GB2039166A - Power source for arc welding - Google Patents
Power source for arc welding Download PDFInfo
- Publication number
- GB2039166A GB2039166A GB7943188A GB7943188A GB2039166A GB 2039166 A GB2039166 A GB 2039166A GB 7943188 A GB7943188 A GB 7943188A GB 7943188 A GB7943188 A GB 7943188A GB 2039166 A GB2039166 A GB 2039166A
- Authority
- GB
- United Kingdom
- Prior art keywords
- power source
- welding
- frequency
- thyristors
- frequency converter
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 238000003466 welding Methods 0.000 title claims abstract description 36
- 238000004804 winding Methods 0.000 claims abstract description 9
- 238000009499 grossing Methods 0.000 claims description 4
- 238000010276 construction Methods 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 238000013019 agitation Methods 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F30/00—Fixed transformers not covered by group H01F19/00
- H01F30/06—Fixed transformers not covered by group H01F19/00 characterised by the structure
- H01F30/12—Two-phase, three-phase or polyphase transformers
- H01F30/14—Two-phase, three-phase or polyphase transformers for changing the number of phases
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/10—Other electric circuits therefor; Protective circuits; Remote controls
- B23K9/1006—Power supply
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
- H02M5/02—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc
- H02M5/04—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters
- H02M5/22—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M5/25—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means
- H02M5/257—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K2103/00—Materials to be soldered, welded or cut
- B23K2103/08—Non-ferrous metals or alloys
- B23K2103/10—Aluminium or alloys thereof
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- Mechanical Engineering (AREA)
- Arc Welding Control (AREA)
- Ac-Ac Conversion (AREA)
Abstract
In a power source (10) for arc welding, two transformers (12) are connected in the manner of a Scott connection in a three-phase network (R, S, T,) and, in addition, a frequency converter (15) is provided for generating an alternating single- phase welding current with a welding current frequency of twice the supply frequency. In order to provide a relatively small structure having relatively low weight, whilst at the same time achieving optimum welding characteristics, the frequency converter (15) is provided as two secondary transformer windings (16, 17) which are associated with two pairs of controllable rectifiers (18, 19, and 20, 21) connected with opposite flow directions (22, 23) in a centre-tapped halfwave circuit. <IMAGE>
Description
SPECIFICATION
Power source for arc welding
The present invention relates to a power source for arc welding, comprising two transformers connected in the manner of a Scott connection in a three-phase network, and a frequency converter for generating an alternating single-phase current with a welding current frequency of twice the supply frequency.
The above statement sets out the state of the art which has become known, for example, from the journal Elektrotechnische Zeitschrift", year 1971, volume 8/9, pages 185 to 188. In this journal a new welding converter with frequency conversion and symmetrical supply loading is described in which the primary three-phase network is loaded symmetrically by a choke which is pre-magnetized with direct current, with single-phase loading and frequency conversion from 50 to 100 Hz.
With the higher frequency, better welding characteristics with respect to ignition, stability of the arc and quality of the welding are achieved by more intensive agitation of the molten pool, leading particularly to better welding results in the alternating-current welding of aluminium. The disadvantageous feature in the known welding converter is the use of the DC-premagnetized choke which, on the one hand, makes the construction too large and, on the other hand, makes the weldingpower source too heavy. In addition, the high open-circuit reactive power consumption with this welding converter is unfavourable. Also, in order to improve the low power factor (approximately 0.4) a capacitor is required, together with an inductance to form a resonant circuit for the third current harmonic.It is also a disadvantage that the welding current can only be adjusted in a ratio of 1:8 and regulation/control can be exercised only via the DC-premagnetizing circuit with relative high power and an inductance-dependent, relatively long time delay.
It is the object of the present invention to provide a welding-power source which overcomes, or substantially reduces, the abovementioned disadvantages.
