Analysis of electromagnetic systems accounting for coupled magnetic and electric circuit behaviour

A complete mathematical model for an electromagnetic system should account for magnetic, electric, mechanical and thermal aspects. Physically these aspects are more or less coupled due to the interdependence of the operative phenomena. A coupled model can treat the problem in several steps (indirect or weak coupling) or by solving the equations simultaneously (direct or strong coupling). The choice of type of coupling depends mainly on the degree of nonlinearities and the relative values of time constants governing the coupled phenomena. Calculated voltage or current waveforms are applications: presented for an E, R, C, iron core coil circuit, a chopper feeding an iron core coil, a current transformer, and an electromagnetic relay