RU2101226C1 - Control device for skip winch electric drive of blast furnace - Google Patents

Abstract

FIELD: metallurgy. SUBSTANCE: device has control command forming unit, unit of path-control cam transducers, rotational-velocity sensor and current pickup. Device is also provided with computing unit and square-pulse generator. Rotational-velocity sensor is made contactless. Computing unit determines drum rotational velocity, compares current velocity value with several preset values and delivers control signals to control command forming unit as soon as the above-indicated values are attained. In addition, computing unit checks counter-travel of skips, faults of mechanical brakes and current load of electric motor armature. If current exceeds permissible value command to switch on operating brake is delivered. EFFECT: more reliable control. 1 dwg

Description

 The invention relates to ferrous metallurgy and can be used in control devices for electric drive blast furnace production.

A control device for a hoisting-and-transport installation is known, comprising a centrifugal tachometer, a converter of mechanical signals into electrical, an electromagnetic coupling, the leading part of which is connected to the machine shaft, the excitation winding is connected to the speed control unit, and the driven part is connected to the shaft of the tachometer (ed. St. USSR N 353897, B 66 B 1/24, 1972)
The disadvantage of this device is the low accuracy of regulation and lack of reliability.

 A control device for an electric drive of a skip winch of a blast furnace is provided, comprising a current sensor included in the anchor circuit of a direct current drive electric motor, an electric motor rotation speed sensor, a control command generation unit, one of the inputs of which is connected to the output of the travel cam switch block, the other input to the boot control body, one of the outputs with a motor starter, and the other output with a control input of the service brake.

 A disadvantage of the known control device is the increased danger to the operating personnel due to the presence of mercury in the centrifugal circuit breaker, as well as low reliability due to the lack of consideration of the weight of the loaded charge when the motor is overloaded.

 The aim of the invention is to ensure the environmental safety of the device and increase the reliability of its operation.

 For this, a device for automatic control of an electric drive of a skip blast furnace containing a current sensor included in the anchor circuit of a direct current drive electric motor, an electric motor rotation frequency sensor, a control command generation unit, one of its inputs is connected to the output of the travel cam switch block, and the other input is to a control panel the boot body, one of the outputs with an electric motor starter, and the other output with a control input of the service brake, is equipped with a computing unit and a gene a square-wave pulse generator, and the speed sensor is made non-contact with the possibility of forming two phase-shifted rectangular pulses, and the inputs of the computing unit are connected to the outputs of the rectangular pulse generator, speed sensor, current sensor, as well as the outputs of the control command generation unit corresponding to the lifting commands and descent of skips, signals about heavy and light material of the charge, signal outputs of the computing unit corresponding to the given speeds of the winch, counterflow skips, a service brake malfunction and overload motor coupled to individual input unit generating a control command and the last output, corresponding to a command to switch an alarm, connected to the input of the alarm unit.

 The drawing shows a diagram of the proposed device for controlling the electric drive of the skip winch of a blast furnace.

 A device for controlling the electric drive of a skip winch of a blast furnace contains a non-contact pulse sensor 1 as a speed sensor connected through a coupling 2 to a DC motor 3, connected through a reduction gear 4 to the winch drum 5, a current sensor 6, a computing unit 7, the third input of which connected to a generator 8 of rectangular pulses, issuing signals of a stable frequency, block 9 travel cam switches connected through a reduction gear 10 to the drum 5 of the winch, block 11 forming control command connection connected to the computing unit 7. The first output of the control command generating unit 11 is connected to the current sensor 6, and the second to the service brake 12. The seventh input of the control command generating unit 11 is connected to the contacts of the travel cam switches 9, and the eighth input to the panel control boot device (not shown).

