Method and apparatus for arc-welding

Claim 2

A welding rectification arrangement comprising transformer means having a plurality of inputs and outputs, at least said outputs being of different phase, rectifier means coupled with said transformer means to produce half-wave outputs for each output phase, means provided for each phase of said transformer means which are regulatable independently of one another for adjusting a previously predetermined asymmetrical amplitude relationship between the individual half-wave outputs, and impedance means coupled with each output phase, said impedance means being variable independently of one another for alternatively influencing the shape of the half-wave outputs, for limiting the current amplitude, and both.

Claim 3

A welding rectification arrangement as defined in claim 1, wherein said transformer means comprises single phase transformers.

Claim 4

A welding rectification arrangement as defined in claim 1, wherein said transformer means comprises at least one polyphase transformer.

Claim 5

A welding rectification arrangement as defined in claim 1, wherein said transformer means incorporates primary winding means provided with selectable taps, said means for adjusting the amplitudes of said half-wave outputs comprising switch means capable of being selectively coupled with given ones of said taps for changing independently of one another the transformer winding ratio for the voltages in each transformer phase.

Claim 6

A welding rectification arrangement as defined in claim 1, wherein said means for adjusting the amplitudes of the half-wave outputs comprises transductor means provided with working winding means which possess a different number of turns for each transformer phase.

Claim 7

A welding rectification arrangement as defined in claim 4, wherein said taps of said primary winding means of said transformer means which can be selectively coupled with said switch means possess a different number of turns in each transformer phase.

Claim 8

A welding rectification arrangement as defined in claim 4, wherein said taps of said primary winding means of said transformer means which can be selectively coupled with said switch means possess the same number of turns for each transformer phase, whereby the different transformer winding ratios in the individual transformer phases can be regulated by said switch means.

Claim 9

A welding rectification arrangement as defined in claim 1, wherein said transformer means incorporates secondary winding means provided with selectable taps, said means for adjusting the amplitudes of said half-wave outputs comprising switch means capable of being selectively coupled with given ones of said taps, said taps of said secondary winding means possessing the same number of turns.

Claim 10

A welding rectification arrangement as defined in claim 8, wherein said taps of said secondary winding means possess a different number of turns.

Claim 11

A welding rectification arrangement as defined in claim 5, wherein said transformer means incorporates secondary winding means, said working winding means of said transductor means being arranged in each transformer phase of said secondary winding means, the number of turns of each said working winding means being different.

Claim 12

A welding rectification arrangement as defined in claim 1, wherein said transformer means comprises two single-phase transformers, a voltage supply means for each single-phase transformer, the voltages supplied to said two single-phase transformers being phase displaced at least 30* with respect to one another.

Claim 13

A voltage rectification arrangement as defined in claim 1, wherein said impedance means coupled with each output phase are at least partially formed of saturatable reactances for influencing the shape of the half-waves.

Claim 14

A welding rectification arrangement as defined in claim 12, wherein said saturatable reactances comprise choke coil means with particle oriented laminated core means.

Claim 15

A welding rectification arrangement as defined in claim 1, wherein said impedance means coupled with each output phase are provided with switch means and taps which can be optionally selected via said switch means.

Claim 16

A welding rectification arrangement comprising transformer means having a plurality of inputs and outputs, at least said outputs being of different phase, rectifier means coupled with said transformer means to produce half-wave outputs for each output phase, means provided for each output phase which are regulatable independently of one another for adjusting a previously predetermined current amplitude relationship between the individual half-wave outputs, and impedance means coupled with each output phase, saiD impedance means being variable independently of one another for influencing the shape of the half-wave outputs.

Claim 17

A welding rectification arrangement comprising transformer means having a plurality of inputs and outputs, at least said outputs being of different phase, rectifier means coupled with said transformer means to produce half-wave outputs for each output phase, means provided for each output phase which are regulatable independently of one another for adjusting a previously predetermined current amplitude relationship between the individual half-wave outputs, and impedance means coupled with each output phase, saiD impedance means being variable independently of one another for influencing the shape of the half-wave outputs.

Claim 18

A welding rectification arrangement as defined in claim 15, wherein said previously predetermined current amplitude relationship between the individual half-wave outputs is an asymmetrical relationship.

Claim 19

A welding rectification arrangement as defined in claim 15, wherein said means for adjusting the current amplitudes of said half-wave outputs comprise adjustable impedance elements.

Claim 20

A welding rectification arrangement as defined in claim 17, wherein said adjustable impedance elements comprise saturatable reactances.

