Abstract: A welding power supply (1) for supply of current to a welding electrode (2), and a method and a computer program for controlling such a welding power supply is described. The welding power supply (1) comprises an output (3) for output of current from the welding power supply (1), and a control unit (9) for controlling the welding power supply (1). The control unit (9) is arranged to control the welding power supply (1) to supply current to the output (3) in the form of a series of alternating positive current pulses (11), having a positive top value (Imax+), and negative current pulses (12), having a negative top value (Imax), and to lower the current in the current pulses from the negative top value (Imax) and the positive top value (Imax+) to a negative switch value (Ix?) and a positive switch value (Ix+), respectively, before switch between a positive current pulse (11) and a negative current pulse (12).

Abstract: The invention relates to a method for regulating a welding current source with a current transformer, which has a series resonant circuit on the primary side and a parallel resonant circuit on the secondary side, the series resonant circuit being supplied with a variable alternating voltage by a bridge circuit and the parallel resonant circuit providing energy to a welding process by way of a rectifier, and a control unit controlling the bridge circuit in dependence on at least one state variable of the welding current source. In order to develop the method in such a way as to make regulation possible at low cost and with as little power loss as possible, it is proposed according to the invention that only the primary current or a state variable on the primary side corresponding to the primary current is recorded as the electrical-current state variable of the welding current source and a control signal dependent on the primary current or on the state variable corresponding thereto is fed to the control unit.

Abstract: The present invention provides a welding control apparatus including: a droplet separation detecting unit that detects separation of a droplet from a tip end of welding wire; and a waveform generator that alternately generates a first pulse for separating the droplet and a second pulse for shaping the droplet and outputs the generated pulse to a welding power source, the waveform generator generating a third pulse having a pulse shape different in a pulse peak current and/or a pulse width from the second pulse to output the generated third pulse to the welding pulse source after a base time of the first pulse if separation of the droplet is not detected within a peak period, a falling slope period, or a base period of the first pulse to thereby restore a droplet supply regularity.

Abstract: A power supply apparatus for use with arc-utilizing apparatuses includes a plurality of power supply blocks of the same capacity. Each power supply block includes an input-side rectifying circuit, an inverter, a transformer, and an output-side rectifying circuit. The inverter is controlled by a control circuit in such a manner that high-frequency current flowing the inverter or current flowing through the output-side rectifying circuit can correspond to a reference signal provided by a reference signal generator. The outputs of the output-side rectifying circuits of the power supply blocks are connected in parallel with each other. The values of the reference signals generated by the reference signal generators are made always equal by the action of equipotential lines.

Abstract: A number of methods to support process quality and maintenance during control of an industrial process such as welding are provided. The methods provide, among other things: automatic process limit programming based on runtime data; user-initiated process limit programming based on upcoming data; correlate equipment deterioration based on capability measurement; correlate tip dressers/formers to new; detect electrical deterioration; integrate process data with programmed data for a visual aid; and quantify process variation in welding tools (pareto of stddev of the c-factor).

Abstract: A system and method for welding with a first and second arc between a first and second electrode, respectively, and a common workpiece, where each of the electrodes is driven by a single power source, where there is a first inductor connected in series with the first electrode and a second inductor connected in series with the second electrode and each of the inductors has sufficient inductive reactance to store enough energy to maintain an existing arc associated with one of the electrodes for a selected general time with essentially no current to the one electrode.

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 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: 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 system for welding with a plurality of welding power supplies connected in parallel. The system includes a first power supply and a second power supply. A reference signal indicative of a welding output of the first power supply is provided to a balancing circuit. The balancing circuit converts the reference signal into a command signal usable by the second power supply. A welding output of the second power supply is responsive to the command signal.

Abstract: The invention provides a plasma welding or brazing process in which a direct current pilot arc is maintained throughout the process. The process comprises the steps of setting a pilot arc power supply (6) to a relatively high level, generating a high voltage spark discharge between a non-consumable electrode (14) of a plasma welding or brazing torch (2) and a nozzle (18) of said torch in order to start the flow of a pilot arc current, detecting the pilot arc current and reducing the pilot arc current to a relatively low level. The invention further provides apparatus for carrying out plasma arc welding, comprising a plasma welding torch, a controller and a power supply. The controller further comprises means for detecting the flow of a pilot arc current and or a main arc current and means for reducing this current on detection.

