SU542183A1 - The device "foscar" automatic regulation of the ore-smelting electric furnace - Google Patents

Description

(54) DEVICE FOSCAR AUTOMATIC REGULATION OF ORE-THERMAL ELECTRIC OVENS

need for lifting voltage. This reduces power consumption.

In order to reduce overloads of the power transformer and increase productivity, the device is equipped with a prohibition unit, the input of which is connected to the input of the comparison unit, and the output is connected to the input of the voltage level switching unit.

The block diagram of the proposed device is shown in the drawing, the device consists of an object for heating 1, control circuits for current 2 and voltage 3. Circuit 2 includes blocks for current conversion 4, setting current 5, setting current correction 6, stabilized power, comparing the actual current with a given value of 8, amplification of the error signal 9, and the executive body 10 of moving the electrodes.

Circuit 3 includes blocks of voltage boosting according to a preset program 11, discrete control of the current correction of job 12, discrete inhibit 13, and the voltage switching actuator 14.

Blocks 11, 12, 13 provide discrete signals that are generated, for example, on relay elements. A disturbing factor is fed to the input of the block 11, for example, the electrode position, the temperature of the exhaust gases, the pressure under the furnace roof, etc.

If the disturbing factor is absent, then the signal from block 12 to block 6 is not received. In this case, the regulation is as follows. The signal from object 1 is converted in block 4 and compared in block 8 with the reference signal from the power source 7 and task block 5. The difference between these signals is amplified in block 9 and corrected to the actuator 10. Thus, the current loop 2 maintains the nominal value current i.e.

If a disturbing factor appears at the input of the block 11, then in the block 12 a relay is activated, and the voltage of the power source drops on the corresponding resistor of the block 6. At the same time, the output signal of unit 5 is reduced, and the furnace current is reduced to a new specified value of 3–3– dPoca D E | - d 3 from block 9 (or 8) the error signal is removed, which is converted to

block 13 in the signal of the ban coming in block 12.

At the moment when the current loop runs out the error signal (), the inhibit signal from block 13 is removed, the signal from the program control unit 11 goes to the actuator 14, which increases the voltage of the transformer by one step. In this case, the furnace current increases.

However, with appropriate selection of resistance in block 6, the transformer windings will not be overloaded, since the voltage rise also occurs at the moment when the furnace current is less than the nominal one by a predetermined value D.

An inrush due to an increase in voltage results in an error signal at the output of block 9.

After that, the mismatch is tested until the executive body processes the disturbance signal arriving at block 11 according to a given program. After this, the current loop will again maintain the previously set current value.

Claims (2)

Invention Formula A device for automatic regulation of a ore-smelting electric furnace containing a unit switching voltage stages of a power transformer connected to a task current correction unit connected to an electrode current comparison unit with a task current, characterized in that, in order to reduce overloads of the power transformer and increase performance, it is equipped with a prohibition unit, the input of which is connected to the input of the comparison unit, and the output to the input of the voltage level switching unit. Sources of information taken into account in the examination: 1 Copyright certificate №-238030, cl. Р27 D 11/10 from 1968 2. US patent N2r3493664 cl. 13-12, from 1970 (prototype).  J