 The first input of the computing unit 7 is connected to a non-contact pulse sensor 1, the second input with a current sensor 6, the third with a rectangular pulse generator 8, the fourth and fifth inputs with the third and fourth output of the control command generation unit 11, the sixth and seventh inputs that supply the skip movement signals “up” and “down” with the fifth and sixth outputs of the block 11 generating commands for controlling the electric drive, the first, second and third outputs of the computing unit 7, giving signals about the value of the skip speed (for example, 20% 50% and 115% of the numbers correspond yut only to a specific example), the fourth and fifth outputs, giving signals of skip countercurrent (PX) and service brake (NT) malfunction, the sixth output, giving an electric motor overload (PD) signal taking into account the material that is poured into the skip (heavy load, light load) connected respectively to the first, second, third, fourth, fifth and sixth inputs of the unit 11 for generating control commands of the DC motor 3 of the skip hoist, consisting of right 13 and left 14 skips, cables 15 and 16, on which the skips hanging on guides 17 and 18 of skips 13 and 14.

 When the right skip 13 is located in the skip pit 19 under loading, the other skip left 14 is at this time on the top 20 in the tilted position. At this time, the DC motor 3 is fixed with a service brake 12.

 When the winch drum 5 is rotated, one cable, for example, 15 is wound onto the drum 5, and another cable 16 is wound. Thus, at the same time one skip rises to the top 20, and the other descends into the skip pit 19.

 The non-contact pulse sensor 1 rotates at the same speed as the DC motor 3.

 When the winch drum 5 is rotated, the non-contact pulse sensor 1 generates rectangular pulses, the period of which is inversely dependent on the frequency of rotation of the DC motor 3. The higher the speed, the shorter the time period.

 The current sensor 6 is included in the anchor circuit of the DC motor 3 and generates an analog signal about the value of the armature current.

Computing unit 7 performs the following functions:
calculates the frequency of rotation of the drum and compares the current speed value with several predetermined values of 20% 50% and 115% of the rated speed of the winch and when these values are reached, it generates control signals to the control unit for electric drive of the skip winch;
controls the anti-skip;
controls the failure of mechanical brakes during parking;
controls the current load of the motor armature.

 The rectangular pulse generator 8 supplies rectangular pulses to the third input of the computing unit, which are used to determine the speed of the winch drum.

 The winch speed is controlled in the computing unit 7 by comparing the values of the period of the signal from the contactless pulse sensor 1 to the first input of the computing unit 7 and the values of the periods previously calculated for the speeds of 20% 50% and 115% of the nominal.

 The magnitude of the period corresponds to the number of pulses received at the third input of the computing unit 7 from the generator 8 of rectangular pulses and calculated over the period from the leading edge of one pulse of the proximity sensor 1 to the leading edge of the next pulse. The pulse frequency of the generator 8 rectangular pulses is selected tens of thousands of times higher than the maximum pulse frequency from sensor 1, for example 300 kHz and 168 Hz.

 When the actual speed reaches the level of the set values, the computing unit 7 provides signals from the first, second and third outputs to the first, second and third inputs of the winch drive control command generation unit 11, when signals from the block 9 of the travel cam switches are also fed to the seventh input to confirm normal electric drive work on certain sections of the track. When reaching a speed equal to 115% of the nominal speed, the block 11 for forming control commands from the second output gives a signal to activate the service brakes 12.

 As a block 11 of the formation of control commands, the block described in the book of B. Levitan can be used. Electrical equipment of ferrous metallurgy enterprises. M. Metallurgizdat, 1995, p. 209-213, and as a computing unit 7 programmable microcontroller (Universal programmable microcontroller "ELKO", ELKO LLP). As a non-contact pulse sensor 1, a photoelectric sensor can be used (A. Thun. Electric drive speed control systems. M. Energoatomizdat, 1984, p. 147-160) or (Gendelman B.R. et al. Sensors in automatic control systems for electrical appliances Industrial energy, 1986, N 9, p. 17), or a pulsed sensor that works on the disruption of generation (Filippov VG Movement digitizers. M. Military Publishing House of the Ministry of Defense of the USSR, 1965, p. 78), as a sensor 6 current sensor described in the mentioned article by B. Handelman and others on with. 17, and as a generator of 8 rectangular pulses, the generator described in the book of B. Goroshkov Radio electronic devices. M. Radio and Communications, 1985, p. 252-253; FIG. 10, 26a.

