JP2009171684A - Power supply device and power supply device for arc processing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply device wherein the number of the winding taps can be reduced in a transformer and further finely adjust output voltage and to facilitate this adjustment. <P>SOLUTION: The connecting positions of taps T provided on the primary windings Pu, Pv, Pw of a welding transformer WT are changed by a selector switch SW2. As a result, the transformation factor of the transformer WT is changed and the voltage value of output voltage for arc processing is adjusted stepwise. In addition, the ignition angles of the thyristors SCR1 to SCR3 of a secondary rectifying circuit DR2 are controlled by an ignition angle control circuit 12. As a result, direct-current output voltage generated from alternating-current voltage obtained as the result of transformation at the transformer at the rectifying circuit DR2, that is, the voltage value of output voltage for arc processing is continuously adjusted. Thus, output voltage for arc processing can be continuously adjusted (finely adjusted) by control of the ignition angles of the thyristors SCR1 to SCR3 at the rectifying circuit DR2 even though the number of taps on the primary windings Pu, Pv, Pw is reduced. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power supply device for, for example, arc machining that performs output voltage adjustment by switching taps provided in a transformer.

  In a power supply device used for an arc machine or the like, for example, as shown in Patent Document 1, a single-phase AC voltage is input to a primary side of a welding transformer from a commercial power source or the like, and two welding transformers are input from the input AC voltage. On the next side, an arc machining output voltage suitable for arc machining is generated. For adjusting the output voltage for arc machining, taps are provided at a plurality of locations on the primary winding of the welding transformer, and the arc machining generated on the secondary side of the welding transformer by switching the connection position of the tap with a switch. The voltage value of the output voltage is adjusted stepwise according to the tap connection position.

In addition, the power supply devices shown in Patent Document 2 and Patent Document 3 are configured to use a three-phase welding transformer and have an input for a three-phase AC power supply. When a plurality of taps are installed on the primary winding of the welding transformer to adjust the output voltage in the power supply apparatus having a three-phase input AC voltage as described in Patent Document 1, the U phase, V phase, W A plurality of taps are provided in each phase winding, and the voltage value of the output voltage can be adjusted by switching the connection of the taps of each phase in conjunction with a switch.
Japanese Patent Publication No.62-30871 JP 2006-223031 A JP 2005-66603 A

  However, in order to enable fine adjustment of the output voltage, it is necessary to increase the number of taps, and in the case of handling a three-phase input AC voltage like the power supply devices of Patent Documents 2 and 3, the primary side Since the taps are provided in the windings of each phase, the total number is three times that. For example, when the voltage value of the output voltage is adjusted in 11 steps, 11 taps are required for each phase, and the total number is 33, which is three times that number.

  For this reason, the arrangement of the tap itself and the routing of the wiring to the tap become complicated, the structure of the welding transformer becomes complicated, and much effort is required to assemble the welding transformer and consequently the power supply device. Even if the number of taps is increased to enable further fine adjustment, it cannot be denied that the output voltage will be adjusted stepwise other than the assembly problem, and fine adjustment that gradually changes cannot be performed. . Furthermore, in order to protect the contact of the switch for switching the connection of the tap, it is necessary to perform all the switch operations for switching the tap with the power supply device stopped, and the adjustment is complicated.

  The present invention has been made to solve the above-mentioned problems, and its object is to enable fine adjustment of output voltage adjustment and to easily perform adjustment while reducing the number of winding taps of the transformer. It is an object of the present invention to provide a power supply device and an arc machining power supply device that can be used.

  In order to solve the above problems, the invention described in claim 1 is a three-phase transformer that converts an input three-phase AC voltage into an AC voltage having a predetermined voltage value, and a post-conversion that is converted by the three-phase transformer. And a rectifier circuit that converts the three-phase AC voltage into a DC output voltage, wherein the primary-side winding or the secondary-side winding of each phase of the three-phase transformer has a different number of turns. A first voltage adjusting unit that has a plurality of drawn taps and adjusts the voltage value of the output voltage stepwise by switching the connection position of the taps; and the rectifier circuit includes at least one in each phase. And a second voltage adjusting means configured to continuously adjust the voltage value of the output voltage based on the firing angle control of the thyristor, which is constituted by a full-wave or half-wave rectifier circuit using a thyristor. And

