Abstract: Temperature is sensed in equipment where life is reduced by overtemperature. The sensed temperature is compared to a set point and an output indication showing overtemperature operation is provided to the equipment operator. In addition, a signal is produced which is proportional to the sensed temperature above a reference or threshold value. This signal is passed through a coulomb meter which indicates the total charge. This charge is an integration of the product of the time of duration and the amount of overtemperature, for indicating the accumulated thermal stesses.