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US 4,442,339 AGranted
Constant voltage DC arc welding apparatus
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsTakaji Mizuno, Hiroshi Suwahara, Hirohisa Segawa
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Abstract
A DC arc welding apparatus compares the output voltage with an adjustable, preset voltage, and the amplified and integrated difference signal is supplied to a current control circuit together with a current feedback signal. The resulting apparatus operates in a constant voltage mode, thus rendering it applicable to consumable electrode welding. A constant current mode may also be realized, as an alterantive, by bypassing the comparator and feeding the preset voltage directly to the current control circuit.
Claims7
A DC welding apparatus comprising:
- (a) a DC power source (1) for supplying current between a welding electrode (5) and a material (7) to be welded through a switching element (2);
- (b) a comparator (16) for comparing a voltage detected across said welding electrode and material to be welded with a predetermined set voltage, to provide a first difference signal therebetween;
- said comparator comprising circuit means for delaying the difference signal;
- (c) a current detecting element (8) for detecting the current flowing between said welding electrode and said material to be welded;
- (d) a current control circuit (11) for subjecting a signal proportional to the detected current and the delayed difference signal from said comparator, which corresponds to a predetermined set current, to comparison to derive a control signal;
- and
- (e) a drive circuit (12) for said switching element, said drive circuit being responsive to said control signal to control the on-off operation of said switching element to maintain a constant arc voltage and reduce the number of welding sputters.
4 more elements
Dependencies are inferred from the claim text.