Home / Examples / Magnetic Analysis (Gauss, Static Analysis/Harmonic analysis) / Example 7: Force between Magnet and Electromagnet

Example 7: Force between Magnet and Electromagnet

General

• In this example, a magnet is placed near the electromagnet used in the example 6.
   

• The electromagnetic force, the current density, and the vectors of magnetic field and the magnetic flux density are solved.
   

• This example can be solved by axisymmetric analysis as well. See Example 25.
  The number of meshes is much less with axisymmetric models, so the simulation time is shorter.
   

• Unless specified in the list below, the default conditions will be applied.
   

• Obtain this session's project file. (Right-click and choose 'Save link as')




• Results will vary depending on Femtet version and the PC environment.

 

Analysis Space

Item	Settings
Analysis Space	3D
Model Unit	mm

Analysis Conditions

Item	Settings
Solver	Magnetic Analysis [Gauss]
Analysis Type	Static Analysis
Options	N/A

 

 

Model

A cylindrical magnet is placed on top of the magnetic core of the electromagnet used in the example 6.

 

Mesh size is set at 1[mm] as the magnetic field changes drastically between the magnets.

 

• Set the gap between the bodies and mesh size properly to obtain valid calculation results.
  See [Calculation of the Electromagnetic Force] for more details.

 

Body Attributes and Materials

Body Number/Type	Body Attribute Name	Material Name
0/Solid	Core	Core
4/Solid	Coil	008_Cu *
3/Solid	Mag	Mag

* Available from the material DB

 

The material properties are set up as follows:

Material Name	Tab	Properties
Mag	Permeability	Material Type: Permanent Magnet
	Magnet	Magnetization Strength: 0.5
Core	Permeability	Relative Permeability 5×103

 

Body attribute is set up as follows to apply current to the loop coil.

Body Attribute Name	Tab	Settings
Coil	Current	Waveform: Constant Current: 1 [A] Turns: 100 [Turns] Direction: Loop Coil/Magnetic Field Direction Specified Magnetic Field Vector: X=0, Y=0, Z=1

Boundary Conditions

No setting.

Results

To see the electromagnetic force, go to the [Results] tab

 

 

 and click [Show Numerical Summary Table] .

 

 

Two magnets are pulling each other with the approximate force of 1.2 [N] in the Z direction.

 

 

Shown below are the vectors of the current density flowing through the loop coil.

 

The vectors of the magnetic field are shown below.

 

 

The vectors of the magnetic flux density are shown below.