Magnets, motion and measurement

[lumen]

Hi Floor,
The setup is the same as your PDF file except the two piece magnetic shield.
A layered opposing magnet seems to work best for the shield and is still easy to insert or remove with no real force.
The only thing I found that works better for the shield is this same configuration but with very thin steel between them but it also causes some attraction to the two working magnets.

That's why I ran the calculation to find the results for the shown magnets. They are all N35's and the sizes shown. The best results were with very little spacing in the fully closed position.
The results would likely be different if using ceramic magnets.

[telecom]

Hi Lumen,
do you have the actual photo/video of your setup?

[lumen]

Yes, but of course it doesn't actually work because you cannot shield the field.

[Floor]

Thanks Lumen for the clairification and experimentations.


Quote from floor earlier in this topic

"The sliding fixtures used must be rigid before you can get good
results.

Flexing of the magnets from their positions can mess things up
quicker than just about any thing else.  Powerful neo magnets
require high precision / very strong fixtures.
                               Use of ceramic magnets recommended.

There is a ratio between the surface area magnets and their flux
density.  Yes
                               Use of ceramic magnets recommended.

Small and yet powerful magnets (neos) are very difficult to align
precisely enough to get good results.

A larger surface area of the magnets makes a workable alignment
easier, because it allows for more margin of error in alignment.
                    example
A miss alignment of 1/16 inch off,  out of a 1 inch by 1 inch surface
area, is off by 1/16.
A miss alignment of 1/16 inch off, out of a 2 inch by 2 inch surface
area, is like being off by 1/32 if the magnet were instead, a 1 inch
by 1 inch surface area.                                                                   

A miss alignment by 1/32 inch might be well within a tolerable / workable
limit when using 1 and 7/8 inch  by 5/8 inch surface area ceramic magnets.

If instead, one were using 1/2 inch by 3/8 inch, n48 magnets, the precision
in alignment might need to be within one thousandths of an inch !

Also, the alignment precision needed, is somewhat dependent upon which
magnet configuration / method / device  you are using.

https://overunity.com/16954/magnets-motion-and-measurement/dlattach/attach/169684/

        regards
                floor"  END QUOTE

Note:
When my ceramic magnets are aligned so that the attracting and repelling forces are in a near balance, new forces arise due to magnetic domain re-orientations. They are along that same balanced vector, and become noticeable as a WEAK stickiness to the shield magnet. 

When using ceramic magnets, those undesirable / sticky  forces have only arisen while the
magnets are at very close proprieties. 

I believe that because magnetic force increases very sharply at the final / very near distance,  that  this is the only point at which  the field strength becomes great enough to significantly reorient some magnetic domains.  I did some tests along these lines and they seemed to verify this theory. 

I don't  how the neos behave in this respect.
I don't have any experience in this regard when it comes to Neo magnets.

        interested to see more of your tests / experiments
                   regards
                      floor

[Floor]

@ Lumen

Yes, but of course it doesn't actually work because you cannot shield the field.

Is this posted in the wrong topic ?