Operating modes and electrothermal model of an induction crucible furnace with a conductive crucible

The mathematical electrothermal model based on a finite element method in the universal ELCUT package is developed for calculation of electric and thermal values of an induction crucible furnace. Electric characteristics depending on the frequency, temperature and current of an inductor are studied. The nonstationary thermal task is solved. Two reference duties of the furnace are allocated and investigated: the cold mode when the crucible magnetic and temperature is lower Curie points and the hot mode when the melted molten metal, a crucible unmagnetized, temperature of a crucible is higher than a Curie point. The experimental stand consisting of the high-pitched adjustable transistor power supply, an inductive crucible furnace with a steel conductive crucible, a microprocessor control system and the system of acquisition is developed. The experiment on the laboratory furnace with a steel crucible with loading from aluminum alloy is made. Results of an experiment are comparable to results of mathematical model operation in an ELCUT package, the adequacy of results of a theoretical research is confirmed. Dependences of the fissile resistance and inductance on frequency, temperature and current in the form of surfaces in the environment of Simulink/Matlab are received. Results of the solution of a thermal task showed that the melted metal heats up evenly, temperatures of a crucible and metal are equal. The conducted theoretical and pilot researches form a basis for creation of structural electrothermal model of an induction crucible furnace of the increased frequency in the environment of Simulink/Matlab. (paper)