Induction heating apparatus and methods for selectively energizing an inductor in response to a measured electrical characteristic that is at least partially a function of a temperature of a material being heated

A method of operating an induction heating apparatus, comprising:

• providing a crucible having a wall disposed about a longitudinal axis and a bottom extending generally radially inwardly from the wall toward the longitudinal axis;
• cooling the wall of the crucible;
• providing at least one material within the crucible;
• providing an inductor proximate the crucible and in operable communication with an induction heating circuit including a power source;
• indicating a temperature of the at least one material by measuring an electrical resistance of the at least one material and correlating the measured electrical resistance to the temperature thereof;
• selecting at least one alternating current characteristic in response to the indicated temperature of the at least one material;
• and
• energizing the inductor with an alternating current exhibiting the at least one selected alternating current characteristic.

A method of determining a temperature of at least one material within an induction heating apparatus, comprising:

• providing a crucible having a wall disposed about a longitudinal axis and a bottom extending generally radially inwardly from the wall toward the longitudinal axis;
• cooling the wall of the crucible;
• providing at least one material within the crucible;
• providing an inductor proximate the crucible in operable communication with an induction heating circuit including a power source;
• measuring an electrical resistance of at least one region of the at least one material within the crucible;
• and
• determining a temperature of the at least one region of the at least one material by correlating the measured electrical resistance of the at least one region of the at least one material to a temperature thereof.

An induction heating apparatus, comprising:

• a crucible;
• a cooling structure disposed about the crucible for cooling thereof;
• an inductor disposed proximate the crucible;
• an induction heating circuit including a power supply having an electrical output operably coupled to the inductor and configured for delivering an alternating current therethrough;
• a measurement device configured for indicating an electrical resistance of an anticipated at least one material positioned within the crucible for inductive heating via energizing the inductor;
• and
• a controller configured for selecting at least one characteristic of the alternating current for energizing the inductor in response to the indicated electrical resistance of the anticipated at least one material.