Induction furnace with improved efficiency coil system

An induction furnace system comprising:

• a crucible;
• an induction coil system for heating and melting the electrically conductive material placed in the crucible, the induction coil system comprising:
• an induction coil surrounding the crucible;
• a capacitor connected across a partial section of the induction coil to form a parallel L-C tank circuit with the partial section of the induction coil;
• and
• a power supply having an input connected to a source of power external to the induction furnace system and a single phase ac output connected across the terminals of the induction coil to supply a single phase ac current to the induction coil, whereby the single phase ac current creates a magnetic field to inductively heat and melt the electrically conductive material placed in the crucible, and the resistance of the parallel L-C tank circuit improves the efficiency of the induction furnace system.

An induction furnace system comprising:

• a crucible;
• an induction coil system for heating and melting the electrically conductive material placed in the crucible, the induction coil system comprising:
• an induction coil surrounding the crucible;
• a capacitor connected across the terminals of the induction coil to form a parallel L-C tank circuit with the induction coil;
• a power supply having an input arranged to be connected to a source of power and an ac output connected across a partial section of the induction coil to supply an ac current to the partial section of the induction coil, whereby the ac current creates a magnetic field to inductively heat and melt the electrically conductive material placed in the crucible, and the resistance of the parallel L-C tank circuit improves the efficiency of the induction furnace system.

A method of inductively heating and melting an electrically conductive material in a crucible comprising the steps of:

• surrounding a first partial section of the crucible with a passive induction coil;
• connecting a capacitor to the terminals of the passive induction coil to form a parallel L-C tank circuit;
• surrounding a second partial section of the crucible with an active induction coil;
• providing a source of ac current to the active induction coil to generate a first magnetic field to inductively heat and melt the electrically conductive material and to induce an induced ac current in the passive induction coil by magnetic coupling the passive induction coil with the first magnetic field, whereby the induced ac current inductively heats and melts the electrical conductive material and the resistance of the parallel L-C tank circuit is reflected into the active induction coil to improve the efficiency of the induction furnace system.

A method of inductively heating and melting an electrically conductive material placed in a crucible comprising the steps:

• surrounding the crucible with an induction coil;
• connecting a capacitor to a partial section of the induction coil to form a parallel L-C tank circuit comprising the capacitor and the partial section of the induction coil;
• and
• providing a source of a single phase ac current to the terminals of the induction coil to generate a magnetic field to inductively heat and melt the electrically conductive material, and whereby the parallel L-C tank circuit improves the efficiency of the induction furnace system.