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Author Topic: AC Homopolar Generator Conundrum  (Read 1771 times)

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Incorrect. The rotor will actually induce its own magnetic field, and then pass through it generating potential. I saw around 80mV. I also saw a little (10%) weight loss when running the rotor vertically and placing a N/S magnet either side of the rotor  ;).

It's been suggested to me that I look into spinning bronze alloy discs (C93200) at high speed... but this will require a lot more learning.

It is safe to say that either your rotor is slightly magnetized, or the magnetic fields from your drive motor (or other source) are cutting through the rotor.

I have hard  aluminum rotors spinning at 15,000rpm, and no measurable voltage was found between the center and outer rim of the rotor.


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It's not as complicated as it may seem...
So we have standard induction, and we have a potential between the center of the disk, and the outer edge.
If the copper disk is say 5mm thick, and has a radius of say 50mm, what would the resistance value be from the center of the disk, to the outer edge ?
Lets say that resistance is 0.001 ohms, and the voltage potential is 100mV. Ohms law states that a current of 100 amps should be flowing through the disk.
So why doesn't the disk get hot if it is standard induction ?, as the disk is a shorted turn.

Also, with my AC example, the magnetic fields are moving with the disk halves in this circumstance, as each field is pulled around by the opposite field as the disk and magnets rotate together.
So there is no relative motion between the magnetic fields and the copper disk halves, and yet a voltage still exists across the 2 half disks.
In fact, with the AC version, the disk does not have to be in two halves. It can be a solid disk, and will still produce a voltage across the opposite outer edges, creating an AC waveform across a resistor.
How can this be standard induction, when the magnets are moving with the disk, and there is no relative motion between the magnetic field and the disk ?
If however, the two half magnets are stationary, and only the disk is spun, we then do get normal induction, where will still get a voltage across the disk, but heat is also generated by the disk.


Brad

100mV and 0.001R yields a power of 10W. That isn't a large amount of power, and depending how long it is run, may not show significant heating in the entire disc. But also this current needs a path through a load. If the load is a 1k resistor there won't be any significant heating. The only way the disc may exhibit some heating, is if the "load" were a dead short circuit. The disc itself is not a shorted turn when it comes to the induction process. so again, unless the external loop is a short circuit, the disc will not heat up.

Regarding the question as to whether a homopolar generator still works if the magnet is mounted to the disc and spins with it, the answer is yes. There is still relative motion between the electrons in the disc and the magnetic field set up by the magnet(s). So it is still conventional induction creating the measured output voltage.
   
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How can this be standard induction, when the magnets are moving with the disk, and there is no relative motion between the magnetic field and the disk ?

In fact, there is relative motion between the moving disk and magnetic field because the magnetic field is stationary.

It would seem to me the whole Faraday Paradox revolves around...
1)Most didn't understand the concept of field lines which Faraday proposed. Faraday claimed the lines of force are not real only imaginary.
2)Most never performed actual experiments to prove whether the magnetic field was stationary or not. For example, a magnet can move in any direction and induce eddy currents except rotation proving the field does not rotate.

For example, I invented a magnetic bearing stabilizer based on the fact that a magnet can move in any direction except rotation on it's polar axis and induce eddy currents. The eddy currents generated in a nearby copper disk oppose any inward/outward, up, down, left, right movement stabilizing the magnet but has no effect on rotation. I invented many devices based on the fact that a magnetic field does not and cannot rotate with the source magnet.

I can show countless experiments proving a magnetic field does not rotate with the source magnet. Can anyone show me one experiment which proves the magnetic field does rotate on axis with the source?. I know they cannot thus I rest my case...

AC





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AC

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In fact, there is relative motion between the moving disk and magnetic field because the magnetic field is stationary.

I was talking about my AC version.
I know in the DC version that there is motion between the magnetic field and the rotating disk, and that the magnetic field does not rotate along with the magnet.


Brad


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Regarding the question as to whether a homopolar generator still works if the magnet is mounted to the disc and spins with it, the answer is yes. There is still relative motion between the electrons in the disc and the magnetic field set up by the magnet(s). So it is still conventional induction creating the measured output voltage.

Ok, i maybe confusing people here.
Regarding this, i was referring to my AC setup, not the DC setup.

With the AC setup, the fields do move with the copper half disks, as each field pulls the opposite field around with it, so the fields rotate with the disk, unlike the DC setup, where the field does not rotate with the disk.


Brad


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