SU1649688A1 - Device for controlling operation of electric-arc furnace - Google Patents

Abstract

The invention relates to electrical engineering. The purpose of the invention is to increase the productivity of the furnace by eliminating the assisted electrodes. The device is equipped with a sensor 5 deviating the stand of the electrode holder from the vertical axis, the output of which is connected to one of the inputs of the coincidence unit 3, the second input of which is connected to the output of the voltage sensor 4, and the third through the element NOT to the output of the arc current sensor 1 through the one-shot 6 is connected to the input of the actuator. When the electrode sticks to the charge, the stand of the electrode holder deviates from the vertical axis, as a result, logical 1 appears at the inputs of the element 3, and a signal appears at its output that generates an actuator control voltage that corresponds to the maximum engine speed upwards. the rack will take a vertical position, the signal from sensor 5 will disappear, at the output of element 3, a logical 0 will appear, the motor will reverse and move the electrode down 4 or more times.

Description

The invention relates to electrical engineering, namely to the control of electric arc furnaces (

The aim of the invention is to increase the productivity of the furnace by eliminating the breakage of the electrodes.

Fig. 1 shows a functional diagram of a device for adjusting the electric mode of an electric arc furnace; in fig. 2 is a diagram of connecting the device to the power controller; in fig. 3 - the stand of the electrode holder with the electrode in the working position (a) and with the electrode resting in the non-conducting mixture (b); in fig. 4 is a diagram of the operation of the device.

The device contains an arc current sensor 1 connected through an HE 2 element to the first input of a coincidence element 3 whose second input is connected to an output of an arc voltage sensor 4. An electrode deflection sensor from the vertical axis 5 is connected to the third input of a co-drop element whose output through the one-oscillator 6 is connected to the actuator 7 for moving the electrode.

The sensor deflection of the stand of the electrode holder from the vertical axis can be performed on a switch of any type.

The operation of the device is considered in conjunction with that used as a reference.

mechanism for moving the electrode by a power regulator (see Fig. 2).

The actuator 7 for moving the electrode 8 includes a comparison unit 9, a reversible thyristor converter 10, an electrode moving motor 11, a moving mechanism 12, a voltage matching unit 13 and a power setting unit 14 (BZM),

At the start-up of the furnace, at the moment of time to, the following signals are established at the inputs of the match 3 element:

at the first input - logical 1 (no arc current),

at the second input - logic 1 (voltage is present),

at the third input is a logical O (the limit switch is open, the electrode is in the position shown in Fig. 3a).

Consequently, at the output of the coincidence element 3 and at the output of the one-shot 6 logical O and the movement of the electrode occurs under the influence of the signal UЈ, which is formed by the comparison and adjustment unit 9. The signal Ue is the mismatch between the set and actual furnace mode described by the equation aUg - big UЈ - 0 The component aUg is formed by the voltage matching unit 13, and the big component is formed by the power setting unit 14. In case of the arc current deviating from the given value, the error signal U в appears (in this case, when starting Uf aUg ), which is fed to the input thyristor converter, where it is converted into motor control voltage. The motor accelerates and, via the electrode moving mechanism 12, moves the electrodes at a speed and direction corresponding to the sign and Uf value (in this case, the electrode moves down).

When an electrode stops in a current-conducting mix (NS stop, time ti, fig. 4), the stand of the electrode holder deflects from the vertical axis under the influence of a twisting moment formed by the vertical (along the axis of the electrode) component of the stop of the electrode holder, and takes The position shown in FIG. 36, the closure is at the same time the limit switch (sensor disconnecting the stand of the electrode holder from the vertical axis). As a result, the following signals appear at the inputs of element 3:

at the first input - logical 1 (no arc current),

at the second input - logic 1 (voltage is present),

at the third input - logical 1 (the small bob is closed).

At the outputs of the coincidence circuit, a logical 1 is set, which starts

one-shot (logic level 1 signal).

Logically 1 block, block9, the passage of the signal 1) Ј and forms eg. -. live command

A thyristor converter that corresponds to the maximum motor speed up, the motor reverses and moves the electrode up. Vertical component force of electrode stop

decreases, respectively, decreases the torque. At time tz, the electrode holder stand assumes a vertical position and the limit switch opens (the standby sensor

electrode holder from the vertical axis). After some time (the delay is formed by the one-shot) at the time point, the logic zero level is set at the output of the one-shot. In the block

9, a blockage on the passage of the signal UЈ is released, as a result of which the motor reverses and moves the electrode downwards.

If a new emphasis on a non-conducting charge occurs, the cycle will repeat and

will continue until the non-conducting portion of the charge is disturbed.

When an emphasis is placed in a conductive mixture (an emphasis of PN, time t4. Fig. 4)

Commands The rise will not occur, since at the first or second input of the element there will be a logical O (there is an arc current or short circuit), respectively, at the outputs of the coincidence element and the single-oscillator is logical O, and the electrode moves under the influence of a signal.

A one-shot (time delay) is needed in order to be able to lift the electrode over the non-conducting portion.

charge to move it.

The device can be used both with an electromechanical drive and with a hydraulic one, as with a cable drive,

and rack or combined. In this case, the principle of operation, the quality of regulation of the device does not change and will be higher than that of the prototype.

Thus, the device allows

increase furnace productivity by preventing electrode breakdowns by more accurately determining the stop, and also automatically destroy areas with a nonconductive charge. In addition, the device can be used in controllers with an absolutely rigid velocity characteristic without reducing the accuracy of determining the electrode abutment into a non-conducting mixture.

Claims (1)

The invention is a device for adjusting the electric mode of an electric arc furnace, containing in each phase an arc current sensor, the output of which is NOT connected to the first input of the coincidence element through the element, the second input of which is connected to the output of dat0 An arc voltage sensor, an actuator for moving the electrode, and a single vibrator, characterized in that, in order to improve the furnace performance by eliminating the electrode breakage, it is equipped with a stand axis deflection sensor for the electrode holder from the vertical axis, the output of which is connected to the third input of the coincidence element output from the input of the specified actuator through the one-shot. 1 fig.g  five hd (rig. 3