Magnetic circuits under steady-state conditions, i.e., with stationary magnetic fields (change of magnetic flux dΦ/dt = 0) can be described with constant sources of a magnetic potential difference or magnetomotive force (mmf). Constant magnetic potential differences are imposed by
For modelling of reluctance actuators with this source component it is assumed that the armature is fixed so that no motion-induced flux change dΦ/dt can occur.