THE INFLUENCE OF TWO MAIN DOPANTS ON THE ELECTRICAL PROPERTIES OF A FIVE OXIDES VARISTOR MATERIAL.

Metal Oxide Varistors are today used for manufacturing state of the art overvoltage protection equipment, at any voltage level, being one of the most common power electronic devices existing on the market. They are widely used because they have a very high non-linear dependence between the applied voltage and the resulting current, and a relatively high energy absorption capability in case of normal overvoltage shocks or even in case of permanent overvoltages. Researches could be carried out both for finding a new material as well as for technical solutions concerning a new design of this piece of equipment, by studying heat extraction and heat transfer inside a new complex varistor device. This paper presents is related to the first approach and presents a newly made material with a new concentration of initial dopants, a Metal Oxide Varistor based on a new mix of five additional dopant oxides, instead of classic two ones. The two main oxides taken in consideration are the one used in a basic two oxides material, the Cr2O3 and the MnO2. The influence of different dopant concentrations on the electrical behavior (non-linearity coefficient, opening voltage and leaking current) will be detailed in this paper. It will present also the measurement procedure and conclusions related to this issue. [ABSTRACT FROM AUTHOR]