SU1590261A1 - Transducer of burning of d.c. current - Google Patents

Abstract

The invention relates to electric welding equipment, namely, sensors for measuring the time of existence of an arc discharge. The purpose of the invention is to improve the accuracy of the sensor by obtaining a more reliable signal about arc burning, regardless of technological short circuits caused by metal transfer. The sensor contains transducers 1 and 2 of the arc current and arc voltage, respectively, element I 3, delay circuit 4, and threshold element 5. The delay circuit is made in the form of two anti-parallel diode-resistor circuits and a capacitor. The sensor does not respond to the short-circuit of the arc gap as when the arc was ignited - does not work if the arc is not lit, and during the arc burning process it does not turn off during the technological short-circuits x. 1 hp f-ly, 2 ill.

Description

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1590261

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I The invention relates to electric welding equipment and can be used to measure the lifetime of an arc discharge. five

The aim of the invention is to improve the accuracy of the sensor by obtaining a more reliable signal about arc burning, irrespective of the technological short circuits caused by | |

j FIG. 1 shows a block diagram of a sensor; in fig. 2 - time diagrams of the current and voltage of the arc and voltage plots on individual elements of mouth-1

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The sensor consists of welding current transducer 1 and voltage 2 arcs, the outputs of which are connected to the inputs of the element 3, the output of which through line 4 of the delay is connected to the input of the threshold element 5. The line of delay consists of two opposite-parallel diode-resistor chains R, D and RD, 2 and capacitor C connected by one output to the common connection point of the resistors, which is the input of the threshold element 5, and the second to the common bus of the circuit. The threshold element can be made on digital circuits with a high threshold voltage,

The device works as follows.

Before the start of welding, the idling voltage of the power source U is applied to the electrode and the product. In this case, a single signal is fed to the input of the I 3 element from the output of converter 2, and a zero signal comes from the output of the current converter 1, as there is no welding current At the output of the element And the signal is zero. At the time of the arc gap closure, the current transducer 1 transfers signal 1 to the input element I, which indicates the occurrence of current in the welding circuit, and a voltage from the output transducer 2 receives a signal equal to zero, as the arc gap is shorted. At the output of the element And still the signal is zero. If after discharge of the melted jumper or separation of the electrode from the arc ignition product. It is not produced, then the current decreases exponentially to zero, and the voltage rises to U, while over time, from the output of the FPG and FPN to the inputs

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element I receive single signals (1), which allow to form at its output 1, coming through the delay line to the input of the threshold element 5. However, the sensor does not work, because the time constant CLc depending on the inductance of the welding circuit is chosen so that The condition,, where € -, is the decay time of the current after the electrode is detached from the product, was satisfied (Fig. 2).

After expiration of time 6, the current in the welding circuit disappears and a zero value of the signal appears at the output of the AND element. During the pause until the next electrode closure to the product, the capacitor C is discharged through a resistor R and the output circuit of element I. If the arc is ignited and the process is established, i. E. , it became more, at the output of the threshold element 5 with a delay Sz a signal appears, which also prompts the sensor to trigger. This sensor state is stable and maintained throughout the entire welding process. The technological short-circuits of the arc pro- gramme for a time of C. s of 5–8 ms do not affect the uninterrupted operation of the device, since the constant discharge of the capacitor C R, C t / K.

Despite the fact that during the technological short circuits of the voltage converter 2, 0 is fed from the output to the input of the element I, 1 is saved at the input of the threshold element, since time t v.j. not enough to discharge capacitor C through R and the output circuit of element I. I

Thus, the sensor provides

reliable operation of the entire welding installation when conducting welding, regardless of whether it is accompanied by metal transfer with arc short-circuits or not.

Form la invention

1. A direct current arc burning sensor containing voltage and current arc transducers, outputs connected to the inputs of the element I, characterized in that, in order to ensure the reliability of fixing the stable arc time regardless of technological short circuits caused by metal transfer 1590261

la, the sensor is provided consistently in the form of condensate and nsvx

the connection and the delay line and the threshold-counter-paralysis and one -zisgorelementGi - DU-p. chains, with a dot

. the diode is the input line

2 Sensor for 1T delay and a common connection point

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w and and with the fact that the lines of delay through the capacitor with a common bus.

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Claims (2)

Claim 1. A DC arc burning sensor, containing arc voltage and current converters connected to the inputs of an element, characterized in that, in order to ensure the reliability of fixing the stable arc burning time, regardless of technological short circuits caused by the transfer of metal ⁵ 1590261 la, the sensor equipped with a series-connected delay line and a threshold element connected to the output of the element I. I " 2. Sensor pop. 1, characterized in that the delay line is made in the form of a capacitor and two counter-parallel diode-resistor circuits, with the common point 5 of the diode being the input of the delay line, and the common point of connecting the resistors with its output connected via a capacitor to a common bus. But ***** + - / I y - V. ' * s ------ 1- I I -1- 1 1 t ' 1 1 i t --1------;------- I 1 [ g " Ϊ P I I ' I | 5 | | 1 Figure 1 ? *