  In the present invention, in the first voltage adjusting means, the voltage conversion rate of the transformer is changed by switching the connection position of the tap provided in the primary side winding or the secondary side winding of each phase of the three-phase transformer, thereby The voltage value of the output voltage is adjusted stepwise. In the second voltage adjusting means, when generating the DC output voltage from the AC voltage after the transformer conversion by controlling the firing angle of the thyristor of the full-wave or half-wave rectifier circuit using at least one thyristor in each phase. The voltage value of the output voltage is continuously adjusted. As a result, even if the first voltage adjusting means has a small number of taps, the output voltage can be continuously adjusted (finely adjusted) by controlling the firing angle of the thyristor in the second voltage adjusting means. In addition, the voltage adjustment by controlling the firing angle of the thyristor can be performed while the power supply device is in operation, so that the voltage adjustment is easy. In addition, voltage adjustment only by controlling the firing angle of the thyristor is not suitable for wide range voltage adjustment, but it can be applied to wide range voltage adjustment by combination with the first voltage adjustment means.

  According to a second aspect of the present invention, in the power supply device according to the first aspect, in the second voltage adjusting unit, the voltage adjustment range by the firing angle control of the thyristor is the switching of the tap in the first voltage adjusting unit. Its gist is that it is set to wrap around the stepwise adjustment voltage by connection.

  In the present invention, in the second voltage adjusting means, the voltage adjustment width by the firing angle control of the thyristor is set so as to wrap around the stepwise adjustment voltage by the tap switching connection in the first voltage adjusting means. Thereby, voltage adjustment of a continuous output voltage in a wide range can be performed.

  According to a third aspect of the present invention, in the power supply device according to the first or second aspect, in the second voltage adjusting unit, a portion before the peak of the half-wave rectification portion where the firing angle control of the thyristor is performed is The gist is that it is set in the control target part.

  In the present invention, in the second voltage adjusting means, the peak portion of the half-wave rectification portion where the firing angle control of the thyristor is performed is controlled, and the rectification operation (voltage generation operation) of the thyristor in the peak portion is controlled. It is controlled and the voltage value of the output voltage is adjusted. Thereby, an increase in the ripple of the output voltage is reduced, and the output voltage is stabilized.

  According to a fourth aspect of the present invention, in the power supply device according to any one of the first to third aspects of the present invention, the second voltage adjusting unit is configured to ignite the thyristor based on a change in the resistance value of the variable resistor. The gist of the invention is that the phase of the trigger signal is changed.

  In the present invention, in the second voltage adjusting means, the phase of the trigger signal for starting the thyristor is changed based on the change in the resistance value of the variable resistor. That is, the firing angle of the thyristor can be easily adjusted simply by changing the resistance value of the variable resistor.

  An invention according to claim 5 is an arc configured to generate an output voltage for arc machining that performs arc machining of a workpiece using the power supply device according to any one of claims 1 to 4. It is a power supply device for processing.

  In this invention, since the power supply device according to any one of claims 1 to 4 is used to configure the power supply device for arc machining, the power supply device for arc machining that can obtain the effects of the above-mentioned respective claims is provided. Can be provided.

  According to the present invention, it is possible to provide a power supply apparatus and an arc machining power supply apparatus that can finely adjust the output voltage while easily reducing the number of winding taps of the transformer and can easily perform the adjustment. it can.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
FIG. 1 shows an arc machine 10 provided with a power supply device 11 for arc machining of this embodiment. The arc machine 10 supplies an arc machining output voltage output from the power supply device 11 to the torch TH, and generates an arc from the torch TH toward the workpiece M, thereby causing the workpiece M to be processed. It is a device that performs arc processing such as welding and cutting.

  The arc machining power supply device 11 includes a three-phase welding transformer WT that converts a three-phase AC voltage input from a three-phase 200 V or three-phase 400 V commercial power supply into an arc machining output voltage suitable for arc machining. ing. On the primary side of the welding transformer WT, an open / close switch SW1 is provided, and U-phase, V-phase, and W-phase input lines L11 to L13 that receive supply of U-phase, V-phase, and W-phase input AC voltages are provided. The U-phase primary winding Pu is between the V-phase input lines L11 and L12, and the V-phase primary winding Pv is between the W-U phase input lines L13 and L11 between the V-W phase input lines L12 and L13. Are each provided with a W-phase primary winding Pw, and these primary windings Pu, Pv, Pw are connected by Δ connection. The open / close switches SW1 on the input lines L11 to L13 of each phase are turned on and off in conjunction with each other, and supply / shut off the input AC voltage to the primary windings Pu, Pv, Pw of each phase.

