Abstract: An electric arc welding system and method for creating a first AC welding arc with a first current waveform between a first electrode and a workpiece by a first power supply and a second AC welding arc with a second current waveform between a second electrode and a workpiece by a second power supply as the first and second electrodes are moved in unison along a welding path where the first and second power supply each comprising an high speed switching inverter creating its waveform by a number of current pulses occurring at a frequency of at least 18 kHz with the magnitude of each current pulse controlled by a wave shaper and the polarity of the waveforms controlled by a signal. The first and second AC waveforms each have a positive portion and a negative portion and a cycle period of about 10-20 ms and timing circuits for determining the push and pull times between the arcs and a waveform adjusting circuit to limit the push and pull times to less than about 5.0 ms.

Abstract: Systems and methods are provided for pulse welding, in which a welding signal is provided to an electrode in series of pulse welding cycles, where the amount of energy applied to the electrode in each cycle is determined and a pulse is provided to initiate a transfer condition of each cycle based at least partially on the energy applied in the cycle.

Abstract: Disclosed is a pulsed arc welding method using a pulse current of alternately repeating first and second pulses as a weld current, wherein the first pulse and the second pulse have a pulse waveform of a different pulse peak current level and a different pulse width, respectively, and the following conditions are satisfied: peak current of the first pulse (Ip1)=300 to 700A; peak period (Tp1)=0.3 to 5.0 ms; base current Ib1=30 to 200A, base period (Tb1)=0.3 to 10 ms; peak current of the second pulse (Ip2)=200 to 600A; peak period (Tp2)=1.0 to 15 ms; base current (Ib2)=30 to 200A; and base period (Tb2)=3.0 to 20 ms. In this manner, the consumable electrode arc welding using carbon dioxide gas alone or a mixed gas made mainly of carbon dioxide gas as a shield gas can benefit from stabilized welding arc, improved regularity of droplet transfer, and significantly reduced generation rates of spatters and fumes.

Abstract: A method and apparatus for providing welding power with an arc-width control is disclosed. The power supply includes a power circuit that provides a welding output characterized by a plurality of welding output parameters, and the power circuit receives at least one control input. A controller provides control signals to the power circuit. The controller receives user inputs for arc width and wire feed speed. The controller has an arc width control module that provides control signals that adjust one or more welding output parameters. The adjustment has a gain responsive to the wire feed speed input, such that there are at least three gains over a range of possible wire feed speeds, in one embodiment. The arc width control module provides control signals that adjust at least five welding output parameters in response to the wire feed speed input and the arc-width control input, in another embodiment.

Abstract: The invention relates to a welding method involving the use of a non-fusing electrode (12) according to which the electrode (12) is provided with power from a power source once the arc (11) between the electrode (12) and the workpieces (13, 14) to be joined has been ignited. The invention also relates to a tack welding method. The aim of the invention is to improve the quality of the weld seam in the starting phase of the welding process. To this end, the invention provides that before the actual welding process, a start program (22) is performed without the introduction of a filler material during which the electrode (12) is supplied with pulsed power in the form of current or voltage pulses over a presettable length of time (23) whereby causing the liquid molten bath to oscillate or vibrate, and that after the execution of the start program (22), the actual welding process is carried out during which the electrode (12) is preferably supplied with constant power.

Abstract: A method of welding with high nickel content and duplex stainless steel electrodes using adaptive outer loop control to change at least one of a peak current or pulse frequency of a pulse waveform used for welding. The pulse waveform is changed based on a detected change in contact tip to work distance between the electrode and the work piece. The arc generated between the work piece and the electrode is shielded by a shielding gas which contains carbon dioxide and an inert gas.

Abstract: In accordance with an AC pulse arc welding method, a periodic welding current is applied, that includes, for a pulse cycle, negative current in electrode negative polarity and positive current in electrode positive polarity. Then, a negative current rate is set by a negative current rate setting value, where the negative current rate represents the ratio of the negative current to the welding current for the pulse cycle. Then, a feeding speed of welding wire as a consumable electrode is set by a feeding speed setting value. The method further includes: setting an average of the welding current by a welding current setting value; and performing automatic calculation of the feeding speed setting value by using a predetermined conversion function based on input of the welding current setting value and the negative current rate setting value.

