Induction furnace monitor

A device for determining the location of a ground fault in an induction furnace and also for determining whether the ground fault is of the internal or external type, the induction furnace including a coil having first and second coil positions, means for applying an alternating current to the coil, a liner, a melt bath within the liner, and means for electrically grounding the melt bath, said device comprising:

• means for measuring a first voltage between the first coil position and the second coil position;
• means for measuring a second voltage between the first position and the ground fault;
• means for monitoring the current in the coil;
• means for monitoring the current in the melt bath ground means;
• and
• means for determining the ratio of the second voltage to the first voltage to provide an indication of the relative position of the ground fault between said first and second coil locations and for comparing the phases of said coil and melt bath ground means currents for detecting penetration of the liner by the melt bath producing a ground fault of the internal type.

A device for detecting and determining the position of a ground fault between first and second positions on a coil, with mutual flux coupling between turns, the first position having a higher voltage potential than the second position, said device comprising:

• means for measuring a first voltage between the first position and the second position;
• means for measuring a second voltage between the first position and an electrical ground;
• and
• computer means for determining the ratio of said second voltage to said first voltage and for determining based on the ratio the turn of the coil and the radial position thereon at which the ground is located.

A method of locating a ground fault between first and second positions on a coil-shaped electrical conductor comprising the steps of:

• determining a first voltage potential between the first position and a ground fault;
• determining a second voltage potential between the first position and the second position;
• determining the ratio of said first voltage potential to said second voltage potential;
• and
• determining the turn of the coil-shaped conductor and the radial position thereon at which the ground fault is located based on the voltage potential ratio.

A method of locating a ground fault between first and second positions on a coil of an induction furnace comprising the steps of:

• determining a first voltage potential between the first position and an electrical ground;
• determining a second voltage potential between the first position and the second position;
• calculating the ratio of said first voltage potential to said second voltage potential;
• and
• calculating based on the ratio the turn of the coil and the radial position thereon at which the ground is located.