JP2006320928A - Arc welding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an arc welding machine which can stably perform the arc welding by performing the short-circuit welding and the pulse welding by using one welding machine. <P>SOLUTION: The arc welding machine comprises a first rectifying circuit 2, an inverter circuit 3 for converting the output of the first rectifying circuit 2 into a high frequency alternating current, an insulating transformer 4 for converting the output of the inverter circuit 3 into a voltage suitable for the arc welding, a second rectifying circuit 5 for rectifying the output of the insulating transformer 4, a first reactor 6 connected to the second rectifying circuit, a current circuit 10 which is connected to the insulating transformer 4 in parallel with the second rectifying circuit 5 and has a reactance larger than that of the first reactor 6, and a control circuit 17 for controlling the inverter circuit 3, wherein a current cut-off mechanism 100 is connected to the first reactor 6, and the current output from the first reactor 6 is cut off by operating the current cut-off mechanism 100 by a command output from the control circuit 17. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an improvement in an arc welding machine in which an alternating current is rectified to become a direct current, an output thereof is changed to a high-frequency alternating current by PWM control in an inverter circuit, and is appropriately transformed by a transformer and then converted to a direct current in a rectifier circuit.

FIG. 5 is a diagram showing a conventional example 1 of a constant voltage type arc welding power source.
In the figure, 40 is the DC reactance of the current superimposing circuit, 41 is the DC reactance of the output side main circuit, 42 is a wire, 43 is a pair of wire feed rollers, 44 is an energizing chip, and 45 is an arc load. It is.
The output main circuit is configured to extend from both ends of the secondary winding 56 to the insulating transformer 4 via the rectifier 16, the DC reactor 41, the energizing chip 44, the wire 42, the arc load 45, and the work. Yes.
The current superimposing circuit passes through the capacitor 51, the full-wave rectifying diode 52, the DC reactance 40, the DC reactance 41, the energizing chip 44, the wire 42, and the arc load 45 from the end of the secondary winding 56. The configuration reaches the middle point of the next winding 56.
Note that the capacitance of the capacitor 51 is selected so that the value of the current flowing through the current superimposing circuit is smaller than the normal welding current, but is large enough to maintain the arc.
The operation will be described below.
For example, if the arc voltage is excessively blown off during arc start and the arc voltage becomes high, the welding current is insufficient. However, the arc is not cut as a result of the current being supplied from the current superimposing circuit.
Although a constant voltage arc welding power source has been described as an example, if it is applied to a pulse welding power source and the current value supplied from the current superposition circuit is set to be slightly smaller than the base current, it will be For example, even if the arc length is increased due to a change in the wire feed resistance and the arc current is cut off by the base current, the arc cut can be prevented from occurring (see, for example, Patent Document 1). ).

FIG. 6 shows a conventional example 2 of a constant voltage type arc welder.
In the figure, the current of the commercial AC power source 1 is converted into DC by the first rectifier circuit 2. The output of the first rectifier circuit 2 is converted into a high frequency of 20 to 200 [KHz] by the inverter circuit 3.
The output of the inverter circuit 3 is converted into a voltage suitable for welding by the insulating transformer 4, converted to direct current by the second rectifier circuit 5, and then passed through the direct current reactor 6, and the arc current is generated by the welding electrode 7 of the arc welding portion. Become. The route from the insulation transformer 4 to the second rectifier circuit 5 and the DC reactor 6 is the same as that of the conventional welding power source shown in FIG. As the DC reactor 6, a reactor of 20 [μH] or less is applied for pulse welding.
The arc welder has a current circuit 10 in parallel with the second rectifier circuit 5. In the parallel current circuit 10, the voltage suitable for welding converted by the insulating transformer 4 passes through the current control circuit 11, is converted into direct current by the third rectifier circuit 12, passes through the direct current reactor 13 and the direct current reactor 6, Supply current to the arc weld.
Further, the current control circuit 11 is constituted by a semiconductor element, and controls the current flowing by turning on / off the gate of the semiconductor by a signal from the control circuit 17. As the DC reactor 13, a reactor of 100 to 2000 [μH] is applied.

