Re: I don't understand (fwd)
---------- Forwarded message ----------
Date: Fri, 19 Dec 1997 13:37:30 EST
From: Esondrmn <Esondrmn-at-aol-dot-com>
Subject: Re: I don't understand (fwd)
In a message dated 97-12-18 18:33:46 EST, you write:
<< Hi All,
I have my Coil up and running with really good performance,
(37" Discharges). I am using 2 variacs. One for voltage
control and the other for current limiting. Both variacs are
rated at 30 amps. I'm using an EMI filter ran in revervse
between the current variac and the PT, to help my home AC
lines. I'm using a Westinghouse potential transformer, 100 to
1 ratio, 15,000 Vac. I am also using 50,000 volt rated high
performance neon sign wire running from the PT to the series
spark gap consisting of 6 tungsten tig welding tips. I also
have a safety gap right before the spark gap
I placed an Amp meter in line after the current limiting
variac and before the PT. What I noticed is that it takes
about 17 amps for the spark gap to fire and the coil runs.
Then the amp meter starts to peg and wildly swing back and
*Is this what is called "kick back"?
*Is this coming from the spark gap and is feeding RF or energy
back through my power system?
*Is this why chokes are used between the PT and the spark gap?
Please help me understand?
Thanks to all,
It sounds to me like your static gaps can't quench the current available from
the potential transformer. Most coils using non internally current limited
transformers require rotary gaps for proper quenching.
I originally had my coil powered with a 12 kv 120 ma neon sign transformer
supply. One RQ style cylindrical static gap (six gaps of .028") worked fine.
Then I switched to a pole pig and even with current limiting in the primary,
the static gaps were overwhelmed and the primary current went sky high.
Adding a rotary gap to the system fixed the problem.