Great info, thanks for that!
So for my needs, I would like to isolate the circuit as much as possible
and even my NST case will be somewhat contained to prevent touching (yes it
will be cooled).
I will be running this coil outside with an extension cord, and thus any
line filter will not have direct connection to the mains box. So I should
be good to ground my secondary, Terry filter, and NST to RF ground?
Again this is a little weak coil with a single NST running a multi-gap
(quenched).
Thanks again!
Matt
On Tue, Jun 19, 2018, 9:02 PM Gary Lau <glau1024@xxxxxxxxx> wrote:
> Re. how to hook up an EMI line filter - I put up a web page detailing how
> to hook it up, how NOT to hook it up, and why. The full answer is more
> nuanced than just forwards or backwards - and again it involves grounding.
> See http://www.laushaus.com/tesla/emifilter.htm
>
> Now back to grounding. I previously wrote:
> > I can't think of any fault condition or inadvertent touch where having
> the NST case tied to mains ground offers any safety advantage.
>
> Actually I can.
> If one were to "assume" that touching the case of an energized NST was OK,
> and
> If the NST case were tied to an RF ground or counterpoise that did not have
> a low impedance path to mains-ground, and
> If some other body part of this person was in contact with a grounded
> object, and
> If the NST had developed an internal or wiring fault that provided a path
> from AC-HOT to the NST case,
> ... then there is a credible risk of shock. This scenario is far more
> plausible where the NST is powering a neon sign and the victim is not a
> high voltage enthusiast. Hopefully everyone reading this understands that
> touching ANYTHING on an operating Tesla coil is not a good idea.
> Unfortunately I cannot think of any way to both eliminate this hazard and
> to keep RF ground transients out of your mains.
>
> Gary Lau
> MA, USA
>
>
> <
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>
> On Tue, Jun 19, 2018 at 8:20 PM, Matthew Sweeney <msweeney23@xxxxxxxxx>
> wrote:
>
> > Thanks Dan, I did pickup some of those little line filters, but I have to
> > hook it up 'backwards' right?
> >
> > Matt
> >
> > On Tue, Jun 19, 2018, 4:06 PM Daniel Kunkel <dankunkel@xxxxxxxxx> wrote:
> >
> > > 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 :)
> > > > > > >
> > > > > > >
> > > > > > <http://www.avg.com/email-signature?utm_medium=email&;
> > > > > > utm_source=link&utm_campaign=sig-email&utm_content=webmail>
> > > > > > Virus-free.
> > > > > > www.avg.com
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> > > > > > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
> > > > > > _______________________________________________
> > > > > > Tesla mailing list
> > > > > > Tesla@xxxxxxxxxxxxxxxxxx
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> > > > > >
> > > > >
> > > > >
> > > > >
> > > > > --
> > > > >
> > > > > Chris Boden
> > > > > President
> > > > > The Geek Group National Science Institute
> > > > > www.thegeekgroup.org
> > > > >
> > > > > --
> > > > >
> > > > >
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