17.4 Potential Current Source

Defines a current source for driving current through a coil region in the finite-element mesh.

PHICOIL defines current-inlet faces on the end faces of a coil region and uses the current-density distribution obtained from a steady-current analysis of the coil region.

PHICOIL defines a current source for driving current through a single conductor region.

Settings

PHICOIL(17.4) JSON key: potential current source object

SERIES_ID(17.4) Series ID.

IN_ROTOR(17.4) Flag indicating whether the defined region is in the rotor.

MAT_IDS(17.4) Material IDs assigned to the region.

SMAT_ID(17.4) Material ID of the face surrounding the conductor.

CURRENT(17.4) Normalized current value.

SIGMA(17.4) Element conductivity

CAL_Je(17.4) Flag indicating whether eddy currents in the defined region are considered

Input format

Text-format section

Type:

Fixed parameter set 1

Number of lines:

2

Number of parameters:

4, 4

Text format

* PHICOIL * SERIES_NO * NO_PARTS * OPTION *
PHICOIL       I          I            I
* MAT_ID * SMAT_ID * CURENT * SIGMA *
    I       I       E        E

JSON format

JSON format from 2024.11

"17_Field_Source" :
[
    {
        "PHICOIL" :
        {
            "SERIES_ID" : I,
            "IN_ROTOR" : I,
            "data" :
            [
                {
                    "MAT_IDS" : [ I ],
                    "SMAT_ID" : I,
                    "CURRENT" : E,
                    "SIGMA" : E,
                    "CAL_Je" : I
                }
            ]
        }
    }
]

Detailed description

PHICOIL defines current-inlet faces on the end faces of a coil region and uses the current-density distribution obtained from a steady-current analysis of the coil region.

Hint

In two-dimensional analysis, using PHICOIL is equivalent to assigning a uniform current density.

In two-dimensional axisymmetric analysis, using PHICOIL produces a current-density distribution concentrated toward the inside of the coil.

In three-dimensional analysis, using it for a coil region produces a current-density distribution concentrated toward the inside of a curved coil region.

PHICOIL

PHICOIL(17.4)

Text-format section

Fixed parameter set 1

[row, col] = [1, 1]
Type=S

Type:

String (S)

Description:

Specifies the potential current source PHICOIL.

SERIES_ID

SERIES_ID(17.4)

Text-format section

Fixed parameter set 1

[row, col] = [1, 2]

Type:

Integer (I)

Description:

Source-term identifier.

Text-format section

NO_PARTS (text format only)

Fixed parameter set 1

[row, col] = [1, 3]
Type=I

Number of properties assigned to the region. Each PHICOIL specified by NO_PARTS must have an independent conductor region and current-inlet face.

IN_ROTOR

IN_ROTOR(17.4)

Text-format section

Fixed parameter set 1

[row, col] = [1, 4]

Flag indicating whether the defined region is in the rotor

Value	Description
0	In the fixed part. Default value
1	In the moving part.

Required for steady AC analysis with slip caused by sliding motion when N_CORRECT(8) ≠ 0.

data

data(17.4)

JSON key:

Potential current source data

data is an array with one entry for each PHICOIL element.

MAT_IDS

MAT_IDS(17.4)

Text-format section

Fixed parameter set 1

[row, col] = [2, 1]

Type:

Integer array (I)

Description:

Material IDs of the elements to which the surface-defined current is assigned ( MAT_ID(16.1) ).

Note

The text format accepts only one material ID, whereas the JSON format accepts multiple material IDs as an array. They are nevertheless treated as the same material property.

When multiple conductor regions are defined as one PHICOIL, use JSON format and specify the material IDs as an array.

SMAT_ID

SMAT_ID(17.4)

Text-format section

Fixed parameter set 1

[row, col] = [2, 2]

Type:

Integer (I)

Description:

Material ID of the surface elements forming the inlet face. The face orientation is arbitrary.

CURRENT

CURRENT(17.4)

Text-format section

Fixed parameter set 1

[row, col] = [2, 3]

Type:

Real (E)

Unit:

A

Description:

Normalized current passing through the face.

For a wound coil, it may be easier to understand this value as the number of turns.

SIGMA

SIGMA(17.4)

Text-format section

Fixed parameter set 1

[row, col] = [2, 4]

Type:

Real (E)

Unit:

\(S/m\)

Description:

Electrical conductivity of the element. The series resistance is calculated.

CAL_Je

CAL_Je(17.4)

Text-format section

Fixed parameter set 1

[row, col] = [3, 1]

Flag indicating whether eddy currents in the defined region are considered

Value	Description
0	Do not consider eddy currents in the defined region Default value
1	Considers eddy currents in the defined region. The conductivity specified by SIGMA(16.1) is used.

Caution

• Define the current-inlet face on a Bn=0 face or a periodic-symmetry face of the analysis region.

• For a curved coil, the current may become nonuniform. Uniformity can be improved by dividing the cross-section into several parts and defining each as a separate PART. In this case, the same SMAT_ID may be used for all parts.

• A coil connected through a periodic-symmetry face must be defined as one PART. In this case, specify only one inlet face.

• Induced current is not included.

Example definition of PHICOIL