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Coil Topology: Open Coil

An open coil is used when the electrical connections leave the simulation domain. This occurs, for example, when symmetry is applied or when solid coils have connectors that extend outside the modeled region.

In this topology, two ports must be defined:

  • Entry port
  • Exit port

For a positive current specification, the current flows from the entry port to the exit port, following the right-hand rule for the resulting magnetic field orientation.

Note that:

  • Entry and Exit ports must be part of the coil volume.
  • Degenerate ports (zero area or disconnected faces) are invalid.

When to use this

  • Symmetric machine sections. A motor or transformer sector model where the coil is cut by a symmetry plane — the cut faces become the inlet / outlet ports.
  • Bus-bars and solid conductors with terminals on the outer surface of the air box.
  • Half- and quarter-models of any winding where the conductor leaves the simulation domain through a meshed face.

Examples

A solid coil, named Coil, with connectors extending to the outer simulation domain. The entry port named Coil::InputPort is marked in blue and the exit port named Coil::OutputPort in red.

Open coil with entry and exit ports
Figure 1: Solid coil with conductors extending outside the simulation domain. Blue face: entry port. Red face: exit port.


An open coil topology can then be defined as:

coil_topology = CoilTopologyOpen(
    "Coil::InputPort" @ Bnd,
    "Coil::OutputPort" @ Bnd,
)