Study of thermal regimes of an electric resistance furnace using AT-503 controller

In this paper were studied some thermal regimes of a low-temperature electric resistance furnace, with indirect heating. To determine the heat losses was used a thermal imager, which achieved a global image of the thermal field inside the furnace and upon the carcass. Thermal images of the furnace carcass revealed the following areas of heat losses greater than admissible in steady-state: furnace door, temperature measuring point and bonding areas of furnace metal carcass. To determine dead time and time constants were analyzed heating and cooling of the furnace until reaching the steady-state. In the experiments has been used AT-503 temperature controller, equipped with a K type thermocouple. Were analyzed following control methods of furnace temperature: on/off with hysteresis of 5°C and autotunig.