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Re: [TCML] Fear of the NST



Matthew,
You might consider using a commercial line filter to keep RF nasties out of
the supply line. You can get a  10-20amp until for around $10-20.
~Dan
Kansas City area

On Tue, Jun 19, 2018 at 10:57 AM, Matthew Sweeney <msweeney23@xxxxxxxxx>
wrote:

> Even for smaller coils (i.e. a single 15kv/30ma NST), should I consider
> tying NST to a new/RF ground (8 ft ground rod) if I want to avoid any
> transients into my neighbor circuits? I live in an old duplex house with
> horribly out of date wiring.
>
> I do have a Terry filter and line filter, but I need to be extra specially
> careful. I assume that RF ground is also secondary ground correct (thus
> RF).
>
> Any other steps I can take? Note that this is a traditional static gap
> coil.
>
> Thanks!
>
> Matt
>
> On Tue, Jun 19, 2018, 9:52 AM Chris Boden <cboden@xxxxxxxxxxxxxxxx> wrote:
>
> > This depends on usage. If it's a little JL or you're just screwing around
> > with an NST, mains ground is what you want. If it's part of a larger TC
> > system then RF ground is better.
> >
> > But regardless of application, Ground it.
> >
> > On Mon, Jun 18, 2018 at 9:40 PM, Gary Lau <glau1024@xxxxxxxxx> wrote:
> >
> > > I disagree with the advice:
> > > >  3. GROUND THE CASE OF THE NST
> > >
> > > The case of the NST is tied to RF ground and is full of high voltage RF
> > > transients that you do not want feeding into your mains..  Unless the
> > coil
> > > is relatively low power and there is no alternate ground or
> counterpoise
> > > available, you should not be connecting RF ground to mains ground.  I
> > can't
> > > think of any fault condition or inadvertent touch where having the NST
> > case
> > > tied to mains ground offers any safety advantage.
> > >
> > > Regards, Gary Lau
> > > MA, USA
> > >
> > > On Sun, Jun 17, 2018 at 6:44 PM, Chris Boden <cboden@xxxxxxxxxxxxxxxx>
> > > wrote:
> > >
> > > > Greetings Mr.Janota :)
> > > >
> > > > NST's are current limited and operate typically at a maximum of 15kV
> > > (with
> > > > 12kV and lower being quite common as well).
> > > > The typical max current output will be 60mA.
> > > >
> > > > What this means is it Most Likely, Probably.....Unusually....wont'
> kill
> > > > you
> > > > if you brush against the output, are a rigorously healthy adult, dry,
> > and
> > > > nontrivially lucky.
> > > >
> > > > This is as opposed to things like Pole Pigs at 10kVA or more (we have
> > > > 100kVA pigs in the lab) with no current limiting which are reasonably
> > > > considered to be fatal (it's not instant, and it hurts the whole
> time).
> > > > There are also pulse capacitors (typical in our lab is 20kV to 50kV
> > with
> > > > 10kJ energies) those don't just kill you, they blow parts off. We
> have
> > > > 400lb caps here that are in the "clean you off the ceiling with a
> > sponge"
> > > > levels of deadly.
> > > >
> > > > That's a long way from your NST, but the idea across the spectrum is
> > the
> > > > same. These toys are not for the emotional, impulsive, or stupid.
> They
> > > will
> > > > hurt you the moment you don't respect them, and kill you if you're
> > > > reckless.
> > > >
> > > > That's the point.
> > > >
> > > > There are millions of people who would like to own a powerful Tesla
> > Coil.
> > > > But very, very few get that far. The fundamental price to own a coil
> is
> > > > simple, be smart enough to build one. It's not hard, but you have to
> do
> > > it
> > > > yourself. Along that path you will have to learn hundreds of new
> > things,
> > > > foremost is safety and a healthy respect for HV. Consider how few
> > people
> > > > you know who have ever run a marathon. The rough number is often
> quoted
> > > as
> > > > 1% of 1% of the people in America have ever run a marathon. The
> number
> > of
> > > > people in the history of the world who have ever successfully built a
> > > > working Tesla Coil wouldn't fill a single run of the Chicago
> marathon.
> > > This
> > > > is a very small community.
> > > >
> > > > To the average person Electricity is composed mainly of magic. It's
> > > > dangerous and terrifying. In reality, it's just science. The
> mechanisms
> > > of
> > > > electrical power have been pretty well worked out by people far
> smarter
> > > > than me. We can build chips at the nano-scale with billions of wires
> > > only a
> > > > few atoms wide carrying energies less than a mouse's fart, and we can
> > > > wrangle million-volt power lines across the desert. But to the
> average
> > > > person they understand as little about how the power gets in their
> > > computer
> > > > as they do about what actually happens when they flush the toilet.
> > > >
> > > > You should have a respectful, healthy fear of HV, but not a crippling
> > > one.
> > > > It's not magic, and it won't jump across the room and bite you. Some
> > > simple
> > > > things to remember will help you a lot.
> > > >
> > > > 1. Keep the plug in your pocket when you're working on the NST. If
> the
> > > plug
> > > > isn't in your pocket, then don't touch it.
> > > > 2. 15kV with a beginner wants a safe radius of 2 inches to anything,
> > and
> > > 3
> > > > feet to anything that's alive. Keep the HV conductors 2 inches from
> the
> > > > case and you're not going to have any problems.
> > > > 3. GROUND THE CASE OF THE NST. The bottom-center hole on a US outlet
> > (the
> > > > mouth of the face) is Ground. This should connect to the uninsulated
> > lug
> > > on
> > > > the side of the NST. The NST will have two big insulated lugs (the HV
> > > > terminals) two smaller insulated lugs right next to each other (the
> LV
> > > > terminals), and one uninsulated lug that just looks like a bolt
> > sticking
> > > > out the side....that one is the ground.
> > > >
> > > > And lastly, while most of the people here would never admit it (and
> > > > certainly never publicly), the vast majority of us have been bit at
> > some
> > > > point because we did something stupid and got a hard lesson in pain.
> > I've
> > > > been bit a few times and thankfully, by sheer dumb luck I survived
> > them,
> > > >
> > > > so far.
> > > >
> > > > Good luck :)
> > > >
> > > >
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> >
> >
> > --
> >
> > Chris Boden
> > President
> > The Geek Group National Science Institute
> > www.thegeekgroup.org
> >
> > --
> >
> >
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