Re: Non shorting toroíd?

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

Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com> 


The best way to check this is with a time exposure (4 sec) with black &
white film.  Expose in a completely dark room and experiment with elevating
the toroid.  B&W film displays corona excellent and you will be able to see
how much you are retarding it.

Without a toroid or with a small sphere the corona angle off the last turn
is usually 45 degrees.  You are looking (with adjustment of height) for
either a horizontal or slightly downward corona spray angle.

The photos will tell the story as film is much more sensitive than the eye
especially with time exposures.

Dr. Resonance
 >
 > Hi all,
 > After having made a toroíd by taping Al repair tape around a big ring of
 > expanded polystyrene, I was disturbed by the e-mail about the heating up
by
 > hf current when the toroíd is close to the upper winding of the secondary
 > and acting as a shorting ring. I have completely overlooked this
phenomenon
 > and now expect the toroíd's core will melt-down and/or the Al strips to
 > loosen from the core (their glue becoming soft).
 > First thing to do: lifting the toroíd a certain distance.
 > If I get corona around the last winding of the secondary, an anticorona
 > ring around it or a small toroïd over it. This one should not act as a
 > shorting ring, so I imagined to split it up in two halves, e.g. remove the
 > conducting layer around the toroïd in two places over a distance of let's
 > say 3 mm.
 > My question is: what can I expect about break-out in these places?
 > My second question is: is there a rule of thumb for the greatest distance
 > between upper winding and heart of the toroïd?
 > Regards, Willem
 >
 >
 >