Abstract: An electric arc welder with a waveform generator controlled to create a welding process involving current flow between an electrode and a workpiece wherein the welding process comprises a succession of pulse waveforms, each having a current ramp up portion, a peak current portion, a current ramp down portion and a background current portion, a voltage sensing circuit to sense a short circuit between the electrode and the workpiece and a reset circuit to reset the waveform generator upon sensing of a short circuit. The preferred electrode is a solid wire which may be in the form of a metal cored wire.

Abstract: An electric arc welding apparatus comprising at least a first consumable electrode and a second consumable electrode movable in unison along a welding path between the edges of two adjacent, mutually grounded plates, a first power supply for passing a first welding current at a first low frequency between the first electrode and the two plates, a second power supply for passing a second welding current at a second low frequency between the second electrode and the two plates, where each of the power supplies includes a three phase voltage input operated at line frequency, a rectifier to convert the input voltage to a DC voltage link and a high frequency switching type inverter converting the DC voltage link to a high frequency AC current, an output rectifier circuit to provide a positive voltage terminal and a negative voltage terminal, and an output switching network operated at a given low frequency for directing a pulsating welding current at the given low frequency from the two terminals across one of the

Abstract: An electric arc welding system for creating a first AC welding arc with a first current waveform between a first electrode and a workpiece by a first power supply and a second AC welding arc with a second current waveform between a second electrode and a workpiece by a second power supply as the first and second electrodes are moved in unison along a welding path, where the first and second power supply each comprising a high speed switching inverter creating its waveform by a number of current pulses occurring at a frequency of at least 18 kHz with the magnitude of each current pulse controlled by a wave shaper and the polarity of the waveforms is controlled by a signal. The first AC waveform has a positive portion substantially different in energy than its negative portion and/or has either a different shape and/or a synthesized sinusoidal portion.

Abstract: An output control method is provided for a pulse arc welding in which a welding current flows for one pulse period consisting of a peak period with a flow of a peak current and a base period with a flow of a base current. External characteristics of a welding power source are preliminarily set by a slope Ks, a welding current reference value Is and a welding voltage reference value Vs. The absolute value va of the welding voltage and the absolute value ia of the welding current during welding are detected. The integration Svb=?(Ks×ia?Ks×Is+Vs?va) dt is calculated from a starting point of an n-th pulse period. The n-th pulse period is ended when the integration Svb becomes no smaller than zero during the base period. Then, the (n+1)-th pulse period is started.

Abstract: A method and apparatus for providing welding power with an arc-width control is disclosed. The power supply includes a power circuit that provides a welding output characterized by a plurality of welding output parameters, and the power circuit receives at least one control input. A controller provides control signals to the power circuit. The controller receives user inputs for arc width and wire feed speed. The controller has an arc width control module that provides control signals that adjust one or more welding output parameters. The adjustment has a gain responsive to the wire feed speed input, such that there are at least three gains over a range of possible wire feed speeds, in one embodiment. The arc width control module provides control signals that adjust at least five welding output parameters in response to the wire feed speed input and the arc-width control input, in another embodiment.

Abstract: A method and apparatus can adaptively control a pulsed power arc welding process. A trainable system can recognize an empirical transfer mode from a signal emitted during an arc welding pulse and determine a pulsed power parameter set to produce a modified transfer mode in a subsequent pulse, by controlling a power source using the parameter set.

Abstract: A method and apparatus for welding is disclosed. The output is preferably a cyclical CV MIG output, and each cycle is divided into segments. An output parameter is sampled a plurality of times within one or more of the segments. The CV output is controlled within the at least one segment in response to the sampling. The parameter is output power, a resistance of the load, an output current, an output voltage, or functions thereof in various embodiments. The control loop is preferably a PI or PID loop. The loop may be applied only within a window. The set point may be taught or fixed. The system can be used to weld with a controlled arc length.

