Energy absorption capability of low voltage Metal Oxide Varistors in AC and impulse currents

Metal Oxide Varistors (MOVs) are widely used surge protective components in electronics, and their reliability is important in reliability of the whole system. In this paper, Energy Absorption Capability (EAC) of low voltage MOVs is characterized and measured by experimental tests in a UL-certified lab. It is demonstrated that EAC curve for the low voltage MOV is different than that of high voltage station class MOV. Failure modes of MOVs are identified and presented. Furthermore, causes and consequences of different behavior are discussed.