Abstract: An arc welding apparatus includes a main power supply circuit for outputting an arc current, a control circuit for controlling the main power supply circuit, and a high-frequency voltage generating circuit for generating a high-frequency voltage. When an operation switch is turned on for a first time since the apparatus is powered on, the control circuit activates the main power supply circuit to output a high voltage, and the high-frequency voltage generating circuit to generate a high-frequency voltage. With the high voltage superimposed on the high-frequency voltage, the control circuit passes a welding arc current through a torch and a base material. The switch is then turned off, and the control circuit passes a pilot arc current through the torch and the base material. The switch is turned on again, and the control circuit activates the main power supply circuit to output a high voltage, thereby allowing smooth arc transition.

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: A power supply unit includes an input-side rectifying circuit (4), an inverter (8) and an output-side rectifying circuit (12), which include power semiconductor devices. The power supply unit is powered during a powering period, and the powering is interrupted during a pausing period. The powering and pausing periods alternate. A fan (18) is driven during each powering period to cool the power semiconductor devices. A temperature detector (30) measures the temperature of the power semiconductor devices and develops a measured-temperature representative signal. A setter (38) produces a reference value, which decreases over the pausing period from the measured-temperature representative signal at the beginning of the pausing period to an intended-temperature representative signal representing the temperature to be attained by the power semiconductor devices at the end of the pausing period.

Abstract: A rectifying circuit (18) converts inputted AC power to DC power. An inverter circuit (22) converts the DC power to high-frequency power in accordance with a switching control signal applied thereto from a control circuit (50). A voltage transformer (24) voltage-transforms the voltage of the high-frequency power. An output-side rectifying circuit (40) rectifies the voltage-transformed power. An output detecting circuit (34) detects the magnitude of the voltage of the rectified power, and a signal representative of the detected voltage is applied to the control circuit (50). The control circuit (50) generates such a switching control signal as to make the rectified power have a predetermined value. The value of the voltage from the rectifying circuit (18) is detected by an input detecting circuit (62), and a signal representative of the detected voltage is applied to the control circuit (50).

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: One of a plurality of voltages is adapted to be applied to power supply terminals (2a, 2b, 2c). A rectifying circuit (6) rectifies the applied voltage and develops a rectified voltage between the output terminals (6a, 6b) thereof. Inverters (16a, 16b) are connected into one of a plurality of inverter connections between the rectifier output terminals (6a, 6b) in response to one of a plurality of inverter connection indicative signals. The inverter connections are set to correspond to respective ones of the plurality of voltages, so that a predetermined voltage can be applied to each inverter whichever one of the plurality of voltages is applied to the power supply terminals. An inverter connection indicative signal generating circuit (34) is manually operated to generate a desired one of the inverter connection indicative signals. A thyristor (8) is disposed between the rectifier output terminals (6a, 6b) and the inverters (16a, 16b).

Abstract: An information processing device, which is communicably connected to a client device used by a user and each of a plurality of server devices to perform information processing for a service, stores on a memory server identification information for identifying the server device to perform the information processing, for each of a series of the information processing required to provide the service, with regards to each of the services. Then, the information processing device receives a message including service identification information for identifying the service, which is sent from the client device, identifies the service based on the service identification information included in the received message, reads out from the memory the server identification information corresponding to the identified service, and sends an information processing request for requesting to perform the information processing, to each of the server devices identified based on the read out server identification information.

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: An input-side rectifier (4), a smoothing capacitor (6), an inverter (8), a transformer (10) and an output-side rectifier (12) operate together to convert an AC voltage supplied from an AC power supply to a DC voltage. The DC voltage is coupled through a DC-to-AC converter (16) to a workpiece (18) and a torch (20). An auxiliary voltage supply (28) supplies the workpiece (18) and the torch (20) with a negative voltage for a short time following the transition of the AC voltage supplied to the workpiece (18) and the torch (20) from positive to negative. The negative voltage has a negative peak value larger than the negative peak value of the AC voltage supplied to the workpiece (18) and the torch (20), and rapidly changes from the negative peak value.

Abstract: The invention relates to a method of production control that is preferably used for manufacture of electronic apparatus such as liquid crystal displays and provides a method of production control that makes it possible to set a feasible quantity to be processed. In a method of production control for a production line having a plurality of production steps, a tentative target quantity to be processed is set for a major production step; the tentative target quantity to be processed is set as a target quantity to be processed when the quantity of work in process that can be actually processed is equal to or greater than the tentative target quantity to be processed; and the quantity of work in process that can be processed is set as the target quantity to be processed when the quantity of work in process that can be processed is smaller than the tentative target quantity to be processed.

