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RE: [TCML] High voltage input snap when adjusting unloaded Terrysaftey
The resistors are the suggested Digi-key 1K 100watt ohmites. All other
components are the suggested Digi-keys. I am baffled by this. In no way am I
criticizing the design as I hold Terry with the highest respect. Weird.
Something about my modified NST perhaps (half shunts removed and submerged
in paraffin and Vaseline)?
From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf
Of Barton B. Anderson
Sent: Monday, December 10, 2007 6:13 PM
To: Tesla Coil Mailing List
Subject: Re: [TCML] High voltage input snap when adjusting unloaded
If your talking about LC filters, I agree it's not a good idea with
NST's. But if it's an RC filter, I think Terry Fritz showed very well in
his documentation the difference "with" and "without" the filter. He
also looked at RC versus RLC networks. The later did attenuate some
dangerous transients, but it also caused resonant conditions (which were
not previously there and were just as dangerous for the transformer). So
I think most have taken on the use of the RC Terry Filter of which
Terry's testing showed that it eliminated dangerous transients when the
spark gap was placed across the transformer and even attenuated
transients when the spark gap was connected in series with the
transformer (of which other testing showed how dangerous this particular
connection was for the NST's).
> I use two concentric rings across my capacitor on my Table Top Tesla Coil.
They are adjusted to approx. 1/4". It produces 18~22 inch sparks at 7 amps.
This seems to protect the oil filled cap and the NST (12kV 60mA) quit well
as there are over 700 hours of operation on the coil with no malfunction
since 1994. The gap has on odd occasions fired for "no apparent reason". I
think all these filters are a waste of time and money and produce other
unwanted side effects as well. Check out the link: (The cap is the big white
> "We put the fire in the wire."
>> [Original Message]
>> From: Jim Mora <jmora@xxxxxxxxxxx>
>> To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>> Date: 12/9/2007 6:38:00 PM
>> Subject: [TCML] High voltage input snap when adjusting unloaded Terry
>> I was adjusting safety gap for my used Terry filter. This will be for 4"
>> demo coil which has a block diagram what stuff is and the wire path.
>> Independent of that, I was setting my safety gaps to fire at 140v
>> in, on the bench. Wow, just before the safeties fire, I get a 2" hot snap
>> accross the filter input. It is a very dry out and that stress has to be
>> seen across the outputs of my 12KV, 30+ma repotted neon. They safties
>> firing immediately afterwards. I closed them a bit, about right, and it
>> still happens unless I ramp the voltage up very slowly. Is this a reverse
>> resonance rise and a discharge of the filter caps? I should mention that
>> need to shunt some transorbs as they are set up for a 15KV PSU. I'm Glad
>> tranny is still working!
>> Has anyone else ever seen this happen with the classic filter?
>> Jim Mora
>> Tesla mailing list
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