From: FutureT [SMTP:FutureT-at-aol-dot-com]
Sent: Thursday, January 22, 1998 2:38 PM
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.....
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.