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: An IGBT (16) intermittently interrupts a current from a positive terminal (12P) of a DC supply (2) to a workpiece (24). An IGBT (20) intermittently interrupts a current from a negative terminal (12N) of the DC supply (2) to the workpiece (24). A control circuit (32) and a drive signal generating circuit (34) ON-OFF control the IGBTs (16, 20). The control circuit (32) causes the drive signal generating circuit (34) to control the IGBTs (16, 20) in such a manner as to provide a repetition of a cycle consisting of an AC period during which the IGBTs (16, 20) are alternately rendered conductive, and a DC period following the AC period during which the IGBT (16) is rendered continuously conductive.

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 casting apparatus has a melting pot (4) in which pieces of metal (8) to be melted is placed. A RF induction heater coil (10) is disposed in association with the melting pot (4) to heat the metal pieces (8). An inverter (18) supplies the coil (10) with high-frequency power to melt the metal pieces (8) in the melting pot (4), and the resulting molten metal is poured into a die (6). A control unit (36), after all of the metal pieces (8) having various sizes and shapes are melted, causes the operation of the inverter (18) to continue for a first time period and, after that, to suspend the operation of the inverter (18) for a second time period so that the heating can be stopped. After that, the control unit (36) causes the inverter (18) to resume its operation to heat the melted metal (8) in the melting pot (4) until the molten metal (8) assumes a predetermined state and, a third predetermined time after that, operates a melting pot driver (9) to cause the molten metal (8) to be poured into the die (6).

Abstract: A drier for oxidative polymerization-drying printing ink is provided, which does not contain cobalt capable of exerting an adverse influence on the environment and health and which is environmentally friendly. A printing ink containing the drier is also provided. The drier for oxidative polymerization-drying printing ink contains a cerium salt of a fatty acid and a manganese salt of a fatty acid.

Abstract: An input-side rectifier (4), a smoothing capacitor (6), an inverter (8), a transformer (10) and an output-side rectifier (12) operate together to convert an AC voltage supplied from an AC power supply to a DC voltage. The DC voltage is coupled through a DC-to-AC converter (16) to a workpiece (18) and a torch (20). An auxiliary voltage supply (28) supplies the workpiece (18) and the torch (20) with a negative voltage for a short time following the transition of the AC voltage supplied to the workpiece (18) and the torch (20) from positive to negative. The negative voltage has a negative peak value larger than the negative peak value of the AC voltage supplied to the workpiece (18) and the torch (20), and rapidly changes from the negative peak value.

Abstract: A power supply apparatus has a case (94) with a control panel (96) mounted thereon. Plural controllers are disposed on the panel (96). A cover (98) is mounted to cover and uncover the panel (96). One (66) of the controllers is so disposed as to be externally operable.

Abstract: A power supply apparatus for a welder includes a rectifier (104) and a smoothing reactor (106) which operate together to convert a commercial AC supply voltage to a DC voltage. The DC voltage is converted to a high-frequency voltage by an inverter (108), which, in turn, is voltage-transformed by a voltage-transformer (110). The voltage-transformed, high-frequency voltage is converted to a DC voltage by a rectifying diode (112) and a smoothing reactor (114), and the resulting DC voltage is applied to a workpiece (118a) and a torch (118b). A current detector (120) develops a load current representative signal, and a control circuit (122) so controls a drive circuit (126) which drives the inverter (108) that the load current representative signal becomes equal to a reference current signal provided by a reference source (124). When a small load current is used, a pulse forming switch (140) is repetitively turned on and off to produce a pulse current from a pulse current setting source (139).

Abstract: A casting apparatus has a melting pot (4) in which pieces of metal (8) to be melted is placed. A RF induction heater coil (10) is disposed in association with the melting pot (4) to heat the metal pieces (8). An inverter (18) supplies the coil (10) with high-frequency power to melt the metal pieces (8) in the melting pot (4), and the resulting molten metal is poured into a die (6). A control unit (36), after all of the metal pieces (8) having various sizes and shapes are melted, causes the operation of the inverter (18) to continue for a first time period and, after that, to suspend the operation of the inverter (18) for a second time period so that the heating can be stopped. After that, the control unit (36) causes the inverter (18) to resume its operation to heat the melted metal (8) in the melting pot (4) until the molten metal (8) assumes a predetermined state and, a third predetermined time after that, operates a melting pot driver (9) to cause the molten metal (8) to be poured into the die (6).