Two models of a reluctance actuator of different modelling depth and their comparison and usage
Components to be used in examples
Pull-in stroke of both solenoid models after a voltage step at time t=0
Slow forced armature motion of both solenoid models so that electromagnetic field and current are quasi-stationary
In electromagnetic or reluctance actuators, a thrust or reluctance force is generated due to a non-zero gradient of the relative magnetic permeability mu_r at surfaces between regions of different permeability (non-saturated ferromagnetic material: mu_r>>1, adjacent air: mu_r=1). In lumped magnetic network models, this force can be calculated as shortly outlined in Reluctance Forces of the User's Guide.
As an example of a reluctance actuator, a simple axisymmetric lifting magnet with planar end planes of armature and pole is shown. Often, a SimpleSolenoid model is sufficient for initial rough design of such an actuator's magnetic subsystem. Higher accuracy can be gained from an AdvancedSolenoid model where the coil-imposed magnetomotive force is split and the leakage flux between armature and yoke is accounted for more precisely.
The differences between these two models in static behaviour can be analysed and compared to results obtained with a more accurate finite element analysis (FEA) in ComparisonQuasiStationary. The resulting differences in dynamic behaviour can be analysed and compared to FEA results with simulation of a pull-in stroke in ComparisonPullInStroke.