  On the other end side of the primary side windings Pu, Pv, Pw of each phase, five taps T drawn out from a portion that increases step by step by a fixed number of turns are provided, respectively. A change-over switch SW2 that switches the connection of the input lines L12, L13, and L11 connected to the other end side of the lines Pu, Pv, and Pw to one of the contacts of each tap T is provided. The change-over switch SW2 for each phase is operated in conjunction with each other and is connected to the tap T at the same position for each phase. That is, the number of turns of the primary side windings Pu, Pv, Pw is changed in five stages by the selection of the tap T by the changeover switch SW2, and the voltage conversion rate of the welding transformer WT is changed in five stages. Thereby, the voltage value of the arc machining output voltage generated on the secondary side of the welding transformer WT is adjusted in five steps on the primary side.

  On the secondary side of the welding transformer WT, the U-phase, V-phase, and W-phase secondary windings S1u, S1v, and S1w are connected to the primary windings Pu, Pv, and Pw made of Δ connection by Δ connection. These secondary side windings S1u, S1v, S1w have two vertices (connection points between the windings S1u, S1v, S1w) via U-phase, V-phase, and W-phase output lines L21-L23, respectively. It is connected to the secondary rectifier circuit DR2.

  The secondary rectifier circuit DR2 is configured by a full-wave rectifier bridge circuit using three diodes D1 to D3 and three thyristors SCR1 to SCR3. Specifically, for three series circuits in which the anodes of the diodes D1 to D3 and the cathodes of the thyristors SCR1 to SCR3 are connected, the corresponding output lines L21 to L23 are between the diodes D1 to D3 and the thyristors SCR1 to SCR3. The cathodes of the diodes D1 to D3 are connected to the plus side output line L31 having the DC reactor DCL, and the anodes of the thyristors SCR1 to SCR3 are respectively connected to the minus side output line L32. A torch TH is connected to the plus side output line L31, and a workpiece M is connected to the minus side output line L32, and machining is performed from the torch TH based on the supply of the arc machining output voltage to the torch TH. An arc for machining is generated toward the object M.

  The gates of the thyristors SCR1 to SCR3 of each phase are connected to their cathodes via the resistors R11 to R13, the diodes D11 to D13, and the secondary winding portions PT1b to PT3b of the pulse transformers PT1 to PT3, respectively. . The thyristors SCR1 to SCR3 are controlled by a firing angle control circuit 12 to be described later through pulse transformers PT1 to PT3, and the voltage value of the arc machining output voltage is adjusted on the secondary side of the welding transformer WT. Continuous adjustment (linear adjustment) is possible.

  An ignition angle control circuit 12 that controls the ignition angles of the thyristors SCR1 to SCR3 is provided on the secondary side of the welding transformer WT, and is connected to the primary windings Pu, Pv, and Pw made of Δ connection with a Y connection ( U-phase, V-phase, and W-phase auxiliary windings S2u, S2v, and S2w connected by a star connection). These auxiliary windings S2u, S2v, S2w are provided to obtain phase detection voltage signals V1u, V1v, V1w for detecting the phase of the AC voltage of each phase. One end of each phase auxiliary winding S2u, S2v, S2w is connected to the ground GND (zero volt potential) as a midpoint, and the other end of each phase auxiliary winding S2u, S2v, S2w is connected to the phase shifter 13u, It is connected to the plus side input terminals of the comparators 14u, 14v, 14w via 13v, 13w. The phase shifters 13u, 13v, and 13w for each phase are configured by resistors and capacitors, respectively. The phase detection voltage signals V1u, V1v, and V1w obtained by the auxiliary windings S2u, S2v, and S2w for each phase are provided. Control voltage signals V2u, V2v, V2w delayed by 60 ° are generated (see FIG. 2, but only the U phase is shown as a representative), and the positive side input terminals of the comparators 14u, 14v, 14w of each phase are used for this control. Voltage signals V2u, V2v, and V2w are input, respectively. The negative side input terminals of the comparators 14u, 14v, and 14w of each phase are all connected to the variable resistor VR, and the negative side input terminal is a comparison that can adjust the voltage by changing the resistance by the variable resistor VR. The voltage Va is input.

