***************************************** (on mail) The file example.zip was checked and NO virus was found The file dmeeker.vcf was checked and NO virus was found *********************************************************
Turbo-Jon wrote: > when I try to read in a .dat file - created by exporting a curve from > MAXWELL - it appears that all the negative Hc values are converted to > positive values. > > or to be more precise the shape of the curve is OK, but it is shifted > from where it originally crosses B=0, (at Hc) up to H=0. REulting in > the entire curve being in the first quadrant. > > is this a problem whith FEMMPLOT or the way it reads in the values This is just how the program models permanent magnets. It thinks of permanent magnets as basically chunks of ferromagnetic material with very thin coils wrapped around them. When you load a B-H curve from a text file, the program shifts the data to the right so that it is in the first quadrant like a "normal" ferromagnetic material. Then, you assign the Hc parameter in the materials dialog, which denotes how far the data needed to be shifted to the right to bring it into the 1st quadrant. For more information, Appendex A1 in the manual talks about modeling of permanent magnets in femm. Because it is very short, I have attached an example .fem file that implements your material and models a bar magnet made out of it. Dave.
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