Abstract: The method for adjusting the impedance of one or more phases of a secondary circuit of an electric furnace, in order to limit the unbalance between the phases themselves comprises the transformer (31), a variable impedance secondary circuit for one or more phases (F1, F2, F3), the rigid and fixed interconnection (32) for each phase (F1, F2, F3) connected to the transformer, the flexible cables (33) connected by means of the proximal end to the fixed interconnection (32), the electrode holding arms (34) connected to the distal end of the flexible cables (33), the conductive electrodes (35) fixed to the respective electrode holding arms (34). The rigid and fixed interconnection (32) of a phase (F1, F2, F3) comprises at least one turn (11), wherein the impedance is either continuously or discreetly variable in order to obtain the desired impedance value.

Abstract: The invention relates to an energy supply device of a melting tank. According to the invention, between an electrode plane of the melting tank and a converter for the current supply of the electrode plane, a separatable plug connection is provided in the supply line, between the electrode plane and the converter. Thereby in case of a defect of the converter, the supply line can be cut off simply and rapidly, and the converter either tended to or replaced. In an especially advantageous form of execution the energy supply device has a reserve converter so that, on failing of the converter, by unplugging the plug connection and replugging it so as to set up a plug connection to the reserve converter, the energy feed to the electrode plane can be restored within the shortest possible time.

Abstract: The invention relates to an energy supply device of a melting tank. According to the invention, between an electrode plane of the melting tank and a converter for the current supply of the electrode plane, a separatable plug connection is provided in the supply line, between the electrode plane and the converter. Thereby in case of a defect of the converter, the supply line can be cut off simply and rapidly, and the converter either tended to or replaced. In an especially advantageous form of execution the energy supply device has a reserve converter so that, on failing of the converter, by unplugging the plug connection and replugging it so as to set up a plug connection to the reserve converter, the energy feed to the electrode plane can be restored within the shortest possible time.

Abstract: Controlled current feed device for electric arc furnace employed to melt metals, wherein the feed line comprises at least a medium tension bar (13), a feed control device and a transformer (17) serving the furnace, the feed control device (16) being arranged between the medium tension bar (13) and the transformer of the furnace (17) and comprising a mutual inductor (19) consisting of a primary coil (19a) and a secondary (19b) coil, the primary coil (19a) being arranged in serial connection on the feed line (10) and the secondary coil (19b) being connected to at least a re-phasing filter (20) comprising at least a condenser (22).

Abstract: An arc control apparatus for a DC arc furnace provides an additional magnetic field which prevents a discharged arc from shifting outward at an arc generating point due to the influences of a magnetic field generated by a feeder circuit, thus directing the arc discharge vertically downward. The arc control apparatus includes an arc furnace in which an object to be melted is disposed. A movable electrode is disposed in the arc furnace for movement relative to the object. A feeder circuit including a power supply and a feeding conductor is connected to the movable electrode and the arc furnace for supplying a voltage therebetween from the power supply through the feeding conductor to generate an arc whereby the object is dissolved. An auxiliary coil is disposed outside and in the vicinity of the arc furnace and connected to the feeder circuit for generating a counter magnetic field in a direction to cancel a magnetic field which is generated at a point of generation of the arc by means of the feeder circuit.

Abstract: An apparatus for transferring the electrical energy from a furnace transformer to the electrodes of a three-phase arc furnace held by coplanar mast arms. A mast arm for the center current phase is made of aluminum or a material with a similar permeability. The conductor of the center current phase, which is made of at least one high-current tube made of a material with good electrical conductivity, is mounted in insulated fashion in the mast arm and has a smaller geometrical diameter than the conductors for the outer current phases provided by the other two mast arms.

Abstract: A d.c. arc furnace for metallurgical purposes includes two or more electrodes arranged on the furnace vessel and projecting into the furnace vessel. To avoid actions of forces departing from the magnetic fields derived form the currents conducted to the electrodes and effecting deflections of the electric arcs, the electric supply means provided for each of the electrodes are each arranged in the immediate vicinity of the electrode to be supplied, the electric supply means of one electrode being arranged so as to be spacially separated from the electric supply means of the remaining electrodes, viewed in the peripheral direction of the furnace vessel.

