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Two strang things my testing has found???
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From: terryf-at-verinet-dot-com [SMTP:terryf-at-verinet-dot-com]
Sent: Tuesday, March 10, 1998 10:45 PM
To: Tesla List
Subject: Re: Two strang things my testing has found???
Hi John,
I am trying to get a full TC system measured with voltage and
current waveforms at every node. This would be a spectacular view of what
these coils are doing. One thing that may ruin some people's day is that
the waveforms recorded by using an antenna system may be mostly noise. The
waves I see are much cleaner and make much more sense than the noisy
multiple order waveforms you see with an antenna. I am going to scope them
side by side when I get time. I can now get the voltages and currents
around the neon and in the secondary system without any problem. I am
building a new "probe friendly" secondary coil that will help with the
secondary measurements. I don't think current measurements in the secondary
will be a problem. The system for measuring voltage I have in mind will
have to be verified. Basically, it consists of having a loop of wire around
the secondary and measuring the voltage on it. Hopefully, this will be
identical to a turn on the secondary at that point. I am hoping the primary
voltage will have a sine distribution along the length of the coil so that
the voltage will be easy to predict. Of course, when the sparks fly, this
bleeding edge experiment may bleed heavily. :-)) Who knows what THAT will
look like???? If all this works, the same probe should work on any system.
Neons, pole pigs, and even them maggies can all be tested with the same
equipment. I hope to have planes and a small kit of hard to get parts (like
PC boards) available so that anyone who wants can build a similar probe
system. Right now, however, the design is too fluid to commit to. I have
gone through three major PC board designs for the voltage transducers in the
last three days!!
I have no problem with you using these results in you brochure if
you wish. I consider all the results I release as public domain. You may
want to check with me to be sure the results are still valid, as
improvements are being made by the hour to the system and I have been known
to screw up occasionally :-)). A small reference in the appendix or
something would guarantee my place in history. :-))
If you wish, when I actually get all the data, I can supply the data
in many ways. The Tektronix scope actually has 2500 data points despite the
650 or so displayed. These points can be read out to a data file that can
be used to make very nice graphs. Personally, I prefer the screen captures
because the look so real.
Speaking of REAL. That little current pulse I mentioned has been
traced to the digital scope being set to the average mode. It was averaging
positive and negative gap firings. This current pulse does not exist.
These darn digital contraptions!! All these knobs, menus, settings........
:-)))
Terry
>
>----------
>From: John H. Couture [SMTP:couturejh-at-worldnet.att-dot-net]
>Sent: Monday, March 09, 1998 12:40 PM
>To: Tesla List
>Subject: Re: Two strange things my testing has found???
>
>
> Terry -
>
> As you know there is very little information available on the waveforms
>that are produced by Tesla coils. I was thinking of writing up a short
>brochure on the subject with sketches and calcs of the waveforms. Your test
>data would be of great value.
>
> John Couture
>
>----------------------------------------------
>
>At 08:54 AM 3/8/98 -0600, you wrote:
>>
>>----------
>>From: terryf-at-verinet-dot-com [SMTP:terryf-at-verinet-dot-com]
>>Sent: Saturday, March 07, 1998 10:47 PM
>>To: Tesla List
>>Subject: Two strange things my testing has found???
>>
>> I have been looking at voltage and current waveforms now for a few
>>days with my VI probe and there are two issue I would like to request
>>information on.
>>
>> First- The output terminals of my 15000 volt, 60 mAmp neon
>>transformer seem to have about 150pF across them internally (like a big
>>parasitic capacitance). This is causing some current spikes with certain
>>input filter circuits. Other filter circuit do better because of this.
>>Anyone ever ran into this before????
>>
>> Second- Just before the primary spark gap fires there is a little
>>current pulse I am seeing. It is about 10% of the real initial pulse but it
>>has opposite polarity. Very strange. I far as I can tell the pulse is real
>>and not a glitch or anything. It seems to almost always be there. If
>>anyone has any information on this I would love to here your thoughts. I
>>will try to get a picture of it on my web page
>>(www.peakpeak-dot-com/~terryf/Tesla/Main.html) ASAP.
>>
>> I have made a number of improvements to my system and it is working
>>very well :-) My spice models and the actual results now show excellent
>>correlation since these improvements. The little spark gap pulse does not
>>show up in the models. However, I use perfect switches and such in the
>>models. This may be hiding something that happens in real systems like this
>>pulse. I have completely overcome the bandwidth issue with redesigned
>>transducers. Now even the voltages and currents show perfect 90 degree
>>phase differences and the levels are all correct! I will write up more
>>information as time permits. I am working on detailed planes for the probe
>>and will publish them when the design is stable.
>> I am begining to set up for real TC tests using this equipment
>>rather than the test circuits I have been using so far. Now that I have the
>>VI probe working so well, it is time to really turn it loose. :-))
>>
>>Thanks
>>
>> Terry
>> terryf-at-verinet-dot-com
>>
>>
>>
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