# Force btwn an electromagnet and a permenant magnet

## Main Question or Discussion Point

hi all, i am currently working on a magnet generator/motor and i have some qns on electromagnetism.

i am currently trying to find out how much does my electromagnet (ferrite core) requires in order to repel a permenant magnet, in this case, a cylindrical NdFeB magnet.

i have been trying to find out from the web and libraries regarding the force between the magnets and the closest i have come to is

http://en.wikipedia.org/wiki/Magnet#Force_between_two_magnetic_poles

there r so many other equations but none of them involves an electromagnet and a permanent magnet. so i would like to ask for advice and correction. thanks!

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I am currently trying to find out how much does my electromagnet (ferrite core) requires in order to repel a permanent magnet, in this case, a cylindrical NdFeB magnet.
How much what? Are you asking how much current you'll need to get x amount of force at a distance d?

This is a complicated subject. Maybe someone with more electromechanical experience can point you to an analysis but I really think it's best if you just take measurements of the force and make some graphs of force vs. distance for different currents.

There are other options. I was looking at http://www.integratedsoft.com/default.aspx" [Broken] a while ago. They have a 30 day free trial. I never downloaded it so I don't know much about it but I bet it could simulate your design.

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How much what? Are you asking how much current you'll need to get x amount of force at a distance d?

This is a complicated subject. Maybe someone with more electromechanical experience can point you to an analysis but I really think it's best if you just take measurements of the force and make some graphs of force vs. distance for different currents.

There are other options. I was looking at http://www.integratedsoft.com/default.aspx" [Broken] a while ago. They have a 30 day free trial. I never downloaded it so I don't know much about it but I bet it could simulate your design.
Thanks Okefenokee for the reply. I am trying to find out how much force does the electromagnet requires to repel the magnet away instead of attracting it. From the force, I would then like to find out the number of turns needed.

The current can be fixed within the current capacity of the copper wire of the coil, so its the number of turns that matters. Anyone can help pls?

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