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Mendocino Motor


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On a Mendocino Motor why does one side float free while the other has a tip to a wall? I know the question might sound trivial but I have worked up the idea why not use the same magnets used to levitate as a counter force on both sides of the shaft? I attached a very rough jpg of what I mean. the green magnets at the end of the shafts is what im referring to. is there some theory or law preventing this?





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Earnshaw's Theorem would apply and is why one point is against a wall. This source explains things pretty well:




Earnshaw’s theorem says it is not stable, but there are loopholes[from Wikipedia]:

Pseudo-levitation constrains the movement of the magnets using some form of a tether or wall. This works because the theorem shows only that there is some direction in which there will be an instability. Limiting movement in that direction allows for levitation with fewer than the full 3 dimensions available for movement.

If we set 2 axially magnetized disc or ring magnets side by side, with their axes parallel, there is a pocket of stability above them. A third magnet can sit in this pocket, but the shaft is free to move along its axis.

If we add a wall to stop this motion, where the levitating shaft starts to move away from the highest point, the wall stabilizes the levitating shaft. By setting the floating magnet slightly closer to the wall than the magnets in the base, the shaft tends to lean against the wall.

With two sets of magnets like this, the shaft is held levitated. It is stable with only one point of contact with the wall.






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Earnshaw's Theorem is so misleading that it would be better to forget it altogether.


Especially, it applies only without gravity - a situation uncommon where humans live.


For instance, a square of pyrolytic graphite floats over a group of magnets and has a stable position, without any contact.

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