RE: an interesting mechanical engineering problem

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Lau, Gary" <Gary.Lau@xxxxxx>

I'm not sure that I agree with using copper stock.  If I was running my
coil using some conventional primary configuration, and then I placed a
6" x 6" sheet of copper stock on top of that primary, I suspect it would
cause losses due to eddy currents induced within the sheet.  When I
performed an experiment to compare AC resistance of various primary
conductors, a 1" x .03" copper ribbon had the lowest DC resistance by a
wide margin, but at frequencies below 100 KHz, the AC resistance of some
heavy Litz wire was significantly lower.  See
http://www.laushaus.com/tesla/primary_resistance.htm.

Of course Litz wire presents some difficulties in terms of being able to
experimentally tap it, but you could make just the last 20% of the coil
out of copper pipe and tap that.

Regards, Gary Lau
MA, USA

> Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>
>
> Hello All,
>
> I'm still an advocate of using flat copper stock. Since the turns are
> further reduced in the modified plans, I would think it would want to
be at
> least 6" wide and sized in thickness to easily handle the skin depth.
The
> upper edge could be rounded to deter corona, especially if the
thickness is
> heavy enough.
>
> I thought the simplest attachment method would be to cut the
circumference
> in 3rds or fourths as transportable. The joints would be machined to
half
> depth to mate together in a flush manner and made as long as seems
lossless.
> One side would be threaded for the bolt pattern.
>
> Conduction could be further improved be using a copper impregnated
> conductive grease that is used on radio tower connections, which I
have been
> using on my big discharge cap flanges. It works great to eliminate
> oxidation.
>
> Regards to all,
> Jim Mora