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Re: How to tune? (fwd)

---------- Forwarded message ----------
Date: Sun, 1 Jul 2007 07:26:06 -0600 (MDT)
From: Chip Atkinson <chip@xxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: How to tune? (fwd)

I think that's Gary Lau.  It's his web site and says "yours truly".  That
and it doesn't look like Terry either. :-)

This is the website I'm talking about:



On Sun, 1 Jul 2007, Tesla list wrote:

> ---------- Forwarded message ----------
> Date: Sat, 30 Jun 2007 22:47:26 -0700
> From: Barton B. Anderson <bartb@xxxxxxxxxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: How to tune? (fwd)
> Hello Drake,
> The guy sitting in the statue of Tesla at Niagara Falls is our 
> illustrious ex-moderator, the famous Terry Fritz! You also gave a 
> half-name (Gary Lashus?), I can only imagine is intended to read Gary 
> Lau. It's very possible Gary or Terry had a document with a step by step 
> tuning procedure, but I can't seem to find it.
> With that said, there are various methods. There is of program 
> prediction where you insert your coil dimensions and out pops the 
> primary tune tap position for your coil.
> http://www.classictesla.com/java/javatc.html
> There are also tuning via measurement of signals and trial and error 
> (which is actually quite good).
> Here is a method noted by Antonio Carlos M. de Queiroz:
> -------------------------------------------------------------------------------
> The method that I use is:
> Connect a 1 Ohm resistor across the output of the signal generator, to
> have a low-impedance signal.
> Connect the signal generator where the spark gap would be, with a
> low-frequency (1-10 kHz) square wave of maximum amplitude.
> The secondary coil and top load shall be in place. Ground can be at the
> oscilloscope ground.
> Look at the voltage over the primary capacitor, or over the primary
> inductor, at the transitions of the square wave.
> Tune the system until you see full notches, like in this photo:
> http://www.coe.ufrj.br/~acmq/tesla/tefpreg1.jpg
> This is the ideal tuning without breakout. To account for streamer load,
> connect a wire to the top load with the length of a reasonable streamer
> and tune
> in the same way. Mark the two positions found. The best point will be
> somewhere between these.
> Note that the waveform shows also the resonance frequency of the two
> tanks, and allows the measurement of the coupling coefficient.
> -------------------------------------------------------------------------------
> You can also tune by trial and error. This typically indicates that you 
> tap a bare wire primary at various positions along the winding of the 
> primary which changes it's inductance and thus, the fundamental 
> frequency of the primary coil to math the fundamental frequency of the 
> secondary resonator. When this procedure is used (the trial and error 
> procedure), the cap is usually a fixed value and only the primary is 
> varied (because it is mechanically the easiest variable).
> There are a couple setup procedures which help this process. First, 
> place a breakout point on your topload so that you can identify leader 
> length visually (your tuning for the longest leader). You also should 
> run the coil at about half power. There are two easy ways to do this:
> 1) Using a variac, adjust the variac to 1/2 power.
> 2) Use 1/2 the number of gaps in the static gap setup to lower the 
> voltage to about 1/2.
> As you tap the primary winding (if your other parameters are now way off 
> base), you'll find the longest spark lengths near the optimal tap 
> position. Some coils (small L primarys) are more finicky than others 
> (large L primarys). You'll find out how finicky your coil is by tuning it.
> So, lets say you've tuned to the long spark length. Now you need to 
> observe the coil running. If your getting any arcs along the secondary 
> or from primary to secondary, there are problems. If primary to 
> secondary, you'll need to increase the proximity between coils. If 
> racing arcs, you'll need to raise the secondary (or lower the primary) 
> to again increase the proximity in that particular direction of the two 
> coils.
> If it's running fine without those pesky problems, you may want to lower 
> the secondary down into the primary until you "see" those problems 
> occur, and then raise the secondary to just get outside the racing 
> sparks. Once you've done that, your tuned for low power.
> Yes, I said "low" power. Now you'll need give the coil all it's got 
> without limiting the power. You may find that the coil is having racing 
> arcs at high power. So, definitely go through the tuning process one 
> more time regardless. The low power tuning helps us in the long run. If 
> something is connected wrong, or whatever, it may prevent the coil from 
> serious damage.
> Longer sparks often load the coil causing a frequency shift during 
> normal running and likely the primary will require a little added 
> inductance to offset the frequency shift. This can be often times termed 
> as running "high on inductance" a few percent (maybe 5% to 8%, sometimes 
> more if the primary coil is several turns). What this means is that from 
> a "calculated" standpoint without spark loading, the coil runs better 
> when it is detuned high on inductance to offset streamer loading. You 
> might be surprised at the number of coilers that actually run high on Lp 
> (and some without realizing it). But, many do realize this. I was very 
> surprised to find out during some TSSP testing that everyone else 
> testing was also tuning the coil high on inductance for "best coil 
> output" and "a nice running coil". I'm not even sure if they all 
> realized it. It was eye opening to me. Following this realization, I 
> threw into Javatc a detuned output in the primary table to identify if 
> the coil is high or low on inductance and how much via a percentage.
> Not sure if any of this will help. Hopefully someone will post the page 
> you lost.
> Take care,
> Bart
> Tesla list wrote:
> >---------- Forwarded message ----------
> >Date: Fri, 29 Jun 2007 22:03:22 -0500
> >From: Drake Schutt <drake89@xxxxxxxxx>
> >To: Tesla list <tesla@xxxxxxxxxx>
> >Subject: How to tune?
> >
> >Hey everyone- I'm getting to the point where my coil is almost done and
> >realized that I lost a very important webpage link.  It was a tutorial on
> >how to set up and properly tune your coil and it was great!  now it's lost
> >:(   If anyone knows where I can find this or a similar step by step guide
> >to setting up my coil I would be obliged.  I think it might have been on
> >gary lashus' (can't really remember his name) page but I really can't find
> >it.  All I remember is the first page on his site was him sitting on some
> >huge statue.
> >
> >thanks a million
> >drake
> >
> >
> >
> >
> >
> >  
> >