3.8. Example 2D Harmonic Magnetic Analyses

3.8.1. Example: Harmonic Magnetic Analysis

Description

This example calculates the current that results from an AC voltage being applied to a thick stranded coil in free space. Scalar parameters for this analysis are:

  • n = 500 (coil turns)

  • r = 3*s/2 meters (the mean radius of the coil)

  • S = .02 (meters; the coil winding width and depth).

 

The following command listing demonstrates how to solve this problem using the current-technology element PLANE233. The electromagnetic elements represent the voltage forced coil and air. INFIN110 elements represent the far-field.


Note:  The example analysis presented here is only one of many possible harmonic magnetic analyses. Not all such analyses follow exactly the same steps or perform those steps in the same sequence. The properties of the material or materials being analyzed and the conditions surrounding those materials determine which steps a specific analysis needs to include.


3.8.1.1. Command Input Stream Using PLANE233

Below is the command input stream using current-technology element PLANE233. All text preceded by an exclamation point (!) is a comment.

/prep7
/title, Voltage-fed thick stranded coil in free space
/com,   Calculate the current in the coil from an applied AC voltage   
/com,
/nopr
et,1,233,,,1         ! air
et,2,233,2,,1        ! stranded coil
et,3,110,,,1         ! far-field
mp,murx,1,1
mp,murx,2,1

! *** Coil parameters
s=.02                ! coil winding depth and width
n=500                ! number of turns
r=3*s/2              ! mean radius
rho=3e-8             ! resistivity

! *** Derived coil parameters
Sc=s**2                ! coil cros-sectional area
Vc=2*acos(-1)*r*Sc     ! coil volume
Rcoil=rho*(n/Sc)**2*Vc ! coil resistance

rectng,s,2*s,0,s/2
pcirc,0,6*s,0,90
pcirc,0,12*s,0,90
aovlap,all
asel,s,area,,1
aatt,2,1,2
asum

asel,s,area,,4
aatt,1,1,3
asel,all
csys,1
lsel,s,loc,x,9*s
lesize,all,,,1  
esize,,8
mshape,0,2d          ! mapped mesh with quads
mshkey,1
amesh,1,4,3          ! mesh far-field and coil   
smrtsize,2
esize,s/4
mshape,1,2d          ! specify triangle elements
mshkey,0             ! free mesh
amesh,5              ! mesh air region

r,1,,Sc,n,r,1,Rcoil  ! coil constants
rmore,2              ! symmetry factor

n1=node(s,0,0)       ! get a node on the coil
esel,s,mat,,2        ! get coil elements
nsle,s
cp,1,volt,all        ! couple VOLT dof in coil
cp,2,emf,all         ! couple EMF dof in coil
allsel,all
csys,1
nsel,s,loc,x,12*s
sf,all,inf           ! set infinite surface flag
csys,0
nsel,s,loc,x,0
d,all,az,0           ! flux-parallel condition
allsel,all
finish

/solu
antype,harm
d,n1,volt,12
harfrq,60            ! 60 Hz.
solve
finish

/post1
set,1
plf2d                        ! Plot real flux lines
*get,ireal,node,n1,rf,amps
set,1,1,,1
plf2d                        ! Plot imaginary flux lines
*get,imag,node,n1,rf,amps
*status                      ! Imaginary and real components of current 
finish

3.8.2. Other Examples

Another Ansys, Inc. publication, the Mechanical APDL Verification Manual, contains other examples of 2D harmonic magnetic analysis:

VM166 - Long Cylinder in a Sinusoidal Magnetic Field
VM185 - AC Analysis of a Slot Embedded Conductor