Re: [TCML] Single-ended NST, wiring

[Frosty <frosty90@xxxxxxxxx>]

Surely the danger is very high anyway, touching the secondary whether it is
grouned to mains, the primary or a seperate dedicated ground is a pretty
bad idea?
On Mar 6, 2013 10:44 AM, <jhowson4@xxxxxxxxxxx> wrote:

> Hmmm. I wonder why this configuration is so prevalent in the small kit
> coils available from information unlimited and in the larger ones used at
> resonance research and the like then. For the purpose of limiting that
> voltage rise perhaps? If the dangers are reasonably high, then one would
> think the kits would be engineered away from this configuration. Heck the
> little information unlimited BTC-30 I built years ago, does not even have
> an RF ground, it just uses the house ground, with no problems I might add.
>
>
>
> Thanks,
> John "Jay" Howson IV
>
>
> "Why thank you, I will be happy to take those electrons off your hands."
>
> ----- Original Message -----
> From: "Jim Lux" <jimlux@xxxxxxxxxxxxx>
> To: tesla@xxxxxxxxxx
> Sent: Tuesday, March 5, 2013 10:45:17 AM
> Subject: Re: [TCML] Single-ended NST, wiring
>
> On 3/5/13 7:08 AM, Jim Lux wrote:
> > On 3/5/13 5:42 AM, jhowson4@xxxxxxxxxxx wrote:
> >> alright so apparently i missed something all these years.
> >>
> >> I thought you wanted to separate the two grounds and because the HV
> >> was grounded you should only use the RF ground in that system, but
> >> apparently not, you use both.
> >>
> >> You want to connect the ground on your transformer to the house
> >> ground, make your circuit like you have shone, and connect the
> >> bottom/inner turn of your primary to the base of your secondary.
> >
> > No.. there is no good reason to connect primary to secondary. Some
> > people do it for historical reasons, but for the vast majority of cases
> > this isn't a good idea.
> >
> > If you are using a Neon Sign transformer, or anything with a grounded
> > centertap, connecting primary and secondary as you describe is
> > DANGEROUS. On a typical NST driven primary, both ends of the primary
> > are "hot" relative to ground.
> >
>
>
>
> I missed the reference to the single ended NST with one end grounded.
> In that case, the danger is not as high.
>
> However, you generally do not want the primary connected directly to the
> secondary in any case: the spark from the secondary is a nice low
> impedance, and you don't want to make it easier to have
> someone/something hit by a spark connected to a HV source with more
> current.
>
> In typical cases, of course, the substantial impedance of the secondary
> winding would be in series as well, but there are cases of injury (and
> death?) when a connection was made between the primary winding and a
> person via a streamer. So that pushes for making the primary winding
> generally "isolated" from ground, so that if something "grounded" (e.g.
> a person) happens to touch it, the hazard is less.
>
> OTOH, you want some non-infinite impedance from primary to ground to
> limit the voltage rise between HV windings in the transformer and the
> core.
>
> >
> >> The NST (4kV, 50mA) for my SGTC is a single end type with one of its
> >> secondary winding ends attached to the metal casing.
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