Re: NST Ground, RF ground, the whole bit...

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

Original poster: "Jon Tebbs by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jgtebbs-at-eos-dot-net>

Hi Ralph, All,

It seems that my choice of terminology has lead to a misunderstanding of my
post...

Tesla list wrote:
> 
> Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Parpp807-at-aol-dot-com>
> 
> Jonathan and all,
> 
snip
> --------------------------------------------
> In a message dated 7/14/01 10:58:31 AM Central Daylight Time,
> tesla-at-pupman-dot-com writes:
> 
> << <<<<All
>  mains connected devices would best be grounded to the mains ground.<<<<<<<
> 
> IMHO the above sentence and the sentence below are contradictory.
> 
> >>>>>Those
>  devices that are intended handle RF should be connected to RF ground along
> with
>  the secondary base i.e.: the NST Filter/Safety Gap, Strike Ring, etc.<<<<<<<
> 
 ------------------------------------------------------------------------------

The _NST Filter/Safety Gap_ is NOT the RFI/EMI filter on the mains side of the
NST, it is that which is located on the HV side. Perhaps I should have used the
term NST Protection Filter. If by chance my reference to the _secondary base_
has been misconstrued to imply the NST case, it refers to the TC secondary. My
apologies for the less than optimal wording.

 ------------------------------------------------------------------------------

> I agree with the sentence below. I think Malcolm wrote it. The way I read it,
> Malcolm is telling us to simply keep 60 Hz, line powered devices away from
> any chance of being hit by RF. The ground from Terry's filter is NOT
> connected to the
> mains connected devices which are grounded thru the  AC power line.
> 
>  >>>>>>Some will argue that if a mains connected device can be struck by a
>  streamer/leader/arc, then it should be connected to RF ground. This, IMHO,
>  would
>  very unlikely _if_ attention is paid to detail in the design and layout
>  stage to
>  avoid the possibility in the first place. >><<<<<
> 
> Yes, including the variac and blower motor.
>
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My reasoning for advocating the NST Protection Filter ground connection be to
the RF ground is based on the RF currents the Safety Gap and Filter R/C is
called upon to handle. "I" do not want those transients returned to the mains
ground or even impressed upon the NST case.

Again, consider the case of a missed "firing" where the primary capacitor
charge
exceeds the breakdown setting of the Safety Gap. The larger than normal bang
energy is dumped through the Safety Gap, with a portion through the resistors
and bypass capacitors. Even in normal operation, the protection filter is
working to divert excess HF an VHF energy from reaching the NST, as Terry has
documented in his paper. "I" prefer to return these to ground by the path of
least inductance and away from the very device being protected.

As we all tend to see things a little differently, I'd like to invite Terry to
comment on his reasoning, perhaps there is something that I am overlooking
here.

-- 
Jon G. Tebbs
<jgtebbs-at-eos-dot-net>

 
> ---------------------------------------------
> <<<<<<<<<<Malcolm, Jon, Jonathan,
> 
> The NST case (or ground lug) connection should be
>  wired to the AC ground prong.
> 
>  Greg
>  http://hot-streamer-dot-com/greg >>>>>>>>
> 
> Greg,
> Does the NST case (or ground lug) go to the AC ground prong when the same
> ground
> in Terry's filter also goes to the RF ground as shown in the schematic?
>
------------------------------------------------------------------------------
> 
> -------------------------------------------
> In a message dated 7/15/01 6:43:23 PM Central Daylight Time, tesla-at-pupman-dot-com
> writes:
> 
> << NST filter. well on terry's filter schematic, it shows the center going to
>  the NST ground, then to the RF ground. I think that's how I'll do it. Now,
>  what about the case of the RSG motor? should that me 60hZ, or RF ground?
> what
>  about any metal used in the base of the pri. circ. (bolts...)
> 
>  Jonathon<<<<<<
> The motor frame may very well be grounded thru the green AC power line
ground.
>
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> 
> -------------------------------------------