Explosion protected heating system for heating an enclosure

An electric, explosion-protected heating system for the heating of a interior space in of an instrument cabinet and the like, said heating system being of the type which includes a radiator having a receiving cavity, a heating element and an excess-temperature fuse having a triggering/melt temperature connected in series with said heating element, the heating element and the excess-temperature fuse being disposed in the receiving cavity and encapsulated therein, the heating element and the fuse being connected via electric connection lines to a temperature control, and an environmental-temperature sensor connected as an indicator of actual temperature to the temperature control;

• wherein said heating system is characterized by:
• a fuse-temperature sensor disposed near said excess-temperature fuse for measuring a current fuse temperature, said fuse-temperature sensor being connected to the temperature control;
• a changeover temperature being set in said temperature control which is safely below a triggering temperature of said excess-temperature fuse at which said fuse melts;
• said temperature control comparing said fuse temperature to said changeover temperature;
• and
• said temperature control having a first control algorithm controlling the heating element to operate in a first temperature range when said fuse temperature is below said set changeover temperature, and said temperature control having a second control algorithm controlling the heating element to operate in a second temperature range when said fuse temperature reaches said changeover temperature to lower the heating performance of said heating element.