Abstract: The furnace vessel for a DC arc furnace has a thermostable wall which preferably consists, in the region situated above the slag line (S), of a plurality of water-cooled wall segments (1) made from steel. These wall segments are fastened to a support structure (13-18). At least one of the wall segments (3) consists of nonmagnetic steel or copper and is preferably arranged on the side of the furnace vessel (5) opposite the power supply device (7). In this way, the influence of the high-current lines which extend below or beside the furnace vessel and cause a deflection of the arc can be compensated.The effect of this nonmagnetic wall segment can be partially or virtually entirely cancelled by a trimming plate (19) which is detachably fastened from the outside to the nonmagnetic wall segment (3), in order in this way to achieve optimum trimming of the deflection of the arc.

Abstract: A secondary circuit having a variable impedance for electric arc furnaces of a type working with alternating current, which is associated with a transformer (11) is disclosed. A secondary circuit comprises at least one rigid connection (12) connected to the outputs (16) of the transformer (11), flexible cables (13) connected through rigid connection elements (29, 129) at first end to the rigid connection (12) and at the other end to specific electrodes (15). At least one branch of the secondary circuit (10) corresponds to a specific phase including at least one of the respective rigid components (12, 17, 29, 129) having at least two parts reciprocally positionable in an adjustable manner according to the required value of overall reactance of the specific branch of the secondary circuit (10) comprising that rigid component (12, 17, 29, 129).

Abstract: Two upper electrodes 16 and 17 are horizontally spaced apart from each other with a predetermined distance and vertically extend through a furnace roof 3 of a furnace shell 2. Upper conductors 20 and 21 are connected to the upper electrodes 16 and 17 and extend in a direction away from the upper electrodes 17 and 16, respectively. Two lower conductors 22 and 23 are connected to a lower electrode 1 and extend in directions along which the upper conductors 20 and 21, respectively. Power source circuits 24 and 25 are arranged between extension ends of the upper and lower conductors 20 and 22 and 21 and 23, respectively. Arcs 12a and 12b generated between the upper electrodes 16 and 17 and the lower electrode 1 are directed to a center of the furnace shell 2.

Abstract: According to the present invention, there is provided a direct current electric furnace for melting metal capable of melting scraps rapidly and also capable of diminishing cold and hot spots formed on the furnace wall, wherein the direct current electric furnace is provided with a single top electrode, a plurality of furnace bottom electrodes, or a plurality of electrode units obtained by dividing a multitude of furnace bottom electrodes of a small diameter into plural units, and electric current controlling thyristor circuits for controlling each individually electric currents flowing through the plural furnace bottom electrodes or electrode units. The electric current controlling thyristor circuits may be substituted by thyristor circuits for controlling electric currents for each of plural groups obtained by dividing the above plural furnace bottom electrodes or the above many furnace bottom electrodes or the above plural electrode units into the plural groups.

Abstract: In direct-current arc furnace the arc is deflected in a direction away from the current supply means (19) through the action of the high-current lines (18) extending under the furnace vessel. This leads to the thermal overloading of a part of the furnace vessel walls. If the high-current lines (18a) are for the major part laid in a plane above the furnace bottom, on or below the furnace platform (20), and are taken downwards to the connection fittings (10) on the furnace bottom only on the side of the furnace vessel (1) opposite the current supply means, the arc will again burn symmetrically.

Abstract: Two DC electric arc furnaces are provided side by side. The both DC electric arc furnaces are connected by a duct. Each of two power source apparatuses is mounted near and associated with each of the DC electric arc furnaces. The anodes of the both power source apparatuses are mutually connected by an anode cable and the cathodes of the apparatuses by a cathode cable. The anodes and the cathodes of the both DC elecric furnaces are connected to the anode cable and the cathode cable, respectively, via a connection circuit adapted to supply electric power alternately to either of the DC electric arc furnaces. When a raw material is molten in one of the DC electric arc furnaces, electric power is supplied by the both power source apparatuses to this DC electric arc furance. The exhaust gas at a high temperature produced in this DC electric arc furnace is sent to the other DC electric arc furnace through the duct and preheats another raw material charged there beforehand.

