Thane Heins Perepiteia.

[Mr.Entropy]

How far can this be explained by conventional physics?

Well, Alan, the acceleration effect alone has a pretty simple explanation, which I gave an approximation to in post 1541 in this thread.  Since then I've thought about it some more, and come to the definite conclusion that there is certainly an eddy current effect that can produce acceleration.  It works like this:

- When a magnet passes by a core with no coil or an open coil, eddy currents are generated.

- The eddy currents counteract the changing magnetic field.  The amount of current generated is exactly enough to reduce the changing field until it produces exactly enough voltage around the eddy current loop to produce the current according to Faraday's law.

- The energy lost in the eddy current depends on (among other things) the resistivity of the material.  This is NOT a linear relationship.  If the core is superconducting, then the current produced is enough to entirely cancel the magnetic field, but the resistance to that current is zero, so (by P=IR), no energy is lost.  On the other hand, if the core is non-conducting, then no current is produced, and again no energy is lost.  For every resistance value in between, there will be some loss, and there will be an R value where the energy loss is maximal.

- Now, when you put a big wad of copper around the core, and allow it to carry an eddy current (by shorting it, if it's a coil), you provide a low resistance path for a current that can counteract the magnetic field in the core.  Copper is a very good conductor -- a lot closer to superconducting than ferromagnetic materials, so (by Faraday's + Ohm's laws) most of the eddy current will be generated in the copper.  There will be more of it, but certainly no more than is required to cancel the magnetic field in the core, and that is limited, and since copper is a good conductor, the P=IR losses will be relatively low.  There are bound to be many configurations in which shorting the coil will reduce the load on the motor.

--

NOW... before any of you spew, I will mention that there are other effects that have been reported in this thread that I can't explain, including:

- putting some iron in the shaft that connects the motor to the rotor increases acceleration;
- acceleration to speeds greater than those achieved when the coils+cores are removed entirely; and
- performance of certain coils changing over time for no good reason.

However, nobody is really concentrating on these effects, so they have not been reproduced consistenly and robustly.  If I start seeing more documentation on these things reproduced against careful controls, I will be impressed.  Aether22 seems to be more disciplined in his experimentation, so now that he's producing results, maybe we'll get it.

Cheers,

Mr. Entropy

[CRANKYpants]

- acceleration to speeds greater than those achieved when the rotor is removed entirely; and

I THINK THIS SHOULD SAY COIL(S) - AT LEAST IN MY CASE IT WOULD APPLY

Thane

[Mr.Entropy]

I THINK THIS SHOULD SAY COIL(S) - AT LEAST IN MY CASE IT WOULD APPLY

Thane

Changed to coils+cores. thanks.  You did remove the cores too, right?

[aether22]

He did

Also worth noting that when the torque on the motor casing was measured it was found to increase on shorting, still that is pretty much the totality of the evidence as I know it right now.

As for disciplined we'll see, I'm still sitting here typing with too many possibilities to test.

[Mr.Entropy]

Also worth noting that when the torque on the motor casing was measured it was found to increase on shorting, still that is pretty much the totality of the evidence as I know it right now.

If you can reproduce that, it's important to know whether the torque increase happens immediately, implying something freaky, or slowly as the RPM increases, which is expected of an induction motor.