Effect of material and design parameters on the life and operating voltage of a ZnO varistor

Abstract

A varistor's life has been defined as the time required to reach a limiting power density at which the power generated exceeds the power dissipated. Based on this concept, a working model for predicting the life of a ZnO varistor has been developed in terms of several critical material and design parameters. The model provides a direction as to whether these parameters should be maximized or minimized in order to enhance a varistor's life. Alternately, given a predetermined amount of the varistor's life, the model predicts a safe operating voltage under a given set of conditions.