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Re: Capacitor Help



Original poster: "MalcolmTesla" <tesla@xxxxxxxxxxxxx>

----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Friday, December 16, 2005 10:44 PM


> Original poster: "Lau, Gary" <Gary.Lau@xxxxxx>
>
> Yes, at first glance it's not clear what is accomplished by wiring a
> safety gap in parallel with the main gap.  There's a couple of reasons.
>
> This doesn't apply to you since you're using a static gap, but when
> using a rotary gap, the safety gap kicks in should there be a fault with
> the RSG mechanics.
>
> For static gap users, it's all too easy to open the gap up just a bit
> more (accidentally or on purpose), and this is where you get into
> trouble.  Having an independent safety gap that is set properly provides
> a measure of fool-proof protection, although having the self-discipline
> to set it properly and leave it there is uncommon!

Are there any guide lines as to setting the safety gap?

> The topic of RF grounds and green-wire grounds confuses many beginners
> and stirs up controversy among seasoned coilers.  You could spend a week
> searching the Pupman archives and still come out confused!
>
> First, unless your coil is low powered (and there is no clear definition
> here), the secondary base should go to an "RF ground", separate from the
> green-wire mains ground.  The RF ground is the return path for the high
> frequency streamer current, and you don't want that going through your
> mains wiring!

OK that makes sense.

> When we use a 3-terminal safety gap, the middle terminal goes to RF
> ground.  Consider what happens should a streamer strike your primary
> (instead of your strike rail).  The entire primary is raised to a very
> high voltage.  If there is a middle terminal at RF ground, the suddenly
> "hot" primary will arc to the middle terminal, and the discharge current
> will go harmlessly into the RF ground.  If you did not have a middle
> terminal, the only path for the streamer current to follow is through
> your NST into your mains wiring.

Ahh OK I finally get it.  So the safety gap is made up of three terminals.
I know others mentioned it as an option and others did not but if I'm
understanding correctly the only way to make a safety gap is with three
terminals because without that third RF ground terminal it's just another
spark gap and nothing is been dissipated.  OK this makes perfect sense now.
I'll be sure to build one.  Unless someone tells me otherwise I'm going to
set the safety gap as small as it will possibly go without interfering with
normal operation.

> So the RF ground should be an independent connection to something that
> is at least capacitively in close proximity to the earth.  This can be a
> ground rod, or a large sheet of metal on the floor, or a rail road
> track, or a chicken wire structure or...

Excellent information.  I'll shoot for steel beams in the roof.  If that's
not an option I'll pickup a 150' extension cord from wal-mart and run an RF
ground outside to a pipe in the ground.  Like someone mentioned before I
don't want to be frying networks, computers or anything else.

Thanks again.  You guys are awesome.  I wonder if there's a simple web page
on Tesla Coil "how to" for beginners like myself that are missing the simple
concepts and lingo the rest of you take for granted.  Most pages I find
assume you already know a lot of the basics or they leave out tiny details
like don't make your strike ring a complete circle or it will act like a
short in the magnetic field of your primary.  Excellent little tips like
that I've picked up on this list.

Thanks again
Malcolm - KC