Re: grounding NST's

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Bob (R.A.) Jones" <a1accounting@xxxxxxxxxxxxx>

Hi all,

I agree with Matt's assertions.
Beyond personal safety, for those that run their coils only say tens of feet
from others the major problem is electromagnetic interference and
destruction
Having a ground strike enter the mains system vie the earth is not a good
idea for the reasons given and more.
The earth grounded rod can have several ohms of impedance and the transient
impedance(HF) of the wiring hundreds of ohms.
So there is a good chance of having several kV left over from a 100kV strike
which will couple in the mains power wiring.
The only worse thing  would be having it enter via one of the mains power
connections.

Any other problem. It may cause is flash over in the mains distribution
system.
ie the house distribution system is not designed to soak up 100kV
transients.

Perhaps someone can measure the voltage between mains earth and their RF
ground when operating their coil.

If you feel the NST case must be grounded then it should be very well
protected from direct strikes.
If it has an output filter then the only connection between the coil side
and the NST side should be via the filter resistors.
Do not connect spark gaps (or capacitors) between the coil side of the
filter and the mains ground.

Robert (R. A.) Jones
A1 Accounting, Inc., Fl
407 649 6400
----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Wednesday, March 22, 2006 5:06 PM
Subject: Re: grounding NST's


> Original poster: Mddeming@xxxxxxx
>
> Another thing to consider during a flashover that the green wire is
> packing a large amount of RF energy, making it, and all green wires
> attached to it, into a large antenna array which will
> radiate/couple  into every nearby wire and piece of equipment. In an
> apartment building, everyone's wiring becomes part of the antenna
> array even if for only a few milliseconds. Under the right
> combination of circumstances, "nearby" could include the houses next
> door or further down the street.
>       When doing a risk/benefit analysis of which way to go, one must
> consider the cost of regaining good will once it has been turned to
> animosity. Zapped equipment and/or an irate neighbor can cause far
> more trouble than any increased effort in grounding. Like skydiving,
> it only takes one major oops to give you a VERY bad day.
>      Of course, one can take the position of the coal mine operators
> around here in WV, "Nothing is wrong UNTIL something goes wrong, and
> then, only IF they can pin it on you." You choose.
>
>
> Matt D.
>
>
>
>
> In a message dated 3/22/06 1:39:44 P.M. Eastern Standard Time,
> tesla@xxxxxxxxxx writes:
> Original poster: dest <dest@xxxxxxxxxxxxx>
>
> Hallo.
>
>  > Original poster: Steve Conner <steve@xxxxxxxxxxxx>
>
>  > Personally I believe that grounding a NST to RF ground is a bad-ish
>  > idea. The reason is that the incoming line voltage powering the NST
>  > is referred to green wire ground. Therefore, any RF voltage appering
>  > on the RF ground will also appear between the NST primary winding and
>  > the core, which might cause flashovers.
>
> ok - let`s asssume that you have grounded your psu to the green wire,
> then when your primary is being zapped, you can get for example 2kv on
> this wire, and since rf current would flow only thru this wire and not
> thru hot or neutral wire you`ll have now 2kv between the green and hot
> one, as well as between green and neutral, coz as you said above "line
> voltage powering the NST is referred to green wire ground".
> so you are guaranteed to have hv in your home wiring - even without
> breakdown of any psu insulation - just by your design.
> do you like this situation?
> do you like it much more than stressing pri-core insulation - probably
> you like to stress home wiring insulation instead?
> if so - can you tell me why (or where i`m wrong)?
>
> -----
> Let the bass kick! =:-D
>
>
>
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>