SU1489936A1 - Arc exciting device - Google Patents

Abstract

The invention relates to the welding industry and can be used in the design, manufacture and modernization of automated welding equipment. The purpose of the invention is to improve the quality of the welded joint by increasing the stability of the arc firing process and enabling the automation of welding processes. The device, based on the readings of the arc current sensor, arc voltage sensor, and electrode feed sensor, controls, according to a predetermined algorithm, the nature of the electrode feed, ensuring reliable excitation of the arc. The device also contains level converters connected to the sensors in series, the outputs of which are connected to the decoder. The one-shot is also connected to the latter, which provides the initial start-up of the electrode feed motor. The decoder controls the operation of the control units for the reverse and the electrode feed, for which its outputs are connected to the inputs of these blocks. 5 silt, 1 tab.

Description

The invention relates to welding production and can be used in the design and modernization of automated welding equipment.

The aim of the invention is to improve the quality of the welded joint by increasing the stability of the arc firing process and ensuring the possibility of automating the welding processes.

Fig, I shows a block diagram of the device; figure 2 - diagram of the device with the expanded electrical circuit of the decoder; in Fig.3-5 t possible variants of electrical circuits level converters (PU).

The device consists (3) of three sensors: sensor 1 of the presence of welding current, sensor 2 of the presence of voltage on the arc gap, and sensor 3, which generates a signal when the electrode is fed into the weld pool. The device also includes PU 4-6, a single vibrator 7, a decoder 8, and a block 9 for controlling the reversal of the feed motor. electrode (BUR) and unit 10 controls the electrode feed mechanism (BUP).

Sensors 1-3 are connected to the corresponding PU 4-6, and the output of sensor 1 is connected to the input of PU 4, the output of sensor 2 is connected to the input of PU 5 and the output of sensor 3 is the input of PU 6. The outputs of PU 4-6 are connected to the first four log 4

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 1489936

I will give the decoder 8, to the p of that input

Then, the one-shot 7 output is connected. The inverse inputs of the one-shot 7 are connected to the inverse outputs of PU 4 and 5.

The decoder 8 consists of () of two logical elements (LE) 2I 11 and 12, two LE 2I-NO 13 and 14 and one LE 2ILI-NOT 15. The upper input of the LE 11 is connected to the direct output of the first PU 4, and the lower, connected also with the lower entrance of LE 13, is connected to the inverse output of the second PU 5 and lower

The inverse input of the one-shot 7, the upper input of which is connected to the inverse output of the first PU 4 and the upper inputs of LE 13 and 14, the inverse outputs of which are connected to the inputs of LE 12. The lower input of LE 14 is connected to the inverted output of LE 15, the upper input of which is connected to the output The third control unit 6, and the lower one - to the output of the one-oscillator 7. The inputs BUR 9 and BUP 10, respectively, are connected to the outputs of LE 11 and 12, which are the outputs of the decoder 8.

As the sensor 2, an arc gap in welding (welding) is used. Sensor 1 is a shunt, current transformer or magnetic amplifier, connected in series in the welding circuit. Sensor 3 can be an optical, electrocontact, electromagnetic or other sensor that converts a mechanical displacement of an electrode into an electrical signal. For example, you can freely rotate as such a sensor.

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Blocks 9 and 10 are non-I for controlling the operation of an electrode supply motor.

For normal operation of digital LEs, a decoder 8, and a one-shot 7, inputs on their inputs must be sent on 15labelled logic levels, and signals with levels of a very wide range are generated at the outputs of sensors 1-3. Thus, the signal taken from the shunt (sensor 1) is equal in magnitude to tens of millivolts, and the signal from the arc gap (sensor 2.) is equal to tens of volts. The levels of these signals vary in the process of welding (surfacing). range, and For device operation levels

The signals from sensors should take only two values — a logical unit if there is an arc current, a voltage is on it, shuffle, or a wire in the weld pool or a logical zero (in the absence of current, voltage, or wire movement). To meet these conditions, PU 4-6 are entered into the device circuit. The designs of these converters can be of the most arbitrary shape and structure and performed using analog microcircuits K140, K551, etc., digital circuits such as K155, K176, etc., as well as all transistors, resistors, diodes, zener diodes. For an example, FIGS. 3-5 show diagrams of these converters. Level 4 transducer (Fig. 3) serves to generate a signal on the presence of arc current. For this, the signal from the shunt is amplified by

The roller is pressed tightly against the electrical amplifier 16 and the transducer. As the latter moves, the roller rotates. The rotation of the roller is converted into an electrical signal. As sensor 3, a conventional tachogenerator can be used. .g

PU 4-6 are needed to convert signals from sensors 1-3 to the normalized level, which is necessary for the stable operation of the remaining elements of the device.

One-shot 7 is necessary for the initial start-up of the electrode transfer motor when welding is started.

The decoder 8 is entered into the circuit of the device for analyzing the state of the output; 55 signals from sensors 1–3, processing them using a set algorithm, and issuing control signals to blocks of BUR 9; and BUP 10.

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It is digitized with a Schmitt trigger 17, which has two outputs, direct and inverse.

