RE: Tracking inside secondary former

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

Original poster: "sundog by way of Terry Fritz <twftesla-at-uswest-dot-net>" <sundog-at-timeship-dot-net>

Hi all,


  In running 2" forms, mainly to destruction to try new ideas (some good,
some not-so-good), I've flat out burned up probably 15-20 coils
deliberately.  Being only 2.5" in diameter and 9-13" long, no huge deal.  A
10# spool of 26ga wire was reasonably priced, and I've wound a ton of coils
off of it.  (still plenty left too!)

 I've tried a million and one things to prevent internal flashovers.  Discs
epoxied or siliconed into the form have been extremely useful, but the #1
thing I found prevents it is proper tuning/coupling.  I run my coils with a
HDPE plug in the bottom to allow for mounting it, and open at the top
(toploads sit on the top.) for the small coils.  The larger coils and those
I'm going to push hard get baffles inside.  Those that I'm *really* going to
crank on (like a 2.5x13 coil to be driven at 2kva) get 3-5 baffles.

 But the most effective thing I've found is to tune it properly.  I *always*
use a breakout, a nice sharp pointy one that sticks at least the minor
diameter of the toroid out from the coil.  That gets it mostly clear of the
field (enough to break out easily).  I do my tuning at full power, by
starting *very* loosely coupled and tuning for best breakout, then slowly
increasing copuling and adjusting the tap point as I do.  I remove the rod
and give the coil a short hit of power to see if it's capable of breaking
out once I'm getting strong streamers, and if it doesn't, I add the rod and
retune (if necessary) and couple a little tighter.

   Breakout, De-couple, Tune.  Those 3 things will save you a *lot* of
burned forms/ruined secondaries. Especially when you get up into running the
large 6-8-10-12+" coils.  At low coupling with a breakout, the racing sparks
are much less severe (barring a serious tuning mistake), and your coil is
much more likely to not suffer any damage.

 And a tip from experience, always start at the *outside* of the primary and
tune inwards!  That way, the voltage peak will be beyond the end of the
coil, instead of tuning too far in and it appearing at the middle to 3/4 up
the coil. That'll ruin a secondary in a real hurry.  Usually I only get bad
racing sparks when tuned too high of a freq, and no output at all (or really
weak) when tuned too low.

As for performance differences, adding baffles won't make your coil work any
better (or worse), but it can give it the ability to work better.  Just
remember, Breakout, Decouple, Tune from the outside in!
													Shad

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Thursday, January 18, 2001 10:56 PM
To: tesla-at-pupman-dot-com
Subject: Re: Tracking inside secondary former


Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<Clearspring1-at-aol-dot-com>

John,

Do you have any idea why you have not experienced secondary coil internal
flashovers and others have?  Just trying to get a handle on all this.
Thanks!

Michael Tandy

>  Did David compare the coil's performance with no baffles at
>  all?  Maybe his coil doesn't really need them.  Many coilers
>  don't use them.  I run my coils open at top and bottom, you
>  can look right through them, and I never got any flashovers,
>  or carbon tracking inside.
>
>  John
>