Jim Miller wrote:
> Jim
>
> Any construction examples anywhere on the net of the non-sparkplug
> approach? Sounds interesting.
ARRL handbook used to have an example. (look for an openwire line
lightning arrestor).. it was just three pieces of sheet metal with
angles cut to make a point.
___ _____ ______
|___> <_____> <______|
You don't need to over think it. When I build protective spark gaps, I
just use reasonably stiff bare wire, bend the end in a circle (say 1/4"
in diameter, or whatever your needle nose pliers do), and bend the wire
to adjust the gap appropriately. I usually use AWG 12 or AWG 14,
because that's what I have scraps of. (after all, RG-8/RG-213 type coax
is 13 AWG center conductor, so there's not much point in making the gap
out of something significantly larger..) OTOH, if you've built your
custom coax out of 1/2" copper pipe as a center conductor <grin>
As far as gaps go.. 71kV/inch for uniform field. A "wire gap" is usually
quite a bit lower.. maybe around 40kV/inch. So, if you want a 1000V
gap, you want to space them maybe 20 thousandths?
If it's not going to arc very often, you can just use the ends of the
wire as a gap. A lot of my improvised gaps are used as "safety gaps" on
things like tesla coils, so they actually arc over a fair amount, and an
"end of the wire" gap erodes pretty quickly, so I've used the "loop of
wire" approach.
>
> 73
>
> jim ab3cv
>
> On Sun, Sep 12, 2010 at 1:21 PM, jimlux <jimlux@earthlink.net
> <mailto:jimlux@earthlink.net>> wrote:
>
>
> You can get non-resistor plugs. I've used them as vacuum HV
> feedthroughs.
>
> As a spark gap, they'd work ok, but a couple pieces of sheet metal might
> be easier and more compact.
>
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