JPS59193764A - Welding current detector for arc welding machine - Google Patents

Abstract

PURPOSE:To discriminate inexpensively the presence or absence of welding current by disposing a magnetosensitive element in proximity to a cable in which the welding current flows, and detecting the change rate of voltage by the magnetosensitive element. CONSTITUTION:A magnetosensitive element 15 is disposed in proximity to a cable 10 in which the welding current of an arc welding machine flows. When the welding current does not flow in this state, the voltage VH between the terminals of the element 15 is set higher than the voltage V0 at the non-inversion input terminal of an operational amplifier 18 and therefore the output of the amplifier 18 is maintained on the low side and a relay 8 for detecting the welding current does not operate. When the welding current flows, the voltage VH between the terminals of the element 15 drops below the voltage V0 and the output of the amplifier 18 inverts so that a transistor 12 turns on and the relay 8 operates as well. The welding current detector is thus made smaller in size.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a welding current detection device for an arc welder.

In recent years, with the spread of arc welding machines, the demand for arc welding machines equipped with a welding current detection function is also increasing. This welding current detection device detects the flow of welding current.In an arc welder, by detecting the welding current, it changes the welding conditions at the start of welding, improves the welding start, and If the welding current stops,
It can be used to stop or correct welding, or when a welding jig and an arc welder are used in combination, the welding current is detected and the jig is moved in conjunction.

Conventional configuration and problems Conventionally, this type of welding current detection device has a coil wound around the secondary side of the core of a DC reactor, and when welding current flows, a voltage is induced in this secondary coil. A method using a variable flow path and a method using a variable flow path were considered.

FIG. 1 shows a conventional example of a welding current detection device using a secondary winding wound around a DC reactor, and FIG. 2 shows a conventional example of a welding current detection device using a current transformer.

In Figures 1 and 2, 1 is an electromagnetic contactor, 2 is a transformer, 3 is a rectifier, 4 is a welding torch, 5 is B) material, 6 is a DC reactor, and 7 is the 2nd part of this DC reactor 6. A secondary winding provided on the next side, 8 is a current detection relay, 9 and 10 are diodes, 11 is a resistor, 12 is a transistor, 13 is a DC power supply, and 14 is a current transformer.

By the way, the secondary winding 7 of the DC reactor 6 shown in FIG.
In the case of using the current transformer 14 shown in FIG. 2, the voltage induced in the secondary coil of the current transformer 14 is transferred to the In addition to the base, the transistor 11 is operated to turn on the current detection relay 8 connected in series to the transistor 11 to obtain a current detection signal 1. However, in these conventional welding current detection devices, current detection The disadvantage is that the parts are quite complicated and expensive.

OBJECTS OF THE INVENTION The present invention eliminates the above-mentioned conventional drawbacks, and aims to provide a welding current detection device at low cost by employing a magnetically sensitive element as the element for detecting welding current.

Structure of the Invention As a further structure, the present invention provides a structure in which a magnetically sensitive element is disposed close to a cable through which welding current flows, or a magnetic collecting ring with a gap is provided around the cable, and a magnetic field is formed in the gap. A magnetic element is provided, and the presence or absence of welding current is determined by detecting the amount of voltage change with the magnetically sensitive element.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to FIGS. 3 to 5 of the drawings.

1.2, 3, 4, 5, 6, 8, 10, 12.13/ are respectively the same conventional magnetic contactor, transformer Oj÷, rectifier, bath contact 1--chi, base material, and DC reactor. , current detection relays, diodes, transistors, and DC power supplies. 15 is a magnetically sensitive element, 16 and 17 are resistors, 18 is an operational amplifier, 19 is a welding current cable, and 20 is a magnetic collecting ring.

Next, the operation of this embodiment will be explained.

If the welding current does not flow due to the welding current cable 1
The voltage v between the terminals of the magnetically sensitive element 15 mounted close to 9
Since H is set higher than the voltage vo of the non-inverting input terminal of the operational amplifier 18, the output of the operational amplifier 18 is kept on the low side, and the welding current detection relay 8 does not operate.

When the welding current flows, the voltage vH between the terminals of the magnetically sensitive element 15 becomes lower than the voltage vo, the output of the operational amplifier 18 is inverted, and the transistor 12 is turned on.
Welding current detection relay 8 also operates.

In addition, in FIG. 4, the magnetically sensitive element 15 is connected to the welding current cable 19.
FIG. 5 shows an embodiment in which the magnetically sensitive element 15 is attached directly to the magnetic collecting ring 2o provided with a gap. In both embodiments, welding current cable 1
The magnetic flux generated around 9 is detected by a magnetically sensitive element 15, and the presence or absence of welding current is determined.

Effects of the Invention When the welding current detection device of the present invention is used, the following excellent effects can be achieved.

(1) The magnetically sensitive element is inexpensive and only needs to be attached close to the welding current cable, so the number of man-hours required is reduced and the welding current detection device can be manufactured at low cost.

b) Since the magnetically sensitive element is small, the welding current detection device can be made small, and the arc welding machine can be made smaller and lighter.

(3) Current detection is possible anywhere on the welding current cable as long as the welding current is flowing.

[Brief explanation of the drawing]

1 and 2 are circuit diagrams of a conventional welding current detection device for an arc welding machine, FIG. 3 is a circuit diagram of an arc fungus liquid-like welding current detection device in an embodiment of the present invention, and FIG. FIG. 5 is a perspective view showing an example of how the magnetically sensitive elements are attached. 1... Electromagnetic contactor, 2... Transformer, 3... Curved rectifier, 4... Welding torch, 5... Base material, 6...
DC reactor, 8 rivers... Current detection relay, 12...
・Transistor, 13---DC power supply, 15 ・Magnetically sensitive element, 16, 17---Resistor, 18------
Operational amplifier, 19...Welding current cable, 20
...Magnetic collecting ring / Name of agent: Patent attorney Toshio Nakao Haga 1 person No. 1
Figure 2 ″ Figure 3 Figure 4 A

Claims (1)

[Claims] A magnetically sensitive element is disposed close to a cable through which welding current of an arc welding machine flows, or a magnetic collecting ring is disposed with a gap around the cable, a magnetically sensitive element is disposed in the gap, and the magnetically sensitive element is disposed in the gap. A welding current detection device for an arc welder that determines the presence or absence of welding current by detecting the amount of voltage change with a magnetically sensitive element.