Fluxite

[Fluxite]

#webby1

These are very astute observations and I can tell you know what you're talking about.

To be clear, the tails you speak of are the attractive forces from the other side of the magnets.  If this is what you mean you are exactly right that they will cause drag on the system.

To minimize this effect the top magnet can be tripled up so as to distance and lessen the attraction of the top of that magnet towards the top of the disk magnets.

If this is what you mean by trails, I will make adjustments.

The shaft is carbon fiber. I use a skateboard bearing which is metal.  My limitation on the 3D printer is that it cannot make the disk larger (unless its in parts).  This fixes the distance of the center bearing to the magnetic fields at play on the disk. Will check for carbon fiber bearings.


Fluxite

What I have found when using any ferromagnetic medium in a "gate" system is that the part of the field I call the tails,, that is the other side of the magnet,, they WILL come around and bite you in the backside.

You are not addressing those tails.

Those tails also come from the metal part.

What I have found is that any possible gain when using a ferromagnetic material in the "gate" is that the losses for that material is as much if not more than the gain.

Hence your testbed not spinning.  NOTE: I understand that the large amount of slop and high friction from the bearings would most likely mean that this is not any form of testbed for force, but rather just the motions,, I call those finger toys.  I will point out that if you get it working that most likely those parts would need to be held within very small tolerances,, maybe even closer than what the 3D printer material can deliver.  Also I have found that often a metal bearing to close to a magnetic field will feel an additional drag,, so those might need to be considered.  There may be methods to deal with that additional drag,, I never bothered to worry about it so I do not know if there is or not.

What do you think the polarity of the fields going back between your magnets is?

All N faces up means there is a S going down between them,, since polarity is a "sense" of rotation.  You can check that yourself with a small magnet   again,, watch out for those tails.