summary

EMSolution has conventionally provided the CUR_FLUX option as a function for outputting the amount of current passing through an arbitrary cross section. However, no examples were available so far. The following is an introduction of the CUR_FLUX option using a model of "DC current field analysis of bulk conductors". This option can also be used in AC steady-state and transient analyses.

Explanation

The function of the CUR_FLUX option is explained using the models shown in Fig. 1(a) and (b), which simulate a conductor with two branches. Fig. 1(a) shows the same half model as in the "DC current field analysis of bulk conductors" and (b) shows the full model with a mirror copy of the mesh in the Y direction. The analytical conditions for both models are the same as in the "DC current field analysis of bulk conductors", and the geometry of the two branches is the same, but the conductivity of one side is halved. This is equivalent to doubling the resistance. The analysis is performed by applying a DC current of 90 A to the underside of the branch as the input current. Calculating the amount of current passing through the branch using the "Surfaces for current flux computation(11.3)" function, we can confirm that the current passes through at a ratio of approximately 1:2 (Table 1). Naturally, the amount of current passing through the Half model and the Full model are identical.

(a) Half model

(b) Full model

Fig.1 Bifurcated conductor model (excluding air region)

Table 1 Amount of Pass Through Current

This is a brief introduction to the function for outputting the amount of current passing through an arbitrary cross section. We hope you will use this function to output the amount of current passing through, for example, in a bulk conductor analysis or rotor bars and end rings of a three-dimensional induction machine analysis.

How to use

Use CUR_FLUX in "11. Printed Output". Use the surface element for output of the amount of current passing through.

The following items must be set

• NO_SURFACES : Number of surface element properties that output the amount of passing current
• MAT_ID_NOS : Property number of the face element
  • The face element must match the face of the conductor volume element.
  • The orientation of the face element (right-hand thread direction) is outward with respect to the volume element. Negative property numbers reverse the orientation of the face element (useful for two-dimensional analysis).

* Q_AVERAGE * HEAT * MAG_FLUX * CUR_FLUX * 0 0 0 1 * FORCE_J_B * FORCE_NODAL * MAGNETIC_ENERGY * IRON_LOSS * 0 0 0 0 * NO_SURFACES * 2 * MAT_ID_NOS * 12 13

The calculation results are output to an output file.

************************************************* * Current fluxes Thhrough surfaces * ************************************************* Surface Mat id Current flux (A) 12 : 3.06607e+01 13 : 5.93393e+01

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Analysis Model

・ inputAC3D_DCCURR.ems : Input condition file
・ pre_geom2D.neu : Mesh file
・ 2D_to_3D : 2D mesh stacking file