Re: [TCML] Tesla Coil Computer Interference (proper grounding)

[Gary Lau <glau1024@xxxxxxxxx>]

Concerning the connection of mains and RF grounds -

If you have an NST connected to a Terry filter, the NST case is connected to
the RF ground if you've hooked it up properly.  If you also connect the NST
case to the green-wire ground, then you have connected your RF ground to
your green-wire ground.  This is wrong and defeats the purpose of having a
dedicated RF ground - to channel RF away from your mains wiring.  They must
remain separate.

What things connect to which ground is often misunderstood.  The ONLY thing
that connects to the green-wire ground should be the Variac case and control
panel chassis - things that an operator cannot avoid touching and must be
connected to the green-wire ground so that if a hot wire touched the Variac
or panel, a fault-current sufficient to trip the breaker would result.  We
don't need to protect the NST case like this because no one playing with a
full deck should ever touch the NST case of an operating Tesla coil.  An NST
powering a sign in a bar is different, as it's conceivable that some fool
might touch the NST, but we're supposed to know better.

Regards, Gary Lau
MA, USA

On Sun, Jul 25, 2010 at 11:53 AM, Joe Mastroianni <joe@xxxxxxxxxxxxxx>wrote:

> Hi Brandon
> When I ran my first coil - first light - I had the secondary, the strike
> ring, and the terry filter RF grounded to an 8' rod pounded into the earth.
> The Variac, of course, was grounded to the wall-socket 3rd prong.  The line
> filter is grounded to the outlet 3rd prong.  I had also connected the NST
> cases to the 3rd prong wall socket ground.  (In fact, I've been running that
> way ever since.)
>
> But on my first run I had some difficulties with tuning -  And several
> items on that same circuit suffered some sort of destructive forces.   Most
> notably, I have a light fixture powered by a constant current LED driver I
> built myself.  The output current adjusting resistor, which was a 2W deal,
> just simply "popped" wide open, in every respect - electrical and physical.
>
> That device was NOT grounded in any way.  So whatever had killed it was
> running along either neutral or hot, because it's too far away physically
> from the coil to have suffered any RF or EMP or whatever you want to call
> the coil's electric field.
>
> I guess what I'm saying is that even with filters and safety gaps and
> ground rods and whatever I still had currents running through the house
> power.
> Lucky for me there's very little on that garage circuit to worry about (now
> that my LED driver is blown).
>
> I did fix the LED driver and am running it on the same circuit again.  Call
> me daring or a fool - it hasn't had any issues since I've been running
> properly tuned.
>
> Cheers,
> Joe
>
>
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