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Author Topic: O.U. Magnet force shielding 1  (Read 12788 times)


  • Guest
Re: O.U. Magnet force shielding 1
« Reply #45 on: October 15, 2021, 05:56:10 PM »
I distinguish between 3 magnetic fields.  These distinctions are in terms of the
distance of the space between two interacting magnets.

When using CERAMIC MAGNETS there are distinct changes in the behaviors
of the magnets at these distances.

1. The very near field is 3/16 of an inch or less.
2. The near field is from 3/16 inch to 1 inch
3. The far field is from 1 to two inches (and beyond).
4. These definitions / distinctions / distances, are by necessity, a GENERALIZATION,
especially in regard to the defining as to what constitutes the near and far fields.

In the very near field...

Magnetic forces may be great enough to cause substantial reorientation of many of the
magnetic domains within (especially those domains which are near the surface) the magnets. 
This causes a dramatic change in the magnetic force available. 
Increase in the rate of ....           
        the change in the magnitude of force per the change in increment of distance

is especially present in magnet interactions which are attractions.  It is a little less dramatic
in repelling forces.

A kind of    shielding or exclusion of other fields
      which originate from the back sides of and / or the distal ends of magnets

seems also to occur. This is perhaps due (at least in part) to the extremeness of the field
density in the very near field ?

Attracting fields pull each the other, toward greater field density.  Repelling forces push
each the other, toward a spreading of the fields.

Attraction forces dominate over repulsion forces in the very near field.

The ratio of force change to change in distance approaches linear in its curvature
(as drawn upon a graph).
... ... ... ... ... ... ...
    Also, but at any distances ...

Attracting forces are more distinctly directional.  The direction of the vector is more
focused / narrow.

Repelling forces may easily fall into balance with an externally applied force.
i.e. ...
When in repulsion, one magnet can suspend / float above another / find a balance
against gravity.

Attracting forces are nearly impossible to balance.  EDIT (not repelling)
It is nearly impossible to suspend / hang one magnet below another by attraction
forces / find a balance against gravity.
... ... ... ... ... ... ... ...
The bottom line in respect to the "magnet force shield 1" design is that I find I must
restrict its operational parameters to within the near range / eliminate the very near and
also the far range, in order that it may still function with a net gain in work input to work
output (5/8 inch output magnet travel). 

It is so tempting to go for the maximum force / longest output strokes but it just doesn't
pan out to O.U. in those conditions.

It is only in the mid distance ranges, that a zero work input for shield insertion and removal
has been achievable.


1/8 to 3/16 inch between shield and fixed magnet   and   1/8 to 3/16 inch between
shield and output magnet.

Out put magnet travel range limited to around 5/8 to 7/8 inch.

... ... ...
I am next, installing pulleys for the shield cross slide (to hang weight incrementally on).

 best wishes
« Last Edit: October 16, 2021, 12:51:06 AM by Floor »


  • Guest
Re: O.U. Magnet force shielding 1
« Reply #46 on: October 21, 2021, 01:25:02 AM »
Update ...

A modified roller from a printer, to make a pulley, for the cross slide unit.

I had to turn the pulley shaft down on each end, (on a lathe) to make the
shaft fit the two, tiny, ball bearings sets.

The two metal brackets holding the pulley, are from the same printer and
are also modified.

JPG attached below..


I didn't make two pulleys...  There fore I'll need to remove the pulley and
mount it at the other end of the cross slide, for shield removal measurements. 
Actually, I can pull the shield magnet completely through.  No need to remount it
in order measure the shield removal work !
CORRECTION / EDIT... again ...
Magnets would then be too close to / influenced by, cross slide rails.
There fore I     will    need to remove the pulley and mount it at the other end of
the cross slide, for shield removal measurements. 

« Last Edit: November 25, 2021, 06:49:35 AM by Floor »