Original poster: Yurtle Turtle <yurtle_t@xxxxxxxxx>
Using silverplated bus bar is fairly standard
practice. It has nothing to do with skin effect. We
literally have miles of the stuff, in 4" x 1/4" up to
three sets of 6" x 1/4" for 3,000 amp service. The
silver plating is to allow getting a solid connection
when splicing, or landing large conductors. Even with
silver plating, corrosion can be a problem, but copper
oxidizes so much easier there's no comparison. All of
our low and medium voltage bus bars are 60 Hz, so
there's essentially no skin effect in play.
Adam
--- Tesla list <tesla@xxxxxxxxxx> wrote:
> Original poster: Mike <megavolts61@xxxxxxxxx>
>
> Hi DC,
> I'd be happy to silver plate your primary, as I
> am well versed
> in that. I used to work in a research lab doing all
> kinds of
> electrochemisty, including once even fixing an
> induction furnace
> who's silver plating had tarnished away over the
> years and quit
> working. I put a better plating on the parts than
> the original
> manufacturer did. That's beside the point.
> I deleted the earlier emails on this thread but
> seem to remember
> you planned to run this monster at about 20kHz.
> Let me point out a
> lil something I thought about. From the
> information I have, The
> skin depth (based on copper, but probably close) at
> 10 kHz is 0.66
> mm. So for fun, I did a lil caclulation based on
> an assumption
> that the skin depth for silver at 20kHz is about 0.5
> mm. I know I
> should be more precise, but I'm lazy tonight.
> First of all your perimeter of the bus bar is
> (5 + 1/4 + 5 +
> 1/4) * 2.54 cm/ in. or 26.67 cm. Then, 1 ft
> length is 12 *
> 2.54 or 30.48 cm, giving you an area of 812.9 sq.
> cm. per foot of
> bus bar. Now multiply that by 0.5 mm (or 0.05cm),
> you get 40.645
> cu. cm per foot if you wish to have ALL silver
> conducting. At a
> diameter of 26 ft, this leads you to need
> pi*26*40.645 cu. cm of
> silver. Multiply that by the density of 10.5g/cu.
> cm and divide by
> 31.1 grams/troy oz. This shows you will need over
> 1100 troy oz of
> silver just for that first turn. I think you
> might gain about 5%
> better conductance for your $$. This was just an
> estimate....but you see where I'm coming
> from....might be a lot
> cheaper to go to six inch bus bar. It also
> depends on how thick
> you want the silver plating to be. I honestly
> can't say at this
> moment if there's really anything to be gained by
> plating the bus bars.
> Mike
>
>
>
>
> Original poster: Yurtle Turtle <yurtle_t@xxxxxxxxx>
>
> You may know this already, but when you go to silver
> plate the bus bars, you can do it in your shop for a
> fraction of the cost of having it electroplated, by
> using Cold Amp. It's a powder and real easy to use.
> We've used it in medium voltage (12,470) switchgear.
>
> Adam
>
> --- Tesla list <tesla@xxxxxxxxxx> wrote:
>
> > Original poster: "D.C. Cox"
> <resonance@xxxxxxxxxxxx>
> >
> >
> >
> >
> > Thanks to everyone who submitted ideas for the
> big
> > primary coil. I
> > have several ideas now and will resolve the
> issues
> > soon.
> >
> > Several members suggested internal primary, but
> if
> > there are any
> > flashovers they would not be visible unless fiber
> > optics were
> > employed to watch for them.
> >
> > The idea I think we will employ (actually
> suggested
> > by several
> > members) is to use 5 inch wide x 1/4 inch copper
> > ribbon buss bar and
> > then silver plate it.
>
>
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