Single-Turn Coil
The Single-Turn Coil node is available both as a domain and as a boundary feature. It models a conductive (for example, metallic) domain or boundary subject to a lumped excitation, such as a total voltage or current. The excitation specified is translated into a conduction current flowing in the domain (as a current density) or the boundary (as a surface current density). The Single-Turn Coil domain node is a contributing feature, it is applied on top of an Ampère’s Law feature that provides the material model (electrical conductivity and relative permittivity). The boundary node is instead exclusive, since the material model is provided in its Thin Layer section.
In 2D and 2D axisymmetric components, the Single-Turn Coil feature can be turned into a Coil group by selecting the corresponding check box in the Settings window.
The Single-Turn Coil feature is obsolete in the Magnetic Field and Rotating Machinery, Magnetic features and will be removed in future versions. The recommended alternative is to use a Coil feature with the Conductor model set to Single conductor.
See Coil Features in the modeling section to learn more about using this node.
This node is not available in 3D for The Magnetic and Electric Fields Interface and The Induction Heating Interface. In 2D and 2D axisymmetric components, the direction of the applied electric field is assumed to be out-of-plane. The settings specify how to compute the electric field and the relative current density.
The approach for 3D components is different than for 2D and 2D axisymmetric components. An additional dependent variable Vcoil, with the dimension of an electric potential, is defined in the domain and the current continuity equation is added to the system of equations. The problem solved in the domain becomes effectively an A-V formulation of Maxwell’s equation and current conservation, similar to the one used in the Magnetic and Electric Fields interface.
For 3D components add boundary conditions for the coil potential. The Gap Feed (at the domain level only), Boundary Feed, Ground, and Floating Potential subnodes are available from the context menu (right-click the parent node) or from the Physics toolbar, Attributes menu. Use these to define the geometry of the coil.
A typical setup is to add a Gap Feed, if the coil is closed in a loop, or a Boundary Feed and a Ground, if the coil is open. In order to avoid unphysical current distribution in the Boundary Feed and Ground case, the boundary conditions should be applied on external boundaries. The Gap Feed subnode is not available for the boundary node for topological reasons.
The 3D Single-Turn Coil is applicable only in Stationary and Frequency Domain studies, since it is a local application of the physical model used in the Magnetic and Electric Fields interface.
Thin Layer (2D and 2D Axisymmetric components)
This section is available for 2D and 2D axisymmetric components at the boundary level. Specify here the properties of the material constituting the thin conductive layer.
Select a Coil conductivity σcoil (SI unit: S/m) — From material (the default) or User defined. For User defined select Isotropic, Diagonal, Symmetric, or Anisotropic based on the characteristics of the coil conductivity, and then enter values or expressions in the field or matrix. The default is 1 S/m.
Select a Coil relative permittivity εr,coil (dimensionless) — From material (the default) or User defined. For User defined select Isotropic, Diagonal, Symmetric, or Anisotropic based on the characteristics of the coil relative permittivity, and then enter values or expressions in the field or matrix. The default is 1.
Enter the Thickness ds (SI unit: m) of the thin conductive layer. The default is 1 mm.
Single-Turn Coil
3D Components
For 3D components, the parameters Coil conductivity and Coil relative permittivity define the material model to be used with the current continuity equation. Normally, these parameters should be the same used in the Ampère’s Law feature active in the domain.
Select a Coil conductivity σcoil (SI unit: S/m) — From material or User defined. For User defined select Isotropic, Diagonal, Symmetric, or Anisotropic based on the characteristics of the coil conductivity, and then enter values or expressions in the field or matrix.
Select a Coil relative permittivity εr,coil (dimensionless) — From material or User defined. For User defined select Isotropic, Diagonal, Symmetric, or Anisotropic based on the characteristics of the coil relative permittivity, and then enter values or expressions in the field or matrix.
When defining this node on a boundary, also enter a Thickness ds (SI unit: m). The default is 1 mm.
2D and 2D Axisymmetric Components
In 2D and 2D axisymmetric components, the direction of the applied electric field is assumed to be out-of-plane. In these space dimensions, the Coil group check box is available. Select the check box to activate the Coil group functionality.
The settings specifying coil name and excitation are the similar to the ones for the Coil node. See the section Coil for a description of these settings.