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Re: flashover


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
> 
> 
>