Re: Suicidal Secondary--Update

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

Original poster: "James B by way of Terry Fritz <twftesla-at-qwest-dot-net>" <zebulan123-at-yahoo-dot-com>

hi Winston
A six inch coil should take 1.5kva fairly easy. in my
experience a three inch coil will take up to 2 kva.
maby i missed this, what is the geometry of the
primary id, od, Angle, ect.
                  james
--- Tesla list <tesla-at-pupman-dot-com> wrote:
> Original poster: "by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <Esondrmn-at-aol-dot-com>
> 
> In a message dated 1/11/02 7:47:35 AM Pacific
> Standard Time, tesla-at-pupman-dot-com
> writes: 
> 
> 
> >
> > > 
> >
> >    Hi everyone. 
> > First I should thank all who gave suggestions.  I
> just got around to 
> > running the coil tonight, and had a chance to put
> a few of your ideas to 
> > work.  I patched the craters from last week's run
> with 5 min. epoxy, put 
> > plexiglass washers around the top half of the
> coil, and rested a 3" dia. 
> > toroid on the top washer as an anti-corona ring. 
> >
> > These worked to some extent, but not as well as I
> hoped.  I got no full 
> > secondary arcs, but had many hot racing arcs
> trying to find a way around 
> > the washers.  There were also arcs running in
> between the washers.  I 
> > did the coupling calcs. that Terry suggested, and
> found that the highest 
> > coupling I achieved was 0.12.  It sure looks like
> I'm overdriving the 
> > heck out of the coil, but I'm only running at
> 1.5kVA.  The bang size is 
> > about 5 joules.  I tried both toploads (6" by 20"
> and 8" by 22" 
> > toroids), with the coil tolerating the smaller one
> best, but with much 
> > decrease in spark length.  My big topload gave the
> coil trouble, but 
> > cranked out 4 1/2 ft. sparks (at the most).  This
> run was done in moist 
> > air, when the racing arcs are less of a problem. 
> Running the coil on a 
> > dry day would probably be a disaster. 
> >
> > I'm sorry if I'm being a nuisance, but I am really
> at a loss here.   I 
> > can't see how many of you are able to crank 4 and
> 5 kVA into a 6 inch 
> > coil similar to mine (achieving sickeningly large
> sparks in the process 
> > :-))  What did I do wrong? 
> 
> 
> -- snip -- 
> 
> Winston, 
> 
> In my opinion, racing sparks on the secondary are
> caused by either running the
> coil out of tune, overcoupling or just overpowering
> the coil - putting in more
> power than it can take.  I use two toroids on both
> of my coils, one right on
> top of the secondary (to prevent sparks from leaving
> from the top windings)
> then another raised up on a hollow cylinder made out
> of aluminum sheeting.  The
> upper toroid is larger and most of the discharges
> will leave from the here and
> go up and out, preventing strikes down into the
> primary.  My 6" coil produces
> sparks that are more than three times it's winding
> length. 
> 
> Have you done the math on this coil so you know
> approximately where it should
> be tapped on the primary?  Is the best tune point
> within a turn or so from
> there?  If so, I would suggest that you are
> overcoupled.  Is your primary
> flat?  A normal flat primary usually provides
> acceptable coupling with the
> first secondary turn set to be even with the top
> plane of the primary.  Lay a
> ruler on the primary and it should be just even with
> the first secondary
> winding.  If you have an inclined or saucer shaped
> primary, the secondary will
> need to be raised up possibly an inch or more to
> prevent overcoupling. 
> 
> Ed Sonderman 
> 
> 
> 


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