Magnet force shield

[dieter]

I think power is not a useful unit here, because we want to know about energy. Excluding for now accelleration and deaccelleration, assuming we can recover or nullify these by a spring.


Work <= Energy, or at unity Work=Energy, as far as I see. Comparing work A and B seems legit to me.

[Cairun]

Message deleted...

[Cairun]

Floor,


You may already know this, but I will share it anyway.
This stems from your video http://www.dailymotion.com/video/x5an8hd_rtangsld2_tech about having to shift the shield magnet down slightly to achieve a "shielding" effect.


I did a few FEMM simulations of your concept and found that if the repelling magnets are vertically centered on the shield magnet then the repelling magnets will
experience a force in the horizontal direction(X direction in FEMM simulation).  As Dieter suggested, this is due to the attraction force being greater than the repelling force for two magnets. The attached pictures(first 3 pictures) show the measurements of the forces acting on both repelling magnets and the shield magnets(the names of the files tell you which magnet is being measured) with the repelling magnets vertically centered on the shield magnet.


The second set of 3 pictures show the force measurement on the magnets with the repelling magnets shifted up/down to balance the attraction and repulsion forces which effectively gets rid of the force experienced by the repelling magnets. 
I believe in order for the shield magnet to not have a cogging point it is crucial to shift the repelling magnets up/down to balance the attraction and repulsion force.


In conclusion, if the repelling magnets are shifted up/down correctly then the shield magnet effectively experiences no force going in between the two repelling magnets.


Anyway, please keep up the good work,


Alex

[Cairun]

FEMM files attached.  To use change the .txt extension to .fem.

[Floor]

@cairun

    thanks

I know the principle is sound.  Any need to fine tune the magnet positions,
is not a major obstacle.

I got effective shielding ... (while the shield magnet was nearly centered)
when I achieved a more precise shield magnet positioning  (but off camera).

                        regards
                             floor