Electromechanical Modeling of a Contactor with AC Coil

Two ways of modeling a contactor with an AC coil are shown in this article. Both models are based on the explicit definition of the inductances by lumped parameters, and the difference between them is the considering or not of the effect of the shading rings. The equations were formulated to obtain the contact operation time and to describe the contactor coil current when the coil is fed with different values of the AC source voltage. The comparison between theoretical and experimental results shows that the models are satisfactory in both cases. This demonstrates the possibility of obtaining accuracy without considering the shading rings. The main advantage of the inclusion of the effect of the shading rings is the obtaining of a qualitative description for the currents in the shaded rings.