FIG. 7 is a modification of the conventional example 2 (FIG. 6) of the constant voltage arc welder.
In the figure, the current control circuit 11 is composed of capacitors 21 and 22. In the case of FIG. 7, the number of turns of the insulation transformer 4 is changed so that the voltage applied to the current control circuit 11 is higher than the voltage applied to the second rectifier circuit 5. Capacitors 21 and 22 are selected to have sufficiently large capacities so that charging is not completed even when the inverter circuit 3 is 100 [%] on.
By doing so, the voltage applied to the insulation transformer 4, the current control circuit 11, and the third rectifier circuit 12 is higher than the voltage applied to the second rectifier circuit 5 from the insulation transformer 4. An attempt is made to flow through the current control circuit 11 through the path leading to the third rectifier circuit 12. However, the current control circuit 11 including the capacitors 21 and 22 causes the current passing from the isolation transformer 4 to pass through the third rectifier circuit 12. Limited.
That is, if the voltage (average voltage) applied to the insulating transformer 4 is high, the current flowing through the rectifier circuit 12 increases. If the voltage applied to the insulating transformer 4 is low, the flowing current decreases.
In short-circuit welding, the voltage applied to the insulating transformer 4 is low during a short circuit, and the voltage applied to the insulating transformer 4 is high during an arc. Since an arc break always occurs at the time of arcing, the voltage applied to the insulating transformer 4 increases during arcing, and a larger amount of current flows from the insulating transformer 4 to the rectifier circuit 12 and the DC reactor 13 via the current control circuit 11, thereby Cutting can be prevented (see, for example, Patent Document 2).

FIG. 8 shows a conventional example 3 of a constant voltage type arc welder.
The welding machine in FIG. 8 has a current interruption mechanism 206 in the vicinity of the welded portion 210. By cutting off the current with the current cut-off mechanism 206, the welding current flows through the resistor 274. As a result, a rapid decrease in welding current can be obtained (see, for example, Patent Document 3).

JP-A-5-318128 JP 2004-249331 A JP 2002-273569 A

In Conventional Example 2, which is an improved version of Conventional Example 1, it is known that it is effective to rapidly reduce the current when the wire is short-circuited to the molten pool of the wire during arc welding in order to improve arc welding performance. Is the fact of
However, in the conventional example 2, since there is the DC reactor 6, it was not possible to obtain a rapid decrease in welding current due to the DC reactor current change suppression function.
In addition, it is a well-known fact that a method in which a welding wire is brought into contact with the workpiece 8 at the start of arc and an arc is generated by reversing the wire is effective for improving quality at the start of arc welding. Then, the welding wire welded to the workpiece | work 8 with the electric current which flows at the moment when the welding wire contacted the workpiece | work 8, and the subject that reverse rotation of a wire did not operate | move normally occurred.
Since Conventional Example 3 has a welding current blocking mechanism 206, the welding current can be rapidly reduced. However, since the welding current flows through the resistor 274 while the current interrupt mechanism 206 is operating in FIG. 8, the resistor 274 generates heat. In arc welding, a very large current of about 50 to 500 [A] flows, so that heat generation is intense and the cooling mechanism becomes large. Further, since the conventional example 3 does not have the DC reactors 6 and 13 as in the conventional example 2, there is a problem in that pulse welding and short circuit welding cannot be used properly.
The present invention has been made in view of such problems, and an object of the present invention is to provide an arc welding machine that can selectively use pulse welding and short-circuit welding and can realize more stable welding.

