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Primary Qs


From: 	FutureT-at-aol-dot-com[SMTP:FutureT-at-aol-dot-com]
Sent: 	Tuesday, September 23, 1997 4:53 AM
To: 	tesla-at-pupman-dot-com
Subject: 	Re: Primary Qs

In a message dated 97-09-22 22:31:39 EDT, you write:

<<     There is no doubt my neon was killed by a "kickback". For 
> months/years I have been wondering how a voltage higher than that 
> generated by the transformer could appear across the transformer 
> terminals (resonant charging and wide-set gaps aside). The answer 
> lies in the impedance of the transformer at the RF frequencies. If 
> some energy still remains in the sec of the coil after the gap has 
> gone out, it is coupled back to a series-tuned primary which is now 
> in series with an ultra high impedance presented by the transformer.
> My filter setup prevents the transformer ringing with the filter caps
> but in the process, I have boosted the impedance across the 
> transformer terminals. I should have used filter caps big enough to 
> limit the rise of a moderate amount of energy that could be fed back 
> while at the same time ensuring an unfavourable ring frequency with 
> the transformer. The only simple answer I have right now is bigger 
> filter caps. Back to the lab.
 
> :(
> Malcolm
  >>

Malcolm, all,

I have seen horrific kickback in both pulsed spark-gap and pulsed
tube type coils.  Static gaps which fire intermittently, or quench
strangely may be causing a similar effect.  Sub-optimal spark-
loading of the secondary/toroid may also allow the secondary to
ring longer than desired, and couple more energy into the high
impedance series neon circuit as you said.  In my TC, I obtain 
rather fast resonator ring down...less time for the neon tar to 
carbonize?

If it's kickback that's doing the damage, then maybe resonant
charging is relatively completely safe.  Have you estimated the
peak voltages of the kickback in your system?

Would simple 3k ohm resistors in series with the neon output
leads reduce the RF enough, esp. with some bypass caps to
ground?

Just tossing out some thoughts here,

John Freau