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Re: Grounding Question.

Original poster: Mddeming@xxxxxxx
Hi Glen,

Yes, the secondary should never be connected to the mains ground. Although it will work, the schematic shown is somewhere between inefficient and quite dangerous. It looks like a reprint out of a 30- to 50-year-old book of the type often sold by outfits that pander to the "fringe science" and occult crowd. By any chance, did you get this schematic from an outfit that also sells free energy gizmos, antigravity devices, UFO books, time travel, or Tesla-coil-based cancer cures? A 4 kV NST is somewhat of a rarity in TC work A matched set of four might be hard to find. This is fairly low voltage for a spark-gap coil. With 8 kV you are looking at a total spark gap of only 2 or 3 millimeters MAXIMUM. Over the last decade, filter chokes have been found to be ineffective/detrimental to NSTs and have been mostly abandoned in favor of "Terry filters" or just safety gaps. More disturbing is the lack of any power controller (Variac, dimmer, etc.), safety disconnect, or even a simple ON/OFF switch!!! :^((( Unless you already have the transformers, or have your heart set on making this particular design, you may want to check the list archives for simpler, more efficient and SAFER designs.

Matt D.

In a message dated 7/17/06 12:13:01 P.M. Eastern Daylight Time, tesla@xxxxxxxxxx writes:
Original poster: "Glen McGowan" <glen.mcgowan@xxxxxxxxx>

I'm building a TC from the attached schematic. From the looks of the
drawing I'm double grounded. The secondary is grounded to the mains
and earth. The NST's are all grounded via a shared grounding plate
which is mains grounded.


C1 and C2 are there to limit noise fed back into the house wiring
(some of it at least). I understand that grounding the secondary to
the grounding plate can produce lethal currents but is there any
advantage to doing this?  This may be a rhetorical question. I assume
the secondary would "choose" the earth ground before it reached the
mains ground because earth would be the shortest distance. But
according to the drawing the NST's HV and LV's are both using the
mains ground as is the secondary (has a "choice" of using mains or earth).

I apologize if the post was hard to follow. I've scratched the same
spot on my head for the past hour. It's starting to bleed.