According to the present invention, there is provided a power source for arc welding, comprising two transformers connected by the
Scott system in a three-phase network, and a frequency converter for generating an alternating single phase welding current with a welding current frequency of twice the supply frequency, characterised in that, as a frequency converter (15), two secondary transformer windings (16, 17) are associated with two pairs of controllable rectifiers (18, 19 and 20, 21) connected with opposite flow directions (22, 23) in a centre-tapped halfwave circuit.
With the advantageous construction of the frequency converter propose according to the invention the above-mentioned object is achieved and a power source is provided the construction and weight of which is reduced by at least 50% in comparison with the known system. In addition, the further disadvantages of the known welding converter are also avoided in that the invention produces a power source having a welding current frequency of twice the supply frequency with nearly optimum parameters and the simplest type of construction.
In the description which follows the power source according to the invention is described in greater detail with reference to the accompanying drawings in which,
Figures 1. 4 and 5 show a block diagrams of power sources according to the invention, and
Figures 2 and 3 show current/voltage diagrams.
Referring to the drawings a power source for arc welding is shown as a whole at 10.
The power source 10 is provided by two welding transformers 12 which are connected to a three-phase network 11, the primary windings 13, 14 of which are connected in the manner of a Scott connection.
In addition, the power source 10 is provided with a frequency converter 15 with which an alternating single-phase current with a welding current frequency of twice the supply frequency can be produced. According to the invention, as a frequency converter, the two secondary transformer windings 16, 17 are associated with two pairs of controllable rectifiers 18/19 and 20/21 connected with opposite flow directions 22 and 23 in a centre-tapped halfwave circuit. In this arrangement each of the secondary windings 16 and 17 is provided with two identical winding parts 16a and 16b and 17a and 17b the centre point M of which is connected to a workpiece 26 via lines 24 and 25. The other end of the secondary winding parts 16a and 16b is connected to one terminal 27 of a smoothing choke 28 via the controllable rectifiers 18 and 19.The other terminal 29 of the smoothing choke 28 is electrically connected to the other connection of the secondary winding parts 17a and 17b via controllable rectifiers 20 and 21. The centre tap 30 of the smoothing choke 28 is connected to a welding torch 32, shown diagrammatically, via a line 31.
It is particularly advantageous if the control lable rectifiers 18, 19, 20, 21 are provided as thyristors. The thyristors 18 to 21 are driven via a control device 33 which is provided with a program transmitter 34 which is associated with the control electrodes of the thyristors, and which can be used to set (program) the opening and closing times of the thyristors 18 to 21, in such manner that, according to the invention, the welding current is single-phase and that its frequency is twice that of the supply frequency. According to Fig. 2 (sections of the primary voltages at the transformers) and Fig. 3 (secondary open-circuit voltage with fully-driven thyristors), the thyristors 18 to 21 are opened, the numbers specified in the halfwaves of Figs. 2 and 3 indicating the thyristors which are on.
The program transmitter 34 is preferably provided as a timing transmitter, known per se, for driving thyristor circuits.
In the illustrative embodiment according to
Fig. 1 four thyristors are provided. Of course, a circuit arrangement can also be used advantageously in which two thyristors 35, 36 and four diodes 37, 38, 39, 40 are connected in accordance with Fig. 4.
In Fig. 5 a circuit is disclosed in which a transformer is operated at a frequency of 100
Hz. The circuit according to Fig. 5 having four thyristors 41 and four diodes 42, in contrast to the welding converter according to the prior art, a power source of particularly simple construction is also produced.
The preferred use of the power source described is for tungsten inert-gas arc welding.
Of course, it can also be used in conjunction with submerged arc-welding systems with high alternating welding currents, with shielded inert gas metal arc welding systems with fusible electrodes and with processes of a similar type.
Instead of the thyristors serving as controllable switches and rectifiers, it will be obvious that other equivalent electric or electronic components can be used. Thus it is possible, for example, to use two different components advantageously, each of which exercises one of the said functions (switching and rectifying), such as, for example, a diode and a switching transistor connected in series.
