David Meeker dmeeker@ieee.org

Version 4.0.1 02Apr2007

• Changed the way that stored energy is computed for permanent magnet materials. Energy in stored in PMs was computed incorrectly in previous versions.

Version 4.0.1 08Dec2006

• Fixed some odd behaviors that were introduced during the implementation of code that treats 1-turn regions as solid. Odd/erroneous behavior could result for regions that were defined as multi-turn but did not have a wire diameter defined. The 08Dec2006 compile fixes this issue.

Version 4.0.1 03Nov2006

• Changed the implementation of wound coils so that 1-turn regions composed of magnet wire, litz wire, etc. are treated as continuum regions rather than solid regions. Previously, all 1-turn regions were treated as solid.
• Modified expressions for effective resistance of wound coil regions. The previous expressions double-booked a (very) small amount of energy stored locally around the coils.
• Fixed memory and handle leaks (fixed versions after 14March2006).

Version 4.0.1 03Dec2005

• Minor bug fixes.
• Re-licensed using Aladdin Free Public License.

Version 4.0 17Sept2004

• Fixed a bug in which permeability was not properly computed in bulk coil regions in DC magnetics problems.
• Changed the way that errors are caught during ActiveX calls so that the any Lua error messages that occurs get piped through as results of the ActiveX function call.
• Made a number of “under the hood” changes to the way things are implemented so that things will run more or less OK under WINE on Linux machines.

Version 4.0 17Jun2004

• Added some cosmetic but useful modifications (thanks Davide Pizzolato). Users can now switch between documents via tabs. The toolbars have been re-arranged so that the display doesn't “jump around” when switched between different document types.

Version 4.0 27May2004

• Added file-based interprocess communication method. This is the basis for an interface to Octave.

Version 4.0 15May2004 Release Candidate 1:

• Wire size and type as as material properties for “bulk” wound coil regions.
• Continuum model of proximity and skin effect losses added. This model automatically accounts for the AC losses in “bulk” wound coil regions.
• Extra “Properties” section in the main menu added for “Exterior Region.” The extra “Exterior Region” properties are only active for axisymmetric problems. These extra parameters are required to model axisymmetric unbounded regions via the Kelvin Transformation approach.
• All intermediate temporary files are now automatically cleaned up.

Version 4.0 01Apr2004 Development Release:

• MathLink interface to Mathematica added.
• Capability to run FEMM as an ActiveX server added.

Version 4.0 26Jan2004 Development Release:

• New drag-and-drop materials library implemented.
• Fixes a number of bugs identified in the 18Nov2003 version.

Version 4.0 18Nov2003 Development Release:

Substantive changes since the last Development Release:

• A somewhat better notion of “circuits” has been implemented for magnetic problems. The “circuit” properties now allow the user to specify either series-connected or parallel connected regions. In addition, series-connected regions can also be assigned a number of turns, so that the modeling of multi-turn coils is simplfied. The number of turns for a region is specified at the block label level (e.g. like the way that magnetization direction is specified.) In the postprocessor, the program calculates the voltage drop, flux link, etc. for each “circuit”. A new button has been added to the postprocessor toolbar to make it easier to see the circuit results.
• Density plot of J has been added to the density plot choices for DC magnetics problems.
• An extra “problem definition” attibute has been added to allow the user to specify the minimum angle constraint used by Triangle when meshing a geometry. The value of this constraint was previously hard-coded. Occasionally, a geometries with sharp angles can arise that require the minimum angle constraint to be reduced for proper meshing.
• A “log plot” button has been added to the BH curve definition dialog that points the entered BH curve with H on a log scale. The log plot can make it easier to visualize the curve at low values of H.
• Extra functionality has been added to the Materials Library that makes it possible to import material definitions from either another input file or alternate versions of the materials library.
• An extra block integral has been added to magnetic problems for calculating moment of inertia.
• The DXF import has been improved. The import routine is now more savvy about identifying and automatically resolving potential DXF import problems. Since it was pointed out to me that most DXF problems involve endpoints of lines that don't meet, all “orphaned” lines are displayed after the DXF import so that the user can inspect for possible problems. Multiply defined regions are also noted in the postprocessor, which is also a common symptom of DXF import errors.
• A preference has been added to the magnetics postprocessor so that Hc is subtracted from what FEMM usually reports a H inside permanent magnets, conforming to the “classic” way of thinking about flux inside magnets.

Some things that are still “to do” include (but aren't limited to):

• Take wire size and type as as material properties for wound coil regions.
• Display boundary labels in some way (e.g. similar to the way that the names of block labels are displayed?)

Version 4.0 16Sept2003 Development Release:

Few changes in solver functionality have been implemented since v3.3 in this development release. The significant change is that the magnetics pre- and post-processors and the electrostatic pre- and post-processors (previously known as the separate program, BELA) are all incorporated into one “interactive shell.”