Re: Secondary breakout -is it necessary to rewind?

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

Original poster: "Barton B. Anderson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <tesla123-at-pacbell-dot-net>

Jolyon,

It's possible an arc between primary and secondary is occuring at high
power (higher voltage/current). It sounds
like you may have developed a carbon track on the wall of the form behind
the secondary winding. I would spend more
time in the area of suspicion and really give it a real good visual
inspection looking for any sign where an arc has
occurred and behind the winding if possible. Should you find such an area
and it's nearly at the bottom of the
secondary, simply remove enough turns to get past the carbon track, clean
the former, and retune.

Take care,
Bart

Tesla list wrote:

> Original poster: "Jolyon Vater Cox by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>
>
> This Tuesday afternoon my 3" x 10 7/8" inch, 880 turn secondary suffered an
> intermittant breakout to the grounded end of the primary.
>
> The secondary was being run from my ignition-coil HVDC supply in conjunction
> with with six parallel pop-bottle saltwater caps, with the primary tapped
at 8
> 1/4 turns.
>
> Will I have to rewind the secondary? I have examined the area from which the
> arc emerged with a magnifying glass and cannot see any evidence of cracked
> insulation or burning.
>
> This appears to be an intermittent fault that (as yet) only appears to arise
> occasionally when the coil is made to produce large sparks i.e.>5 inches.
> Before the "incident" it was my intention to coat the secondary in Tuffkote
> epoxy varnish -in view of the present circumstance should I be contemplating
> this and is varnishing at all likely to prevent the re-occurance of  an
> "occasional" problem of this type?