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[TCML] HV tolerant EMI filters?

As part of my effort to build an “ultimate” (to me at least) control panel / primary supply
for “My Last Tesla Coil”, I included a corcom type EMI filter in the supply side of the line
to try to make the coil as “friendly” a load as possible.

 During tune up during a recent demo, the primary took a strike, the safety gaps didn’t
fire (that I noticed, it was all over in the blink of an eye) and somehow, HV nastiness 
got past the Terry filter, NST, and torched the filter. 

During the event _something_ made brief arcing flames inside the panel visible through
the ventilation grill, but there’s no side of physical damage to anything.

I’ve been scratching my head trying to find the path. All components, the NST, the Terry
filter, appear fine.  There’s a fine dusting of what looks like smoke residue on some 
cables, but I’m damned if I can find any arc or penetration marks anywhere.  The
ground of the coil was to earth and isolated from the supply/panel ground.

It seems to me that the strike’s HV had to pass through the Terry filter and the NST
to get to the corcom, but then I would expect damage to those parts. Curious.

I have some ideas to improve the situation for next time, but I’m now wondering 
whether anyone makes any EMI/RFI filters with rather high voltage peak ratings.
My initial web searches from the usual suspects haven’t turned up any.

I suppose I could put a monster industrial MOV unit at the filter, but that seems like
a bandaid which will just wear out eventually, the way MOVs tend to do.


 - Bill “Gomez” Lemieux
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