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US 4,061,899 AGranted
Arrangement for stabilization and ignition of welding arcs by ignition pulses
AssigneeMesser Griesheim GmbH
InventorsMax Gillitzer, Franz Tajbl
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AssigneeMesser Griesheim GmbH
InventorsMax Gillitzer, Franz Tajbl
Estimating the term…
Welding arc stabilizing and igniting is effected with at least one pulse-forming condenser switched by spark gap or semiconductor switch to deliver a sharp discharge pulse through the winding of a pulse transformer, the magnetic energy thus built up in the transformer being then dissipated by a unidirectional diode bypass of the winding through the switch. The pulses are delivered by the transformer to the welding electrodes, and can be combined with pulses of lower voltage and longer duration by an appropriate series condenser-resistor combination in the transformer output. The pulse-forming condenser can be charged by simple resistor connection to the input of a step-down welding current transformer, or by transformer coupling to any source of AC welding current. Trigger means can also be connected as by transformer coupling for operation from the welding current to trigger the pulse discharge switching at the appropriate times in the current waves, although the triggering can be effected through the use of voltage-dependent pulse switching and the charging of the pulse forming condensers to voltages at least as high as that needed to actuate the switching. The switching means can also be protected by a blocking condenser in series in the output of a pulse-forming condenser, and the blocking condenser can be bridged by a resistor to bleed off the charge developed in the blocking condenser by a discharge pulse.
A device for stabilization of alternating current welding arcs and for the ignition of alternating current or direct current welding arcs by stablization or ignition pulses of alternate polarity, which pulses are generated by at least one discharged capacitor charged from a current source and discharged by a discharge circuit comprising two controllable discharge switches, rectifier means, and a pulse transformer with primary and secondary windings, each switch being connected to supply the transformer primary with discharge current in a different direction, the transformer secondary supplying the stabilization or ignition pulses, and the rectifier means being connected to form short-circuiting paths through the respective switches to dissipate from the transformer primary the energy liberated by its magnetic flux after each pulse, regardless of its polarity.
A device for generating pulses that stabilize alternating current welding arcs and ignite alternating current or direct current welding arcs, said device comprising a discharge capacitor connected for charging from a current source and for discharging through a discharge circuit comprising first and second controllable discharge switches, a rectifier, and a pulse transformer with a primary winding having first and second parts and a pulse output winding, one pole of the discharge capacitor being connected to one end of both primary winding parts, the other ends of each primary winding part being connected through the respective switches to the second pole of the discharge capacitor to deliver capacitor discharges in opposite directions to the primary winding, said rectifier being connected between the poles of the capacitor to form across the primary winding parts short-circuiting paths that include the respective switches, for dissipating current generated by the transformer flux after each capacitor discharge is completed, regardless of the direction.
In a welding arc igniting and stabilizing circuit having a pulse transformer with input winding means connected for receiving current surges and output winding means connected to deliver igniting and stabilizing pulses between the workpiece being welded and the welding electrode, the improvement according to which the input winding means is connected in an input network that alternately passes current surges of opposite polarity through the input winding means and causes the output winding means to deliver consecutive pulses of opposite polarity, and the input network contains passive rectifier means connected through selectable switches to short circuit the electrical energy developed in the input winding means by the transformer's magnetic flux at the completion of each input surge, and to effect such short-circuiting through the respective switches of the energy developed by the surges of the respective polarities.
Dependencies are inferred from the claim text.