High Temperature Heating Control Using Three Phase Silicon Carbide(SiC) Heaters

Electric heating is most commonly used in many industrial applications, especially where conventional source of energy is not available or not practical. Industrial heating is an evergreen topic for research and development. Innovations never end in this particular field. Apart from other heating methods, electrical heating occupies major portion of the segment. Especially resistance heating plays a critical role with its numerous advantages. Nicrome is the most popular electrical resistance heating material but used up to only 600 to 700°C. For high temperature up to 1600°C, Silicon Carbide (SiC) heating elements are more preferred due to its typical high temperature withstand capacity. Unfortunately, SiC heating elements are sensitive to thermal shock. They offer negative temperature co-efficient of resistance in initial phase of heating. It means their resistance decreases with the increase of temperature. This particular characteristic makes them difficult to control. They tries to draw more current from the supply line and results in more I2R loss and abrupt thermal shock. With conventional methods of heating control, these typical characteristics deteriorate the performance of SiC heating elements over a period of working life.