Re: Force calculation on an axisymmetric model

[jim271@xxxxxxxxxxx]

--- In femm@xxxxxxxxxxx, Paulo José Gameiro Pereirinha 
<ppereiri@xxxx> wrote:
> Hello! 
> 
> I'm in Portugal and trying to compute the atraction magnetic force 
on an
> plunger electromagnet with axisymmetric geometrie. I'm using the 
Femm 3.0. 
> To compute the force exerced on the iron can I just define a 
contour in the
> air around the iron (which means that one side of the contour will 
be on
> the line of coordinate z=0) and integrate the Maxwell Stress 
Tensor? (i.e.
> is this command valid for axisymmetric models?). If I do so, I 
obtain
> -2.783e-3 N, but the experimental result is about 1.35 N. I'm 
sending the
> model in attachement.

After changing the permeability, as Dr. Meeker pointed out, you might 
also check your model for the current density of your coil. The 
force is proportional to the current squared, so a 50 or 60 percent 
increase in current density will make the calculated force close to 
your measured value.