| If a magnetic field cannot rotate, then we have no electricity, | since generators depend on rotating magnetic fields. ...as do | their opposites; motors.
If a magnetic field has to rotate then we have no transformers.
Rotating an array of alternating north and south poles does not mean the field itself is rotating. The orientation of the north to south line is radially from the axis. Whether the field does rotate or not is not important as what is happening is that the field changes in polarity. That change in field strength and polarity is sufficient to induce current in the windings.
Faraday's disk had magnetic field oriented along the axis, not radially. Unlike a modern AC generator, the rotation of the disk did not result in (significant) changes in the field strength anywhere. This can be tested using very carefully designed magnets that give a very smooth field as the disk is rotated. That would be a good start to see whether this theory works or not.
If the disk has a brush touching the outer rim, and another touching the axis, these would not be where any magnetic field changes would be inducing voltage, because the fields are not really changing there, due to the field orientation along the axis.
I don't know whether it works or not. I only see that the arguments in favor of it are plausible, and the arguments against it aren't looking at all perspectives (and hence while also plausible against it, they are by no means certain).
Consider TWO disks on the same axis but with some space between them, with the axis constructed so that they conduct separately from each disk, but is insulated between the disks. The disks are constructed alike, but one disk is reversed so its magnets face in the opposite direction, or more specifically, its rotation will be in reverse to the other to. Along the rim of each disk, connect them with a lot of individual wires, or maybe even a solid strap. Now spin that. If Faraday's disk is for real, then why would this arrangement not also work? What it should do is induce voltage in one direction on one disk, and in the opposite on the other. Since they are connected in series, the sum voltage should be presented between the two ends of the axis.
Again, I have no idea if this will work. But if one works, I think the other should work. But my design lessens the stray magnetic effects and so it should be a cleaner test.
If it does work, I have some more variations on the design that should be more interesting (but more complex to explain).
Another test is to reverse everything and try to make a motor out of it. Would putting a voltage across the disk, or disks, cause a rotational force? Would be interesting to find out.
| Einstein had something to say about relativity too. The fact is | that to generate electricity you have to "cut" magnetic "lines of | force". Farady was quite clear here. You have to have relative | motion.
Faraday's concept does not contradict Einstein, given the explanation that the field remains stationary while the disk (think of it as a million radial wires) cuts across the field. The issue comes down to whether the field is, for this purpose, actually rotating with the magnets, or stationary.
Remember, a transformer works by a field that is not physically in motion because the windings themselves do not move (aside from tiny vibrations mechanically carried from the core). The field merely changes to induce voltage in other windings.