Re: oil dielectric

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

Original poster: "Mark Fergerson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <mfergerson1-at-cox-dot-net>

Tesla list wrote:
> 
> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Xyme3-at-aol-dot-com>
> 
> In a message dated 05/12/2002 2:23:53 PM Pacific Daylight Time,
> tesla-at-pupman-dot-com writes:
> 
> >
> > ?
> >
> >   Sure, but why? Tesla (and others) built "demonstration"
> > coils with the primary/secondary assembly immersed in oil
> > but AFAIK not the primary alone.
> >
> >   Tesla's stated reason was to minimize corona losses,
> > flashover (what we today call racing arcs IIUC) on the
> > secondary, and pri/sec arcs, and he preferred oil because
> > it's "self-healing". Still makes sense in light of today's
> > knowledge, but why just the primary?
> >
> >   Mark L. Fergerson
> 
> I was concerned about strikes to the primary from the torrid. I had not
though
> of corona's forming around the secondary, i a novice at this.  Also i had
> considered insulated wireing with a porus spacer. I think this would overcome
> some of the problems with dielectric breakdown in the wireing. Heavy wire or
> copper tubeing would be used to construct a large flat coil.

  There's an "accessory" commonly used to prevent that,
called a "strike rail", which is a grounded not-quite-circle
of wire (to avoid being a shorted turn) mounted slightly
above the primary (in a plain-vanilla solenoid configured
coil). It basically forms part of the second plate of a
capacitor (along with any purpose-designed ground plane and
the rest of the Universe), the first plate of which is the
topload.

  You can think of it as a lightning rod without going too
far wrong.

  OTOH with some structural fiddling you can omit the rail
as some coilers here will verify.

  Your other design ideas sound viable if only because
they've been done and work.

  Mark L. Fergerson