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Re: flashover

Andrew,
   What is the height of the bottom turn of your secondary above your
primary. It may be as simple as overcoupling. Try raising your secondary and
inch and see what what happens.
Good luck
George
----- Original Message -----
From: Tesla List <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, May 25, 2000 6:51 PM
Subject: Re: flashover


> Original Poster: "R.E.Burnett" <R.E.Burnett-at-newcastle.ac.uk>
>
>
> Andrew,
>
> Check the ground connection to the bottom of your secondary,  and the
> ground connection to the NST case.  Both should have a low resistance
> path to your ground rods.
>
> The only time that I have seen arc-over this severe is if the secondary is
> not grounded properly.  Try not to breath the PVC fumes,  they're nasty.
>
> Cheers,
>
> -Richie,
> On Thu, 25 May 2000, Tesla List wrote:
>
> > Original Poster: "A W" <fateagk-at-home-dot-com>
> >
> > I am still trying to get my first coil together. I have been plagued
> > with flashover arcs from my primary to the secondary. I am using a
> > 7.5kv/30ma NST, saltwater bottle caps with total of .013uf, a single
> > static gap(2 brass bolts), and a 4" PVC secondary wound 21" with #24
> > magnet wire. I originally had a 14 turn primary of 1/4" refrigeration
> > tubing in a flat spiral. It had 1/4" spacings and had an inner turn
> > diameter of 7". It arced so bad that it seemed to turn the distance
> > between the primary and secondary into a 1.5" gap. I put a section of 6"
> > PVC between them, changed the coupling, wrapped both in electrical tape,
> > covered the first turns of the primary in clear tubing, tried different
> > tapping points on the primary, all to no avail! I scrapped the 1/4"
> > refrigeration tubing primary and have made a new primary. I made a 11.5"
> > diameter helix spiral primary using 12ga wire. Remember, my secondary is
> > 4" diameter PVC. It is now arcing over 3" to get to the secondary. I
> > cannot make it stop. I am using the same 7.5/30 NST. I have checked the
> > entire circuit and cannot find anything that looks fundamentally wrong,
> > so why is this happening. I have tried it both with the RF ground on the
> > secondary, and without. I have wrapped the bottom half of the secondary
> > in electrical tape, and placed a section of 6" diameter PVC around the
> > primary. It has now burned the PVC, smoke was everywhere! I have been
> > checking tons of websites on the internet and I have yet to see an
> > instance where the primary requires more than three times the diameter
> > of the secondary. Could it be my transformer? I am getting to frustrated
> > with this! HELP!
> >
> > Thanks,
> > Andrew
> >
> >
> >
>
>