Claim 21

A welding rectification arrangement comprising transformer means having a plurality of inputs and outputs, at least said outputs being of different phase, rectifier means coupled with said transformer means to produce half-wave outputs for each output phase, means provided for each output phase which are regulatable independently of one another for producing an asymmetrical current amplitude relationship between the individual half-wave outputs.

Claim 22

A welding rectification arrangement comprising transformer means having a plurality of inputs and outputs, at least said outputs being of different phase, rectifier means coupled with said transformer means to produce half-wave outputs for each output phase, means provided for each output phase which are regulatable independently of one another for producing an asymmetrical current amplitude relationship between the individual half-wave outputs.

Claim 23

A welding apparatus adapted to be connected to a welding electrode, said apparatus comprising: polyphase transformer means having an n-phase alternating current secondary circuit output, n being an integer; rectifier arrangement means coupled with said n-phase alternating current secondary circuit output and adapted to be connected to said welding electrode, said rectifier arrangement means comprising branch circuits conducting half-wave current; impedance means connected in at least n-2 phases of said alternating current secondary circuit output prior to said rectifier arrangement means; disconnectable impedance means provided in at least one branch circuit of said rectifier arrangement means, whereby said disconnectable impedance means conducts only said half-wave current of said at least one branch circuit; and said impedance means and said disconnectable impedance means being dimensioned for providing a welding current output from said rectifier arrangement means comprising at least three amplitude values, each value differing from one another, said at least three amplitude values periodically following one another as a function of the frequency of the network and the number of said phases.

Claim 24

A welding apparatus adapted to be connected to a welding electrode, said apparatus comprising: polyphase transformer means having an n-phase alternating current secondary circuit output, n being an integer; rectifier arrangement means coupled with said n-phase alternating current secondary circuit output and adapted to be connected to said welding electrode, said rectifier arrangement means comprising branch circuits conducting half-wave current; impedance means connected in at least n-2 phases of said alternating current secondary circuit output prior to said rectifier arrangement means; disconnectable impedance means provided in at least one branch circuit of said rectifier arrangement means, whereby said disconnectable impedance means conducts only said half-wave current of said at least one branch circuit; and said impedance means and said disconnectable impedance means being dimensioned for providing a welding current output from said rectifier arrangement means comprising at least three amplitude values, each value differing from one another, said at least three amplitude values periodically following one another as a function of the frequency of the network and the number of said phases.

Claim 25

An apparatus as defined in claim 20, wherein said impedance means connected in said at least n-2 phases of said alternating current secondary circuit output are primarily inductive reactors.

Claim 26

An apparatus as defined in claim 20, wherein said impedance means connected in said at least n-2 phases of said alternating current secondary circuit output are primarily capacitive reactors.

Claim 27

An apparatus as defined in claim 20, wherein said impedance means connected in said at least n-2 phases of said alternating current secondary circuit output are constructed as LC-circuit.

Claim 28

An apparatus as defined in claim 20, wherein said impedance means connected in said at least n-2 phases of said alternating current secondary circuit output are constructed as transductors.

Claim 29

An apparatus as defined in claim 20, wherein said disconnectable impedance means provided in said at least one branch circuit of said rectifier arrangement means is primarily an ohmic resistor.

Claim 30

An apparatus as defined in claim 20, wherein said disconnectable impedance means provided in said at least one branch circuit of said rectifier arrangement means is primarily an inductive reactor.

Claim 31

An apparatus as defined in claim 20, wherein said disconnectable impedance means provided in said at least one branch circuit of said rectifier arrangement means is primarily a transductor.

Claim 32

An apparatus as defined in claim 25, wherein said ohmic resistor is adjustable, whereby the average output voltage of the entire apparatus can be changed by several volts.

Claim 33

An apparatus as defined in claim 20, wherein said at least three amplitude values of said welding current comprises a base amplitude, an auxiliary amplitude and a main amplitude, said impedance means and said disconnectable impedance means being dimensioned for constraining said main amplitude to be in the range of 2 to 10 times the value of said base amplitude and for constraining said auxiliary amplitude to be in the range of 1.2 to 7 times the value of said base amplitude.

Claim 34

An apparatus as defined in claim 20, wherein said impedance means connected in said at least n-2 phases of said alternating current secondary circuit output possess cores formed of grain-oriented sheet metal, whereby the ratio of the value of said main amplitude with said auxiliary amplitude is automatically changed from essentially 4 to 1 to essentially 1 to 1 and the curve shapes of said amplitudes are influenced.