In electromagnetic devices, a change of a coil's magnetic flux linkage Ψ reacts on the electrical subsystem in that a voltage v is induced due to Faraday's law:
v = - dΨ/dt
This reaction can possibly be neglected for
In these cases, the magnetic potential difference or magnetomotive force imposed by a coil can easily be modelled with a signal-controlled source. Except for the neglected dynamics, steady-state actuator forces will be calculated properly in actuator models based on these sources.