Re: Triggered Gaps

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

Original poster: "Andy Cobaugh by way of Terry Fritz <twftesla-at-qwest-dot-net>" <kb3ewy-at-rcn-dot-com>

A great construction article written by Ted Rosenberg can be found here

http://hot-streamer-dot-com/temp/tgap.pdf

I followed the directions almost exactly.  I used a vortex gap with a third
trigger electrode mounted in it as the main gap assembly.  I did notice that
with my setup, 28nF tank cap and 15/60 NST, that the fan speed controller
did not give me enough phase range.  I solved with an external variac
feeding the circuit about 90V.  I scoped the waveforms to confirm this, but
I have not had a chance to try it out on the coil.  I'm sure it will do the
trick though.

The basic circuit consists of a fan speed controller from Home Depot.  The
5A triac is replaced with a 15A or greater Triac from Digi-Key.  Voltage is
dropped with a few resistors and capacitors to enable running a 12V ignition
coil off of 120V.  The circuit also includes MOVs for protection.  Ignition
coil was bought from Autozone, discrete components from RadioShack, 25A
triac from Digi-Key, fan controller from home depot.

You can see my gap at:
http://users.rcn-dot-com/tcobaugh/hv/sparkgap.htm



Your high voltage enthusiast and general mad scientist,

Andy C.
Ham Call: KB3EWY
http://users.rcn-dot-com/tcobaugh/