17.2 Internal Current Source

17.2 Internal Current Source#

Use this source to define internal currents in the finite-element mesh. ELMCUR specifies an internal current for each finite element.

Settings#

ELMCUR(17.2) JSON key: internal-current source object

SERIES_ID(17.2) Series ID.

OPTION(17.2) Option specifying how the current is assigned.

IN_ROTOR(17.2) Flag indicating whether the defined region is in the rotor.

MAT_ID(17.2) Material ID assigned to the region.

IN_SURFACE(17.2) Number of the element face through which current enters

OUT_SURFACE(17.2) Number of the element face through which current exits

CURRENT(17.2) Normalized current value.

SIGMA(17.2) Element conductivity

CAL_Je(17.2) 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, 5

Text format#
* ELMCUR * SERIES_NO * NO_MAT_IDS * OPTION *
ELMCUR       I          I            I
* MAT_ID * IN_SURFACE * OUT_SURFACE * CURENT * SIGMA *
    I         I        I               E     E

JSON format#

JSON format from 2024.11#
"17_Field_Source" :
[
    {
        "ELMCUR" :
        {
            "SERIES_ID" : I,
            "OPTION" : I,
            "IN_ROTOR" : I,
            "data" :
            [
                {
                    "MAT_ID" : I,
                    "IN_SURFACE" : I,
                    "OUT_SURFACE" : I,
                    "CURRENT" : E,
                    "SIGMA" : E,
                    "CAL_Je" : I
                }
            ]
        }
    }
]

Detailed description#

ELMCUR defines internal currents in finite elements. Therefore, all elements in the region assigned to ELMCUR should preferably have the same size. Because the current inlet and outlet are specified by element face numbers, the element orientations in the ELMCUR region must be consistent.

Hint

Because it is difficult to create a finite-element mesh satisfying the above conditions for three-dimensional analysis, use in two-dimensional analysis is recommended.

ELMCUR#

ELMCUR(17.2)#
Text-format section
Fixed parameter set 1#
[row, col] = [1, 1]
Type:

String (S)

Description:

Specifies the internal-current source ELMCUR.

SERIES_ID#

SERIES_ID(17.2)#
Text-format section
Fixed parameter set 1#
[row, col] = [1, 2]
Type:

Integer (I)

Description:

Source-term identifier.

Text-format section
NO_MAT_IDS(17.2)#

NO_MAT_IDS

Fixed parameter set 1#
[row, col] = [1, 3]
Type=I

Number of material IDs for elements to which element current is assigned.

OPTION#

OPTION(17.2)#
Text-format section
Fixed parameter set 1#
[row, col] = [1, 4]
Option specifying how the current is assigned#

Value

Description

0

Specify the current passing through an element face (\(A\)). Default value

1

Specify the current density (\(A/m^2\)).

IN_ROTOR#

IN_ROTOR(17.2)#
Text-format section
Fixed parameter set 1#
[row, col] = [1, 5]
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(17.2)#
JSON key:

Internal-current source data

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

MAT_ID#

MAT_ID(17.2)#
Text-format section
Fixed parameter set 1#
[row, col] = [2, 1]
Type:

Integer (I)

Description:

Material ID of the elements to which element current is assigned ( MAT_ID(16.1) ).

IN_SURFACE#

IN_SURFACE(17.2)#
Text-format section
Fixed parameter set 1#
[row, col] = [2, 2]
Type:

Integer (I)

Description:

Number of the element face through which current enters.

OUT_SURFACE#

OUT_SURFACE(17.2)#
Text-format section
Fixed parameter set 1#
[row, col] = [2, 3]
Type:

Integer (I)

Description:

Number of the element face through which current exits.

CURRENT#

CURRENT(17.2)#
Text-format section
Fixed parameter set 1#
[row, col] = [2, 4]
Normalized current value#

Value

Description

0

Current passing through one element face (\(A\)). Default value

1

Current density (\(A/m^2\))

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

SIGMA#

SIGMA(17.2)#
Text-format section
Fixed parameter set 1#
[row, col] = [2, 5]
Type:

Real (E)

Unit:

\(S/m\)

Description:

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

CAL_Je#

CAL_Je(17.2)#
Text-format section
Fixed parameter set 1#
[row, col] = [2, 6]
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

  • Available for hexahedral and triangular-prism elements. The elements must be in the total-potential region.

Yes.

  • Elements with different values of IN_SURFACE(17.2), OUT_SURFACE(17.2), or CURRENT(17.2) must be assigned different MAT_ID(16.1) values in the input mesh data file. For these material definitions, set SIGMA(16.1) = 0 and MU(16.1) = 1.0.

  • Connection to the power source of CIRCUIT(17.8) or NETWORK(17.9) is required.

Hint

  • Reversing IN_SURFACE(17.2) and OUT_SURFACE(17.2) reverses the current direction.

  • In a two-dimensional calculation, set IN_SURFACE(17.2) = 1 and OUT_SURFACE(17.2) = 2 to assign current in the z ( \(\theta\) ) direction.

  • When OPTION(17.2) = 1, the current passing through the inlet face is calculated internally. For coils whose cross-sectional area changes, OPTION(17.2) = 0 is recommended.

  • Element face numbers are defined as shown in the following figure.

../../_images/elmcur.png

Definition of ELMCUR element face numbers#

The bottom face is ① and the top face is ②; faces ③④⑤⑥ are defined in the direction of a right-handed screw advancing from the bottom to the top.