Abstract: System for controlling the positions of each of the three electrodes of a three phase electric furnace to maintain optimum real power delivered to the furnace in the event of electrode short circuiting or arc extinction due to scrap movement in the furnace. The system includes means for determining the magnitude of arc voltage and arc current and means to change the position of selected electrodes when either arc voltage or arc current is determined to be zero.

Abstract: In an electric arc furnace having a fluid-cooled electrode support arm which is provided with an electrode holding means, the outside of the electrode support arm is plated with cooper and the electrode holding means is electrically insulated with respect to the support arm, by way of which the electrode current is carried to a contact jaw that bears against the electrode. In an electric arc furnace with for example three parallel electrode support arms the electrode current is taken partly by way of a heavy-current tube and partly by way of the electrode support arm in order to balance the different reactance in relation to the two other electrode support arms. In order to eliminate reactance asymmetry, a reactance loop is provided in at least one heavy-current conductor between the transformer of the electric arc furnace and the associated electrode support arm.

Abstract: A DC arc furnace having a vertical arcing electrode adapted to be connected with a negative current lead and a hearth adapted to contain a melt below the electrode and having a hearth electrode, the hearth electrode extending laterally from the axis of the arcing electrode symmetrically with respect to the axis and having a plurality of electrical connections extending to the outside of the hearth and spaced laterally from the arcing electrode's axis symmetrically with respect to the axis, the connections being adapted for connection with a positive current lead and application of DC to the electrodes powering an arc between the arcing electrode and melt; wherein the improvement comprises a positive current lead below the bottom of the hearth and having an upper end positioned on the arcing electrode's axis below the hearth's bottom and extending from the positive current lead's upper end vertically downwardly on the axis to a low position where the magnetic field of the positive current lead cannot appreciab

Abstract: The disclosed arrangement refers specifically to a smelting arrangement which includes two metallurgical vessels serviced by a common, electrode carrying lid which is pivoted about a vertical axis as between one or the other position in relation to the two vessels. The current feed arrangement is designed such that beginning with a bus system extending from the transformer, conductors are run in a triangular arrangement down to a first plane, in freely sagging suspension and up again to the electrodes in such a manner that the conductors undergo a slight displacement only in the vertical suspension region near the transformer, equivalent to a slight torsion of a triangular prism, while the suspended portions of the conductors remain invarient during the pivoting about an axis that runs through the center of the triangle defined by the connect points at the transformer.

Abstract: The disclosed invention is an apparatus for connecting two current conducting tubes, which also conduct fluids such as for example, a coolant. The connection apparatus conducts current from one tube to the other through a sleeve, the said tubes having a machined external surface against which the sleeve is pressed. A hose receiving hydraulic pressure is disposed between the sleeve and an external casing for providing a removable pressure against the sleeve for clamping the pipes in the sleeve. The present invention may be used in conjunction with a holder assembly for electrodes in an electrothermal smelting furnace.

Abstract: An electrode and conductor arrangement for a three-phase electric arc furnace supplied with power from a transformer, including three electrodes which extend downwardly into the furnace, and a plurality of current conducting paths each composed of a rigid conductor, which is conductively connected to a respective electrode and a flexible conductor connected in series between the rigid conductor and the transformer, the rigid conductors extending parallel to one another, the electrodes being spaced from one another in the horizontal direction transverse to the longitudinal axes of the rigid conductors, in which the conducting paths associated with the center electrode are spaced a minimum distance, in the horizontal direction transverse to the longitudinal axes of the rigid conductors, from the conducting paths associated with each of the outer electrodes, there are only two conducting paths, spaced vertically apart, connected to each outer electrode, the vertical spacing between the two conducting paths assoc

Abstract: A DC arc furnace has power lines arranged completely symmetrically with respect to the arc so as to prevent the arc from bending angularly.

Abstract: A DC arc furnace has shielding between the arc and its power lines preventing or retarding the magnetic field created by the power lines from deflecting the arc.