Metal oxide varistors

Mov varistor valve main ingredient is zinc oxide, zinc oxide varistor has a very excellent nonlinear characteristics. Under normal operating voltage of the resistance value is very high, in fact, the equivalent of an insulator, and in the over-voltage is applied, the resistance of the resistive sheet is small, residual pressure is very low. But under normal operating voltage, since the valve sheet to withstand long-term effect of power frequency voltage generated by the degradation caused by changes in resistance characteristics, resulting in increased flow through the valve leakage current. The resistive component of the current sharp increase in temperature will rise valves on thermal crashes, serious, mov metal oxide varistor or even cause explosion arrester. In accordance with the provisions of rules 1, MOA total of six test items, namely (1) Composite arrester Insulation resistance (2) Leakage Current DC U1mA and 0.75U1mA under (3) AC operating voltage under leakage current (4) Power frequency Power frequency reference voltage (5) Base insulation resistance (6) Check discharge counter action case reference current.