Coil Geometry
The Coil Geometry subnode of the Coil is available if the Conductor model of the parent feature is Homogenized multi-turn and the Coil type is Linear or Circular. This feature was previously called Reference Edge. This subnode is used to specify the direction of the tiny wires constituting the multi-turn coil.
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In Linear coils, the wires are all parallel and straight lines. Select an edge or a group of co-linear edges. The direction of the wires and the coil length is taken to be the direction and the length of the edges. To avoid unphysical currents, a Linear coil should be terminated on external boundaries.
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In Circular coils, the wires are wound in circles around the same axis. Select a group of edges forming a circle or a part of a circle around the coil’s axis. From the selected edges, the coil axis is computed, and the direction of the wires is taken to be the azimuthal direction around the axis. The coil length used is simply the length of the edges; the best approximation is obtained when the radius of the edges is close to the average radius of the coil.
Select the Use robust geometry analysis method check box to use an alternative algorithm for the computation of the coil axis and direction. This method works even in models without geometry (for example with an imported mesh), but requires that the selected edges form a complete circle.
Coil Geometry
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The direction of the coil is shown in the Graphics window with a red arrow. Select the Reverse direction check box to reverse the direction of the coil.
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The length of the coil is computed from the length of the selected edges. To manually specify the length, select the Override length of the edges check box, and enter the Total length of the edges Ledges (SI unit: m).
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In domain features, the average cross-section area of the domain is computed automatically from the domain volume and the length of the edges. The cross-section area is used, for example, to compute the coil current density. To manually specify a cross-section area, select the Override domain area check box, and enter the Average domain cross section area Adomain (SI unit: m2)
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If the model represents only a part of a geometry obtained from symmetry cuts (for example, a quarter of a circle), use the settings under Symmetry specification to specify appropriate correction factors. Enter the Coil length multiplication factor FL and Coil area multiplication factor FA (dimensionless integer numbers). The actual length of the coil, used to compute the coil voltage and resistance, is then computed as the product FL·Ledges. The cross-section area of the coil is computed as FA·Adomain.
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See Using Coils in 3D Models in the modeling section to learn more about this node.
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The Magnetic Fields Interface
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Theory for the Magnetic Fields Interface