Abstract: An electric arc welder operated to perform a short circuit welding process between an electrode and a workpiece, where the process comprises a succession of alternate short circuit conditions and arc conditions, with a first current waveform during the short circuit condition and a second voltage waveform during the arc condition. A first waveform generator constructs the first waveform from a series of current pulses controlled by a pulse wave modulator operated at a rate greater than 18 kHz and a second waveform generator constructs the second waveform from a series of current pulses controlled by a pulse wave modulator operated at a rate greater than 18 kHz. The second waveform generator has a circuit to generate the second waveform with a generally constant arc parameter, generally voltage.

Abstract: A welder using a circuit or method of changing polarity of an AC welding current comprising: the generation of a polarity changing signal, commanding a change in the polarity of the current a given time after generation of the polarity changing signal and reducing the given time upon detection of a short in the welding current.

Abstract: An electric arc welder for depositing weld metal along a groove between two edges of a metal workpiece where the welder comprises a first electrode driven by a first wire feeder toward a point in said groove, a second electrode driven by a second wire feeder toward the point and a main power source with a first output terminal connected to the first electrode and a second output terminal connected both to the second electrode and directly or indirectly to the metal workpiece to create a second electrode path and a workpiece path. The power source includes a high speed switching output stage for creating current with a selected AC waveform between the first and second output terminals where the waveform of the main power source is generated by a waveform generator controlling a pulse width modulator circuit to determine the current operation of the output stage.

Abstract: A method and apparatus for feeding wire in a welding system include one or more motors disposed adjacent the wire to drive it. A wire feed motor is also disposed along the wire path, and is closer to the source of wire than the torch, and closer to the source than the one or more motors. The motors may be a pair motors disposed on opposite sides of the wire and move the wire to and away from an arc end of a torch. They preferably reversing the direction of the wire within one process cycle. The or more motors may be a stepper motor, a servo motor, a zero backlash motor, a gearless motor, a planetary drive motor, or a linear actuator (such as a piston), in various embodiments.

Abstract: An electric arc welding system and method for creating a first AC welding arc with a first current waveform between a first electrode and a workpiece by a first power supply and a second AC welding arc with a second current waveform between a second electrode and a workpiece by a second power supply as the first and second electrodes are moved in unison along a welding path where the first and second power supply each comprising an high speed switching inverter creating its waveform by a number of current pulses occurring at a frequency of at least 18 kHz with the magnitude of each current pulse controlled by a wave shaper and the polarity of the waveforms controlled by a signal. The first and second AC waveforms each have a positive portion and a negative portion and a cycle period of about 10–20 ms and timing circuits for determining the push and pull times between the arcs and a waveform adjusting circuit to limit the push and pull times to less than about 5.0 ms.

Abstract: Electric arc welder (10) performs a given weld process with selected current waveform performed between electrode (24) and workpiece (26). Welder (10) includes a controller with a digital processor (30), sensor (44) for reading instantaneous weld current, and circuit (56) to convert the instantaneous current into a digital representation of the level of instantaneous weld current. Digital processor (30) has program circuit (64, 66) to periodically read and square the digital representation at a given rate, register (70, 72) for summing a number N of square digital representations to give a summed value, and an algorithm (82, 84, 86, 88) for periodically dividing the summed value by the number N to provide a quotient and then taking the square root of said quotient to thereby digitally construct rms signal (40) representing the root mean square of the weld current.

Abstract: A method and apparatus for MIG welding is disclosed. When in an ac mode the output is unbalanced, or the balance may be controlled. The balance may be controlled to provide a desired deposition rate and/or to obtain a desired dilution. The frequency may be any frequency, for example 30 Hz, 60 Hz, 90 Hz, or more. The weld path may have groove with angle of less than 50 degrees. A consumable, cored, wire may be used, and provide at rates of 30 or 35 pounds per hour using a single arc. In various embodiments the balance may have a negative portion of at least 1.5 times the positive portion. The process may be started using an extended negative portion, for example 0.5 or 0.75 seconds.

