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Author Topic: dumb question about magnets  (Read 3323 times)

loop888

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dumb question about magnets
« on: April 17, 2008, 05:22:42 AM »
hello,

FIRST OFF!!
being this my 1st post and looking for the most simply real idea "from the very bottom of my heart" that stand for my joy here at OverUnity:
congratulations, my pleasure and thank you  to you all who care and want to try and believe in a better world! You guys deserve it all! 

:) !!

well, here goes the subject:

i was looking for neodymium magnets and as messure of power theres the pull force, in lbs..
now, reading a little more it looks like that pull force is the power you need to detach the sticky magnet from a solid flat iron/metal/suitable surface.

my questions are:

* how much pull force have a magnet when is not in contact with a surface?.
obviously this pull force gonna change with distances, there's some easy way to calculate/estimate the pull force from ALMOST contact with the surface to 0 attraction zone?
(the value i have is the "pull force" the seller told me my magnets have)

* what you think is more powerfull/useful? Attraction or repulsion?

thanks! Saludos =D

Honk

  • Sr. Member
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  • Posts: 497
Re: dumb question about magnets
« Reply #1 on: April 17, 2008, 08:40:19 AM »
This online tool will help you answer your pull questions.
http://www.magnetsales.com/Design/Tools1.htm

Feynman

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    • Feynman's Lab
Re: dumb question about magnets
« Reply #2 on: April 18, 2008, 10:16:27 AM »
Hey loop,


Quote
* how much pull force have a magnet when is not in contact with a surface?.
Good question... I think it depends on

(1) the orientation of the magnet (which way its pointing),
(2) the distance from the surface
(3) the composition of the surface

Let's assume the surface is steel and the orientation of the magnet is fixed.  From my understanding, the magnetic force will generally decrease with r^2 (radius squared).  I reviewed some information, and this is not always the case. . .

I think you will get your full pulling force of the magnet when it is closest to the object.  Your question is actually really good; I am also investigating these topics for my motor.   I have not found a good way to estimate pull force through air.  Let me know if you figure this out!
Quote
* what you think is more powerfull/useful? Attraction or repulsion?

Well , they both have their places I think..  To me, repulsion is more interesting because you can get magnetic 'superpoles' by forcing two opposing magnets into very close proximity.  Bedini uses this principle in some of his monopole motors.


Here are my N45 neodynium magnets... they have pull force of 18lb apiece.
(http://img132.imageshack.us/img132/1308/p1000666na1.jpg)