Re: Ground - where should it stop?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jason Petrou by way of Terry Fritz <twftesla-at-uswest-dot-net>" <jasonp-at-btinternet-dot-com>

I always ground all of my coil "bits" to a separate ground, i.e. a 12" bit
of copper pipe buried in the ground - i dont want any problems with RF (I
live in the bottom floor of a block of flats) and to pee off the neighbors!

Jason

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, April 27, 2001 10:05 PM
Subject: RE: Ground - where should it stop?


> Original poster: "G by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<nieporgo-at-email.uc.edu>
>
> When I built my first coil, I tested the potential between my NST
> cases and mains ground, and it was almost 0. So, I leave them
> floating. I see no good reason to require the ground on the cases and
> my blower motor, because I never work on the equipment energized. It
> seems to me that the NST is going to have one less reason to arc to
> case if it isn't grounded. The only failure mode I see remaining is
> an NST secondary-to-primary strike, and case ground will have no
> influence on this either. While grounding will help throttle HV
> strikes from the TC secondary, my primary circuit goodies are out of
> range, so I am not concerned.
>
>
> >Original poster: "Lau, Gary by way of Terry Fritz
> ><twftesla-at-uswest-dot-net>" <Gary.Lau-at-compaq-dot-com>
> >
> >You ask a very good question, and I'm not sure there is a consensus.
> >
> >Most of the circuits I've seen, including my own coil, have the mains
> >ground going only as far as the variac case.  The NST case is connected
> >to the RF ground, as is the middle electrode of the safety gap and
> >bypass caps, and secondary base.
> >
> >In a thread a couple of months ago, Malcolm Watts mentioned that he
> >connects his NST case to the mains ground, and for a good reason.  No RF
> >ground is perfect.  There will be some very high voltage noise present
> >between the RF ground and the mains ground.  If your NST case is at RF
> >ground and your NST primary is ar mains ground (ons side is neutral,
> >same as ground), then this high voltage noise will be trying to break
> >down your NST primary-to-core insulation.  I can't say though that I've
> >ever heard of this taking out an NST.  I'm not sure how such a failure
> >would manifest itself.
> >
> >If the NST case is connected to the RF ground, then it's very important
> >to use an EMI filter between the NST primary and variac.  I added a page
> >to my web site explaining the importance of hooking up an EMI filter in
> >the correct direction.  See
> >http://people.ne.mediaone-dot-net/lau/tesla/emifilter.htm
> >
> >One problem with a mains-grounded NST case is that should a streamer
> >strike the primary circuit, it would be directly coupled to the mains
> >ground.  Malcolm pointed out that he's taken precautions to prevent
> >primary strikes.
> >
> >I'm not sure the issue is settled.
> >
> >Gary Lau
> >MA, USA
> >
> >
> >Original poster: "Matt S. by way of Terry Fritz <twftesla-at-uswest-dot-net>"
> ><matt777777-at-hotmail-dot-com>
> >
> >I have another question that I was hoping for some help with... (thanks
> >to
> >all who responded to my lest one).
> >I have seen conflicting (to me) information on where to stop the house
> >ground.
> >I am planning on running it (the house ground) up to my
> >variac/controller
> >cabinet, and then I am unsure of whether to run it through the
> >(relatively
> >long) cord to my NST(s) or not.  I will be grounding my secondary and
> >the
> >center of my safety gap (and strike rail) to a (separate) RF ground
> >(buried
> >Cu pipes)
> >---------so, my question is.... should the house ground be run to the
> >NST
> >ground terminal on the input side or should it stop at the controller
> >cab.
> >with the RF ground hooked up to the NST ground terminal?
> >(I am hoping to have my NSTs right under the primary  - i.e. in harm's
> >way
> >sort of).
> >Thanks in advance - I have no doubt that this has been asked before, but
> >
> >there are so many occurances of "ground" in the archives, it could take
> >days
> >to find..(!)
> >Matt
>
> --
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