Mathematics of insulation-aging calculations

Equations are developed for the calculation of insulation aging in apparatus, in which it is recognized that the temperature of the apparatus usually changes in accordance with an exponential relation. The results from this method are compared with the simplification usually made of assuming rectangular temperature cycles and also with the assumption of a triangular temperature cycle. Insulation aging rate is based on the use of the Arrhenius chemical reaction rate theory, which relates insulation deterioration to the reciprocal of the absolute temperature. All aging values are in terms of relative aging, which assigns a value of unit aging to a specified temperature. To establish the errors involved in the simplifying assumptions conventionally used in aging computations, the calculations in this paper are carried out to more significant figures than basic aging data and time constants would justify.