RE: Very Confused On Grounding

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Lau, Gary" <gary.lau@xxxxxx>

You're right - connecting the RF ground to the NST case will cause it to
couple to the mains.  But the NST secondary is also full of RF,
particularly if one does not have a filter network between the NST and
main gap, and you'll get at least as much coupling from the secondary to
the primary.  Good reasons to use an EMI filter on the NST primary side!

The trouble with connecting the mains ground to the NST case is if and
when the safety gap (between NST sec & case) fires.  If the case were
connected to mains ground, you'd have the current in the firing safety
gap going through the mains ground, and the potential between the mains
ground and the neutral would not be good for most appliances.

In addition to the secondary base, the RF ground should be used for
anything that may get hit with a secondary streamer.  Should the primary
see a streamer strike, the safety gaps will fire, and the ground
terminal of the safety needs to conduct this current safely to the RF
ground.

The mains ground is strictly for personal safety - things that one might
touch like the Variac case.  The goal is to keep RF out of the mains
ground, so it's generally not used at all beyond the Variac.  The RF
ground is NOT good for personal safety, since it often has a high
impedance at 60Hz, compared with the mains ground.

Regards, Gary Lau
MA, USA

> Original poster: "Daniel Koll" <dk_spl_audio@xxxxxxxxxxx>
>
> In the Terry Filter he shows one side be grounded to RF (spark gap
side)
> and the other side of the filter be tied to the NST case.  Wouldn't
this
> cause major RF on the NST case and maybe inducing into house
> lines?  Shouldn't the RF ground just be for the strike rail, end of
> secondary, and the middle of the spark gap?  If so were should the
other
> said of the filter go?  Am I supposed to use the houses ground at
> all?  Someone please clear all this up for me, I can't afford to make
a
> costly mistake.  Thanks
>
>