Abstract: An input-side rectifier (4), a smoothing capacitor (6), an inverter (8), a transformer (10) and an output-side rectifier (12) operate together to convert an AC voltage supplied from an AC power supply to a DC voltage. The DC voltage is coupled through a DC-to-AC converter (16) to a workpiece (18) and a torch (20). An auxiliary voltage supply (28) supplies the workpiece (18) and the torch (20) with a negative voltage for a short time following the transition of the AC voltage supplied to the workpiece (18) and the torch (20) from positive to negative. The negative voltage has a negative peak value larger than the negative peak value of the AC voltage supplied to the workpiece (18) and the torch (20), and rapidly changes from the negative peak value.

Abstract: An electric arc GMAW welder is provided, which welder includes a high speed switching power supply with a controller for creating a first or second weld process across the gap between a workpiece and a welding wire advanced toward the workpiece. The first process uses a first current waveform and the second process uses a second current waveform. A circuit is provided for shifting between the first and second weld processes. The shifting circuit includes a counter for counting the waveforms in the first and second processes and a circuit to shift from the process being processed to the other weld process when the waveform count of the weld process being processed reaches a preselected number for such weld process.

Abstract: An operating system is provided for an electric arc welder including a high switching speed inverter power source for creating an arc voltage and arc current between an electrode and a workpiece. This operating system regulating the arc voltage to provide a voltage with a slope by using an error circuit to create an error output and having a first input with a signal representing the set voltage and a second input representing the sum of the actual arc voltage and the actual arc current multiplied by a slope constant. A DSP program reduces the error output by adjusting the voltage output of the inverter power source to change the actual arc voltage. The slope constant is in the range of 0–10%.

Abstract: A power supply connectable to a source of AC line voltage for AC electric arc welding by an AC arc current across a welding gap between an electrode and a workpiece, the power supply comprises a high capacity transformer that converts said line voltage to an AC output voltage, and a rectifier that converts the AC output voltage to a DC voltage between a positive terminal and a common terminal at generally zero volts and a negative terminal and the common terminal. The power supply has a first switch that connects the positive terminal to the common terminal across the gap when a gate signal is applied to the first switch, a second switch for connecting the negative terminal to the common terminal across the gap when a gate signal is applied to the second switch and a pulse width modulator operated for generating pulses at a frequency of at least about 18 kHz.

Abstract: An electric arc welder for creating a succession of AC waveforms between an electrode and workpiece by a power source comprising an high frequency switching device for creating individual waveforms in the succession of waveforms. Each of the individual waveforms has a profile determined by the magnitude of each of a large number of short current pulses generated at a frequency of at least 18 kHz by a pulse width modulator with the magnitude of the current pulses controlled by a wave shaper. The welder is provided with a profile control network for setting more than one profile parameter selected from the class consisting of frequency, duty cycle, up ramp rate and down ramp rate and a magnitude circuit for adjusting the waveform profile to set total current, voltage and/or power.

Abstract: An electric arc welding apparatus comprising at least a first consumable electrode and a second consumable electrode movable in unison along a welding path between the edges of two adjacent, mutually grounded plates, a first power supply for passing a first welding current at a first low frequency between the first electrode and the two plates, a second power supply for passing a second welding current at a second low frequency between the second electrode and the two plates, where each of the power supplies includes a three phase voltage input operated at line frequency, a rectifier to convert the input voltage to a DC voltage link and a high frequency switching type inverter converting the DC voltage link to a high frequency AC current, an output rectifier circuit to provide a positive voltage terminal and a negative voltage terminal, and an output switching network operated at a given low frequency for directing a pulsating welding current at the given low frequency from the two terminals across one of the

Abstract: An IGBT (16) intermittently interrupts a current from a positive terminal (12P) of a DC supply (2) to a workpiece (24). An IGBT (20) intermittently interrupts a current from a negative terminal (12N) of the DC supply (2) to the workpiece (24). A control circuit (32) and a drive signal generating circuit (34) ON-OFF control the IGBTs (16, 20). The control circuit (32) causes the drive signal generating circuit (34) to control the IGBTs (16, 20) in such a manner as to provide a repetition of a cycle consisting of an AC period during which the IGBTs (16, 20) are alternately rendered conductive, and a DC period following the AC period during which the IGBT (16) is rendered continuously conductive.

