SNOAA04A March 2020 – June 2021 FDC1004 , FDC1004-Q1 , FDC2112 , FDC2112-Q1 , FDC2114 , FDC2114-Q1 , FDC2212 , FDC2212-Q1 , FDC2214 , FDC2214-Q1 , LDC0851 , LDC1041 , LDC1051 , LDC1101 , LDC1312 , LDC1312-Q1 , LDC1314 , LDC1314-Q1 , LDC1612 , LDC1612-Q1 , LDC1614 , LDC1614-Q1 , LDC2112 , LDC2114 , LDC3114 , LDC3114-Q1

3 Using the Electromagnetic Problem Answer File

Open the .ans file
1. The .ans file will generate in the same directory as the .FEM file. Open the .ans file.
2. Note that if any changes are made to the .FEM file, solving the problem again will overwrite the .ans file.
3. The .ans file should show the magnetic field lines, which should bend around the target. The outer boundaries represent a gradient to infinity, so the magnetic field lines may contort in this region. Only the region contained by the innermost boundary line is of interest.
  Figure 3-1 Axisymmetric Answer File Showing the Contour Plot of the Magnetic Field Around the Coil and the Target

Change the contour plot options
1. Navigate to View → Contour Plot, or click on the Contour Plot button
2. In the Contour Plot Options, change the number of contour lines, as well as their upper and lower bounds, and click OK.
  Figure 3-2 Contour Plot Options Menu
Add various density plots
1. Navigate to View → Density Plot, or click on the Density Plot button
2. In the Dialog menu, check the Show Density Plot box.
3. Select the desired Plotted Value, generally |Flux Density| (T) or |Current Density| (MA/m²). Flux density is useful for determining optimal target placement, because we want the target in the area of highest flux density. Current density is useful for displaying eddy currents.
  Figure 3-3 Axisymmetric Answer File Showing Flux Density Plot
  Figure 3-4 Axisymmetric Answer File Showing Current Density Plot That Shows Eddy Currents on the Target
Change the mesh
The mesh is one of the most important aspects in generating an accurate answer file. Generally, it is best to choose a small mesh around the coils, the target, and the axis of symmetry (for axisymmetric problems).
1. To display the mesh, navigate to View → Show Mesh, or click the Show Mesh button
2. To change the mesh, return to the .FEM file.
3. To select the desired material, click the green materials button then right-click near the desired material node and press the space bar. The Properties for selected block menu should open.
4. Uncheck the Let Triangle choose Mesh Size box.
5. Enter a new Mesh size. A mesh size around 0.01 is a good starting point. Note that the problem must be solved again to reflect any changes.
View the inductance of the coil
1. Click the Inductor button at the top.
2. The Circuit Properties menu should open. The inductance will be listed as Flux/Current.
  Figure 3-5 Circuit Properties Menu