In order to solve the above problem, the present invention is configured as follows.
The invention according to claim 1 relates to an arc welding machine, wherein a first rectifier circuit that rectifies an alternating current to obtain a direct current, and is connected to an output side of the first rectifier circuit to connect the first rectifier circuit. An inverter circuit for converting the output into a high-frequency alternating current; a transformer connected to the output side of the inverter circuit to convert the output of the inverter circuit to output it from two secondary coils; and the secondary side first A second rectifier circuit connected to a coil to rectify the output of the transformer to be a direct current, and connected between an output side of the second rectifier circuit and a welding torch to smooth the output of the rectifier circuit; An arc welding main circuit comprising a first reactor applied to the welding torch,
An arc welding secondary connected between the secondary second coil and the welding torch and providing the output of the rectifier circuit to the welding torch via a second reactor having a reactance greater than the reactance of the first reactor. Circuit,
A control circuit for controlling the inverter circuit;
The arc welding machine further includes a current interrupting mechanism in the arc welding main circuit, and the current interrupting mechanism interrupts a current output from the first reactor according to a command output from the control circuit. It is characterized by that.
According to a second aspect of the present invention, in the arc welding machine according to the first aspect, the arc welding subcircuit is connected to a current control circuit connected to the secondary side second coil and to an output side of the current control circuit. And a third rectifier circuit that rectifies the output of the current control circuit, and the second reactor connected to the third rectifier circuit.
According to a third aspect of the present invention, in the arc welder according to the second aspect, the current control circuit is constituted by a semiconductor element, and the gate of the semiconductor element is turned ON / OFF by a signal from the control circuit. It is characterized by controlling current.
According to a fourth aspect of the present invention, in the arc welder according to the second aspect, the current control circuit is constituted by a capacitor or a coil, and the current is controlled by a function of limiting an alternating current of the capacitor or the coil. It is characterized by being.
According to a fifth aspect of the present invention, in the arc welding machine according to any one of the first to fourth aspects, the current interrupting mechanism is disposed between the first reactor and the welding torch. It is a feature.
According to a sixth aspect of the present invention, in the arc welding machine according to any one of the first to fifth aspects, the control circuit outputs a command to the current interrupt mechanism when the arc is on, and the first reactor outputs It is characterized by cutting off the current that is generated.
A seventh aspect of the present invention is the arc welding machine according to any one of the first to fifth aspects, wherein the control circuit is configured to reduce the current when the arc voltage in the arc state decreases by a predetermined value from a target value. A command is output to the shut-off mechanism, and the current output from the first reactor is shut off.
According to an eighth aspect of the present invention, in the arc welding machine according to any one of the first to fifth aspects, when the control circuit performs pulse welding, the current interrupting mechanism is operated in a base current section of pulse welding. Then, the base current is supplied from the arc welding subcircuit, and the operation of the current interrupting mechanism is stopped in the peak current section of the pulse welding.

With the configuration as described above, the arc welding machine of the present invention not only realizes short-circuit welding and pulse welding with a single welding machine, but also realizes more stable arc welding by rapidly reducing the current by a current interrupting mechanism. Can be realized.
Also, the wire start-back arc start method can be applied without problems by interrupting the current at the time of arc start, and as a result, spatter can be suppressed and welding quality can be improved.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an arc welder according to the present invention.
The current of the commercial AC power source 1 is converted into DC by the first rectifier circuit 2. The output of the first rectifier circuit 2 is converted into a high frequency of 20 to 200 [KHz] by the inverter circuit 3. The output of the inverter circuit 3 is converted into a voltage suitable for welding by the insulation transformer 4, converted to direct current by the second rectifier circuit 5, then passed through the direct current reactor 6, and the arc welded portion (7, 8 in the figure). The arc current is generated by the welding torch 7). According to the present invention, the current interrupt mechanism 100 is provided between the rectifier circuit 5 and the welding torch 7 (between the rectifier circuit 5 and the DC reactor 6 in FIG. 1). The current interrupting mechanism 100 functions to interrupt the welding current flowing through the DC reactor 6 according to an instruction from the control circuit 17. As the DC reactor 6, a reactor of 20 [μH] or less is applied for pulse welding.
The above is the arc welding main circuit.
The welding machine of the present invention has a current circuit (arc welding subcircuit) 10 in parallel with the second rectifier circuit 5. In the arc welding subcircuit 10, the voltage suitable for welding obtained from the insulating transformer 4 passes through the current control circuit 11, is converted into direct current by the third rectifier circuit 12, passes through the direct current reactor 13, and sends current to the arc welded portion. Supply.
The current control circuit 11 is composed of a semiconductor element, and controls the current flowing by turning on / off the semiconductor gate with a signal from the control circuit 17. As the DC reactor 13, a reactor of 100 to 2000 [μH] is applied.

