Application note
AN0006Switching Cycle Performance
What actually drives contact wear: inrush current, power factor, and the loads that shorten cycle life.
Summary
The electrical switching life of high-voltage contactors and relays depends on several interacting parameters, including voltage, current, load characteristics, circuit inductance, and environmental conditions, all of which stress the contact system during each make and break event. Because these factors vary so much between applications, switching cycle performance cannot always be predicted from datasheet values alone. This application note explains the primary factors that drive contact wear, such as inrush current, power factor, and the difficulty of closing into capacitive loads or breaking inductive loads. It also provides guidance for interpreting lifecycle data and validating contactor performance under real-world conditions.