Abstract: A TIG welding apparatus comprises; a twin electrode type welding torch 1 having a first and a second welding electrode 1a, 1b arranged approximately parallel and either side of an insulation plate of a predetermined thickness, and a main unit 2 which supplies to the first welding electrode 1a a first welding current varied at a first period F, and to the second welding electrode 1b a second welding current varied at the first period F and at an opposite phase to the variation of the first welding current. The main unit 2 superimposes a variation of a second period fm being shorter than the first period F, onto the first and second welding currents. As a result, the arc current is increased without increasing the welding current.

Abstract: A method and apparatus for welding include initiating a pulse welding process includes initiating a welding arc by providing CC type welding power, maintaining the arc by providing CV type power. Then, pulse type welding power is provided. The method and system can be used to start short circuit, or other welding processes by providing short circuit power, or welding power of a given mode, instead of providing pulse power. Also, in one alternative, a method and system of initiating a pulse, short circuit, or given welding process includes initiating a welding arc by providing CC type welding power at least until a pseudo-equilibrium for the arc is established. Then, providing welding power in a pulse, short circuit, or the given mode.

Abstract: A method and apparatus for multi process welding includes providing a controlled short circuit output and a pulse output in response to a user selection across a workpiece output stud and a torch output stud.

Abstract: An electric arc welding apparatus comprising at least a first consumable electrode and a second consumable electrode movable in unison along a welding path between the edges of two adjacent, mutually grounded plates, a first power supply for passing a first welding current at a first low frequency between the first electrode and the two plates, a second power supply for passing a second welding current at a second low frequency between the second electrode and the two plates, where each of the power supplies includes a three phase voltage input operated at line frequency, a rectifier to convert the input voltage to a DC voltage link and a high frequency switching type inverter converting the DC voltage link to a high frequency AC current, an output rectifier circuit to provide a positive voltage terminal and a negative voltage terminal, and an output switching network operated at a given low frequency for directing a pulsating welding current at the given low frequency from the two terminals across one of the

Abstract: An electric arc welding system for creating an AC welding arc between an electrode and a workpiece wherein the system comprises a first controller for a first power supply to cause the first power supply to create an AC current between the electrode and workpiece by generating a switch signal or command with polarity reversing switching points in the first controller, with the first controller operated at first welding parameters in response to first power supply specific parameter signals to the first controller. The system has at least one slave controller for operating a slave power supply to create an AC current between the electrode and workpiece by reversing polarity of the AC current at switching points where the slave controller is operated at second welding parameters in response to second power supply specific parameter signals to the slave controller.

Abstract: An electric arc welder for performing a given weld process with a selected A.C. pulse current waveform performed between an electrode and a workpiece, where the current waveform includes a positive segment and a negative segment, with at least one segment including a peak current and background current. The welder comprises: a power source with a controller having a digital processor including a program to calculate the real time power factor of the weld current and weld voltage where the program includes an algorithm to calculate the rms weld voltage, the rms weld current and the average power of said power source; a circuit to multiply the rms current by the rms voltage to produce an rms power level; a circuit to divide the average power by the rms power to create a value representing the actual real time power factor of said power source; and, a circuit to adjust said background current to maintain said power factor at a given level, which is manually adjusted to set the heat of the weld.

Abstract: A method and apparatus for welding is disclosed. The output is preferably a cyclical CV MIG output, and each cycle is divided into segments. An output parameter is sampled a plurality of times within one or more of the segments. The CV output is controlled within the at least one segment in response to the sampling. The parameter is output power, a resistance of the load, an output current, an output voltage, or functions thereof in various embodiments. The control loop is preferably a PI or PID loop. The loop may be applied only within a window. The set point may be taught or fixed. The system can be used to weld with a controlled arc length.

Abstract: An electric arc GMAW welder is provided, which welder includes a high speed switching power supply with a controller for creating a first or second weld process across the gap between a workpiece and a welding wire advanced toward the workpiece. The first process uses a first current waveform and the second process uses a second current waveform. A circuit is provided for shifting between the first and second weld processes. The shifting circuit includes a counter for counting the waveforms in the first and second processes and a circuit to shift from the process being processed to the other weld process when the waveform count of the weld process being processed reaches a preselected number for such weld process.

