Jim Lux Pipe Cap TSG

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "S & J Young by way of Terry Fritz <teslalist-at-qwest-dot-net>" <youngs-at-konnections-dot-net>

Coilers,

A few months ago, Jim Lux posted a link to his design for a triggered spark
gap made of copper pipe caps.  I built one and finally tested it today.  I
can testify it is a good design, and very cheap too!

Here is what Jim posted:

"I have an idea (untested for now) on a way to build a blown triggered gap
that is low cost, adjustable, etc.

It uses two copper pipe caps as the electrodes. A hole is bored in one, and
the trigger electrode is mounted in that hole.  Air flows through the cap,
through the annular hole around the trigger electrode, and then, out
radially through the gap. The trigger electrode can most anything, but
something like a TIG electrode might be the best thing.

Write up at http://home.earthlink-dot-net/~jimlux/hv/captrig1.htm
Diagram at http://home.earthlink-dot-net/~jimlux/hv/images/triggap1.gif "

My design uses 1.25 inch copper caps, which make a good fit over 1 inch PVC
elbows and Ts.  Caps are spaced about half an inch apart, but can be slid
back and forth on the PVC fittings to change the gap spacing.  The triggered
cap has a half-inch hole with the trigger electrode being a 3/16 brass
threaded rod.  The end of the rod is roughly flush with the back side of the
pipe cap.  It is triggered with a variable pulse rate generator driving an
HEI coil.  This is used with a DC resonant charging setup, but the Lux
design should work just as well with an AC supply, provided the trigger is
synched with the 50 or 60 Hz mains power.  Cooling/quenching air is from a
small vacuum cleaner blower, running at about 3/4 its normal input voltage.

Performance seems a bit better than my other TSG using tungsten rods and an
annular ring trigger electrode.  Pipe caps only get a bit warm with 1 KW DC
supply.

At 1 KW DC power and 200 BPS, I get 66 inch sparks between twin coils with
breakout points.

Good as this design is, I still cannot crank up the power beyond 1 KW DC
without the gap power arcing.  Thus for my resonant charging setup, my ARSG
can out-perform (72 inch streamers) the Lux TSG, but the Lux setup is safer
and more fun to play with than the RSG.

The Lux design is great for using lower voltage supplies.  With the gap at
about 1/4 inch, it will fire reliably at only 4 KV.

Bottom line:  try it - you'll like it!

--Steve Y.