Re: neons & rsg

From: 	FutureT-at-aol-dot-com[SMTP:FutureT-at-aol-dot-com]
Sent: 	Saturday, August 02, 1997 1:17 PM
To: 	tesla-at-pupman-dot-com
Subject: 	Re: neons & rsg

In a message dated 97-08-02 17:07:04 EDT, you write:

>      I know many have said not to use rotary gaps with neon xformrs. 
>What is the theory behind this? Could you use a rsg with a neon if you 
> use protective chokes on the neon outputs?

If the optimum capacitor size is used for a particular neon xformer, the
gap will only be able to fire once per half cycle.  Whenever a gap fires
once per half cycle, it's best to fire at the peak.  Using a fixed static
gap, firing will occur near the peak, but with a rotary, the firing may
attempt to occur "anywhere" along the half cycle.  If the gap presents
too soon, while the voltage is still too low, it will not fire.  Thus the gap
may not fire at all on that half cycle and may wait until the next half
cycle to fire.  Due to resonant charging effects, the cap will be charged
to an extra high voltage if this occurs, and this will stress the
It is also possible that the irregular firing of a non-sync rotary causes
occasional voltage resonant spikes which can damage the transformer.
Another way to look at all this is that a fixed gap LIMITS the firing 
voltage, whereas a rotary does not.

If a synchronous rotary is used, the situation is changed for the better.
The synchronous rotary will fire at the same place at every half cycle,
and will not skip a firing, thus the voltage will not rise as high as if a
half cycle was skipped.  Sync-gaps work very well with neon trannies,
and I suspect that they can outperform a regular static gap.  I have
never blown out a neon tranny while using a sync-gap and I do not 
use any chokes...but i do use a safety gap.

Some people do use non-sync rotaries on their coils, and obtain
reasonable results, but YES it is probably important to use chokes,
safety gaps, and perhaps even current limiting resistors in series
with the chokes.  The wrong sized chokes can make the situation 

Interestingly, a non-sync rotary will not be any better than a static
gap towards producing spark output length...unless perhaps you 
have paralleled  quite a few neon trannies so that the power input 
is high, and the superior quenching abilities of the rotary are called 

John Freau