Calculating Magnetic Energy in Permanent Magnets

[souky101]

Hi folk
Is there a method to calculate the magnetic energy stored in a permanent magnet ?
Thanks for help

 

[mfb]

Sure. Magnetic field strength corresponds to energy density. Integrate over the whole volume and you get the total energy.

 

[souky101]

Thanks for your reply.
Can you illustrate with some practical example on a piece of permanent magnet..

 

[mfb]

It is not really practical. You have to measure the field strength everywhere, then plug that into the volume integral.
To get an order of magnitude estimate, these measurements can be very coarse.

 

[souky101]

Sure the permanent magnet' manufacturers follow specific practical design mathematical calculations / equations. .

 

[mfb]

It doesn't really matter for them. The magnetic field strength and direction have to be right. Who cares if there is 1 J or 2 J energy in the magnetic field?