From:  FutureT [SMTP:FutureT-at-aol-dot-com]
Sent:  Thursday, January 22, 1998 2:38 PM
To:  tesla-at-pupman-dot-com
Subject:  Re: Help....again...

In a message dated 98-01-22 10:59:18 EST, you write:

<< Hello all,
> I have aquired a 15kv 30ma transformer, about 40ft #6 bare wire for 
> primary coil.  I also have plenty of 2" pcv and I also have 4" pcv.  Now 
> I would like some suggestions for the demesions of the primary and the 
> secondary and the toroid so as I get the biggest spark.  I'd really 
> apriciate the help, and thanx for all the help so far.....
> Dan


The 4" pvc is much better (more inductance in the coil with wider
secondary in general).  A good length is 23" or so.  I like to use
# 28 formvar magnet wire, but thicker wire will work.  I used 33
turns of #12 pvc wire  for the primary, and a .007uF cap.  My 
toroid was 5" by 20" aluminum dryer duct.  I also used a 
synchronous rotary gap.  The only protection for the tranny was
2 safety gaps at each tranny HV bushing.  Spark output using
a 12kV, 30ma tranny was 42" max.  15kV, 30ma gave 44" or so.
However my secondary was 6 1/2" dia by 23" high.  (I later did
some experiments using a 4" by 23" secondary, using a different
tranny...and result were similar to the 6 1/2" pvc.  And of course
I had to retune (tap inwards) with the smaller secondary.  A static
gap gave about 28" spark and operation was somewhat erratic.  It
seems the sync-gap is unbeatable for neon systems.

John Freau