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Main >> Applications >> Sample problems >> Iron sphere AC magnetic field shielding

Iron sphere AC magnetic field shielding

This is an example of the iron sphere shielding simulation performed with the QuickField software.

Problem Type: axisymmetric problem of AC magnetics.

Iron sphere shield model
D = 22 cm, t = 1 cm.

Relative magnetic permeability of steel μ = 100,
Conductivity of steel σ = 1'000'000 S/m,
External field B = 2.0 T, frequency f = 50 Hz... 100 kHz.

Determine the shielding factor at different frequencies.

LabelMover parametric tool is used to automate frequency sweep. LabelMover generates a set of QuickField problems (multiplying frequency by 2 at each step), simulates problems, calculates the magnetic flux density in the point of interest and place the results in the table.

Magnetic field strength distribtion at 50 Hz.
Magnetic field strength around the shield


Magnetic flux density
inside the spherical shield

50 Hz

267 mT (13%)

800 Hz

24 mT (1.2%)

6.4 kHz

3.3 mT (0.17%)

102.4 kHz

0.13 mT (0.007%)

  • Video:

    See more in QuickField for Electromagnetic Shielding Applications webinar.
  • View simulation report in PDF
  • Download simulation files (files may be viewed using any QuickField Edition).