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'levitating alternator' question


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hello guys, i have tried to build an alternator which also doubles as a magnetic thrust bearing



here is the rotor:



the inner 6 magnets are all facing the same way, and the outer 6 magnets are all facing the opposite way, this creates a 'horseshoe' magnetic field in a zig-zag pattern around the circle of the rotor... the 'star' is made out of mild steel and is acting as the 'magnetic flux conductor'


here is the base:



similarly, the outer ring of magnets are oriented in the opposite direction from the inner magnets, and the large flat disc is also made of mild steel... this is actually supposed to act as 2 large concentric magnets instead of 2 rings of smaller magnets, they are supposed to create a magnetic field which is as uniform as possible

and here are the rotor and the base arranged , the rotor is held up by the magnetic repulsion


when it is in actual use, it will be loaded down and compressed , so the base and the rotor will be closer in proximity... at least mechanically, the base magnets are providing a uniform enough magnetic field to allow the rotor to spin without any 'bumps' or 'dips'



this is therefore a magnetic bearing which allows the rotor to spin freely, without any friction from contact with the base

however, the purpose of the 'star' shape of the rotor was to create a regularly fluctuating magnetic field as the rotor rotates... and i have wound these coils in order to generate a voltage from the fluctuation of the magnetic field:




there are 3 coils for every magnet and they are glued on a piece of paper with a printout of the positions so while their placement isnt perfect, they should still at least be within a tolerable margin of error, and every magnet should be directly passing over a coil simultaneously when the rotor rotates , and each of these 6 coils with a magnet over it at the same time are wired in series... the inner coils are wound in the opposite direction from the outer coils, just as the inner magnets are facing the opposite way to the outer magnets...

thus, it should act as a 3-phase alternator



however, in my tests of turning the rotor, i could not measure any voltage coming out of the coils... my guess is that the magnets of the base are 'shielding' the coils from the rotor magnets' fields, and the movement of the rotor magnets does not cause enough of a perturbation in the magnetic environment of the coils to generate a measurable voltage... my idea would be to glue short nails into the space in the middle of the coils, with the flat end facing up (to catch as much flux as possible from the moving rotor magnets) and the pointed end facing down (so as to present as little ferromagnetic material as possible to the stationary base magnets) , and get the maximum amount of magnetic fluctuation happening within the coils as possible


my question would be, does what i am attempting have a sound physical basis i.e. should i scrap it or should i get it to work? and if it is possible to get it to work, how do i do it?

Edited by carmatic
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  • 3 weeks later...

Okay so I'm gonna take a shot at this.


I would like to critique/comment your design on just some initial thoughts:


-I think the coils could be better wounded

-Depending on how you are turning this "magnetic bearing", there are going to be rotational losses, if and when you get any induction into these solenoids, due to the back emf it will produce.

-The magnetic field interaction from the bottom magnets, as you suggested, will effect the magnetic field the coils are experiencing.

-With that you might want to get a very well wounded coil and try varying its orientation to see where it peaks, or if any current is flowing. Maybe try one with a core, though using a core will cause more rotational loss.


Granted I'm no expert, but hopefully this will help.

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