  Here, the other ends of the auxiliary windings S2u, S2v, S2w of each phase are connected to each other on the cathode side via diodes D21 to D23, respectively, and the cathode is connected to the ground GND via the smoothing capacitor C1. . That is, the DC voltage generator 15 that generates the DC voltage VDC by the diodes D21 to D23 and the smoothing capacitor C1 from the phase voltages (phase detection voltage signals V1u, V1v, V1w) generated in the auxiliary windings S2u, S2v, S2w. The constructed and generated DC voltage VDC is supplied to the variable resistor VR via a resistor R21. The variable resistor VR generates a comparison voltage Va from the supplied DC voltage VDC and gradually changes the resistance value so that the voltage value of the comparison voltage Va changes gradually.

  The output terminals of the comparators 14u, 14v, and 14w for each phase are connected to the bases of the trigger generation transistors Tr1 to Tr3 via capacitors C11 to C13, respectively. Each of the comparators 14u, 14v, 14w has a voltage value of the control voltage signals V2u, V2v, V2w exceeding the comparison voltage Va based on the input of the control voltage signals V2u, V2v, V2w of each phase and the comparison voltage Va. An output signal that becomes H level during the period is output to the bases of the transistors Tr1 to Tr3 via the capacitors C11 to C13. The collectors of the transistors Tr1 to Tr3 are connected to the DC voltage generator 15 via the primary winding parts PT1a to PT3a and the common start / stop relay contact CR constituting the pulse transformers PT1 to PT3 of the respective phases. The emitters are connected to the base via diodes D31 to D33, respectively, and are also connected to the ground GND.

  The firing angle control circuit 12 configured as described above will be described focusing on the U phase with reference to FIG. 2, and is input to the comparators 14 u, 14 v and 14 w based on the change in the resistance value of the variable resistor VR. The voltage value of the comparison voltage Va rises and falls between zero volts and a predetermined voltage, so that, for example, in the U phase, the rise of the output signal of the comparator 14u to the H level is 0 ° to the U-phase control voltage signal V2u. It changes in the range of 30 °.

  When the output signal of the comparator 14u rises to H level, the capacitor C11 at the subsequent stage outputs a base current for turning on to the transistor Tr1 in a short time of the rise, and the transistor Tr1 is turned on based on this base current. As can be seen from the change in the collector potential of the U-phase transistor Tr1, the collector potential becomes zero (ground GND level) for a short time from the rise of the output signal of the comparator 14u based on the transistor Tr1 being turned on. The primary winding part PT1a generates a whisker-like trigger signal.

  The generated U-phase trigger signal is input to the gate of the U-phase thyristor SCR1 via the pulse transformer PT1, and the thyristor SCR1 rises from the rising edge of the output signal of the comparator 14u, that is, from 0 ° to the control voltage signal V2u. Based on a trigger signal that rises in any of the 30 ° ranges, the switch is turned on. V-phase and W-phase trigger signals are similarly generated. The generated V-phase and W-phase trigger signals are input to the gates of the thyristors SCR2 and SCR3 of the V-phase and W-phase, respectively. The thyristors SCR2 and SCR3 are used for rising of the output signals of the comparators 14v and 14w, that is, for control. Each of the voltage signals V2v and V2w is switched to the ON state based on a trigger signal that rises in any of the range of 0 ° to 30 °.

  The firing angle control of the thyristors SCR1 to SCR3 of each phase is performed in a range from 0 ° to 30 ° including the control voltage signals V2u, V2v, and V2w for the U phase, V phase, and W phase. This is a half-wave rectification part, and a part in which the output voltage of the rectification circuit DR2 is changed by the control. In particular, 0 ° of the control voltage signals V2u, V2v, V2w is a boundary point that exceeds the immediately preceding rectified portion. Accordingly, by gradually changing the resistance value of the variable resistor VR, the firing angles of the thyristors SCR1 to SCR3 of each phase are changed in the range of 0 ° to 30 °, and the thyristor SCR1 in the pre-peak portion of the half-wave rectification portion is changed. The rectification operation (voltage generation operation) of SCR3 is controlled, and the voltage value of the output voltage is adjusted. Incidentally, by changing the firing angle of the thyristors SCR1 to SCR3 from 30 ° to 0 °, the voltage value of the output voltage is increased.