 The device operates as follows.

 When the starter (not shown) of the DC motor 3 is turned on, its rotation is transmitted through a reduction gear 4 to the skip winch drum 5 and then through the gear 10 to the travel cam switch unit 9, which signals the seventh input of the skip winch control command generation unit 11 about the position skips all along their path.

 The control of the countercurrent (PC) skips is as follows.

 When rotating the DC motor 3, the non-contact pulse sensor 1 simultaneously rotates, issuing two series of rectangular pulses that are phase-shifted to the first input of the computing unit 7.

 If a command is received from the fifth output of the control unit 11 to the sixth input of the computing unit 7 to raise the skip 13 “up”, then after the start of movement, the pulses of the first series of the contactless pulse sensor 1 are ahead of the phase pulses of the second series. Conversely, when moving “down”, the pulses of the second series are ahead of the pulses of the first series.

 In the case of a mismatch between the directions of the set and the actual movement (counterflow), the computing unit 7 gives the control signal PX from the fourth output to the fourth input of the control command generation unit 11, which in turn from the second output gives a signal to activate the service brake 12, thereby preventing an accident.

 When the actual speed reaches the level of the set values, the computing unit 7 provides signals from the first, second and third outputs to the first, second and third inputs of the control command generation unit 11, where the signals of the traveling cam switch unit 9 are also input to the input 7 to confirm the normal operation of the electric drive certain sections of the road. Upon reaching 115% of the rated speed, the control command generation unit 11 from the second output gives an alarm to activate the service brake 12.

 The malfunction signal (NT) of the service brake 12 is generated when the command to move “up” and “down” is not received in the computing unit 7, the service brake 12 is turned on, and the contactless pulse sensor 1 continues to produce two series of pulses that are received to the first input of the computing unit 7.

 Computing unit 7 from the fifth output gives a signal about a malfunction of the service brake 12 to the fifth input of the control command generation unit 11, which after 7 outputs a signal to turn on the light and sound alarms (not shown in the drawing).

 The skip hoist electric drive is controlled taking into account the type of loaded charge (heavy load, light load), information about which comes from the control panel of the loading organ (not shown) to the eighth input of the control command generation unit 11 and then from the third and fourth outputs to the fourth and fifth inputs of the computing unit 7.

 Information about the load is supplied to the second input of the computing unit 7 from the current sensor 6 included in the anchor circuit of the DC motor 3.

 If the armature current in size exceeds the permissible limit corresponding to the load being lifted, then from the sixth output of the computing unit 7, a control signal PD on engine overload is sent to the sixth input of the control command generation unit 11, which from the second output gives a signal to apply the service brake 12.

Claims (1)

 A device for controlling the electric drive of a skip winch of a blast furnace containing a current sensor included in the anchor circuit of a DC drive electric motor, a motor speed sensor, a control command generation unit, one of the inputs of which is connected to the output of the travel cam switch block, the other input to the boot control panel body, one of the outputs with a motor starter, and the other output with a control input of the service brake, characterized in that it is equipped with computing with a rectangular pulse generator and a speed sensor made non-contact with the possibility of forming two phase-shifted rectangular pulses, and the inputs of the computing unit are connected to the outputs of the rectangular pulse generator, speed sensor, current sensor, as well as the outputs of the control command generation unit corresponding to the commands to raise and lower the skips, signals about the heavy and light material of the charge, the signal outputs of the computing unit corresponding to the given speeds of the winch, rotivohodu skips, failure of the service brake and an overload of the motor are connected to separate inputs of the control unit for generating commands, and the last output, corresponding to a command to switch an alarm, connected to the input of the alarm unit.