The cause of welding instability in MAG short-circuit welding or CO ₂ welding at a large current is arc breakage. In the arc welding machine of the present invention, if current is supplied to the arc weld zone to suppress arc breakage, the welding is stable. We use that to do.
Although the DC reactor 13 has a large reactance of 100 to 2000 [μH], it is in parallel with the path from the insulating transformer 4 to the DC reactor 6 via the second rectifier circuit 5, so that it hinders current rise in pulse welding. do not do. The DC reactor 13 works effectively when an arc break occurs during the arc period of short circuit welding.
Arc break is a condition in which the arc cannot be maintained because the welding current decreases due to a sudden distance between the welding rod and the work piece due to vibration of the molten pool or gas explosion in the molten pool. It is.
In order to prevent arc breakage, a DC reactor 13 that supplies current in response to a decrease in welding current is effective. Since the main DC reactor 6 has a small reactance, it hardly contributes to prevention of arc breakage. However, since the DC reactor 13 in parallel has a large reactance of 100 to 2000 [μH], it plays a role in preventing arc breakage sufficiently. Plays on.
In addition, the DC reactor 13 is connected in parallel with the main DC reactor 6 even with respect to a steep current rising change at the time of arc start, so that an increase in current is not hindered.
Similarly, with respect to a steep current rising change from the base current to the peak current in the pulse welding machine, the DC reactor 13 is placed in parallel with the main DC reactor 6 and therefore does not hinder the current increase.
Further, since the reactance of the main DC reactor 6 is as small as 20 [μH] or less, it does not prevent a steep current rising change from the base current of the pulse welding to the peak current.

The control circuit 17 controls the current control circuit 11 so that an appropriate amount of current flows from the isolation transformer 4 through the current control circuit 11 to the third rectifier circuit 12 and the DC reactor 13.
The appropriate amount of current supplied to the arc welded portion is a current having a value of 5 to 250 [A], and varies depending on the welding method and the welding current.
For example, in normal pulse MAG welding, it is 30 to 60 [A] close to the base current value.
Further, even in pulse welding, since the base current value is small in pulse MIG welding on aluminum, it is 5 to 10 [A].
In the case of a welding method other than pulse welding, the arc period is 50 to 250 [A], although it varies depending on the welding conditions. When welding is unstable, it is necessary to increase the amount of current, but control is performed so that current does not flow as much as possible during a short circuit.
Moreover, since an arc break always occurs at the time of arc, in short-circuit welding, control is performed so that more current flows at the time of arc than at the time of short-circuit. That is, the larger the arc current at the time of welding, the more current, specifically, the current of 10 to 80% of the arc current is controlled to flow through the current circuit 10.
In the configuration diagram of FIG. 1, the current control circuit 11 controls the alternating current output from the isolation transformer 4. However, even if the direct current is controlled between the rectifier circuit 12 and the direct current reactor 13, the same effect is obtained. Obtainable.

The current interrupt mechanism 100 operates to interrupt the welding current flowing through the DC reactor 6 in accordance with an instruction from the control circuit 17. For this reason, most of the current flowing through the arc welded portion comes from the current flowing through the DC reactor 13. For example, when the current control circuit 11 controls the current flowing through the DC reactor 13 to be 20 [%] of the arc current, the arc current changes to nearly 20 [%] when the current interrupting mechanism 100 is activated. Will do.
In Conventional Example 3, the current that flows when the current cut-off mechanism operates depends on the resistance value of the resistor 274, but in the present invention, it can be changed to an arbitrary current by the current control circuit 11. In addition, since no current flows through the resistor after the current is cut off, no heat is generated by the resistor.

FIG. 2 is a block diagram of the second embodiment of the present invention.
In the figure, the current control circuit 11 includes capacitors 21 and 22. In the case of FIG. 2, the number of turns of the insulation transformer 4 is changed so that the voltage applied to the current control circuit 11 is higher than the voltage applied to the second rectifier circuit 5 with respect to the voltage converted by the insulation transformer 4. Capacitors 21 and 22 are selected to have sufficiently large capacities so that charging is not completed even when the inverter circuit 3 is 100 [%] on.
Since the voltage applied to the insulation transformer 4, the current control circuit 11, and the third rectifier circuit 12 is higher than the voltage applied to the second rectifier circuit 5 from the insulation transformer 4, the current passes through the current control circuit 11 from the insulation transformer 4. The current control circuit 11 including the capacitors 21 and 22 limits the current passing from the insulating transformer 4 through the third rectifier circuit 12.
That is, if the voltage (average voltage) applied to the insulating transformer 4 is high, the current flowing through the rectifier circuit 12 increases. If the voltage applied to the insulating transformer is low, the flowing current decreases.
In short-circuit welding, the voltage applied to the insulating transformer 4 is low during a short circuit, and the voltage applied to the insulating transformer 4 is high during an arc. In the present invention, the voltage applied to the insulating transformer 4 is increased during the arc, and more current flows from the insulating transformer 4 to the rectifier circuit 12 and the DC reactor 13 through the current control circuit 11 because the arc breakage always occurs during the arc. Thus, arc breakage can be prevented.