Abstract: A method and apparatus for welding is disclosed. It includes source of power and a controller. An output feedback circuit provides feedback to the controller. The controller includes a comparator that compares the fedback signal to a threshold and/or detects a short on the output. A standby/welding control is responsive to the comparator. Also, an arc end control may be provided that terminates the arc in response to detecting an increase in arc length.

Abstract: An electric arc welder operated to perform a short circuit process with a first waveform controlling a short condition followed by a second waveform controlling an arc condition, wherein the welder includes a comparator to create an arc signal when the short condition terminates and a controller shifting the welder from control by the first waveform to control by the second waveform in response to creation of the arc signal.

Abstract: A method and system for welding with a plurality of welding power supplies connected in parallel. The system includes a first power supply and a second power supply. A reference signal indicative of a welding output of the first power supply is provided to a balancing circuit. The balancing circuit converts the reference signal into a command signal usable by the second power supply. A welding output of the second power supply is responsive to the command signal.

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 plasm-arc torch system, a circuit, and a method for controlling a pilot arc. A rate of change sensor, such as a dv/dt sensor, monitors the output of an error amplifier to determine whether to close a switch to re-attach a pilot arc before a transferred arc becomes extinguished. The switch selectively connects a tip into a circuit path with an electrode and a power supply to allow the pilot arc to form between the tip and the electrode. The error amplifier preferably provides an error signal for use by a pulse-width modulator for providing a current regulated power supply capability. The power supply preferably regulates the output current to a first level when a pilot arc is present, and to a second mode when a transferred arc is present. The pilot arc may also be re-attached between the tip and the electrode by use of a pilot regulator that attempts to maintain the current flowing through the tip at an intermediate level between the first level and the second level.

Abstract: An electric arc welder comprising a plurality of power supplies connected to a single welding station with a D.C. input for passing an arc welding current across an electrode and workpiece, each of the power supplies including a switching type inverter with an output D.C. current determined by a signal applied to the input of the power supply, a circuit connecting the output D.C. currents in parallel at the input of the welding station, a feedback circuit including a sensor for creating a current signal representing the arc current, a command signal source, and a circuit for creating a master current signal based upon the sensed current signal and the command signal, and a circuit for applying said master current signal to the input of the plurality of power supplies whereby the D.C. current to the D.C. input of the welding station is equally shared by the power supplies.

Abstract: In an electric arc welder including a main transformer with a primary stage coupled to a secondary stage in which is created an AC output current, a first switch opened and closed at a given rate to pass a series of first pulses of DC current in a first circuit having a first lead and through at least a portion of the primary stage in a first electrical direction, with each of the first pulses having a length determined by the time the first switch is closed, a second switch opened and closed at the given rate to pass a series of second pulses of DC current in a second circuit having a second lead through at a least a portion of the primary stage in a second electrical direction with each of the second pulses having a length determined by the time the second switch is closed, and a control circuit for rapidly closing the first and second switches in sequence to induce an AC current in the output stage, the improvement comprising: a first current transformer surrounding the first lead of the first circuit to d

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: A DC voltage resulting from rectifying and smoothing a commercial AC voltage is converted into a high-frequency voltage in an inverter which is operated in response to the closure of a start switch. A transformer transforms the high-frequency voltage, and the voltage-transformed high-frequency voltage is converted to a DC voltage by a rectifier and reactor for application between a torch and a workpiece with a gap disposed therebetween. In response to the closure of the start switch, an igniter operated from the voltage-transformed high-frequency voltage is enabled by an igniter driver to thereby apply a high-frequency voltage between the torch and the workpiece to generate an arc therebetween. A current detector detects current attributable to the arcing. A timer starts operating upon closure of the start switch and causes a disabling commander to disable the inverter when no current is detected by the current detector during a time period longer than a period required for an arc to be generated in the gap.