SU974611A1 - Device for regulating electric arc furnace power - Google Patents

Description

(54) DEVICEQ FOR REGULATING THE POWER OF THE ARC

one

This invention relates to electrothermal conditions.

The automatic power regulator of arc steel-smelting furnaces, for example, the metering machine modulator module, STU-022, is known, which in the control circuit of each electrode contains current and voltage sensors on the arc, a reference unit, a reference unit, an amplifier, a displacement motor of an electrode P1.

However, this device does not provide for ignition of the arc after its break for the minimum possible time and with minimum losses of electric power.

The closest to the proposed is a device for power control for an electric arc furnace, containing in the control circuit of each phase current sensors and arc voltage connected to the two inputs of the first comparison unit, the third input of which is connected to the reference block, and the output through the first key with the output of the first switching unit, connected by the input to the source of the nominal voltage, the electrode speed sensor, connected to the first input of the second unit, compared to ELECTRICAL

NIL connected with the second input to the second task unit, and the output via the second key with the control input of the second switching unit, the first input of which is connected to the power supply unit, and the output is connected with the electrode displacement engine, the control inputs of the two keys and the first switching unit associated with current sensor 2.

with

A disadvantage of the known device is 10 with its low speed when detecting the moment of an arc break.

The purpose of the invention is to increase the productivity of the furnace by reducing the time needed to eliminate arc breaks.

15

Claims (2)

The goal is achieved by the fact that the current sensor is connected to the control inputs of two switches and the first switching unit. It is connected via a serially connected 20 unit determining the current pause intervals to the threshold element, and the second input of the second switching unit is connected to the output of the first switching unit. 39 On f. G, I presents the block diagram of the device; Fig. 2 is a block diagram of the determination of the magnitude of the current pauses. The device contains an arc current sensor 1, a voltage sensor 2 across the arc, a standard power regulator 3, a comparison unit 4, blocks 5 and b tasks, power blocks 7 and 8, an electrode displacement motor 9, an electrode displacement speed sensor 10, blocks 11 and 12 switching blocks and 13, 14, block 15 for determining the arc current pause size, threshold element 16. The block for determining the arc current pause size contains a zero-body 17, a key block 18, a pulse generator 19, a pulse counter 20. The device operates as follows in a way. When the signal proportional to the current-arc pauses coming from the block 15 of the threshold value is exceeded, a signal appears at the output of the threshold element 16 This signal closes the key 13, opens the key 14 and, acting on the switching unit 12, connects the electrode moving motor 9 to nominal voltage. At the moment when the electrode speed is reached, measured by the electrode speed sensor 10, the magnitude of the switching speed specified by task block 6, a signal appears at the output of comparator 4, which is fed through the open block 14 to the control input of switching unit 11 . As a result, the electrode displacement motor 9 is fed directly} from the power supply unit, corresponding to the motion of the electrode at a steady rate equal to the switching speed. At the moment of contact of the electrode with the charge, a signal appears at the output of the arc current sensor 1. This leads to the opening of the key 13, and the further control of the electrically direction of the electric arc furnace comes from the standard power regulator 3. The device allows to reduce the time needed to eliminate breaks. A device for controlling the power of an electric arc furnace, containing in the control circuit of each phase current sensors and arc voltage, connected to two inputs of the first comparison unit, the third input of which is connected to the task unit, and the output through the first switch to the output of the first switching unit, connected by an input to a source of nominal voltage, an electrode speed sensor connected to the first input of the second comparison unit connected by the second input to the second reference task output through A second key with a control input of the second switching unit, the first input of which is connected to the power supply unit, and the output is connected with the electrode displacement motor, the control inputs of the two switches and the first switching unit are connected with a current sensor, in order to improve performance furnaces by reducing the time for the elimination of arc breaks, the current sensor is connected with the control inputs of two switches and the first switching unit through a series-connected unit for determining the size of current pauses and a threshold element The second input of the second switching unit is connected to the output of the first switching unit. Sources of information taken into account in the examination 1. Sidorenko M, F. and others. Automation and mechanization of electric steelmaking and ferroalloy production. M., Metallurgists, 1975, p. 30-44. 2. USSR author's certificate according to the application No. 2689503/07, cl. H 05 B 7/148, 1978. ffmf f7 KW 20