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RE: Induction heating in toroid / short circuit of secondary



Hi Ken,
Thanks for the thoughts.
Received my EE in '65 (35 years ago) and I'm still learning/refining !
I'm an Amateur too, K3MNN (Pgh, PA, /6 L.A. for past 33 years)

Some clarification.
1.) In pointing out open Vs closed toroids:
  Behavior, i.e. max point to point power arc achievable, 
  corona, spurious Sec arcing, etc.
  remained Unchanged !

Your comment infers it is the EM field that is responsible.

So why is there no change when I Open the toroid ? (& vice versa?)
  I keep the open end distance great enough such there is No arcing.
    (except when specifically testing for sparks between the open ends)
    (so there is no shorted turn via arc conduction in the major axis)
  The toroid is just a large ROC top secondary turn,
  aiding or opposing, with no discernable difference in TC performance;

or could the minor 8" dia shorted portion create an EM field ?
 
  Thats why I question EM Vs ES field influence. 

  From my tests, I would conclude the whole effect is ES.
  Same max ppArc, same corona inhibition, eliminates turn to turn arcs, etc.
  The shorted turn EM fails to alter any operating characteristic,
perceivable.

2.) I use the largest possible toroid to intentionally 
    inhibit spontaneous breakout, permitting my control
    to place a projection of sufficient length and ideally 
    cone shaped to a sharp point for field concentration,
    encouraging maximum charge accumulation & concentration per bang
    in the topload Capacitance before unleashing its stored energy as
    as a singular optimal power discharge 
    possessing maximum length & brightness (pk current) 

    Selection of a smaller ROC to optimize multiple breakout
    is the more typical coiler objective. 

3.) While R in a toroid shorted turn may be very low,
    in the presence of an intense EM field
    Current is verrrry high (kA's) then so it the power
       unless as proposed the toroids EM field is able to squash
       down the opposing field without wasting significant energy. 
         which is hard to accept (no free lunch)

    That's why I checked for arc production between the open ends, 
    to check for significant induction.
    Ends arced, so it appears there is !
         or can you present another mechanism responsible ?

-----Original Message-----
From: Tesla List [mailto:tesla-at-pupman-dot-com]
Sent: Wednesday, December 22, 1999 4:44 PM
To: tesla-at-pupman-dot-com
Subject: Re: Induction heating in toroid / short circuit of secondary

Original Poster: Kennan C Herrick <kcha1-at-juno-dot-com> 

On Tue, 21 Dec 1999 22:01:54 -0700 Tesla List <tesla-at-pupman-dot-com> writes:
>Original Poster: Dale Hall <Dale.Hall-at-trw-dot-com> 
>
>Ok Ken,
>We'll be keeping a keen eye on your submitted word from now on....
>The double 'rr' may come from  spell checkers suggesting toroid is
torrid !

"Torrid toroids"?  I like that.  But better:  >Torrid Toroid Toploads<.

> and they have no idea concerning dielectric.
>
>Regarding toroid toploads,
>
>Is it at all possible a toroids intense electrostatic field
> impulse could affect (interact with) the electromagnetic field ?
>
>I know theory says they're in different planes, 
> but can TC high intense energy physics alter that ?

I write only as an amateur (but EE grad >50 years ago):  I think there
would be no such interaction at all.  The only interaction, as I said
before, would be in a magnetic field set up by the shorted turn of the
toroid, tending to deflect the field of the secondary from passing
through the toroid--which we don't much care about.
>
>I admire how the toroid appears to shield or provide 
> influence to produce even field distribution, 
> preventing corona, innerwinding arcs, etc.

That's its business:  We want no place to exist on our T.c.'s where the
radius of curvature is so small that voltage breakdown to air will
occur--except at the very top.  At the top, we want the object there--the
toroid or sphere or whatever--to have its smallest radius of curvature
just small enough so that a breakdown to air will occur at the largest
voltage that can appear there.  That way, we will get the maximum length
of spark at breakdown, without allowing energy to dribble away too much
beforehand.

>Re: my ~8"x24" AL dryer duct toroid(s): 
>I do not observe a significant change in affect
>between leaving the toroid shorted and open (but close ~1/4"), 
>and aiding or opposing Sec winding direction. 
>Open, I'm able to draw ~1/8" point-point arcs at the edges, 
>suggesting EM induction and some energy wasted. (?)
>But as well, I can produce similar arcs from any loop
>even further from the TC.

As soon as you draw an arc you will be dissipating power because of the
resistance of the arc itself.  With no arc (toroid shorted), very little
power because the toroid's resistance, assuming its ends are well-joined,
will be very low.

KCH

>-----Original Message-----
>From: Tesla List [mailto:tesla-at-pupman-dot-com]
>Sent: Tuesday, December 21, 1999 10:33 AM
>To: tesla-at-pupman-dot-com
>Subject: Re: Induction heating in torroid / short circuit of 
>secondary
>
>Original Poster: Kennan C Herrick <kcha1-at-juno-dot-com> 
>
>Here is a thought on the subject:
>
>A "shorted" toroid constitutes a single shorted turn adjacent to the
>secondary.  There will be a circulating current in it but the power 
>it
>might subtract from the system will be very small since its resistance 
>is
>very low ((I^2)R--remember?).  Its only deleterious effect might be 
>to
>set up its own magnetic field that would be in opposition to the field 
>of
>the secondary--tending to push aside that latter field.  Apparently 
>that
>doesn't happen to any great extent, or else if it does, it doesn't 
>matter
>all that much, at the top end of the secondary coil where that 
>magnetic
>field is the weakest.  Or else--the field tending to be pushed aside
>merely "sneaks out" between the secondary and the toroid.  That it 
>might
>be deflected from passing completely thru the toroid is of no
>consequence, of course, since the purpose of the toroid is not at all 
>to act as a part of the transformer per se.
>
>Ken Herrick