Explosion protected heating system for heating an enclosure with two temperature control algorithms

摘要

An electric heating system is disclosed for the heating of the interior of an instrument cabinet which includes a radiator having a receiving cavity with a heating element and a melting fuse connected in series as an excess-temperature fuse encapsulated in the receiving cavity. The heating element and the excess-temperature fuse are connected to a temperature control. An environmental-temperature sensor and a fuse-temperature sensor are encapsulated in the receiving cavity near the melting fuse connected to the temperature control. The current fuse temperature of the excess-temperature fuse is determined by the fuse-temperature sensor. The temperature control operates in a first control algorithm within a fuse temperature range below a preset changeover temperature. The temperature control switches over to a second control algorithm when the changeover temperature has been reached or exceeded and lowers the heating performance of the heating element for the protection of the excess-temperature fuse.