Induction furnace with improved efficiency coil system

摘要

An induction furnace system has an active induction coil surrounding a crucible. A passive induction coil also surrounds the crucible. The passive induction coil is connected in parallel with a capacitor to form an L-C tank circuit. A source of ac current is provided to the active induction coil to produce a magnetic field that inductively heats and melts an electrically conductive material in the crucible. The magnetic field also magnetically couples with the passive induction coil to induce a current in the passive induction coil. This induced current generates a magnetic field that inductively heats and melts the material. The resistance of the L-C tank circuit is reflected back into the circuit of the active induction coil to improve the overall efficiency of the induction furnace system. The crucible may be open-ended to allow the passage of the electrically conductive material through the crucible during the heating process.