Re: Practical limit to number of turns on primary ? ? ?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" <FutureT-at-aol-dot-com>

In a message dated 1/30/03 8:49:27 PM Eastern Standard Time, 
tesla-at-pupman-dot-com writes:

Terry, all,

In my old research coil I was refering to, I often used a potential
transformer so there were no shunts.  I'm not working on any
TC projects at the moment, except I just modified my 555 timer
based staccato circuit for tube coils.  I added a zero-crossing
trigger for better stability and precision.  I used the zero-crossing
design from John Tebbs' STSG phase controller circuit.  My 555 timer
board was based on Dave Sharpe's 556 timer circuit and his circuit
in turn was based on my original TTL staccato circuit.  The TTL
circuit is sensitive to RF interference, and started to act up as the
spark lengths increased.  I don't plan to use the TTL design anymore,
although it's OK at low powers.  I'll eventually update my website,
but I don't know when.

John


>Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>
>
>Hi,
>
>If John's transformer is saturating the shunts, giant power may indeed be
>being pulled from a seemingly "too small" NST.  Gary Lau's coil does seem
>to be doing this too.  Saturated shunt NSTs are probably the next "big
>thing" coming our way ;-))
>
>Work and other things have prevented me from continuing my NST experiments
>yet, but stay tuned ;-))
>
>I would think in this case, a wattmeter like John has should be "pretty
>close"  The harmonics are within the range of the older instrument grade
>devices.  There will always be some error, but it should not be
>dramatic.  Even a Pearson current probe (1%), Tek HV probe (2%), Tek scope
>(2%) can add to 5% error (ignoring digitizing error...).  But big 30% error
>should not exist in any case.  So, it's probably a "real thing" :-))))
>
>If anyone can find a "better coil" John is certainly the guy to do it
>;-))  I would be more prone to not question "if", but "how and why" ;-))  I
>would not go rewriting John's spark length formula too fast...  But power
>transfer and efficiency in Tesla coils is a messy and difficult subject in
>which sweat things are expected ;-))  These days, a few miracle
>breakthroughs a year is normal :-)))
>
>Cheers,
>
>      Terry
>