DE1077348B - Device for regulating the electrode position in electric ovens - Google Patents

Description

Electrode regulation devices in electric arc furnaces have e.g. B. the task of keeping the furnace output constant by adjusting the arc length »

There are electrical and hydraulic electrode regulators known. In the case of purely electrical regulation, the required adjustment is made Electrodes by a lifting or lowering motor assigned to the electrodes, which drives the electrodes in the required Measures raises or lowers. These lifting motors are controlled by contactors, magnetic amplifiers, Leonard machines and Amplidyne.

Finally, there are also hydraulic electrode regulators of electric arc furnace became known, in which a Ferraris motor for adjustment a slide that turns off or opens a pressure line is used. This engine thus fulfills just the job of a regulating engine. Because this motor only rotates in one direction due to a special circuit can act, is for the opposite movement, so to move back and close the Pressure line blocking valve, a return spring acting on the armature of the motor is necessary. This Motor, a device that works on the principle of the Ferraris motor, only fulfills the task a switching element designed as a relay. A direct power transmission of the output from this engine Torque for the electrode adjustment cannot take place.

Such a device requires a special machine set for raising and lowering the electrodes, the one consisting of a pressure medium pump and a hydraulic one assigned to each electrode Engine exists.

In contrast, the invention proposes a device for regulating the electrode position in electric ovens, in which the control values are derived from the current and voltage of the phase assigned to the electrode to be adjusted and a motor serving as a lifting and lowering motor that continuously sweeps over the range from clockwise rotation to standstill to counterclockwise rotation Control three-phase motor, whereby according to the invention the vectorial sum of the current and voltage values of the respective electrode corresponding to the current and voltage values of each electrode from a first output winding of the intermediate converter directly feeds the one winding (vy) of the three-phase motor and the two oppositely connected second output windings of the intermediate converter via a known phase-rotating element excite the second winding (ux) of the three-phase motor, while the third winding (wg) of the three-phase motor is connected to the output of a magnetic amplifier, which is made up of an additional alternating current network z or fed from the furnace transformer and from the first device for regulating
the electrode position in electric furnaces

Applicant:

Demag Elektrometallurgie GmbH,
Duisburg, Wolfgang-Reuter-Platz

Dipl.-Ing. Hans Ernst, Duisburg,
has been named as the inventor

Output winding of the intermediate converter is controlled via a full-wave rectifier.

A delay in the response time occurs when according to the invention, the regulating device is practically not a function, since the driving force and regulating element function exercise a control element and a prime mover combined in itself.

The phase shift that creates the rotating field in the motor is in a manner known per se by means of an ohmic resistor or a capacitor generated. In order to bring the control and drive motor to a standstill immediately after the correct adjustment has been achieved A winding of the three-phase motor is necessary to achieve and prevent the motor from running Direct current via a controlled magnetic amplifier and an intermediate rectifier fed. The motor then acts as a brake motor and thus prevents it from continuing to run beyond the regulated one Value addition. The voltage for the working and bias winding of the magnetic amplifier is taken from an additional AC network or a tap on the furnace transformer.

There is also the option of connecting the three-phase motor directly to the output shaft to equip this motor acting special brake motor.

In the figure, an embodiment of the invention is shown. For understanding the invention insignificant parts are left out of consideration in the illustration.

The winding vy receives a differential current from phase T via voltage and current transformer 1. The winding ux of the rotating field motor 2 in turn receives the necessary phase shift via the capacitor 3 or an ohmic resistor in order to generate a rotating field in the motor 2.

- - - - - 909 75W351

The voltage for the winding ux is taken from a winding of the current transformer 4 in a summation circuit. The winding et '.:; is controlled via a. Magnetic amplifier 5 and intermediate rectifier supplied with direct current. The magnetic amplifier 5 is designed so that a direct current flows through a rectifier to the winding ms of the motor 2 when the windings vy and ux are de-energized, so that the motor is braked. This occurs when the electrode current has the desired value. If the target value or the target voltage of the electrodes changes, the differential voltage occurring in the windings vy and ux causes a torque in the motor 2 corresponding to the raising or lowering.

The invention is not restricted to the exemplary embodiments described above, it encompasses rather, all possible embodiments of the inventive concept.

Claims (3)

PATENT CLAIMS: 2Q 1. Device for regulating the electrode position in electric furnaces, in which the control values are derived from the current and voltage of the phase assigned to the electrode to be adjusted and a three-phase motor that serves as a lifting and lowering motor and continuously sweeps the range from clockwise to standstill to counterclockwise, thereby characterized in that the vector sum formed in an intermediate converter (4) of the alternating current values corresponding to the current and voltage values of each electrode from a first output winding of the intermediate converter directly feeds one winding (vy) of the three-phase motor (2) and the two oppositely connected second output windings of the Intermediate converter excite the second winding (ux) of the three-phase motor via a known phase-rotating element (3) , while the third winding (ws) of the three-phase motor is connected to the output of a magnetic amplifier (5), which is derived from an additional alternating current network or from the Ofe ntransformer is fed and controlled from the first output winding of the intermediate converter via a full-wave rectifier. 2. Device according to claim 1, characterized in that the third winding (ms) of the three-phase motor is supplied with direct current via the magnetic amplifier and an intermediate rectifier. - 3. Device according to one of the preceding claims, characterized in that the three-phase motor is equipped with an additional brake motor. Considered publications:
German patent specifications No. 947 722, 968 530. 1 sheet of drawings © 909 75OT51 3.60