Hi Woo,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).
Take care, Bart Dr.Hankenstein wrote:
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 cylinder) http://www.drspark.org/images/wwt44.jpg Regards, Woo dr.hankenstein@xxxxxxxxxxxxx "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 saftey Hello,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 (measured) 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 start 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 I need to shunt some transorbs as they are set up for a 15KV PSU. I'm Glad the tranny is still working!Has anyone else ever seen this happen with the classic filter?Thanks, Jim Mora _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla_______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla
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