D-C arc welding apparatus
First Claim
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1. A welding apparatus comprising:
- an engine welder including an alternator means for generating an a-c voltage, said engine welder also including a means for converting said a-c voltage into d-c voltage;
a battery welder including a battery;
changeover means for connecting said engine welder and said battery welder in parallel, said change over means also separately connecting said engine welder to engine welding outputs and said battery welder to battery welding outputs;
switching means for blocking and passing current between a negative terminal of said battery welding outputs and a ground terminal of said battery;
a shunt resistor connected between said switching means and said ground terminal of said battery;
current approximation means for detecting current flowing in said shunt resistor and for generating a welding current waveform substantially representative of a current flowing through said battery welding terminals; and
controller means for controlling said switching element dependent on said welding current waveform.
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Abstract
A d-c arc welding apparatus including an engine-driven welder converting the a-c power generated by an engine-driven alternator into d-c power for use as the drive power of the welder, a battery-driven welder using a battery as the drive power of the welder, and a changeover switch for selecting between a high-power mode in which the above-mentioned welding d-c outputs are connected in parallel and fed to the welding apparatus, and a low-power mode in which either of the above-mentioned welding d-c outputs is supplied independently to the welding apparatus.
105 Citations
12 Claims
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1. A welding apparatus comprising:
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an engine welder including an alternator means for generating an a-c voltage, said engine welder also including a means for converting said a-c voltage into d-c voltage; a battery welder including a battery; changeover means for connecting said engine welder and said battery welder in parallel, said change over means also separately connecting said engine welder to engine welding outputs and said battery welder to battery welding outputs; switching means for blocking and passing current between a negative terminal of said battery welding outputs and a ground terminal of said battery; a shunt resistor connected between said switching means and said ground terminal of said battery; current approximation means for detecting current flowing in said shunt resistor and for generating a welding current waveform substantially representative of a current flowing through said battery welding terminals; and controller means for controlling said switching element dependent on said welding current waveform. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A welding apparatus comprising:
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a battery welder including a battery and battery welding outputs; switching means for blocking and passing current between a first terminal of said battery welding outputs and a first terminal of said battery; a shunt resistor connected between said switching means and said first terminal of said battery; current approximation means for detecting current flowing in said shunt resistor and for generating a welding current waveform substantially representative of a current flowing through said battery welding terminals; controller means for controlling said switching element dependent on said welding current waveform; a shortcircuit current limiting means for blocking operation of said switching element when a peak value of said current flowing in said shunt resistor exceeds a predetermined value; and a shortcircuit protective timer means for blocking said operation of said switching element when a peak value of said current flowing in said shunt resistor exceeds a predetermined value and exists for more than a predetermined time.
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Specification