Scheme PU 5 is shown in figure 4. Arc voltage is limited by the zener diode 18 and digitized by a Schmitt trigger 19.

A similar view is the scheme of PU 6 when used as a sensor 3 tachogenerator. When an optical converter is used as this sensor for the PU 6, it can be shown in FIG. When the wire moves, the light incident on the photoresistor 20 periodically interrupts. In this case, its resistance periodically changes. This change is detected and amplified by a transistor circuit, the signal is then postponed.

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It is digitized with a Schmitt trigger 17, which has two outputs, direct and inverse.

Scheme PU 5 is shown in figure 4. Arc voltage is limited by the zener diode 18 and digitized by a Schmitt trigger 19.

A similar view is the scheme of PU 6 when used as a sensor 3 tachogenerator. When an optical converter is used as this sensor for the PU 6, it can be shown in FIG. When the wire moves, the light incident on the photoresistor 20 periodically interrupts. In this case, its resistance periodically changes. This change is detected and amplified by a transistor circuit, the signal is then fed to a Schmitt trigger 21, at the output of which a sequence of pulses is formed, which with one vibrator 22 is converted into signal 1. In the absence of a one-shot pulse 22 its output is formed by Oh ..

For simplicity, the single-oscillator circuits 7 and 22 (respectively, in Figs 1, 2 and 5) do not show the time specifying the RC circuits.

In Fig. 5, the transistor part of the circuit, as well as the Schmitt trigger 21, can be replaced by optoelectronic switches with integrated amplifiers in microcircuit design, for example, the K249, K262 series, etc.

The monovibrator 7 and the decoder 8 can be manufactured using digital circuits, for example, the K155 series.

BUR 9 and BUP 10 can be made on electromagnetic relays, transistor or thyristor switches, magnetic amplifiers and other elements. BUR 9 is a reversing device in the form of the above elements. Its function. When the start-welding button is pressed, the arc gap is energized. If the electrode is not closed to the product, then the current in the welding circuit is b

- switch the direction or the ph-q det is zero and at the direct output

Is the electric current in the motor windings to change the direction of rotation of its core (rotor).

BUP 10 is an engine rotation control device. Its functions are to control the switching on and off of the engine, to regulate the speed of rotation of its shaft. A typical example of such a block is a unified thyristor control unit.

 the operation of welding surfacing engines, which is included in the ADF-1000, Al401, A-874 automatic machines complex, etc.

The arc excitation device should perform the following functions: to ensure the reversal of the electrode supply at the moment of its short circuit to the product, turning off its supply when the end face is injected into the product without electrically. contact or at the time of turning off the power source.

The table shows the required operating conditions of the device in various combinations of the state of the welding system power source - welding machine - electrode (1 indicates the presence of arc current signals.

PU 4 will be O, and on the inverse - 1. At the output of PU 5 - 0. A positive vibrator from the output of the PU starts the Single Vibrator 7. At its 2g output for a short time it forms 1, generating a logical O on LE 15.

Let us now analyze the state, LE 1, 13, and 14.

40 On the upper and lower inputs of the LE 1 O, therefore formed at the output; also O and BUR 9 is disabled. The feed motor can only rotate in the direction that the electrode feed 45 is down.

On the upper terminals (inputs) of the LE and 14 1, on the lower inputs of these elements - O. Therefore, at their output

50 are formed 1, which generate the same signal at the output of LE 12 allowing rotation of the electrode feed motor. When moving the latter to the weld pool on the sensor 3

55, a signal is generated, which arrives through PU 6 to the upper input of LE 15 and holds a logical O on its course after the termination of the signal at the output of the one-shot 7.

the voltage and supply of the electrode, as well as the on state of the mechanisms of reverse and supply of the electrode, O correspond to the absence of the mentioned signals and the switched off state of the mechanisms).

To perform the above functions, the electrode feed sensor is introduced into the weld pool, the decoder and the one-shot. The decoder is necessary for a logical analysis of the current situation of the welding process in accordance with the table and issue

signals to the control units of the reverse and feed electrodes. A single vibration input € W for the initial start of the electrode feed motor.

To match signal levels with

sensors with input signals of the decoder and a single vibrator between their inputs and sensors installed level converters.

The device works as follows.

When the Start-welding button is pressed, a voltage is applied to the arc gap. If the electrode is not closed to the product, then the current in the welding circuit of BuPU 4 is O, and in the inverted one is 1. At the output of the PU 5, the front of the negative impulse from the output of the PU 5 starts the One-Vibrator 7. At its output for a short time 1, generate a logical O at the output of LE 15.

Let us now analyze the state of LE 1, 13, and 14.

On the upper and lower inputs of the LE 11 O, therefore on the output, O and BUR 9 are also formed disabled. The feed motor can only rotate in the direction that drives the electrode down.

On the upper pins (inputs) of LE 13. and 14 1, at the lower inputs of these elements - O. Therefore, at their outputs

formed 1, which generate the same signal at the output of LE 12, allowing the rotation of the electrode feed motor. When moving the latter to the weld pool on the sensor 3

a signal is generated, arriving through PU 6 at the upper input of LE 15 and supporting logical O at its output after the termination of the signal at the output of the one-shot 7.