In addition, a coil may be used in the current control circuit 11 instead of the capacitors 21 and 22. A case where coils 31 and 32 are used instead of the capacitors 21 and 22 is shown in FIG. Since the coil has a function of limiting the alternating current, it plays the same role as a capacitor.
The current interrupt mechanism 100 operates to interrupt the welding current flowing through the main DC reactor 6 according to an instruction from the control circuit 17. For this reason, most of the current flowing through the arc welded portion comes from the current flowing through the DC reactor 13. For example, when the current control circuit 11 controls the current flowing through the DC reactor 13 to be 20 [%] of the arc current, the arc current changes to nearly 20 [%] when the current interrupting mechanism 100 is activated. Will do.
In Conventional Example 3, the current that flows when the current cutoff mechanism operates depends on the resistance value of the resistor 274, but in the present invention, it changes to a current that depends on the capacitor or coil in the current control circuit 11. In addition, since no current flows through the resistor after the current is cut off, no heat is generated by the resistor.

FIG. 4 is a block diagram of the third embodiment of the present invention.
In the third embodiment of the present invention, as shown in the figure, the current interruption mechanism 100 is provided on the side closer to the arc welded portion than the DC reactor 6. For this reason, when the electric current interruption mechanism 100 works, the electric current which flows into an arc welding part becomes only the electric current which flows through the DC reactor 13. FIG.
For example, when the current control circuit 11 controls the current flowing through the DC reactor 13 to be 20% of the arc current, the arc current rapidly increases to 20% when the current interrupting mechanism 100 is activated. Will change. In other words, unlike the conventional example 3, there is no influence of the DC reactor (DC reactor 6 in FIG. 4). Further, since there is the DC reactor 13 having a large reactance, even if the current interrupting mechanism 100 interrupts the current on the side closer to the arc welded part than the main DC reactor 6, there is a possibility that the arc will be cut off due to the effect of the DC reactor 13. Absent.

The fourth embodiment relates to the operation timing of the current interrupt mechanism 100 in the first to third embodiments.
The flow of the arc welding process according to the fourth embodiment is as follows.
(1) Start (2) Current interrupt mechanism 100 operates (3) Welding voltage applied to wire (4) Wire feed (5) Continue wire feed until wire contacts base material (6) Wire is base material When the wire 8 is touched, the wire feed is stopped. (7) The wire is pulled back. (8) An arc is generated. (9) A small current of several [A] to 60 [A] is maintained. (11) Execute normal arc welding sequence (12) End

Conventionally, a large current flowed when the wire contacted in (6). However, in the present invention, since the main current is already interrupted by the current interrupt mechanism 100, a large current does not flow. As a result, spatter can be suppressed and welding quality can be improved.
Further, when the current interrupting mechanism 100 is operating, since the current flows through the DC reactor 13 having a large reactance, the small arc current in (9) is maintained, and wire burn-up is prevented while changing from wire pull back to normal feed. It is effective for.

In the fifth embodiment, the operation timing of the current interrupt mechanism 100 can be set as follows.
(1) Start (2) Perform arc welding (2-1) Voltage control during arc period in arc welding (2-2) During the arc period, the base material 8 and the wire tip are short-circuited, and the arc voltage decreases rapidly. . When the value of the reduced arc voltage is equal to or less than a value obtained by subtracting a preset value from the target arc voltage value, it is determined that a short circuit has occurred.
(2-3) Current interruption mechanism 100 operates (2-4) A small current of 10 to 100 [A] is maintained between 10 [μs] and 2 [ms] in a short circuit state (2-5) Short circuit open Current is passed (2-6) The short circuit is opened and the arc state is established. (3) The following (2-1) follows.

In normal welding, when the short circuit occurs, the resistance value decreases and the current value increases, so that the short circuit state cannot be smoothly shifted. In the welding machine of the present invention, as described above, when the arc voltage value is equal to or less than a value obtained by subtracting a preset value from a target value, current interruption is performed.
As a result, the current value rapidly decreases, so that the arc state can be smoothly shifted to the short-circuit state.

