[Prev][Next][Index][Thread]
Re: flashover
Hi Andrew,
This sounds to me like you started out with a coupling problem and things have
snowballed on you. The helix was probably the wrong direction to go with this
problem as it will just increase coupling. At this point in the game, I would
recommend inspecting the secondary thoroughly! Check for carbon tracks on the
secondary, ohm it out, etc... If everything looks fine and nothing has been
damaged from the troubles, then I would fit the flat primary back into place
and go backwards on the secondary (install it a good distance above the primary
and you should get no sparks - then lower it 1/2 way down, try again - if
nothing 1/2 way down - keep using this method until you get sparks - if you get
sparks with racing arcs, then 1/2 way up between the prior position, etc..
etc..). This method is a little backwards but I think is the method to use at
this point. If you still can't get sparks, there is something very wrong with
the secondary. I would post back to the list again at that point and let us
know your construction details and hookup method.
Good luck,
Bart
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