Re: Rf Grounding

["Albert Hassick" <uncadoc-at-xxxxxxxx> (by way of Terry Fritz <twftesla-at-xxxxxxxxxx>)]

David, Yes the grounds will ultimately become one when dumped to the
earth since the earth/ bare copper/alum/white bonded neutral are all one
and the same. What we are trying to do is reduce electrical interference
as much as possible in our Tesla hobby. The Tesla coil with its spark gap
is a 'dirty' system of transmission by todays standards(but if Tesla had
implemented his 'one world' system it would not be a problem).  It is
best to try to isolate your house ground from the Tesla Secondary ground
for the mere simple reason of hi-frequency/voltage backing up into your
tv,vcr,computer and other sensitive devices in your and your neighbors
households through your powerlines.  A good dedicated isolated Tesla
ground which is set on the opposite side or rear side of your home, away
from the power company ground will allow you to fire your Tesla without
having to worry quite so much about generated noise.  You do not want to
use your power company ground post at your panelboard for the mere simple
reason that it will generate noise into the circuits, since the home
panelboard shares a bare copper ground and a white neutral that are
basically at the same potential. Imagine all your Teslas power running
rampant through your house ground and white neutral wire and you will see
why you should have separate grounds for a Tesla.  An isolated ground,
away from the house ground rod will allow any transients from your Tesla
on the high voltage side to seek a remote ground, far away(hopefully)
from your house ground or cold water pipe.  This way, any high voltage
faults or transients from your Tesla will be directed directly to earth
at a node which is somewhat isolated from the power company ground node, 
thereby eliminating for the most part the damaging transient, since your
remote ground will sink your overload into the earth at a different
position, and will thereby prevent the spike from going into the power
company ground since the transient will be absorbed by the earth before
it has a chance to travel any distance to your house power
line/ground/neutral..  You see, the earth will absorb the charge and
dissipate it harmlessly.  The separation of the house and Tesla grounds
by some distance gives much less likelyhood to a fried PC in your
neighbors house. But when you have a big high voltage/high frequency load
with a lot of energy dumped to ground at the power company/house ground
rod, you can see that there is a much better chance of these damaging
transients getting back into your panelboard since they can possibly
travel along the neutral (white)post in and out of your house wiring, and
easily propagate themselves as high frequency/high current pulses/spikes
into the power line. These surges get back into the black/red wires of
your house by jumping across small electical equipment/light bulbs and
appliance motor windings that are plugged into the wall socket.  The
overcurrent at ground from a high powered Tesla can easily enter a common
household ground if precautions are not taken. This may become the
biggest detriment to our hobby as more and more list members delve into
pole pigs and such for bigger arcs.   So, place and keep a good isolated
ground for a big coil always. The bigger the coil and the more current
you pump into your Tesla tank circuit, so also grows the need for a good
isolated earth ground.  The idea of Metal oxide varistors in the Tesla
coil , which I think was suggested by Terry, may help to arrest and clamp
some of these spikes.  I think the MOV system is an excellent idea for
all coilers!  AL.

On Sun, 12 Nov 2000 14:22:13 -0700 "Tesla list" <tesla-at-pupman-dot-com>
writes:
> Original poster: Tesla729-at-cs-dot-com 
> 
> Hey guys,
> 
> I have a question about RF grounding and I was hoping 
> some of you may be able to answer my question. Does 
> the RF ground need to be completely electrically sepe-
> rated from the other AC service mains ground(s)? From
> what I gather, this seems to be what people are saying.
> It seems to me that whether these grounds are connected
> by a wire or by the conduction to the ground itself, they
> are not going to be completely electrically isolated from
> each other. It would make sense to have the RF ground
> as close as practical to the base of the Tesla coil, but I
> can't see disallowing any wire connection between the RF
> and AC mains ground. I mean they are going to be polarized 
> to the same ground. Just MHO.
> 
> Keeping 'em Sparkin' in Memphis,
> David Rieben
> 
> 
>