edge)
>>> 1115.9 ft = Length of Wire
>>> 4.65:1 = H/D Aspect Ratio
>>> 28.4093 Ohms = DC Resistance
>>> 30794 Ohms = Reactance at Resonance
>>> 1.36 lbs = Weight of Wire
>>> 18.229 mH = Les-Effective Series Inductance
>>> 20.096 mH = Lee-Equivalent Energy Inductance
>>> 19.905 mH = Ldc-Low Frequency Inductance
>>> 19.223 pF = Ces-Effective Shunt Capacitance
>>> 17.437 pF = Cee-Equivalent Energy Capacitance
>>> 32.248 pF = Cdc-Low Frequency Capacitance
>>> 5.61 mils = Skin Depth
>>> 11.652 pF = Topload Effective Capacitance
>>> 108.1284 Ohms = Effective AC Resistance
>>> 285 = Q
>>>
>>> _______________________________________________
>>> Tesla mailing list
>>> Tesla@xxxxxxxxxxxxxx
>>> http://www.pupman.com/mailman/listinfo/tesla
>>>
>>>
>>>
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>>
>>
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