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RQ Gap (fwd)



---------- Forwarded message ----------
Date: Sat, 17 Jan 1998 17:50:30 -0700 (MST)
From: Tesla List Owner <listown-at-pupman-dot-com>
To: Tesla List <mod1-at-pupman-dot-com>
Subject: RQ Gap (fwd)



---------- Forwarded message ----------
Date: Sat, 17 Jan 1998 13:30:22 -0700
From: "Gregory R. Hunter" <ghunter-at-mail.enterprise-dot-net>
To: Tesla List <tesla-at-pupman-dot-com>
Cc: ghunter-at-enterprise-dot-net
Subject: RQ Gap

Dear Coilers,

Finally test fired my first Richard Quick style spark gap.  I used
nine 2" segments of 22mm copper pipe inside a 6" length of 4" sch 40
PVC pipe, topped by a 4.5" muffin fan.  I used a HDPE plastic bottle
to plug the center axis space, and strips of foam weather strip tape
to plug the area between the first & ninth electrode.  I must say it
was a real pain to build.  Adjusting all the gaps with a feeler
gauge just about drove me insane.  What a pain in the butt!

Previously I was using two gaps made from four spherical brass
drawer knobs.  I had one gap in each leg of the primary winding,
with the capacitor in parallel with a single 15kv 30ma NST.  With this
setup my best spark length was about 14" (not too bad for 450VA!).

The RQ gap caused marked changes in the behavior of the
coil.  For one thing, breakout from the 8" foil covered sphere on
top was nearly absent--just a few glimmers of output spark.  Very
puzzling.  However, when I brought a metal object near the
discharge terminal, I was rewarded with a fierce, crackling spark. 
I found I could draw a thick, intense arc out to about 18".  I
topped the sphere with a thumbtack, and the breakout came back
hotter and brighter than it had ever been before.

So the RQ gap caused longer, more intense sparks, yet somehow
retarded breakout.  Weird.  To cure the no breakout problem, I
tried a small 2.5" X 9" foam & foil toroid which had given
dissapointing results before.  Now, with the RQ gap in place, I was
treated to a wild show.  The little toroid sprouted five or six
writhing, crackling multi-branched sparks of dazzling length and
intensity.  It never behaved like that before.  It's almost like
having a new coil.  It seems far more powerful now.

The RQ gap has greatly boosted the performance of my little coil.  
I'm not sure what the difference is.  Better quenching, perhaps?  My 
coil now requires either a smaller terminal or a sharp point on a 
larger terminal in order to give breakout, yet gives much longer, 
hotter sparks than before.  Obviously, the electrical characteristics 
of the whole system have changed.

A secondary advantage of the RQ gap is increased firing times.  I can 
run the coil for 5 or 10 minutes straight.  The RQ gap barely warms 
above room temperature.  My old brass knob gaps used to get hot as 
pistols after a minute or two!

The RQ gap was a real chore to build and adjust, but was well worth 
the effort.  I highly recommend it.

Greg