Finally got around to building a small test version, here’s what I wrote about it.
Okay I decided to build one of those magnetic motors to see what the results would be. The easiest way is to use a DVD with four magnets around the periphery.
I machined up a base and spindle from alloy bar I had in the workshop. I used my lathe and made very sure that everything was as accurate as I could get it, to eliminate any errors or influence. The base tapers to a sharp point and that locates under the cap of the spindle for minimal frictional losses. I tried it by spinning an empty DVD on it, with a ~ 60 rpm initial spin it took a couple of minutes to slow to a stop so the friction is quite low.
I then put two very powerful donut magnets on the edges (use two because that makes the magnetic field stronger and they grip the DVD really well without having to use glue) and made sure each pair was 90° from the next pair. Checked the balance in case there was some variation from the individual magnets and it remained very good.
I then introduced a hand-held magnet at a few different angles and all that happened was that the DVD disc re-aligned itself with the new magnetic field. If I moved the hand-held magnet the DVD disc would also follow that magnet.
I then hand spun the DVD disc with the hand-held magnet held in a stable non-moving position and it came to a halt after 3 – 4 revolutions. I repeated the test half a dozen times with little variation.
I could, however, easily make the DVD disc rotate nicely by manually flipping the hand-held magnet around. This is how an electric motor works – the flip the magnetic field on either the inner or outer ( depends on the design on the motor) part of the motor so it provides a moving magnetic field for the other half to work against. Unless you have an actively moving magnetic field like that, you simply will not get continuous rotation.
In short, it doesn’t work.
This is what it’s supposed to do, but it can’t because of physical laws