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Re: Damages to Electronic Equipment
----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Re: Damages to Electronic Equipment
> Date: Tuesday, February 15, 2000 11:48 PM
>
> Original Poster: "Max Erhard" <max.erhard-at-softhome-dot-net>
>
> How much does the risk of damage decrease if the coil is a long way away
> from any computers (a have a rather long garden). Can damaging
> interference propagate purely through the mains wiring, even if the
> house earth is not used.
yes... and in a particularly insidious way... The mains wiring can carry
the RF power with both conductors in parallel (as if the two wires were
connected together and act as one wire) with reference to external earth.
("Common mode" or in telco-speak: "longitudinal" )
This is why filters (and transient suppressors) need to go between Line and
Neutral AND between Line/Ground and Neutral/Ground.
>
> Tesla List wrote:
> >
> > Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>
> >
> > Hi,
> >
> > Very glad you computer is still around!
> >
> > I have blown a telephone answering machine (AT&T) about 20 feet away.
I
> > can set off a CO2 detector 25 feet away. So the EMI off a Tesla coil
can
> > go far. It does not matter if there are walls or floors in the way.
> >
> > When I run a lot of power, I remove ALL the wires from the computer so
it
> > is just a metal box. Any wires leading into it are ways for nasty
signals
> > to get conducted to it. All those long wires between things are very
> > likely to pick up RF so they need to be disconnected from anything your
> value.
> >
> > Find a very good ground for the Tesla coil. This will insure that the
RF
> > has a place to go.
> >
> > A good line filter (I use three) and MOVs (Metal Oxide Varistors,12 of
> > them) to filter and clamp any AC line strikes. I do use a scope and
> > sometimes a laptop near my coil. The scope is just darn tough and I
run
> > the laptop off batteries. I also have a cheap printer. I realize I am
> > taking a risk with these and I accept that.
> >
> > I cannot explain or predict every last detail of how to protect
everything
> > in your situation especially over E-mail. Basically, you need to get
any
> > wires that come within say 20 feet of the coil removed or disconnected
from
> > the computer. This includes AC, LAN, phone, etc. A chicken wire cage
may
> > go a long way here but it must not be connected to the ceiling and
such.
> > It would almost have to be in it's own cheap wood frame. If it were
hooked
> > to the ceiling and grounded, it may only act like a transmitting
antenna
> > and could make matters worse.
> >
> > I would think about making the coil fairly portable and finding another
> > nice safe location to run it. Tesla coils are nasty and when they do
> > decide to destroy electronics, the damage is "bad".
> >
> > Cheers,
> >
> > Terry
> >
> > At 09:40 PM 02/14/2000 -0500, you wrote:
> > >do i have any probs. running only a 7.5kv-at-30ma nst tesla
> > >coil?interferencewise?
> > >
>
>