RE: Very Confused On Grounding

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Malcolm Watts" <m.j.watts@xxxxxxxxxxxx>

Hi Gary,

On 17 May 2005, at 11:47, Tesla list wrote:

> Original poster: "Lau, Gary" <gary.lau@xxxxxx>
>
> Hi Malcolm:
>
> I do advocate tying the RF ground to the NST case.  While I agree with
> your logic, I don't think it's realistic to think that one can prevent
> primary streamer strikes, without locating the strike rails in such a
> manor that they become the preferential target.  I no longer use a
> strike rail, and primary strikes are not a problem.
>
> Regards, Gary Lau
> MA, USA

There is an alternative answer - make the coil bigger and in
particular, taller. Yesterday someone was bemoaning the fact that
most of what they were getting was strikes to the strike rail (and
obviously in lieu of that it would have been the primary). While it
is satisfying in some respects to squeeze a zillion feet of spark
from a 1" tall secondary I've found the results for a given power
input to be more satisfying for larger coils. That is probably a
reflection of my prime coiling interest which is bang for power
expenditure but it does kill two birds with one stone. Apart from
that, my view on building a coil that allows frequent strikes in the
vicinity of the primary and strike rail (if one is fitted) is that
one is robbing oneself of a degree of satisfaction and probably
preventing the coil from reaching as far as it can at the running
power level. I once saw a number of protracted runs on video of "an
awesome system" (so proclaimed by the builder) running at around
10kVA that was, in my opinion, anything but interesting - at the
higher power levels the strike rail was reached somewhere around 80%
of the time.

     There is no doubt the RF grounding approach works reliably
enough although it would be interesting to know what's going on
inside the transformer case when a secondary discharge strikes the
case vis-a-vis the transformer primary. In either case the CM filter
between the transformer and mains should take care of mains-borne
interference problems. In my experience it is not difficult to design
a coil to mostly avoid primary strikes and a length of wire
judiciously placed and connected to the RF ground takes care of the
odd streamer which wants to connect.

     I am a little disappointed that the original poster failed to
respond to the safety gap claim they made.

Regards,
Malcolm

>  > Original poster: "Malcolm Watts" <m.j.watts@xxxxxxxxxxxx>
>
>  > Speaking of which - I don't see why a safety gap discharge should
>  be > a requirement for grounding the NST case to the RF ground. ??
>  The > safety is simply shorting the NST secondary. As long as
>  streamers > from the secondary are never allowed to come into contact
>  with the TC > primary or transformer case I don't see a reason to tie
>  the NST case > to the RF ground. ?? I've always tied my transformer
>  cases to the > mains ground. Anyone advocating the RF ground approach
>  care to > elaborate? > > Malcolm
>
>
>