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Re: grounding question



Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi John,

This will work. Terry and I have done this with a 1KW coil spitten out 5 foot arcs. If inside, you need to be careful on what the streamers hit. Best not to hit anything other than a strike target that is directly gounded to the system RF ground close to the base of the coil. Some may also recommend a counterpoise under your coil that is connected to RF ground. I presume you are on the first floor and this copper pipe is readily available. You may also want to get the electrical stuff in the science room shut down for the demo. A lot depends on what the surroundings are (above and below the coil, and in the walls surrounding the coil. Keep as much clearance from the walls and ceiling as possible. Dont let arcs hit the walls or ceiling as this may hit internal wiring or cause a fire. If this is a perminent installation, much care is needed for safety. If only a one time demo, the area needs to be supervised to keep unauthorized people at a safe distance and out of the equipment. You be the judge.

Gerry R.

Original poster: John <guipenguin@xxxxxxxxx>

Thank you.

If I am going to have my coil running in a science room.... could I use the metal sink pipe as RF ground?

On 10/7/06, Tesla list <<mailto:tesla@xxxxxxxxxx> tesla@xxxxxxxxxx> wrote:
Original poster: "Gerry Reynolds" <<mailto:gerryreynolds@xxxxxxxxxxxxx> gerryreynolds@xxxxxxxxxxxxx>

Hi John,

If you are operating outside and the NST is under the primary (or
very close to it), I would ground the NST to RF ground (a copper rod
staked in the ground).  The strike ring will be tied to the base of
the secondary. The base of the secondary will be connected to RF
ground.  Safety of the NST chassis during operation is not as much an
issue if located there as no one should be close to the NST while
operating.  Any secondary strike to the strike ring will return
directly to the base of the coil.  Any stike to the primary will arc
to the safety gap and go to the NST chassis and then return to the
base of the coil via RF ground.  Any overvoltage of the primary
circuit will also be shunted via the safety gap to the NST chassis
where it wants to go.  This grounding will help keep voltage
transients off of the mains ground and out of the house where it can
do damage to equipment.  The mains ground can be used to ground the
variac and line filter, but should stop there and not go the the NST.

BTW, grounding the center terminal of the safety gap directly to the
NST chassis is correct as it is intended to protect the NST.

Gerry R.

>Original poster: John <<mailto:guipenguin@xxxxxxxxx> >guipenguin@xxxxxxxxx>
>
>I think I am going to build this simple NST protection filter for my
>new coil.
><<http://hot-streamer.com/greg/filter.htm>http://hot-streamer.com/g reg/filter.htm >http://hot-streamer.com/greg/filter.htm
>
>I see the center safety spark gap is grounded to the NST's chasse,
>which is grounded to mains ground.
>
>Now, am I correct in thinking that I should NOT ground the primary
>circuit to the same ground as the end of the secondary (as I see in
>many schematics) as this could pose a threat from putting you in
>contact with the primary circuit through a secondary spark?
>for a spark gap Tesla coil, is this circuit that I linked the only
>thing that should be ground to mains ground?     and then ONLY have
>the end of the secondary coil to a separate RF ground?
>
>I want to make sure I have everything as safe as possible before I
>even start building my design.
>
>
>
>Thanks again,
>
>       John.
>
>