Induction heating apparatus and methods of operation thereof

A method of operating a cold-crucible-induction melter, 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;
• and
• inductively heating the at least one material while substantially maintaining a desired electromagnetic flux skin depth as the at least one material increases in temperature.

A method of operating a cold-crucible-induction melter, comprising:

• providing a crucible having a wall disposed about a longitudinal axis and a bottom extending generally radially inwardly therefrom;
• cooling the wall of the crucible;
• providing a molten material substantially filling the crucible;
• providing an inductor proximate the crucible and in operable communication with an induction heating circuit including a power source;
• and
• substantially maintaining a desired electromagnetic flux skin depth within the molten material, upon energizing the inductor, as the temperature of the molten material varies.

An induction heating apparatus, comprising:

• a crucible;
• a cooling structure disposed about the crucible for cooling thereof;
• an inductor disposed proximate the crucible;
• a variable-frequency power supply having an electrical output operably coupled to the inductor and configured for delivering an alternating current therethrough;
• a controller configured for selecting a frequency of the alternating current delivered from the variable-frequency power supply and for energizing the inductor;
• and
• wherein the frequency is selected for producing an electromagnetic flux exhibiting a desired electromagnetic flux skin depth within an anticipated at least one material positioned within the crucible.