Faraday's Homopolar Motor

[Tom Booth]

Apparently the "spikes" in the ferrofluid are not caused by or do not follow the "magnetic lines of force". That is, there is not a 1:1  relationship of a single ferrofluid "spike" gathering around a single magnetic "line of force" as I had assumed.

I've been watching random videos, and this one is interesting because the magnet is kept stationary but the collection of ferrofluid spikes are played with, pushed around the metal object stuck to the magnet.

The spikes are apparently caused by the cohesion of the magnetized ferrofluid with itself rather than the spikes being superimposed on or representing the individual lines of force emanating from the magnet.



When he pushes the spikey blob gathering around the magnetized metal ball, the whole thing moves around, back and forth and rotates almost as if it were a solid object with spikes.

[magluvin]

what would be key to tell if the mag field is moving with the ring mag or not would be to rotate the magnet ring with the induced copper disk and see if there is any drag on the rotation when current from the disk is on a load. if there is drag, what is it draging against if both are spinning? if there is no drag....lenzless gen...

mags

[Tom Booth]

Here is something else unexpected, to my mind, or assumptions anyway.

In the various Homopolar motors I've seen so far, the wire revolves around a magnet with the current going through the magnet.

For example:






In what I think must be about 99% of such videos, the current is in line with the magnet or centered around the magnet in one way or another.

But apparently this is not necessary?

Take this example that reproduces Faraday's original motor:



In this case, the current is traveling (I would assume anyway) through the wire, the water and the aluminum foil but not through the battery or the magnets. At least not centered around the magnet I wouldn't think, especially when the wire is to the side closet to the foil, then the stack of magnets is off to the side, so the current is going directly between the wire and foil. But the wire still revolves around the stack of magnets.

I guess it makes sense but was just a little surprising to me.

I still don't really understand, or know, why the wire rotates one way and not the other, or why it should necessarily revolve around the magnet at all.

I'm more familiar with the idea of regular motors with coils that basically form electromagnets with a commutator to switch from coil to coil so one turns on and the other off and the force revolves that way, but with the Homopolar motor, there is no switch.

Like the motor with the two screws. If there is a current passing through the screw creating a magnetic field, how is that creating angular rotation around the magnet that is revolving along with the screw?

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Then this thing has no magnet at all,





though looking very similar to the motor with two screws, it is not self starting, but supposedly works on a different principle,... The ball bearings deform from getting hot from the current????

As previously discussed, the ballbearings deforming from heat theory seems highly implausible to me for reasons previously discussed. Like it works under water where it does not seem like the bearings could possibly get hot enough to swell or deform, and the rapid heating and instant cooling necessary seems unlikely.

[Tom Booth]

A couple interesting videos:

[magluvin]

experiment i mentioned earlier...

https://m.youtube.com/watch?v=s56ghlm0oJw

mags

[Tom Booth]

experiment i mentioned earlier...

https://m.youtube.com/watch?v=s56ghlm0oJw

mags

The magnet is aligning itself with the earths magnetic field?

So the resulting rotation when the current is applied is in an East-West direction?

That seems rather extraordinary.

If there is a kind of vortex rotating magnetic field on the flat face of the magnet,  touching the side of the magnet with the conductor on top or bottom but off-center might produce an unusual response of some kind.

   

Not sure.

Touching it dead center in your demonstration, sometimes seemed to produce a weird twisting effect, which might be expected messing around at the center of a vortex or gyroscope-like force.

The way the magnet sometimes flies off when touched, reminds me of a game we had when I was a kid.



The way the top rotating at high speed,  flies off instantly when touched.

Anyway, very interesting.

[magluvin]

the magnet could be set at any angle. it has something to do with the current flowing through the magnet in relation to the mags field polarity at the time. i thought it may be the field of current in the wire that touches the top, but you can angle the wire any way and the mag will still go in the same direction. also the foil. place the foil input anywhere around the foil and the mag will go in the direction it will, depending on the magnets polariy orientation and direction of the current.

the earths field is quite strong. when i began the test as descibed, i had a hard time getting a 3/4 by 1/8 mag to stand on edge. was checking for screws in the table pulling it down, etc. but it was the earths field. checked it in many locations. typical compas is very weak magnetically and or damped rotation via oil or water encasing it. here is the vid on that i had posed before the foil mag vid...

https://m.youtube.com/watch?v=6gOO7OHHeMM

mags

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anyone can easily do the foil experiment. AA batt should do it. test touching the sides also and learn things from it. ?

mags

[Tom Booth]

Thanks, I bought a few nickel size neodymium magnets to play with. I may, when I have the time to set it up, do some experimenting.

I'm wondering if maybe stacking several magnets to make a cylinder would make a more stable magnetic "roller" to shock into some kind of rotation/motion.