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Re:Re: Terry's Tesla Coil Tuner
Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>
Hi Al,
There are many options available for measuring the parameters of a full
power coil which I can do fairly easily. Please see the following:
http://hot-streamer-dot-com/TeslaCoils/MyPapers/MyPapers.htm
For a relatively simple and safe top voltage and current probe system see:
http://hot-streamer-dot-com/TeslaCoils/MyPapers/planant/waveant3.html
Fiber-optic probe details can be found at:
http://hot-streamer-dot-com/TeslaCoils/Misc/Project_color.pdf
A frequency counter, and DVMs are not much use here for disruptive coils.
The counter will not lock onto the frequencies of interest and the DVMs
won't measure anything fun unless you get one of the 40kV probes for about
a hundred bucks (Jameco 132290 is what I use). However, the scope is able
to do it all.
There are some direct measurement options like Pearson current monitors and
true high voltage probes like the TeK 6015 but that is getting into some
major cash. Also, you have to be really careful about what you do so you
don't fry the scope. The antenna and the fiber probe are isolated, so that
risk is removed.
I would suggest the Plane wave antenna is a good, fast, safe, and cheap
first step in this area. Far better than a wire on a scope probe...
I think you can measure anything you want at any power level. See the
paper below where that was done for a 1kW coil. The same techniques can be
used for any power level.
http://hot-streamer-dot-com/TeslaCoils/MyPapers/modact/modact.html
We often play with equations and facts that such testing provides.
However, that stuff is based on actual measurements which are extremely
important to insure that all the fancy models and such are telling the
truth. Many old myths have been torn apart by the recent development of
such direct measurement tools. Now, much work can be done by computer
models so even folks that don't have a coil can do research into Tesla
coils. That work can then be verified buy those of us that have the
technical equipment at hand. Paul's secondary behavior project is a case
in point...
I also like to point out that the function of inductive kick LTR coils and
the true secondary voltage profiles were predicted by computers. Only
latter did actual measurements verify those purely computed results. In
the case of LTR coils, I would go as far as saying that computer models
"discovered" that effect...
In all, Tesla coils operate in a very predictable and understandable way
once you start looking hard at them. The tools we know have can, in some
cases, predict things better than we can measure. However, there is still
much work to be done!
Cheers,
Terry
At 02:16 PM 2/10/2001 -0500, you wrote:
>Hi Terry, Mike, All. Terry, I have a frequency counter but have
>been leery to use it when approaching the Tesla coils that I have. Also I
>have several DVM'S and a solid state scope with the appropriate high
>voltage probe and an antenna I made wound around the probe to approach,
>but never ever get right next to the operating secondary coil just to see
>what kind of wave form the fully operational Tesla would produce with a
>constant voltage of 15kv at roughly 200 to 400ma input power from
>modified neons...all the time adjusting the tank capacitor bank by adding
>or deleting 2.0 and 1.2mf oil can caps in various series/parallel
>combinations to augment the barium titanate cap bank that we have, and we
>also throw in an old bank of trusty beer bottle caps as needed to tweak
>the tank for maximum output. Now then; Are these schemes that you and
>others follow while measuring voltages performed on a actual working
>coil firing at high magnitude, or are you just messing around with lower
>scale voltages without the coil being lit up and firing at full capacity.
> In other words, are you just ringing these circuits at minimum power in
>a circuit minus the secondary coil or can your measurements be preformed
>in the actual full maximum voltage operation of a Tesla coil? Meaning,
>does anyone have any instruments that will show the true workings of a
>fully powered coil in operation? Seems a lot of the list I have read is
>dedicated to trying to estimate the power of a Tesla by just ringing the
>tank circuit without a secondary attached at full power, or am I wrong
>about that? Or do we just speculate about the parameters of our coils
>while testing them without a secondary coil attached? If that is the
>case, then how can a true measurement be made without having a fully
>operational coil. Please, no baloney about extrapolated parameters with
>under fired coils, since I have seen a awful lot of that stuff on the
>list. Does anyone out there have a true way of showing a wave form on
>the scope and frequency counter while maximum power is applied to the
>coil as an entity? Is this possible at full output while the coil is
>generating 6 to 8 foot plus sparks from the top of the secondary coil?
>Al.
>
>On Fri, 09 Feb 2001 08:00:08 -0700 "Tesla list" <tesla-at-pupman-dot-com>
>writes:
>> Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>
>>
>> Hi Mike,
>>
>> I hooked up the ARB and ran the 100kHz to 600kHz spectrum to check
>> out the
>> square wave/harmonics thing. As it turns out it is pretty cool!
>> the following
>> is the spectrum with just a resistor in the circuit which clearly
>> shows the
>> square wave harmonics:
>>
>> http://hot-streamer-dot-com/temp/TCTs1.jpg
>>
>> Next is the same spectrum with the bi-color led. As it turns out,
>> the LED
>> seems to remove the harmonics! Probably because they cannot
>> overcome the turn
>> on voltage of the LEDs
>>
>> http://hot-streamer-dot-com/temp/TCTs2.jpg
>>
>> One problem is that the stray capacitance in the timing circuit
>> makes the
>> "calibration" thing worthless. It has to be calibrated against a
>> frequency
>> counter as it turns out. Many DVMs have a frequency function too.
>> Since I
>> cannot control how the circuit is built, there is no way to come up
>> with an
>> easy fixed calibration scheme. I will probably offer a $5
>> calibration
>> "service" to those that don't have access to a frequency counter. I
>> am already
>> going to send people the 1.8nF cap for free since it is easy to mail
>> (small).
>>
>> I still need to clean the plans up a lot before this is ready for
>> prime time.
>> Many thanks to all who have given their thoughs on this!
>>
>> Cheers,
>>
>> Terry
>>
>>
>>
>> At 11:39 AM 2/9/2001 +0000, you wrote:
>> >On Thu, 08 Feb 2001 07:55:53 -0700, you wrote:
>> snip..
>> >One problem I've found with using square waves for tuning is that
>> you
>> >can get strong responses at harmonics.
>> >
>> >Have you tried using a single-colour LED in series with the 555's
>> >supply? (maybe with a parallel resistor)
>> >
>> >
>>
>>
>
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