A Study of the Erosion Characteristics of Three-Phase AC Contactors

A method is presented for evaluating the relation between contact erosion loss and the make--break operation in three-phase ac contactors. Because of the spread of weight loss among the 12 contacts in one contactor, consideration of the following conditions is suggested for material comparison: l) the total weight loss of the 12 contacts; 2) the trend of the total weight loss versus the progress of the makebreak operations; 3) the ratio of total erosion losses among the three phases; 4) the contactor life. The erosion is found to progress at a slightly accelerated rate rather than a constant rate. Different failure modes exist between materials made from different processes