Re: the mechanical engineering problem

["Tesla list" <tesla@xxxxxxxxxx>]

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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