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Re: conical secondaries (fwd)
---------- Forwarded message ----------
Date: Sat, 16 Jun 2007 19:16:28 -0700
From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: conical secondaries (fwd)
Hi Gary,
If you were to design an experiment to compare secondary geometry's, you
would be hard pressed to make any sense of it. How does a cone compare
to a helical coil? Inductance is just a value. Geometry is just as
important. One thing I've realized is that geometry and inductance are
separate beast. Building concentric inductance's with different
geometry's says nothing. I can build the same inductance for 3 separate
coil geometry's (even all helical) and they would all act different.
This is one of those "things" that cannot be quantified through
comparison experiments. As soon as you make a comparison, someone will
point out why it is invalid (and they will be right).
However, the human factor is something to take account of. For example,
if a coiler spends several years building helical secondary's and then
begins building conical secondary's and finds he can get more out of his
conical's (as based on his previous experience with coils), then there
may be something there, even if we don't know why at this point in time.
If several other coilers decided to give it a try and also report the
same, that would be proof that we should take the reports seriously and
figure out why. Those things have not occurred yet, so for now it's all
just pie in the sky.
Take care,
Bart
Tesla list wrote:
>---------- Forwarded message ----------
>Date: Sat, 16 Jun 2007 17:33:53 -0400
>From: "Lau, Gary" <Gary.Lau@xxxxxx>
>To: Tesla list <tesla@xxxxxxxxxx>
>Subject: RE: conical secondaries (fwd)
>
>If I were to design an experiment to compare secondary geometries, I
>think the most important thing would be to have all coils built to have
>identical inductances. If they did not, then you would need different
>primary capacitances, and the power throughput from the NST would vary
>due to that alone. We surely don't want a variable power supply!
>
>But let's be real. We can talk all day long about ideal experiments,
>but really, I don't believe that they're going to happen. I think the
>best we can hope for is to get reports that "I built a coil using a
>15/30 NST with a pancake secondary and I get X inches of spark". And "I
>built a coil using a 15/30 with a helical secondary and I get Y inches
>of spark". Yes, a very uncontrolled and far from ideal comparison, but
>I suspect that's as good as we're going to get.
>
>So how about it - what kind of performance have folks seen with pancake
>or conical coils, and with what size power supply?
>
>I believe that it's possible to optimize a coil's performance in either
>of two directions - long, thin purple sparks, or short, brighter, whiter
>sparks. I don't think the deciding factor is secondary geometry, but
>rather a low BPS with big bang size (thin purple) vs. a higher BPS with
>smaller bang size (brighter whiter). But I must admit that I say this
>without having any personal experimental experience or data to back it
>up, and I would be interested in the experience of others is this
>regard. I have always strived for the longest sparks (OK, bragging
>rights), and my long thin purple sparks are achieved with largest
>possible bang size. I've not pursued the other direction.
>
>Regards, Gary Lau
>MA, USA
>
>
>
>
>>Date: Sat, 16 Jun 2007 10:39:16 -0500
>>From: David Thomson <dwt@xxxxxxxxxxxx>
>>To: 'Tesla list' <tesla@xxxxxxxxxx>
>>Subject: RE: conical secondaries (fwd)
>>
>>Hi Gary,
>>
>>Probably the best way to test my observations would be to build three
>>
>>
>coils,
>
>
>>each with the same wire length, wire gage, and same number of turns
>>
>>
>for each
>
>
>>of a flat spiral, solenoid, and conical coil. The best cone design
>>
>>
>would be
>
>
>>a height equal to the base diameter, or nearly so. Then it would be a
>>simple matter of choosing a constant top load and variable power
>>
>>
>supply. I
>
>
>>predict the conical coil will handle more power than either the flat
>>
>>
>spiral
>
>
>>or solenoid coils. I doubt it would increase the spark length by
>>
>>
>much, but
>
>
>>the spark will be brighter and more robust in a conical coil than in a
>>solenoid coil. Since the specific application here is a very small
>>
>>
>coil,
>
>
>>the conical coil could make the difference between being able to see
>>
>>
>the
>
>
>>streamer or not seeing the streamer for a given coil size.
>>
>>BTW, my observations are based upon the two different manifestations
>>
>>
>of
>
>
>>sparks I observed and spoke of earlier. A flat spiral coil produces a
>>thick, white arc indicating maximized current. A solenoid coil
>>
>>
>produces a
>
>
>>thin purple spark, indicating maximized potential.
>>
>>The solenoid coil is too narrow at the base to accommodate a flat
>>
>>
>spiral
>
>
>>maximized current, and a flat spiral has no height at the terminal to
>>accommodate a solenoid maximized potential. The conical coil
>>
>>
>accommodates
>
>
>>the high current and high potential both, thus allowing more power to
>>
>>
>be
>
>
>>stored in the coil per coil size.
>>
>>Dave
>>
>>David W. Thomson
>>
>>
>>
>>>-----Original Message-----
>>>From: Tesla list [mailto:tesla@xxxxxxxxxx]
>>>Sent: Saturday, June 16, 2007 8:44 AM
>>>To: tesla@xxxxxxxxxx
>>>Subject: RE: conical secondaries (fwd)
>>>
>>>
>>>---------- Forwarded message ----------
>>>Date: Sat, 16 Jun 2007 10:12:38 -0400
>>>From: "Lau, Gary" <Gary.Lau@xxxxxx>
>>>To: Tesla list <tesla@xxxxxxxxxx>
>>>Subject: RE: conical secondaries (fwd)
>>>
>>>By what means are you measuring to conclude that "flat
>>>spirals handle higher current" and "solenoids handle a higher
>>>potential"? I think the only measure of performance
>>>differential that I would trust is comparing spark length
>>>using the same power supply and VA consumption. Do we agree
>>>that spark length a suitable basis for comparison?
>>>
>>>Gary Lau
>>>MA, USA
>>>
>>>
>>>
>>
>>
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