Abstract: An arc welding apparatus includes: a switching device connected to both terminals of a secondary winding of a transformer whose opposite primary winding serves as a smoothing reactor on an inverter's secondary side; an output voltage detector detecting an output voltage between a welding wire and a workpiece; and a control circuit controlling the switching device and a circuit on the inverter's primary side. The control circuit includes: a first control portion that turns off the circuit on the inverter's primary side and turns on the switching device when the output voltage detected by the output voltage detector rises to a first predetermined voltage; and a second control portion that turns on the circuit on the inverter's primary side and turns off the switching device after a lapse of a predetermined time after the switching device is turned on.

Abstract: An arc welding apparatus includes: a switching device connected to both terminals of a secondary winding of a transformer whose opposite primary winding serves as a smoothing reactor on an inverter's secondary side; an output voltage detector detecting an output voltage between a welding wire and a workpiece; and a control circuit controlling the switching device and a circuit on the inverter's primary side. The control circuit includes: a first control portion that turns off the circuit on the inverter's primary side and turns on the switching device when the output voltage detected by the output voltage detector rises to a first predetermined voltage; and a second control portion that turns on the circuit on the inverter's primary side and turns off the switching device after a lapse of a predetermined time after the switching device is turned on.

Abstract: A power supply apparatus for use with arc-utilizing apparatuses includes a plurality of power supply blocks of the same capacity. Each power supply block includes an input-side rectifying circuit, an inverter, a transformer, and an output-side rectifying circuit. The inverter is controlled by a control circuit in such a manner that high-frequency current flowing the inverter or current flowing through the output-side rectifying circuit can correspond to a reference signal provided by a reference signal generator. The outputs of the output-side rectifying circuits of the power supply blocks are connected in parallel with each other. The values of the reference signals generated by the reference signal generators are made always equal by the action of equipotential lines.

Abstract: Welding conditions are set for a power supply apparatus for use with a welding machine, using a control panel unit (96). A memory (105) stores therein welding conditions as set through the control unit (96), and holds the set welding conditions after turning off of a main power supply switch (1) of the power supply apparatus. Upon turning on of the main power switch (1) for starting welding, the welding conditions stored and held in the memory (105) are read out and set in the power supply apparatus.

Abstract: A heat-generating component cooling structure includes a hollow heat sink having a portion made of a thermally conductive material. The heat sink has an interior path extending from first to second ends of the heat sink. A fan device is disposed at the first end of the heat sink and is adapted to cause air to flow through the interior path. Fins are disposed in the path in the heat sink. Heat-generating components of an electrical circuit are mounted on an outer surface of the heat sink.

Abstract: A power supply apparatus for use with arc-utilizing apparatuses includes a plurality of power supply blocks (2a, 2b) of the same capacity. Each power supply block (2a, 2b) includes an input-side rectifying circuit (4a, 4b), an inverter (10a, 10b), a transformer (12a, 12b), and an output-side rectifying circuit (18a, 18b). The inverter (10a, 10b) is controlled by a control circuit (30a, 30b) in such a manner that high-frequency current flowing the inverter (10a, 10b) or current flowing through the output-side rectifying circuit (18a, 18b) can correspond to a reference signal provided by a reference signal generator (34a, 34b). The outputs of the output-side rectifying circuits (18a, 18b) of the power supply blocks are connected in parallel with each other. The values of the reference signals generated by the reference signal generators (34a, 34b) are made always equal by the action of equipotential lines (40, 42).

Abstract: An opening is formed in a case. Air is caused to flow through the interior of the case. A panel closes the opening. A printed circuit board is disposed behind the panel within the case. A plurality of components, including a control device which can be operated on the front surface of the panel and a display device providing a display viewable on the front surface of the panel, are mounted on the printed circuit board. The printed circuit board is enclosed in a closed receptacle disposed within the case.

Abstract: An opening is formed in a case. Air is caused to flow through the interior of the case. A panel closes the opening. A printed circuit board is disposed behind the panel within the case. A plurality of components, including a control device which can be operated on the front surface of the panel and a display device providing a display viewable on the front surface of the panel, are mounted on the printed circuit board. The printed circuit board is enclosed in a closed receptacle disposed within the case.

Abstract: An input rectifier of a power supply apparatus rectifies a selected one of two, higher and lower AC voltages applied to it. First and second inverters are connected in the output of the input rectifier. A high-frequency transformer is connected to the output of each of the first and second inverters. An output rectifier is connected to the output of each of the high-frequency transformers. When the higher one of the two AC input voltages is applied to the input rectifier, a switching circuit connects the first and second inverters in series between output terminals of the input rectifier. When the lower AC voltage is applied to the input rectifier, the switching circuit connects the first and second inverters in parallel between the output terminals of the input rectifier. When the first and second inverters are connected in series between the output terminals of the input rectifier, a voltage balancing control unit operates to suppress imbalance between input voltages to the first and second inverters.

Abstract: Welding conditions are set for a power supply apparatus for use with a welding machine, using a control panel unit (96). A memory (105) stores therein welding conditions as set through the control unit (96), and holds the set welding conditions after turning off of a main power supply switch (1) of the power supply apparatus. Upon turning on of the main power switch (1) for starting welding, the welding conditions stored and held in the memory (105) are read out and set in the power supply apparatus.

Abstract: A heat-generating component cooling structure includes a hollow heat sink having a portion made of a thermally conductive material. The heat sink has an interior path extending from first to second ends of the heat sink. A fan device is disposed at the first end of the heat sink and is adapted to cause air to flow through the interior path. Fins are disposed in the path in the heat sink. Heat-generating components of an electrical circuit are mounted on an outer surface of the heat sink.

Abstract: An input rectifier of a power supply apparatus rectifies a selected one of two, higher and lower AC voltages applied to it. First and second inverters are connected in the output of the input rectifier. A high-frequency transformer is connected to the output of each of the first and second inverters. An output rectifier is connected to the output of each of the high-frequency transformers. When the higher one of the two AC input voltages is applied to the input rectifier, a switching circuit connects the first and second inverters in series between output terminals of the input rectifier. When the lower AC voltage is applied to the input rectifier, the switching circuit connects the first and second inverters in parallel between the output terminals of the input rectifier. When the first and second inverters are connected in series between the output terminals of the input rectifier, a voltage balancing control unit operates to suppress imbalance between input voltages to the first and second inverters.

Abstract: A small-sized DC power supply apparatus adapted for receiving input commercial AC voltages of different value includes an AC-to-DC converter 4 which converts an input commercial AC voltage to a first DC voltage. The first DC voltage is converted to a high-frequency voltage in an inverter 10 including IGBTs 10a-10d which are rendered conductive when a conduction control signal is applied thereto. A transformer 12 transforms the high-frequency voltage, which is, then, converted to a second DC voltage in a high-frequency-to-DC converter 16 for application to a load 22. The conduction control signal with a pause period disposed therein is generated in a controller 14. The conduction control signal occurs at a fixed period. The pause period disposed between the successive occurrences of the conduction control signal becomes longer as the input commercial AC voltage is higher.