Abstract: A power supply connectable to a source of AC line voltage for AC electric arc welding by an AC arc current across a welding gap between an electrode and a workpiece, the power supply comprises a high capacity transformer that converts said line voltage to an AC output voltage, and a rectifier that converts the AC output voltage to a DC voltage between a positive terminal and a common terminal at generally zero volts and a negative terminal and the common terminal. The power supply has a first switch that connects the positive terminal to the common terminal across the gap when a gate signal is applied to the first switch, a second switch for connecting the negative terminal to the common terminal across the gap when a gate signal is applied to the second switch and a pulse width modulator operated for generating pulses at a frequency of at least about 18 kHz.

Abstract: A process for applying a weld overlay to a tube with a single pass of a weld head. An inverter-type alternating current pulsed power source, composed of a primary inverter and a secondary inverter, is used to control the melting rate of welding wire during welding of the overlay to the tube. The primary inverter controls the value of output current, and the second inverter changes the polarity of output current between electrode negative. For a given welding current, the wire melting rate increases significantly as the electrode negative ratio increases, and this makes a relatively high welding speed attainable. Increasing the electrode negative ratio at a fixed, predetermined wire feed rate decreases the weld penetration depth, which correspondingly lowers the dilution rate and results in a smooth and narrow welding bead.

Abstract: An electric arc welding system for creating a first AC welding arc with a first current waveform between a first electrode and a workpiece by a first power supply and a second AC welding arc with a second current waveform between a second electrode and a workpiece by a second power supply as the first and second electrodes are moved in unison along a welding path, where the first and second power supply each comprising a high speed switching inverter creating its waveform by a number of current pulses occurring at a frequency of at least 18 kHz with the magnitude of each current pulse controlled by a wave shaper and the polarity of the waveforms is controlled by a signal. The first AC waveform has a positive portion substantially different in energy than its negative portion and/or has either a different shape and/or a synthesized sinusoidal portion.

Abstract: A power supply for arc welding includes switching elements PTR, NTR for switching the polarity of the direct voltage from a power circuit PMC. The element PTR is connected in parallel to a series unit of a switching element TR1 and a resistor R1. Likewise, the element NTR is connected in parallel to a series unit of a switching element R2 and a resistor R2. A necking determination circuit ND determines whether a constriction occurs at the molten bridging portion between the welding wire and the base material. When the constriction occurs during the “electrode positive” mode, the switching element PTR is turned off, while the switching element TR1 is brought into the conduction state. When the constriction occurs during the “electrode negative” mode, the switching element NTR is turned off, while the switching element TR2 is brought into the conduction state.

Abstract: A welder using a circuit or method of changing polarity of an AC welding current comprising: the generation of a polarity changing signal, commanding a change in the polarity of the current a given time after generation of the polarity changing signal and reducing the given time upon detection of a short in the welding current.

Abstract: A method and apparatus for MIG welding is disclosed. When in an ac mode the output is unbalanced, or the balance may be controlled. The balance may be controlled to provide a desired deposition rate and/or to obtain a desired dilution. The frequency may be any frequency, for example 30 Hz, 60 Hz, 90 Hz, or more. The weld path may have groove with angle of less than 50 degrees. A consumable, cored, wire may be used, and provide at rates of 30 or 35 pounds per hour using a single arc. In various embodiments the balance may have a negative portion of at least 1.5 times the positive portion. The process may be started using an extended negative portion, for example 0.5 or 0.75 seconds.

Abstract: A method and apparatus for welding include initiating a pulse welding process includes initiating a welding arc by providing CC type welding power, maintaining the arc by providing CV type power. Then, pulse type welding power is provided. The method and system can be used to start short circuit, or other welding processes by providing short circuit power, or welding power of a given mode, instead of providing pulse power. Also, in one alternative, a method and system of initiating a pulse, short circuit, or given welding process includes initiating a welding arc by providing CC type welding power at least until a pseudo-equilibrium for the arc is established. Then, providing welding power in a pulse, short circuit, or the given mode.