Claims (5)
1. A power source for arc welding, comprising two transformers connected by the system in a three-phase network, and a frequency converter for generating an alternating single-phase welding current with a welding current frequency of twice the supply frequency, characterised in that, as a frequency converter (15), two secondary transformer windings (16, 17) are associated with two pairs of controllable rectifiers (18, 19 and 20, 21) connected with opposite flow directions (22, 23) in a centre-tapped halfwave circuit.
2. A power source according to claim 1, characterised in that, between the frequency converter (15) and the welding location (26, 32) a smoothing choke (28) is provided.
3. A power source according to claim 1 or claim 2, characterised in that the controllable rectifiers (18 to 21) are in the form of thyristors.
4. A power source according to claim 3, characterised in that the thyristors (18 to 21) are driven via a control device (33) which is provided with a program transmitter (34), preferably in the form of a timing generator, for setting the opening and closing time of the thyristors (18 to 21).
5. A power source for arc welding, substantially as hereinbefore described with reference to the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19782855663 DE2855663A1 (en) | 1978-12-22 | 1978-12-22 | POWER SOURCE FOR ARC WELDING |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2039166A true GB2039166A (en) | 1980-07-30 |
Family
ID=6058119
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB7943188A Withdrawn GB2039166A (en) | 1978-12-22 | 1979-12-14 | Power source for arc welding |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS55144379A (en) |
| AT (1) | ATA710779A (en) |
| BR (1) | BR7908448A (en) |
| DE (1) | DE2855663A1 (en) |
| FR (1) | FR2444528A1 (en) |
| GB (1) | GB2039166A (en) |
| IT (1) | IT1126528B (en) |
| SE (1) | SE7909925L (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5340963A (en) * | 1990-02-15 | 1994-08-23 | Miller Electric Mfg. Co. | Alternating current power source for welding |
| US6114655A (en) * | 1997-06-11 | 2000-09-05 | Illinois Tool Works Inc. | Method and apparatus for producing welding power |
| US7573000B2 (en) | 2003-07-11 | 2009-08-11 | Lincoln Global, Inc. | Power source for plasma device |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100655089B1 (en) * | 2004-10-04 | 2006-12-08 | 이성래 | Structure of signboard frame |
-
1978
- 1978-12-22 DE DE19782855663 patent/DE2855663A1/en not_active Withdrawn
-
1979
- 1979-11-05 AT AT0710779A patent/ATA710779A/en not_active Application Discontinuation
- 1979-11-30 SE SE7909925A patent/SE7909925L/en not_active Application Discontinuation
- 1979-12-07 IT IT27943/79A patent/IT1126528B/en active
- 1979-12-10 JP JP15930579A patent/JPS55144379A/en active Pending
- 1979-12-14 GB GB7943188A patent/GB2039166A/en not_active Withdrawn
- 1979-12-21 BR BR7908448A patent/BR7908448A/en unknown
- 1979-12-21 FR FR7931507A patent/FR2444528A1/en active Granted
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5340963A (en) * | 1990-02-15 | 1994-08-23 | Miller Electric Mfg. Co. | Alternating current power source for welding |
| US6114655A (en) * | 1997-06-11 | 2000-09-05 | Illinois Tool Works Inc. | Method and apparatus for producing welding power |
| US6278081B1 (en) * | 1997-06-11 | 2001-08-21 | Illinois Tool Works Inc. | Method and apparatus for producing welding power |
| US7573000B2 (en) | 2003-07-11 | 2009-08-11 | Lincoln Global, Inc. | Power source for plasma device |
| US7796005B2 (en) | 2003-07-11 | 2010-09-14 | Lincoln Global, Inc. | Power source for plasma device |
Also Published As
| Publication number | Publication date |
|---|---|
| BR7908448A (en) | 1980-08-26 |
| JPS55144379A (en) | 1980-11-11 |
| FR2444528B3 (en) | 1981-10-02 |
| IT1126528B (en) | 1986-05-21 |
| SE7909925L (en) | 1980-06-23 |
| FR2444528A1 (en) | 1980-07-18 |
| ATA710779A (en) | 1982-07-15 |
| DE2855663A1 (en) | 1980-07-03 |
| IT7927943A0 (en) | 1979-12-07 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |