Re: Toroidless Tesla Coil Schematic Scan

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

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

In a message dated 5/22/01 2:47:25 PM Eastern Daylight Time, tesla-at-pupman-dot-com 
writes:

> Original poster: "albert hassick by way of Terry Fritz 
<twftesla-at-qwest-dot-net>" <
> uncadoc-at-juno-dot-com>
>  
>  Hi everyone.  Barton B. Anderson was kind enough to figure out how to
>  open my Visionner scan of my toroidless Tesla.  Here is the website he
>  placed it on;    www.classictesla-dot-com/temp/May72001.gif   So now fellow
>  list members can view my scheme of my Tesla and perhaps help figure out
>  why it works equally well with/without topload by retuning the primary
>  coil and or sparkgap for any given topload.  Thanks for all your help! 
>  Al.

Hi Al, Bart,

Thanks, I looked over the schematic.  One possibility Al is that what you're
seeing may have something to do with the quenching, since it's a strong
amount of power you're using.  Toroids do tend to hurt the quenching,
so adding the toroid may be causing the spark gap to power arc
somewhat, by causing it to overheat. If this is the case, then using 
a breakout rod on the toroid should help some.  If the gap is power-
arcing part of the time.... less time will be available for cap charging.
It would be interesting to try using a rotary gap instead, or in series
with some static gaps.  The rotary would need to provide the proper
BPS though.

I'm assuming here that your toroid is smooth without
a lot of edges.  It there are too many edges (such as on a hexagonal
toroid), and if the toroid is not big enough, it may not add much spark
length.... so that's another possible explanation.  If the toroid is big
enough, and large enough, it will reduce the number of streamers to
somewhere around 1 to 3 streamers.  If you have more streamers 
than that, then the toroid may be too small, or have too many edges.  
It would help if you gave all the specifications of your coil; secondary
size and wire, # of turns, toroid sizes and types, etc.  You may have
given some of these specs in the past, but i don't have the info
at hand.

That's an interesting gap arrangement you're using with one
gap across the transformer, and one in series.  I assume you've 
tried using both in series across the transformers?  You seem to
show a section of the primary as shorted out by the tap wire, I'm
not sure if you meant to draw it that way.  If it is indeed shorted,
that would tend to hurt the performance a lot I would think.  I didn't
think a TC would work that way at all, but I never tried it.  It
would perhaps tend to cause a different degree of performance
degradation depending on where it's tapped, (for instance when
you move the tap to retune with a toroid).  So this could be the
explanation for what you're seeing too.   

I don't think there's any particular aspect of the charging circuit
wiring that makes it work the way it does, rather I would expect 
that one of the above issues is the explanation.  What I mean 
is that I don't think it's the use of the various chokes, isolation
xfrmers, etc., that is causing the atypical behaviour, but it's 
hard to really say for sure, since these elements do affect the
quench too, from a power arcing point of view.

Basically what I'm suggesting in the various explanations above,
is that something becomes inefficient when a toroid is added.
If the cause of that inefficiency can be found and corrected, then
the toroid should help the spark length.  Another thing which
I didn't mention above, but mentioned previously, is that if the
secondary is very large relative to the spark length.... there may
not be enough power available to support a large toroid.

It would be also of great interest if you could determine the
power actually being drawn by the system, so that an overall
assessment of efficiency could be made.  Even a VA measurement
would be of some value.

John Freau