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Re: Two layer primary
Tesla list wrote:
> Original poster: "Lau, Gary" <Gary.Lau-at-compaq-dot-com>
> I would like to rebuild my primary as a two-layer flat pancake. The reasons
> for this are:
> 1) I am also increasing my secondary inductance so that I can
> correspondingly increase my primary inductance to achieve a higher surge
> impedance and hopefully further lower my gap losses.
> 2) The required higher primary inductance would make a single-layer primary
> too large in diameter to fit the confines of my base assembly.
> 3) By making a two-layer primary, the same inductance can be achieved with
> fewer feet of tubing, thereby further lowering primary losses.
It all sounds good.
> I'm drawing a blank on how to begin this construction. The two layers will
> be joined at the center, so the two terminals will be at the outside of each
> spiral. This means that the full primary potential (and much more if there
> are unused turns!) will be present across whatever gap separates the two
> spirals, so extra care must be taken to insulate against surface flashovers.
Why not connect the inner of the lower to the outer of the upper? This would
relieve about 1/2 the potential and decrease if all turns are not used (volts
per turn). I don't know how far apart your planning to seperate the windings,
but it wouldn't take too much to not have to worry about flashover thereby
needing no insulation between.
> Obviously a Lexan plate must be built between the layers, and there can be
> no holes through this plate, as I suspect a flashover will find such holes.
> The no-holes rule complicates plans to mount the two spirals. I don't like
> the idea of gluing - it's potentially messy, and mistakes and changes are
> made and glue is kind of permanent. Short of using two back-to-back
> insulating disks with holes that are offset, I'm short of good ideas.
> Has anyone done this before, and can you point to any URL's that illustrate
> how it was done?
> Gary Lau
> Waltham, MA USA