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Re: Tracking inside secondary former



Original poster: "Mark Fergerson by way of Terry Fritz <twftesla-at-uswest-dot-net>" <mfergerson1-at-home-dot-com>

Tesla list wrote:
> 
> Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<Clearspring1-at-aol-dot-com>
> 
> Bart and Mark,
> 
> Thanks for your explanations of the propagation of internal flashovers and
> the resultant carbon tracking.  I believe you have also helped answer my
> wonderings whether "more is better" when it comes to internal baffles
> intended to thwart such flashovers.  I am thinking an extra baffle in the
> middle of the former would be cheap insurance.  (To the inquiry that appeared
> earlier about how to place such a baffle: with a friction fit, merely pushing
> the baffle midway into the former with an appropriately-sized, squared-off
> pipe or piece of wood should work fine.)

  Quite welcome. Yes, baffles are indeed cheap insurance from all
reports. I also fancy the idea (forgot whose) about attaching the
baffles to a nonconductive pipe/rod for easy removal. The top/bottom
ones are attached to the form w/nylon screws IIRC.

  Obviously, to completely prevent internal flashover a solid form
with as high a dielectric constant as possible would be ideal.
Unfortunately, as Tesla himself pointed out, solid dielectrics _will_
eventually break down and do not "self-heal" the way liquids, gases,
and vacuum do. There's also the pesky losses caused by RF absorption
which can never be zero except in vacuum. So, well-placed baffles are
apparently the best compromise, unless you want to pioneer
vacuum-filled secondaries...

> Bart points out the basic rule of the increased arc distance found with
> "insulator"/air interfaces as one of the main dynamics, which makes perfect
> sense.  This leaves me wondering why David had such success with his Sonotube
> baffles which were a "snug" fit in the secondary former, but were not sealed
> to the former.  Perhaps a significant volume of air is required for this
> interface phenomenon to take place?

  Hm. "Real" HV insulators are naturally as nonconductive as possible,
but also include surface "ripples" to increase the distance any
possible arc has to travel. It might be as simple as that. Bart?
David? Anyone?

  Mark L. Fergerson