Homopolar Generators (N-Machine) by Bruce de Palma

[gyulasun]

Mag on foil vid

https://www.youtube.com/watch?v=s56ghlm0oJw&feature=youtu.be

Mags

Hey Mags,

I have watched your video a few times and I noticed an uncertainty in the moving direction of the  magnet when you touched its top with the wire (video time 1:03). The magnet "hesitated" to start up to the right hand direction and first went to the left a few mm, then moved towards the right.
I wonder if this "hesitation" came about because it may depend on which part of the magnet top the wire was touched to: just in the exact center where the Bloch wall is as I indicated in your drawing with the dotted black lines in the attched picture or the moving direction may depend on whether you touch the wire more towards one of the edges of the magnet? (I mean the area between the dotted center line and the pole edges of either the North or the South sides I indicated with a single red and blue line.)
I could not see from the video how much the wire was off from the exact center line or maybe this is not so important? Of course the Bloch wall is but one mm or less in thickness for that cylinder magnet thickness and you may have cared to always touch the wire within that 1 mm thick 'center line' i.e. in the Bloch wall area.

Thanks for showing this interesting phenomena.

Gyula

[Magluvin]

Hi mags

Like you said many believe that field is stationary but im still not satisfied without experimental proof. Experimenting is the only way i can see to end up this mind bogling paradoxes.  If only i have a large magnet i will do that experiment.

There are vid demos that show when 2 disk mags are held apart, in attraction, when one of them is spun, with a drill if I remember correctly, the other did not spin. But, if we allow the test magnet to be free in 2 or 3 dimensions, the magnet as a whole can be moved in many directions, so say a large disk mag is spinning on axis, the fields departing the face of the mag has no affect on a conductor in its path, but if we move the conductor and the mag stationary, the conductor will have current.  In tests I have done, if we small mags mounted to the surface of a coil, each of those fields from the individual mags will not produce current in the coil, as the fields tend to remain as the are, whether the assembly moves through air or spins like an HP motor/gen.

Im sure that if we spin a disk mag on axis, we could sense(hall sensor, small pickup coil) highs n lows in field strength due to imperfections within the magnet, but no apparent dragging of the fields as if the magnet were moved in any other way, other than spinning on its axis.

So myself, if there are no field lines, it kinda has me thinking differently about how the fields induce current in a wire.  More on that later as I gain more understanding on it myself.

Mags

[Magluvin]

I haven't looked at it this way but this seems completely possible. In fact if you prevent it from sliding and forced it to roll I can't tell how it will even induce a back EMF. Atached is my analysis of such setup. The upper illustration shows the generated forces, the lower images show the 2 different motion cases. Something to ponder on indeed.

Nice illustrations.  Thanks for those

As you show it is like I envision what may be going on.But as I stated to TK, there may be more complex things going on within the mag with currents flowing as we have them. The currents flowing say downward should cause field 'around' the mag in a horizontal plane. I need to make a better axle for the stationary spinning disk so the mag is more free to move. It was snug till it snaps into the plexi frame so it would not jump out. Spins ok, but too much current needed causes damage and very short testing period.

Got a few new ideas for testing, as I will describe in my next reply to Gyula.


Mags

[Magluvin]

Hey Mags,

I have watched your video a few times and I noticed an uncertainty in the moving direction of the  magnet when you touched its top with the wire (video time 1:03). The magnet "hesitated" to start up to the right hand direction and first went to the left a few mm, then moved towards the right.
I wonder if this "hesitation" came about because it may depend on which part of the magnet top the wire was touched to: just in the exact center where the Bloch wall is as I indicated in your drawing with the dotted black lines in the attched picture or the moving direction may depend on whether you touch the wire more towards one of the edges of the magnet? (I mean the area between the dotted center line and the pole edges of either the North or the South sides I indicated with a single red and blue line.)
I could not see from the video how much the wire was off from the exact center line or maybe this is not so important? Of course the Bloch wall is but one mm or less in thickness for that cylinder magnet thickness and you may have cared to always touch the wire within that 1 mm thick 'center line' i.e. in the Bloch wall area.

Thanks for showing this interesting phenomena.

Gyula

Hey Gyula

The wire has bad spots on it so at times making contact would not happen. But I do get what you mean. It should be mapped out what effects making contact on the magnet have in different areas.  I got some copper washers that I can press onto the mag where it could be centered or slid to the left or right edge. Also in the foil, set up a little plexi tracking walls to keep the mag straight with a back stop and arrange the wire to contact the mag consistently in particular areas. And some more ideas for free floating and to pivot on edge.  Lots to do. Neat stuff though.

The pendulum didnt do anything.  So as you say, possibly change the positions of the contacts, where possibly they are not directly across the mag, maybe at 1/4 turns. 1/3. etc

Mags

[Magluvin]

Happy Belated New Years @All


Hi Magluvin,

Thanks for sharing. That is very interesting.

A small test platform could be setup to see if it's sliding or rolling as TK and Broli state.

If the friction is too great for the top rail it can be replaced with a smaller wire with a slight slack to it so it droops and touches the top of the magnet.

If you feed in a bipolar square wave into the rails it should oscillate back and forth.

These all need testing still but it opens some really interesting ideas like a linear homopolar generator.

Hey Dream

Good Idea. 

Probably good to just glue light weight plastic washers to the sides as to not add extra weight to the moving assy. Tk is getting very good rotation with 6 amps. My 4 AAs are pumping an even 4 amps, just to get it moving as shown. The 12v 12ah agm, things happen too fast to see what happened at times.   

Mags