David, Thank you
for the quick reply. The ‘right
double click’ trick is great, that’s what I was looking for. You are
the alpha-geek, thank you sooooooo much!!! Jay -----Original
Message----- "Jay D.
Greener" wrote: Hey Everybody, I just
recently started with FEMM and E-mag analysis in general; please forgive any Problem
Background: I’m using
SolidWorks2000 to generate an axisymmetric dxf model of a pot core Findings:
1.The .DXF seems to import in a random position w.r.t. the FEMM coordinate Questions:
1.The FEMM manual specifically say’s “AutoCAD” DXF…is SolidWorks DXF 1) Femm could still use a little work on
the dxf import filter, but a lot of problems stem from the fact that dxf is
really just a drawing format rather than a finite element format.
Problems like lines not quite meeting, points almost being coincident, etc,
aren't problems for a drawing format, but they are a headache if you are trying
to specify a consistent geometry. There's a really good explanation of
problems and possible solutions w.r.t. dxf import on the IES website at http://www.integratedsoft.com/demos/2DDXFImport.htm.
Although this site is specifically about dxf import issues with IES Magneto,
all of the wisdom applies to doing dxf imports in femm as well. 2) Do a right button double-click when the
mouse pointer is close to the point you are interested in. The program
will then pop up a message box with the exact coordinates, applied property,
and group membership of the nearest point. The right button double-click
works in other modes to enquire about the location and properties of the
nearest object without actually opening it. This is an "undocumented
feature" that I really should get around to documenting... Anyhow,
if you are worried about trivial displacements from z=0 due to import inaccuracies,
you can explicitly define an A=0 boundary condition and apply it to your
centerline. This ought to fix things. 3) Hang applied an A=0 boundary condition
to all the outer edges of his model. This makes it so that no flux can
cross out of your problem domain. In contrast, if you don't apply any
boundary condition (like in no-air your model), that's as if you surroundedthe
actuator with an infinitely permeable iron. The flux would rather travel
in that lower reluctance path outside the solution domain rather than through
your actuator. When you add back the air, it puts a high reluctance
barrier between your actuator and the "infinitely permeable iron," so
the flux again prefers to stay inside your actuator. Dave. |