Summary

Here, the iron core used in the "Static magnetic field analysis using ELMCUR (element current source)"is replaced by a copper block, and an alternating current is applied to the coil to analyze the eddy currents in the block.

Explanation

The mesh files pre_geom2D.neu and 2D_to_3D can be the same as the previous one (ELMCUR model). Prepare the file input, place it in the same directory, and run the program. List.1 shows a part of the output file output. It shows the coil current, voltage, interlinkage flux, and the current and voltage seen from the power supply. The number of coil turns is 3,000. The coil impedance, including eddy currents, is obtained from the output voltage and is calculated as follows:

$$R+j\omega L = 70.5692 + j365.305 (\Omega)$$

と計算されます。

The heat generation of each phase and one-cycle average for material property is output. Fig. 1 and Fig. 2 show the coil current and eddy current distributions at phase 0 and -90 degrees (current file). Fig. 3 shows the time-averaged heating density (heat file).

Fig.1　Current density distribution (phase 0 degrees)

Fig.2　Current density distribution (phase-90 degrees)

Fig.3　Average heating density distribution

List.1

*************************************************************************************
*                       Step No.　 1　　　 Time -5.000e-003 sec                     *
*************************************************************************************

Phase angle -90 degrees (imaginary part)
***　 Sources　　 *******************************************************************
ID No.  Amplitude（Current）      Voltage             Flux
  1        6.12303e-017        3.65305e+002       -7.85071e-002

***　 Power Sources　　 *************************************************************
ID No.      Current         Voltage
  1       6.12303e-017    3.65305e+002                                          ← Impedance imaginary part

*** Total Joule heatin loss in regions　 **********************
MAT No.         Q （W）
   1         1.0474e+000
 Total       1.0474e+000

*************************************************************************************
*                       Step No.　 2　　　 Time 0.000e+000 sec                      *
*************************************************************************************

Phase angle 0 degrees (real part)
***　 Sources　　 *******************************************************************
ID No.  Amplitude（Current）      Voltage             Flux
  1        1.00000e+000        7.05692e+001        1.16280e+000

***　 Power Sources　　 *************************************************************
ID No.      Current         Voltage
  1       1.00000e+000    7.05692e+001                                          ← impedance real part

*** Total Joule heatin loss in regions　 ********************************************
MAT No.     Q （W）
   1     2.0355e+000
 Total   2.0355e+000

*** Total Joule heatin loss （ 1 cycle average ） in regions　***********************
MAT No.     Q （W）
   1     1.5415e+000                                                                ← Average total heat generation of copper region
 Total  1 .5415e+000     

How to use

To perform an AC analysis, assume AC = 1.

* STATIC * STEP * AC * TRANSIENT * DISPLACEMENT * NON_LINEAR * 0 0 1 0 0 0

Specify the frequency. Here, 50 Hz (= 0.02 second per cycle) is assumed.

* FREQUENCY * 50 （omitted） * TIME_ID * OPTION * 1 2 * AMPLITUDE * TCYCLE(s) * PHASE(deg) * 1.0 0.02 0.0

Download

・ input.ems ：Input condition file
・ pre_geom2D.neu ：Stator mesh file
・ 2D_to_3D ：2D mesh extension file