Re: the mechanical engineering problem

["Tesla list" <tesla@xxxxxxxxxx>]

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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