Cylindrical coaxial coils interaction force - QuickField simulation example
In the lab the forces are measured by electrotic balance on which one of the coils is installed. Tests are performed with currents varying, and different conductors and ferromagnetics are placed between coils.
How to find force between two coaxial cylindrical coils?
Answer Typical applications Geometry
Given
Task
Solution
Results
Engineering question
Set up an axisymmetric QuickField AC Magnetics problem for coaxial cylindrical coils and evaluate interaction force from computed field results.
coaxial solenoid coils, cylindrical windings, coaxial coil assemblies
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Simulation problem
Problem Type
Plane-parallel problem of DC magnetics, AC magnetics.
Due to symmetry of the formulation only upper half of the problem (above ab line) is defined, and at the axis of symmetry (line ab) the boundary conditions are set.
Current density in the coil j = 0.1 A/mm².
Relative magnetic permeability of the steel disc μ= 1000.
Electrical conductivity of steel disc σ= 10 MS/m.
Electrical conductivity of aluminum disc σ=37 MS/m.
Coils are wound by insulated wire, so cross-section conductivity in coils σ= 0 S/m.
Find the force between the coils carring current with and without the shield between them.
Along the horizontal symmetry axis (line ab) Bn =0.
Equation B=rot A in cylindrical coordinate system leads to A=const at the axis ab. The field fades at the infinity, so due to the condition of continuity of the potential A=0 at the line ab.
Field distribution around the coils:
Shield type
Frequency
Interaction force, mN
Problem name
No shield
50 Hz
0.533
lab2.pbm
Steel
50 Hz
0.098
lab2_Fe.pbm
Aluminum
50 Hz
0.282
lab2_Al.pbm
No shield
-
0.533
lab2c.pbm
Steel
-
0.138
lab2c_Fe.pbm
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