  Note that the firing angle control of the thyristors SCR1 to SCR3 can be expanded to a range of 0 ° to 60 °, and in this way, a wider voltage adjustment is possible. On the other hand, in this embodiment, by limiting the ignition angle control to 0 ° to 30 °, the output voltage of the rectifier circuit DR2 when the ignition angle control is 30 ° or more, that is, the output voltage for arc machining. Ripples can be reduced, and the arc machining output voltage can be stabilized.

  Thus, the output voltage of the rectifier circuit DR2, that is, the voltage value of the arc machining output voltage supplied to the torch TH can be adjusted even on the secondary side of the welding transformer WT. In the present embodiment, the tap T on the primary side is adjusted. On the secondary side, the output voltage can be continuously adjusted so as to wrap around the stepwise adjustment voltage. That is, in the arc machining power supply device 11, the arc machining output voltage can be continuously adjusted in a wide range by combining the switching of the primary tap T and the secondary firing angle control. It has become.

  Moreover, the adjustment of the arc machining output voltage in the secondary side firing angle control is easy because the adjustment is possible even during the arc machining, and the power supply device 11 is not repeatedly started and stopped. Therefore, it is possible to contribute to the contact protection of the open / close switch SW1 of the power supply device 11. In addition, since the thyristors SCR1 to SCR3 are used, the stop control of the power supply device 11 is easy, and the thyristors SCR1 to SCR3 are stopped when the wire is fed by an automatic feeder as an electrode for generating an arc in the torch TH. Anti-stick time limit (time limit for preventing the wire from being joined to the workpiece M after processing by delaying the suspension of voltage supply to the torch TH and preventing the wire from being joined after processing) by the control. Is also easier.

Next, characteristic effects of the present embodiment will be described.
(1) In this embodiment, the voltage conversion rate of the welding transformer WT is changed by switching the connection position of the tap T provided in the primary side windings Pu, Pv, Pw of each phase of the welding transformer WT with the changeover switch SW2. Thus, the voltage value of the arc machining output voltage is adjusted stepwise (first voltage adjusting means). Further, by the firing angle control of the thyristors SCR1 to SCR3 of the secondary side rectifier circuit DR2 by the firing angle control circuit 12, the output when the DC output voltage is generated by the rectifier circuit DR2 from the AC voltage after the transformer conversion. The voltage, that is, the voltage value of the arc machining output voltage is continuously adjusted (second voltage adjusting means). Thus, even if the number of taps T provided in the primary windings Pu, Pv, Pw is as small as five as in this embodiment, the arc is controlled by the firing angle control of the thyristors SCR1 to SCR3 in the rectifier circuit DR2. Continuous adjustment (fine adjustment) of the processing output voltage can be performed. In addition, voltage adjustment by controlling the firing angle of the thyristors SCR1 to SCR3 can be performed even when the power supply device 11 is in operation, so that voltage adjustment is easy. Further, voltage adjustment only by controlling the firing angle of the thyristors SCR1 to SCR3 is unsuitable for a wide range of voltage adjustment, but it also supports a wide range of voltage adjustment by combination with voltage adjustment by switching connection of the tap T. be able to.

  (2) In this embodiment, the voltage adjustment width by the firing angle control of the thyristors SCR1 to SCR3 is set so as to wrap around the stepwise adjustment voltage by the switching connection of the tap T. Thereby, voltage adjustment of the output voltage for continuous arc machining of a wide range can be performed.

  (3) In the present embodiment, the pre-peak part of the half-wave rectification part in which the firing angle control of the thyristors SCR1 to SCR3 is performed is the control target, and the rectification operation (voltage generation of the thyristors SCR1 to SCR3 in the pre-peak part Operation) is controlled, and the voltage value of the output voltage is adjusted. Thereby, an increase in the ripple of the output voltage of the rectifier circuit DR2, that is, the output voltage for arc machining can be reduced, and the output voltage for arc machining can be stabilized.

  (4) In this embodiment, the phase of the trigger signal for firing the thyristors SCR1 to SCR3 is changed based on the change in the resistance value of the variable resistor VR. That is, it is possible to easily adjust the firing angles of the thyristors SCR1 to SCR3 only by changing the resistance value of the variable resistor VR.

