The impact of power system disturbances on AC-coil contactors

This paper is concerned with the impact of voltage sags on the performance of AC-coil contactors in industrial power systems. Sags have been commonly characterized in terms of magnitude and duration. However several experiments are presented which show that sag magnitude and duration are insufficient to characterize contactor performance. The results of these experiments show that contactor drop out and recovery depend on point on wave occurrence of the event as well as duration. The effect of the contactor shading rings on contactor transient performance is discussed.