The Gabriel Device, possible COP=8

[gyulasun]

...
Copper has a very low permeability, so if we use copper as the material in a transformer's core, then... nothing or almost no magnetic flux would flow?

Yes I think so. More precisely, it would behave as if it had an air core. However, depending on the volume or sizes of a copper core, magnetic flux may induce eddy currents in it and a kind of counter flux would manifest. Think of normal laminated transformer cores: they were introduced just for minimizing eddy currents.

But in classical theory... is almost imposible to make a transformer using copper as the core?

I believe it would be pointless to use copper core even if you were using laminated copper sheets, it would have no useful effect compared to the same transformer when you removed the copper core and check the performance. 
(Of course there are air core transformers designed for higher frequencies with acceptable efficiency.)

Another question I have is about the magnetic reluctances, I think that if you try to power a device using back-emf, you can get COP>1 if you energize a first coil with a high reluctance core and then you collect the back emf in a secondary coil containing a high permeability core. The collapsinng field would produce more energy in the high perm. core that the energy nedded to produce the magnetic field in the primary core. I think I read something about this sometime ago.

Well, my question would be: how could you mechanically arrange the two coils with their differing permeability cores to achieve that the input current's magnetic field in the first coil should not 'see' the other core, then the collapsing field of this first coil should immediatly 'see' the other core?

[SchubertReijiMaigo]

Hello again, Copper and Bismuth are diamgnetic, what does that mean ?
Diamagnetic repel magnetic field, superconductors are perfect diamagnetic u=0...
I don't think diamagnetic is a good choice for this app, but fully saturated ferromagnetic screen like Tesla said would be better...
My father see to cut the mild steel toroid with dremel, if everything is OK test will start next week...

[gyulasun]

Diamagnetic materials has a permeability of less than 1. How less?

Vacuum has a permeability, u=1.0 and air has u=1.0000004

Copper u=0.999991

Bismuth u=0.99983

So the difference is very very small with respect to the air. It involves very strong magnetic fields to experience a small difference.

[SchubertReijiMaigo]

OK, so the with small value of B, Copper and Bismuth look like air...
I wonder what kind of effect we can have here, maybe a normal trafo, since if the outer/primary is wind through air or something like air, you have a conventional trafo, this is why I'am a little skeptic here, but I wait for your tests before concluding anything.

[Mavendex]

I assembled Teslas construction to see if it would work I could not get power to transfer in either direction, dropping 2kw in and 0 volts out.

Permeability is key in the construction teslas iron version must have been enormous, but just goes to show you that mabye it wasn't actually constructed but just conceptualized.

In this construction is a Steel shell constructed, a iron powdered core, electrically isolated, and wire the perm of the outershell probably 100 or so the inner core had a perm. of around 68.