Abstract: A power supply apparatus for a welder includes a rectifier (104) and a smoothing reactor (106) which operate together to convert a commercial AC supply voltage to a DC voltage. The DC voltage is converted to a high-frequency voltage by an inverter (108), which, in turn, is voltage-transformed by a voltage-transformer (110). The voltage-transformed, high-frequency voltage is converted to a DC voltage by a rectifying diode (112) and a smoothing reactor (114), and the resulting DC voltage is applied to a workpiece (118a) and a torch (118b). A current detector (120) develops a load current representative signal, and a control circuit (122) so controls a drive circuit (126) which drives the inverter (108) that the load current representative signal becomes equal to a reference current signal provided by a reference source (124). When a small load current is used, a pulse forming switch (140) is repetitively turned on and off to produce a pulse current from a pulse current setting source (139).

Abstract: A system and method for controlling a weld-current in an arc welding apparatus involves programming of a waveform generator to supply a control signal to a weld-current power supply, the control signal being derived from a reference waveform consisting of selected segments having fixed or predetermined amplitudes and variable durations. The reference waveform may be dynamically adjusted in response to changes in welding conditions by feeding the output of an arc current and/or voltage detector back to the waveform generator and varying the duration of selected predetermined amplitude segments.

Abstract: An electric arc welding system for creating a first AC welding arc with a first current waveform between a first electrode and a workpiece by a first power supply and a second AC welding arc with a second current waveform between a second electrode and a workpiece by a second power supply as the first and second electrodes are moved in unison along a welding path, where the first and second power supply each comprising a high speed switching inverter creating its waveform by a number of current pulses occurring at a frequency of at least 18 kHz with the magnitude of each current pulse controlled by a wave shaper and the polarity of the waveforms is controlled by a signal. The first AC waveform has a positive portion substantially different in energy than its negative portion and/or has either a different shape and/or a synthesized sinusoidal portion.

Abstract: A system for creating an actual waveform at the output of an electric arc welder and caused by a waveform generator where the welder has a display and customizing screen to design a commanded waveform for processing by the waveform generator. The system includes a program to display a target waveform on the screen, a program to display the commanded waveform on the screen, a computer terminal to manually customize the commanded waveform to generally match the target waveform controlling the waveform generator to cause the actual waveform produced by the welder to match with the target waveform.

Abstract: Electric arc welder (10) performs a given weld process with selected current waveform performed between electrode (24) and workpiece (26). Welder (10) includes a controller with a digital processor (30), sensor (44) for reading instantaneous weld current, and circuit (56) to convert the instantaneous current into a digital representation of the level of instantaneous weld current. Digital processor (30) has program circuit (64, 66) to periodically read and square the digital representation at a given rate, register (70, 72) for summing a number N of square digital representations to give a summed value, and an algorithm (82, 84, 86, 88) for periodically dividing the summed value by the number N to provide a quotient and then taking the square root of said quotient to thereby digitally construct rms signal (40) representing the root mean square of the weld current.

Abstract: An electric arc GMAW welder is provided, which welder includes a high speed switching power supply with a controller for creating a first or second weld process across the gap between a workpiece and a welding wire advanced toward the workpiece. The first process uses a first current waveform and the second process uses a second current waveform. A circuit is provided for shifting between the first and second weld processes. The shifting circuit includes a counter for counting the waveforms in the first and second processes and a circuit to shift from the process being processed to the other weld process when the waveform count of the weld process being processed reaches a preselected number for such weld process.

Abstract: Process for the arc welding in pulsed mode of one or more workpieces made of carbon steel, stainless steel, aluminum or aluminum alloy, with the use of a gas shield, in which an electric arc welding torch is supplied with at least one consumable wire at a wire feed speed (Vwire) and the consumable wire is subjected to current pulses, in order to melt the end of the consumable wire in which, for a given pulse frequency, a wire feed speed (Fwire), a mean current (Imean) value and an rms current (Irms) value are chosen, so as to detach one drop of molten metal per current pulse and to obtain a low degree of spatter.