Coil Index¶

Scalar field that labels each cell with the zero-based index of the CoilSpecification it belongs to, in the order the specifications were added to the ExcitationCoilModel. It complements Coil Group: Coil Index tells which coil a cell belongs to, Coil Group tells which body of that coil.

Registered name: "Coil Index".

Per-cell value:

Cell location	Value
Inside the `i`-th `CoilSpecification`	non-negative integer \(i = 0, 1, \dots\)
Outside every coil	NaN

The NaN outside-coil value renders as the configured NaN colour in ParaView, so coil cells stand out visually against the rest of the mesh without needing a threshold filter.

The same index is used as the coil_index argument of all coil reports (current, voltage, resistance, back-EMF, flux linkage), so this coefficient is a convenient way to confirm which integer addresses which physical winding.

Example: IPM-motor stator¶

Figure 1: Coil Index on the 24-slot stator of the IEEJ IPM benchmark. Three CoilSpecifications — one per phase — are added in the order U, V, W and receive indices 0, 1, 2. All eight conductor bodies of phase U share the same colour, and likewise for V and W. The surrounding air domain is rendered in ParaView's NaN colour (green here).

Combine Coil Index and Coil Group to distinguish every individual sub-coil at a glance: the index identifies the phase, the group identifies the sub-coil within that phase.