FEM EquationMagnetodynamic2D

This equation perform analyses using a 2D version of the Maxwell's equations when the unknown is the z-component (or φ-component).

For info about the math of the equation, see the Elmer models manual, section Computation of Magnetic Fields in 2D.

For more general analyses in 3D using the Maxwell's equations FreeCAD supports Elmer's Magnetodynamic equation. Nevertheless, if it is possible to perform the analysis in 2D, this is recommended since the math behind this is then more simple and the calculation time is therefore faster.

Usage

 * 1) After adding an Elmer solver as described here, select it in the tree view.
 * 2) Now either use the toolbar button [[Image:FEM_EquationMagnetodynamic2D.svg|24px]] or the menu.
 * 3) Change the equation's solver settings or the general solver settings if necessary.

Solver Settings
For the general solver settings, see the Elmer solver settings.

The magnetodynamic 2D equation provides these special settings:
 * : The harmonic actuation frequency. It only used if is set to true.
 * : Calculates the current density.
 * : Calculates the Electric vector field.
 * : Calculates the electromagnetic fields for every mesh element. This is useful to see discontinuities in meshes. Note: at the moment FreeCAD cannot display these results properly. Therefore it is at the moment of no practical use.
 * : Calculates the linear and quadratic harmonic power loss. See the Elmer models manual, section Loss Estimation Using the Fourier Series for details
 * : Calculates the Joule heating.
 * : Calculates the Magnetic field strength.
 * : Calculates the Maxwell stress tensor field.
 * : Calculates the fields for every mesh node. The default is true. If no other is set to true, it only calculates the magnetic flux density.
 * : Calculates the forces for every mesh node. The results can be used for further mechanical analysis.
 * : Calculates the Joule heating scalar field for every mesh node.
 * : If the driving force is harmonically actuated (AC current). If set to true, must have a value > 0.

Constraint Information
The magnetodynamic 2D equation takes the following constraints into account if they are set:


 * [[Image:FEM_ConstraintElectrostaticPotential.svg|24px]] Electrostatic potential constraint
 * [[Image:FEM_ConstraintCurrentDensity.svg|24px]] Current density constraint
 * [[Image:FEM_ConstraintMagnetization.svg|24px]] Magnetization constraint
 * [[Image:FEM_ConstantVacuumPermittivity.svg|24px]] Constant vacuum permittivity

Results
The available results depend on the solver settings. If none of the settings was set to true, only the electric electric potential  (called av in the results) is calculated. Otherwise also the corresponding results will be available.

The possible results are:
 * Current density in $$\rm A/m^2$$
 * Electric field vector values in $$\rm V/m$$
 * Harmonic power loss in $$\rm W$$
 * Magnetic flux density in $$\rm T$$
 * Maxwell stress tensor values in $$\rm As/m^3$$
 * Magnetic field strength in $$ \rm A/m$$
 * Nodal force in $$\rm N$$
 * Joule heating in $$\rm J$$
 * Potential in $$\rm V$$