Abstract: A voltage generation circuit (20) is provided which generates a voltage. A voltage application circuit (30) is provided which has electrodes (11, 12) which are fed a respective voltage for causing creation of an instantaneous high electric field in a region of interest as a target such as a living body tissue or cell. The voltage application circuit (30) is high-impedanced for excitation of a free resonant circuit including the target. It is arranged such that the relative position of the target with respect to one of the electrodes (11, 12) is adjustable.

Abstract: A pulse arc welding machine in which current pulses are periodically applied between a welding wire and a base method. A voltage is measured between the welding wire and the base metal to determine if whether an arc to a short-circuit exists therebetween. If a short-circuit exists, a new current pulse is delayed until the arc is reestablished.

Abstract: A short circuiting arc welding machine increases an arc current density by adding a pulsed current having upper and lower limits to a current flowing when an arc is produced, thereby increasing the depth of bead penetration into a workpiece, removing welding defects, and speeding up the welding operation. The welding machine is capable of alternately changing the direction of flow of a welding current at desired periods to produce arcs in straight, reverse and mixed polarities for achieving intermediate characteristics of arcs of straight and reverse polarities, with a resultant ability to adjust in a wide range a wire melting rate and the amount of heat applied to the workpiece.

Abstract: A short circuit transfer arc welding machine including a wire electrode which is fed towards a base metal, a DC source for applying a voltage across the base metal and the wire electrode, a switching element for interrupting the voltage, a voltage detector for detecting a voltage developed across the base metal and the wire electrode, a first comparator for determining when a detection voltage outputted by the voltage detector reaches a voltage value corresponding to the short circuiting of the base metal and wire electrode, a second comparator for determining when the detection voltage of said voltage detector reaches an arc discharge voltage, and a switching element control circuit for closing the switching element in response to a signal from the first comparator and for opening the switching element in response to a signal from the second comparator.

Abstract: A pulse arc welding apparatus in which pulse current and base current are alternately supplied a welding unit 13 comprises a series circuit of a transistor 2, a reactor 3 and a current detector 4 connected between a single power source 1 and the welding unit, and a control circuit 20 for switching the transistor on and off in response to inputs from the current detector, pulse current upper and lower limiters 7, 8, and base current upper and lower limiters 21, 22.

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 power source includes first and second control circuit for controlling the current provided during short-circuit and arc intervals, respectively. A transistor in series with the power supply is controlled in response to either of the control circuits.

Abstract: A hot-wire arc welding apparatus comprises a non-expendable electrode, means for supplying a current to initiate an arc between the nonexpendable electrode and a workpiece, an arc current control means for controlling the current from the supplying means, a wire feed means for feeding a filler wire into the arc, a wire feed control means for controlling the wire feed means to feed the filler wire at a given rate of feed, a voltage applying means for applying a voltage between the filler wire and the workpiece, a wire voltage control means for controlling the voltage from the voltage applying means, and a reference voltage generator for generating an output voltage which increases gradually or incrementally with time, each of the arc current control means, the wire feed control means, and the wire voltage control means being connected to the reference voltage generator and responsive to the output voltage therefrom for controlling the operation thereof.

Abstract: A hot wire welding system including a non-melting metal electrode, a supply of filler metal to be fed to a weld puddle formed by an arc, a D.C. power source for supplying both an arc current and a filler metal heating current, a first control circuit for controlling the filler metal heating current with a constant voltage characteristic, and a second control circuit for controlling the arc current with a constant current characteristic. By eliminating one of the two power supplies which was required in prior art systems, a significant reduction in size and complexity is obtained.

Abstract: An arc welding apparatus includes means for controllingly supplying an output current to an arc-producing electrode, an output current setting unit for controlling the supplying means, means for feeding a filler wire, and means for applying voltage to the filler wire. A first function generator is connected between the output current setting unit and the feeding means for producing an output which is a function of an output current setting and which is delivered to the feeding means to control the rate at which the filler wire is fed. A second function generator is connected between the first function generator and the applying means for producing an output which is a function of the output from the first function generator and which is fed to the applying means to control the voltage applied to the filler wire.

Abstract: In a welding apparatus employing a switching element between a power source and a filler wire, a protection circuit operates to discontinue the function of the switching element when a short-circuit is detected between, for example, the filler wire and a welding electrode, so that the switching element is protected from damage due to an overcurrent.

Abstract: A welding apparatus is made capable of avoiding the occurrence of welding wire spattering following a short circuit, for example, by providing an arithmetic circuit having a plurality of selectively operated delay elements which smooth the response to a rapid change in welding conditions.

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.

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.