Magnetic braking of magnets sliding along a sloped aluminum surface

[foxpup]

Hi all,

I've done another experiment involving the same high strength cylindrical magnet on aluminum.  Its crude but I think demonstrates my point about the behavior of these magnets.

http://www.youtube.com/watch?v=aYcAt--xJcw&feature=channel_page

I really do think this is the result of nonsymetry in the way the magnets are magnetized and nothing fancier than that.
(my own humble opinion)

What's weird is that weeks ago this magnet just showed up in my possession, stuck to the front of my filing cabinet.

Enjoy!

[lostcauses10x]

hmm this actually could be dependent on the direction of the magnet poles.
Think of the direction of induced current, and the current dispersal. If such is directed at the surface of the plate, the pattern of current flow will change at the surface.
Think of skin effect of current flow in a wire. 

One direction of polarity it goes at the surface, the other direction it goes from the surface.

[wattsup]

Here is my explanation as to why the magnet slides slower on one pole then the other based on Lumens video. (Allready posted here)
http://www.youtube.com/watch?v=a0YCTwWvykw

I am sure it has to do with the way the magnetic fields exit the magnet and re-enters the magnet. It is not magnetic attraction but simply the direction in which the magnetic field tear through the mass of the AL as it falls.
http://www.overunity.com/index.php?topic=7039.msg179592#msg179592

[exxcomm0n]

Hey all,

I've been following this "from the shadows" since the X0 post in the Mylow HJ replication thread as I've always been fascinated by this behavior (mag in a copper tube) since I first saw it when Dennis Lee (?) showed it in one of his Tube vids (not the best source, I know. But it is demonstrated plenty of other times by others w/ less of an agenda).

The question I have (and will test shortly using an aluminum level. Thanks foxx!) is what happens when you roll a longer axially magnetized cylinder mag down the slope.

If there is a difference in field strength of the polarities and the eddy currents produced by them, wouldn't the rolling cylinder mag consistently roll towards one side of the aluminum slope? If you rotate the mag 180 degrees will it then consistently roll off the opposite edge?

I think I saw TK say something about using "more" cylindrical mags (longer?), but I ASSUME that it is 1 polarity down, and 1 polarity up as that's what shows this effect so well.
I was just wondering if TK had rolled any of those cylinders laying down with both polarities in contact with the aluminum stock?

I found the 4' al level and tried rolling a 1/4" W X 1/2" L N42 neo that had 1 end "sharpied" black to differentiate the 2.
It's not a good test IMHO because of the variance in thickness of the al (very thin on the sides, very thick in the middle), but it did show some interesting effects when rolling the neo down the length.

I need better control materials for the al slope (i.e. consistent thickness of al, true measurement of slope angle, etc.) to really have any data that matters, but I did notice some peculiar behavior as it was rolling down.

No matter how carefully I placed it, it would not roll longer than 1' without rolling off the level. Sometimes when rolling a polarity would seem to hit the thick middle of the levels I-beam like structure and the mag would swing vertical to the floor and then off the level.

As I said, nothing conclusive to my tests and they were hardly done in a controlled method, but it's acting wacky enough for me to start looking around for al bar stock.

@ TK, lumen, X0, etc.

If this experiment is something you haven't tried yet (unless you know of the reason for this effect and choose not to [re]validate it) , please give it a whirl.


I just think that if one polarity is stronger, the mag should roll off the bar to one side consistently. This has NOT been my experience with it yet, but my al stock is hardly of uniform thickness.

Another "wild hair" (or is it hare?) thought:

If there would be, for lack of a better term, magnetic "turbulence" from having both polarities in contact with the same al stock, could someone use a long cylinder mag and roll it down 2 al lengths sitting side by side with side rails on the outer edges to see if the cylinder has one side that falls through the center gap between the 2 "rails" every time?

I'll try to locate some al that fits the criteria above to set up a test.

Just some thoughts gents.

[Yucca]

@all

I tried a good sized neo disc sliding down aluminium ladder surface inclined just off vertical.

Video, about 2 mins long:
http://www.youtube.com/watch?v=A458J8dttu4

Definitely noticed that north side facing alu will always hug the surface. But when south side faces alu it drops away from the surface, it seems to drop away when the magnet reaches it´s terminal velocity which is quite slow due to the lenz braking.

I think there must be a repulsive force that fights gravity and lifts the mag away from the alu surface because the surface was not vertical and gravity wants to keep in on the surface.

If this effect could be seperated somehow from the lenz braking then perhaps it could be used for some gain?

I would like to see this experiment done in the southern hemisphere, so any Aussies or Kiwis etc. try it and tell.

NOTE:
I made sure to lift a non sticky plastic stick off the front magnet face to release it, using fingers or supporting underneath the bottom edge can cause the magnet to be influenced by mr hand. But trapping the magnet against the alu by using a stick and then pulling the stick away will not influence its horizontal position as much.

EDIT:
My young daughter, asked "why" it does this? After the vid I tried to explain but couldn´t stop her calling "why", I think my last answer was "because one sides different"