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Don Foreman
 
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Default PHOTOS of my Franceformer and the sparks

On Thu, 20 Oct 2005 03:46:27 GMT, Ignoramus27736
wrote:

Made a 1/4" spark gap... I see sparks... Very exciting...

http://igor.chudov.com/projects/High.../Franceformer/

i

That's a neon xfmr. Three of those in series should make a dandy
Jacob's ladder! The buzzzzzzzZZZAP noise it makes adds to the fun.
With 3 or 4 of them in series, a Jacobs ladder should be able to
sustain an arc over an inch long before it goes out at the top and
starts again (ZAP) at the bottom.

The nameplate ratings can be confusing. They deliver rated voltage
under open circuit conditions, rated current at short or near-short
conditions. Once a spark/arc is initiated, voltage drops to about 1KV
in a short gap. 1KV is a near short condition for a 30KV xfmr.

A job I once had was designing electronic oil ignition xfmrs, 30KV at
30 mA. They ran at about 30KHz. In normal use the rectified AC
wasn't filtered -- but if a filter cap was added, the arc/spark was
eery quiet -- just sort of a soft hiss. A Jacob's ladder with that
was like the audio was missing.