The electrode goes down to contact with the product.

Consider two cases of contact of the electrode with the product. In the first case, the electric contact of the end of the electrode with the product is provided, in the second case, due to the presence of slag at the end of the electrode, there is no contamination of the product,

In the first case, at the direct output of the LL 4, 1 appears, and at the inverse, O. The short-circuit voltage decreases to zero and at the output

PU 5 - 1. The electrode, abutted against the product, stops at the output of PU 6 - O.

A short-circuit current pulse is triggered on the upper input of the one-shot 7, while the lower input of the LE 14 is O. On both the inputs of the LE 11 is 1, therefore, there is a similar signal at its output allowing BUR 9 to work. rotate 25 puppy engine feed electrode.

At the upper inputs of elements 13 and 14 - O, and at the lower LE 13 - 1. So as the same signal at the lower input of LE 14, then at both inputs and at the output of the KLE 12 - 1. Work is permitted. BUP 10. Feed motor The electrode was rotated in the opposite direction from the original one, giving the electrode upward before initiating the arc. In this way, at the output of NU 5, an O is formed, switching off through LE 11 BUR 9, the electrode begins to flow into the bath. The welding process is in progress (surfacing. Since the character of the signals at the inputs of the LE 1 is not modified} 1ils, but at both the inputs of the LE; 13 - O, the output signals of these elements will remain the same, allowing the operation of the BUN 10..

In the second case, when an electric range is not provided when the electrode is touched to the product, 1 is formed at the inverse output of НУ 4, and at outputs of НУ 5 and НУ 6 - O.

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So far character.-Voltage on

Since the arc and current have not changed, the one-shot 7 will not start. The electrode resting on the product by the end does not move. At the output of LE 15 - 1. At the upper entrances of the LE 13 and 14 - 1. But this (the output of the LE 14, on which. Oh, the work of the LE 12 is prohibited and O is formed at its output. The electrode feed motor is turned off. Elect d

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Rod, in contact with the product, is not fed into the weld pool.

But the lower input of LE 11 is disabled and BUR, 9,

When moving the welding machine relative to the product with the welding speed, the electrode scratches the surface of the product until the moment of electrical contact. At the moment of providing contact, O appears at the upper inputs of the LEs 13 and 14 and a one-shot 7 is started with a current pulse. The motor I is fed into the electrode feed, the latter enters the weld pool.

When the welding source is turned off, 1 is formed at both inputs of the LE 13, and O is generated at its output. A similar signal will also be generated at the LE 12 output, which will prohibit the electrode feed through the BUN 10.

Thus, the breakdown of the electrode feeder, the fire part of the welding apparatus is prevented, the arc arc process is stabilized and the quality of the welded joint is improved.

The replacement of the proposed device in comparison with the prototype allows us to simplify the processes of automation and rototization of welding productions, ensure reliable excitation of the Arc, and improve the quality of welded structures.

Claims (1)

Invention Formula The arc excitation device containing the arc current sensor, arc voltage sensor and control units for the reversal and operation of the electrode supply motor, while the arc voltage sensor is connected to the inputs of both control units, in order to improve the quality of the welded joint by increasing the stability of the arc ignition process and ensuring the possibility of automation of welding processes; the sensor of the electrode supply to the weld pool, three level transducers, the one-shot and des frator comprised of two logic elements 2I, two logic elements. 2I-NOT and one logical element 2ILI-NOT, with the current sensor output 51 arc connected to the entrance of the first level transmitter, the output of the arc voltage sensor is with the input of the second level converter, and the output of the electrode supply sensor is with the input of the third level converter, the direct output of which is connected to the first input of the logic element 2IL-NOT, the second input of which is connected to the output of the single-oscillator and the output is connected to the first input of the first logic element 2И-НЕ, whose second input is connected to the first inputs of the one-oscillator and the second logic element 2I-NOT, as well as to the inverse output of the first level converter, 1 o Power supply included. The electrode goes to the product. The source is included. Electrode ups to the product. No electrical contact The source is included. Short circuit of the electrode to the product. Operating mode 89936 my ten ten 15 the output of which is connected to the first input of the first logic element 2I, the second input of which is connected to the same second inputs of the one-vibration and the second logic element 2I-NOT, as well as to the inverse output of the second level converter, while the output of the first logic element 2I is connected to the input of the reverse control unit motor supply electrode, and the second logic element 2I its output connected to the input of the control unit of the motor supplying the electrode, and the inputs to the outputs of logic elements 2I-NOT. ABOUT 1 o oh oh Phil. Compiled by V.Puchinsky Editor A.Lezhnina Tehred L.SerdyukovaKorrector M.Vasilyeva Order 3621/18 Circulation 894 RCIIPI State Committee for Inventions and Discoveries at the State Committee for Science and Technology of the USSR 4/5, Moscow, Zh-35, Raushsk nab. 113035      ,, - ™ ... “, -“ in-and .. -, -.-. ,, - Production and publishing plant Patent, Uzhgorod, st. Gagarin, 101 Fi.CH l-vwn Subscription