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1. The problem statement, all variables and given/known data

A disc magnet of radiusRand heightHattracts a mild steel plate.

Coercive force Hc, Remanence Br and Bhmax are known.

Main problem is to find an approximative formula that gives the pull force of the magnet at a given distancex. :shy:

I have found a formula that gives the force (eq.2), but the results are 4 times smaller then the experimental results.

[PLAIN]http://img293.imageshack.us/img293/2019/clipboard01aj.jpg [Broken]

2. Relevant equations

Eq.1 [PLAIN]http://img707.imageshack.us/img707/1124/img0028144742812.png [Broken]

Eq.2 [PLAIN]http://img833.imageshack.us/img833/730/img0017144742796.png [Broken]

3. The attempt at a solution

Experiment:

Neodymium magnet N48

@0mm - F=42N

@0.1mm - F=33N

Next step it will be to try the FEA analysis with Quickfield, but I need tiny analytical relations

Thank you!

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# Approximative pull force of a permanet magnet

Can you offer guidance or do you also need help?

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