In addition, you may change embodiment of this invention as follows.
In the above embodiment, the primary side windings Pu, Pv, Pw are provided with a plurality of taps T, and the output voltage is adjusted on the primary side of the welding transformer WT by switching connection of the taps T. Taps may be provided on the windings S1u, S1v, and S1w, and the output voltage may be adjusted on the secondary side of the transformer WT.

  In the above embodiment, the Δ-Δ conversion type welding transformer WT in which the primary windings Pu, Pv, Pw and the secondary windings S1u, S1v, S1w are Δ-connected is used. You may comprise a power supply device using a Y-delta conversion and also a YY conversion type three phase transformer. Further, when the secondary side of the transformer is configured by a Y-connected winding, a half-wave rectifier circuit can be used instead of a full-wave rectifier circuit as in the above embodiment.

  In the above embodiment, the rectifier circuit DR2 is configured by the three thyristors SCR1 to SCR3 and the three diodes D1 to D3. However, the rectifier circuit DR2 may be configured by six thyristors. The voltage adjustment range by control can be expanded.

  In the above embodiment, the portion before the peak of the half-wave rectification portion where the firing angle control of the thyristors SCR1 to SCR3 is performed is the control target, but the portion after the peak may be the control target. By doing so, it is possible to expand the voltage adjustment range by controlling the firing angle of the thyristors SCR1 to SCR3.

  -You may change suitably the structure of the ignition angle control circuit 12 of the said embodiment. For example, although the auxiliary windings S2u, S2v, S2w are Y-connected, the control circuit may be configured using a Δ-connected one. Moreover, although bipolar type transistors Tr1-Tr3 were used, you may comprise using another switching element. Further, the adjustment of the firing angles of the thyristors SCR1 to SCR3 (trigger signal phase adjustment) is performed by the variable resistor VR. However, the adjustment may be performed by a device other than the variable resistor.

  -In the said embodiment, although implemented in the power supply apparatus 11 for arc processing, you may implement in the power supply apparatus of uses other than the object for arc machining.

It is a circuit diagram which shows the power supply device for arc processing of this embodiment. It is a wave form diagram of each place of a power supply device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Power supply device 12 ... Firing angle control circuit (2nd voltage adjustment means)
DR2 ... Secondary side rectifier circuit (rectifier circuit)
Pu, Pv, Pw ... Primary winding S1u, S1v, S1w ... Secondary winding SCR1-SCR3 ... Thyristor (second voltage adjusting means)
SW2 ... changeover switch (first voltage adjusting means)
T ... Tap (first voltage adjusting means)
VR: Variable resistor WT: Welding transformer (three-phase transformer)

Claims (5)

A three-phase transformer that converts an input three-phase AC voltage into an AC voltage having a predetermined voltage value, and a rectifier circuit that converts the converted three-phase AC voltage converted by the three-phase transformer into a DC output voltage. A power supply unit comprising:
A voltage value of the output voltage by switching a connection position of the taps, having a plurality of taps drawn from locations with different numbers of turns on the primary side winding or the secondary side winding of each phase of the three-phase transformer. First voltage adjusting means for adjusting stepwise,
The rectifier circuit is composed of a full-wave or half-wave rectifier circuit using at least one thyristor in each phase, and a second value that continuously adjusts the voltage value of the output voltage based on the firing angle control of the thyristor. A power supply apparatus comprising a voltage adjusting means. The power supply device according to claim 1,
In the second voltage adjusting means, the voltage adjustment width based on the firing angle control of the thyristor is set so as to wrap around the stepwise adjusted voltage due to the switching connection of the tap in the first voltage adjusting means. Power supply. The power supply device according to claim 1 or 2,
The power supply apparatus according to claim 2, wherein the second voltage adjusting unit is configured such that a part before peak of a half-wave rectification part where the firing angle control of the thyristor is performed is set as a part to be controlled. The power supply device according to any one of claims 1 to 3,
In the second voltage adjusting means, the phase of a trigger signal for firing the thyristor is changed based on a change in the resistance value of the variable resistor.   An arc machining power supply device configured to generate an arc machining output voltage for performing arc machining of a workpiece using the power supply device according to any one of claims 1 to 4. .

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