Abstract: A DC welding device is provided with an adder which sums the signals from a base current setting circuit and a shorting current setting circuit and applies the same to a welding current control unit. When a short circuit occurs, the shorting current circuit outputs a gradually increasing signal until the short is removed, whereupon a gradually decreasing signal, which reaches zero after a predetermined time, is output.

Abstract: A pulse arc welding machine including a wire electrode, a wire feeding unit for feeding the wire electrode to a base material, a base current source for supplying a base current between the wire electrode and the base material, a pulse current source for supplying a pulse current superposed on the base current, a detector for detecting the arc discharge voltage between the wire electrode and the base material, and a controller. The controller compares a detected output value from the detector with a preset reference value to thereby control the amount of heat applied to the wire electrode wherein the arc voltage between the wire electrode and the base material is maintained substantially at a value determined by the reference value.

Abstract: A pulse arc welding machine in which, when any one of the material and diameter of a consumable wire electrode or the shielding gas used is varied, a peak current value and pulse width of a pulse current applied between a consumable wire electrode and a base material being welded as well as a wire feeding speed required for optimum welding conditions are automatically adjusted. The welding machine includes a consumable wire electrode, a wire feeding unit for the wire electrode, a base current source, and a pulse current source for supplying a pulse current superposed on the base current. A sensor detects the arc discharge voltage between the consumable electrode and the base material being welded. The quantity of heat applied to the electrode is corrected by comparing an output detection signal produced by the sensor with a preset arc voltage and then producing a pulse width instruction signal in response to the difference signal for setting the pulse width of the pulse current.

Abstract: A pulse arc welding machine in which the repetition frequency of the pulse currect is unaffected by the frequency of the power source and the mean value of the pulse current applied can be accurately controlled over a broad range while the arcing is maintained stable. A pulse peak current supplying circuit is connected in series with an arcing region formed between a consumable wire electrode and a material to be welded between the output terminals of a standard direct current source while a base current supplying circuit is connected in parallel with the pulse peak current supplying circuit. The pulse peak current supplying circuit and the base current supplying circuit are both composed of a switching element such as a transistor coupled in series with an inductive element. Diodes are provided for suppressing high voltage transients in the circuit.

Abstract: An electrical welding device which requires no high frequency insulation and an electrical discharge gap for maintaining the arc discharge is made large. A main power source supplies an arc discharge current through an electrical conductor to the welding electrode. A high frequency electric power source applies a high-frequency high voltage between the electrode and the material to be welded to generate a high frequency discharge for arc ignition in the electric discharge gap. A high frequency magnetic choke element, which is preferably a plurality of stacked annular ferrite discs, surrounds a predetermined part of the electrical conductor. A high-frequency bypass capacitor is utilized to ground the electrical conductor between the magnetic choke element and the main power source.

Abstract: Typically, a bottom of a cup-shaped electrode opposes to that of a similar electrode through a predetermined gap and in a mixture of helium and hydrogen. A step-up transformer connected across an AC source through a resistor applies a voltage in excess of a discharge breakdown voltage for the gap across the electrodes to cause a pilot glow discharge between them before the source voltage reaches a glow hold minimum voltage for the electrodes. A rectified voltage resulting from a transformer connected across the resistor turns a bidirectional triode thyristor on to apply the source voltage across the electrodes through the conducting thyristor. This smoothly transits the pilot glow discharge to a glow discharge between the electrodes. The latter discharge heats a liquid forcedly flowing along inner surfaces of the electrodes. Also an auxiliary electrode can be operatively coupled to the electrodes to cause similarly a pilot glow discharge between it and either one of the electrodes.

Abstract: Typically, a bottom of a cup-shaped electrode opposes to that of a similar electrode through a predetermined gap and in a mixture of helium and hydrogen. A step-up transformer connected across an AC source through a resistor applies a voltage in excess of a discharge breakdown voltage for the gap across the electrodes to cause a pilot glow discharge between them before the source voltage reaches a glow hold minimum voltage for the electrodes. A rectified voltage resulting from a transformer connected across the resistor turns a bidirectional triode thyristor on to apply the source voltage across the electrodes through the conducting thyristor. This smoothly transits the pilot glow discharge to a glow discharge between the electrodes. The latter discharge heats a liquid forcedly flowing along inner surfaces of the electrodes. Also an auxiliary electrode can be operatively coupled to the electrodes to cause similarly a pilot glow discharge between it and either one of the electrodes.

Abstract: Typically, a bottom of a cup-shaped electrode opposes to that of a similar electrode through a predetermined gap and in a mixture of helium and hydrogen. A step-up transformer connected across an AC source through a resistor applies a voltage in excess of a discharge breakdown voltage for the gap across the electrodes to cause a pilot glow discharge between them before the source voltage reaches a glow hold minimum voltage for the electrodes. A rectified voltage resulting from a transformer connected across the resistor turns a bidirectional triode thyristor on to apply the source voltage across the electrodes through the conducting thyristor. This smoothly transits the pilot glow discharge to a glow discharge between the electrodes. The latter discharge heats a liquid forcedly flowing along inner surfaces of the electrodes. Also an auxiliary electrode can be operatively coupled to the electrodes to cause similarly a pilot glow discharge between it and either one of the electrodes.

Abstract: Typically, a bottom of a cup-shaped electrode opposes to that of a similar electrode through a predetermined gap and in a mixture of helium and hydrogen. A step-up transformer connected across an AC source through a resistor applies a voltage in excess of a discharge breakdown voltage for the gap across the electrodes to cause a pilot glow discharge between them before the source voltage reaches a glow hold minimum voltage for the electrodes. A rectified voltage resulting from a transformer connected across the resistor turns a bidirectional triode thyristor on to apply the source voltage across the electrodes through the conducting thyristor. This smoothly transits the pilot glow discharge to a glow discharge between the electrodes. The latter discharge heats a liquid forcedly flowing along inner surfaces of the electrodes. Also an auxiliary electrode can be operatively coupled to the electrodes to cause similarly a pilot glow discharge between it and either one of the electrodes.