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RE: [TCML] Newbie Grounding Question
Hi Gary,
I have a question in reference to your statement about strikes to the primary not being able to overvolt the cap because of conservation of energy. I understand that the energy can't be higher but couldn't the voltage from the topload be dangerous for the cap? I suppose that there are easier paths to ground in the primary circuit than through the cap dialectric. My pig coil runs with one side of the xfmr., gap, strike rail and inside primary turn all tied to the rf ground.
I have seen other references to this in the archives but this seems like a good time to ask.
Scott
"Lau, Gary" <Gary.Lau@xxxxxx> wrote:
I think the use of a ground ring, usually referred to as a strike ring, is controversial. The down side is that it must be situated high enough above the primary so as to make the ring the preferred target, and this in turn reduces the likelihood of getting that really long spark to another intended target.
Whether a strike to the primary coil is actually a bad thing is worth consideration. One's gut-level response is that it is bad, but, at least with non-solid-state coils, primary strikes happen all the time with no ill effects. A primary strike cannot damage (overvolt) the cap, as conservation of energy prohibits the cap from achieving a higher charge than what it started out with. The NST is the only other vulnerable component, and safety gaps and R-C filter "should" keep that safe. I personally don't use one with my 15/60 NST coil.
Regards, Gary Lau
MA, USA
> -----Original Message-----
> From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On
> Behalf Of Tim Meehan
> Sent: Friday, December 28, 2007 11:13 AM
> To: Tesla Coil Mailing List
> Subject: Re: [TCML] Newbie Grounding Question
>
> What about the ground ring? I am guessing that it is RF ground only.
>
> Do all coils need the ground ring - or only high power ones?
>
> On Dec 27, 2007 8:06 PM, bartb wrote:
>
> > Hi Ken,
> >
> > Your right, this area of connection varies with the builders and their
> > reasons. You'll no doubt get both connection concepts listed. There are
> > two main reasons for the division in agreement. One is safety. The other
> > is preventing common transients on mains ground. You'll have to choose
> > as it's an endless debate. Either will work of course.
> >
> > I connect RF ground to the NST, NST filter, secondary. My NST is placed
> > under the coil. I don't even run a mains ground out to the coil. I keep
> > mains ground at the control panel only (anything I am in contact with).
> > This method helps prevent transients on main ground (which I am more
> > concerned with). However, I also use a braided line which powers the
> > NST. The braid itself connects to RF ground. I run quite a bit of power
> > and can get strikes down to the floor quite often, so to prevent the AC
> > input from being hit, this braided shield helps to keep the strike from
> > heading back to the house.
> >
> > One thing important is to be sure RF ground is "always" connected. If
> > not, those transients "will" find a way back to the house. But if you
> > give them a nice low impedance path somewhere else, they'll take that
> > path instead. And that is the whole point of an RF ground connection to
> > the NST. I do the same with all my transformers and for the same reason.
> >
> > No one can guarantee that devices in the house will always stay in good
> > working order, but we can surely do our best to try to prevent known
> > issues.
> >
> > Take care,
> > Bart
> >
> >
> > kkociolek8577@xxxxxxxxxxxxxxxx wrote:
> > > Hi Everyone,
> > >
> > > I've been an EE for 25 years and always wanted to build a TC. I made a
> > half-
> > > arsed attempt in my younger days but it never got off the ground. I've
> > been
> > > digging through the archives and am a little bit confused about what
> > > connects and what does not connect to an RF ground. Some say that the
> > only
> > > connection to an RF ground is the bottom of the secondary. Others state
> > that
> > > the center tap and core of the nst, the spark gap housing, mid point of
> > > filters, all on the high side of the nst should connect to RF ground.
> > Others
> > > say this is lethal. Maybe I'm misunderstanding all this info. Can
> > someone
> > > set me straight? Thanks.
> > >
> > > Ken
> > >
> > > --
> > > WOW! Homepage (http://www.wowway.com)
> > >
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> > >
> > >
> > >
> > >
> >
> >
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