The electrical resistance of a silicon carbide (SiC) heating element changes with temperature. Therefore, it is important to distinguish between cold resistance and hot resistance during selection, installation, and operation.
Cold resistance refers to the resistance measured at room temperature when the SiC heating element is not energized. It is mainly used for factory inspection, element matching, and checking the initial resistance value.
Hot resistance refers to the actual electrical resistance of the SiC heating element at its operating temperature. Because SiC heating elements have temperature-dependent electrical characteristics, their resistance can change significantly as the temperature increases.
During operation, the working current and power should be considered based on the element's resistance characteristics at operating temperature, rather than simply using the cold resistance value. With long-term use, SiC heating elements normally undergo resistance aging, which can cause the resistance to increase. Higher operating voltage may therefore be required to compensate for the loss of power.
Understanding the difference between cold and hot resistance is essential for proper SiC heating element selection, electrical system design, and service-life management.
