On Fri, 3 Sep 2010 10:34:19 -0400, "Oppie"
wrote:

Post it to www.instructables.com when you are done (and if you don't fry
yourself first). There are lots of 'Steam-Punk' projects there.
The Jacobs ladder is typically made with an ignition transformer from an oil
burning heating system. The secondary on these transformers is center tapped
with the tap going to case/earth. The output current is limited by the
internal core gap (iirc).
Might be a lot safer since the meter will not measure KV directly, that you
use a suitable scaling resistor and simply measure the mains (primary) side
of the transformer. For added effect, put a filament lamp of 100W or so in
series with the primary. Brightness is proportional to the current drawn and
gives a further current limit control. This may not give enough power for
the arc to travel up the column though.

Be safe!

"glutinous" wrote in message
.. .
I have just bought a vintage (1943?) DC 25-kilovolt meter (for a
Steam-Punk style 10kv Jacob's Ladder project).



Thank you for the observations, Oppie.

As I just replied to PeterD, the Jacob's Ladder I referred to is built
and functions well, using (and I always get a childish pleasure out of
saying this) a 10kv FART transformer from a neon rig. It makets a nice
spark between two 30-inch copper rods, approx 2.5 inches at the wide
end.

In fact I already have a (low wattage) vintage industrial filament
lamp fitted to the front of the box it's built into, but it's wired in
parallel to the primary, and lights up when the low-voltage switching
side operates a relay to supply current to the FART (he he he snurk).
Anyway, I'm guessing it'd limit the juice so less spark.

It's an idea to try the meter on the mains side: it doesn't _really_
have to show a genuine 10kv, it's more for the look of the thing (tho'
it would be cool if it did - obviously without the frying bit).

BTW, the low-voltage relay side is operated by a small, old-style,
bakelite base circuit-breaker type switch (as in "throw the...").

Cheers!