When performing pulse welding, it is often effective to reduce the base current. In particular, when performing pulse welding of aluminum, pulse welding can be stably performed by setting the base current to a small value of 4 to 20 [A].
Example 6 is for reducing the base current in this way, and the base current is lowered by the following pulse welding flow.
(1) Start of arc welding (2) Stop current interrupting mechanism 100 (2-1) Apply pulse welding peak current (3) Operate current interrupting mechanism 100 (3-1) Apply pulse welding base current (4 ) Repeat (2) to (3-1) below

  When performing pulse welding, the current interruption mechanism 100 is stopped, the base current is supplied from the arc welding subcircuit, and the current interruption mechanism 100 is operated when the peak current of pulse welding is supplied. Since the DC reactor 6 has a small reactance, the rise and fall of the pulse current can be made steep.

  The present invention provides stable arc start and arc welding and can be widely applied to arc welding machines.

It is a block diagram of the 1st Example of this invention. It is a block diagram of the 2nd Example of this invention. It is the figure which used the coil for the current control circuit. It is a block diagram of the 3rd Example of this invention. It is a figure which shows the prior art example 1 of the arc welding power supply of a constant voltage system. It is a figure which shows the prior art example 2 of the arc welding power supply of a constant voltage system. It is a figure which shows the modification of the prior art example 2 of the arc welding power supply of a constant voltage system. It is a figure which shows the prior art example 3 of the arc welding power supply of a constant voltage system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Commercial AC power supply 2 1st rectifier circuit 3 Inverter circuit 4 Insulation transformer 5 2nd rectifier circuit 6 DC reactor 7 Welding torch 8 Base material 10 Current circuit 11 Current control circuit 12 Rectifier circuit 13 DC reactor 16 Rectifier 17 Control circuit 21 , 22 Capacitors 31, 32 Coils 40, 41 DC reactance 42 Wire 43 Wire feed roller 44 Current-carrying chip 45 Arc load 51 Capacitor 52 Full-wave rectifier diode 56 Secondary winding 100 Current cut-off mechanism 206 Current Blocking mechanism 210 Welded part 274 Resistance

Claims (8)

A first rectifier circuit that rectifies an alternating current into a direct current, an inverter circuit that is connected to an output side of the first rectifier circuit and converts the output of the first rectifier circuit into a high-frequency alternating current; and the inverter circuit A transformer connected to the output side of the inverter to convert the output of the inverter circuit to output from two secondary coils, and a DC connected to the first secondary coil to rectify the output of the transformer. And a first reactor connected between the output side of the second rectifier circuit and the welding torch and smoothing the output of the rectifier circuit and applying the output to the welding torch. Arc welding main circuit;
An arc welding secondary connected between the secondary second coil and the welding torch and providing the output of the rectifier circuit to the welding torch via a second reactor having a reactance greater than the reactance of the first reactor. Circuit,
A control circuit for controlling the inverter circuit;
An arc welding machine equipped with
The arc welding main circuit further includes a current interrupting mechanism, and the current interrupting mechanism interrupts a current output from the first reactor according to a command output from the control circuit. Welding machine.   The arc welding subcircuit includes a current control circuit connected to the secondary side second coil, a third rectifier circuit connected to the output side of the current control circuit and rectifying the output of the current control circuit; The arc welder according to claim 1, further comprising: the second reactor connected to the third rectifier circuit.   3. The arc according to claim 2, wherein the current control circuit is constituted by a semiconductor element, and controls the current by turning on and off the gate of the semiconductor element by a signal from the control circuit. Welding machine.   The arc welding machine according to claim 2, wherein the current control circuit is configured by a capacitor or a coil, and controls the current by a function of limiting an alternating current of the capacitor or the coil.   The arc welding machine according to any one of claims 1 to 4, wherein the current interrupting mechanism is disposed between the first reactor and the welding torch.   The arc welding machine according to any one of claims 1 to 5, wherein the control circuit outputs a command to the current interrupt mechanism when the arc is turned on to interrupt the current output from the first reactor. .   The control circuit outputs a command to the current interrupt mechanism when the arc voltage in the arc state is lowered by a predetermined value from a target value, and interrupts the current output from the first reactor. The arc welder according to any one of claims 1 to 5.   When performing pulse welding, the control circuit operates the current interrupt mechanism in the base current section of pulse welding to supply the base current from the arc welding subcircuit, and the current interrupt mechanism of the current interrupt mechanism in the peak current section of pulse welding. 6. The arc welder according to claim 1, wherein the operation is stopped.

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