Sansha Electric Manufacturing Company, Limited

Thermal Dynamics Corporation

Hideo Ishii

Tetsuro Ikeda

Kenzo Danjo

Masao Katooka

Haruo Moriguchi

Toshikazu Fujiyoshi

Takeshi Morimoto

Toru Arai

Masayuki Ono

Kunio Shikata

Yuji Ikejiri

Atsushi Kinoshita

Kenji Morimoto

Satoshi Hamada

Kunio Karino

Yoshimasa Kawashima

Kazunori Nakata

Takeshi Omura

Shuji Yokoyama

Yoshiaki Komuro

Goro Nakano

Fumi Noda

Michael R Dumont

Nathaniel S Hansen

Susumu Takenaka

Kumiko Kurohara

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.

Arc welding apparatus and method

A printed circuit board () includes an insulating substrate () on which conductive films () are formed. Semiconductor devices () disposed external to the printed circuit board () have their leads () connected to the conductive films. A flexible portion () is formed in the insulating substrate () at a location near the location where the leads () are connected to the conductive films ().

Heat sink arrangement for electrical apparatus

A rectifying circuit () converts inputted AC power to DC power. An inverter circuit () converts the DC power to high-frequency power in accordance with a switching control signal applied thereto from a control circuit (). A voltage transformer () voltage-transforms the voltage of the high-frequency power. An output-side rectifying circuit () rectifies the voltage-transformed power. An output detecting circuit () detects the magnitude of the voltage of the rectified power, and a signal representative of the detected voltage is applied to the control circuit (). The control circuit () 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 () is detected by an input detecting circuit (), and a signal representative of the detected voltage is applied to the control circuit (). The control circuit () controls the operation of the inverter circuit () in accordance with the detected voltage representative signal from the input detecting circuit () and the saturation magnetic characteristic of the voltage-transformer ().

Power supply apparatus

A power supply unit includes an input-side rectifying circuit (), an inverter () and an output-side rectifying circuit (), 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 () is driven during each powering period to cool the power semiconductor devices. A temperature detector () measures the temperature of the power semiconductor devices and develops a measured-temperature representative signal. A setter () 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. The reference value is prepared from the measured-temperature representative signal at the beginning of the pausing period, the intended-temperature representative signal, and the length of the pausing period. An error amplifier () and a fan control unit () control the rotation rate of the fan () to make the measured-temperature representative signal track the reference value.

A welder power supply apparatus () includes an inverter (), which is driven intermittently when an electrode () and a workpiece () are separated from each other and no arc is being generated between them, whereby power loss generated in the inverter () when the inverter () is driven in the non-load state of the power supply apparatus and power loss caused by exciting current flowing through an transformer () disposed in the output of the inverter () can be reduced. The inverter () is driven continuously when output current (Io) becomes higher than a threshold value (Ib) after the electrode () and the workpiece () are brought into contact with each other for starting arcing between them. In this manner, the arcing can be initiated without fail.

Power supply apparatus for welder

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

One of a plurality of voltages is adapted to be applied to power supply terminals (). A rectifying circuit () rectifies the applied voltage and develops a rectified voltage between the output terminals () thereof. Inverters () are connected into one of a plurality of inverter connections between the rectifier output terminals () 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 () is manually operated to generate a desired one of the inverter connection indicative signals. A thyristor () is disposed between the rectifier output terminals () and the inverters (). When one of the plurality of voltages is applied to the power supply terminals, a voltage detecting circuit () generates an inverter connection indicative signal corresponding to the voltage applied to the power supply terminals. A judging unit () determines whether or not the inverter connection indicative signals from the voltage detecting circuit () and the inverter connection indicative signal generating circuit () match. When the two signals match, a thyristor control unit () provides a CLOSE signal to the thyristor (). When the two signals do not match, an alarm circuit () is activated.

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.

Heat-generating component cooling structure

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.

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.

Power supply apparatus for arc-utilizing apparatus

An input-side rectifier (), a smoothing capacitor (), an inverter (), a transformer () and an output-side rectifier () 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 () to a workpiece () and a torch (). An auxiliary voltage supply () supplies the workpiece () and the torch () with a negative voltage for a short time following the transition of the AC voltage supplied to the workpiece () and the torch () 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 () and the torch (), and rapidly changes from the negative peak value. The auxiliary voltage supply () produces a DC voltage having a negative peak value larger than the negative peak value of the AC voltage supplied to the workpiece () and the torch (), by means of a transformer (), a rectifier () and a smoothing capacitor (). The smoothing capacitor () is coupled to the workpiece () and the torch () through a transistor () and a current-limiting resistor (). A differentiating circuit () is coupled in parallel with the current-limiting resistor (), and includes a resistor () having a smaller resistance value than the current-limiting resistor ().

An IGBT () intermittently interrupts a current from a positive terminal (P) of a DC supply () to a workpiece (). An IGBT () intermittently interrupts a current from a negative terminal (N) of the DC supply () to the workpiece (). A control circuit () and a drive signal generating circuit () ON-OFF control the IGBTs (). The control circuit () causes the drive signal generating circuit () to control the IGBTs () in such a manner as to provide a repetition of a cycle consisting of an AC period during which the IGBTs () are alternately rendered conductive, and a DC period following the AC period during which the IGBT () is rendered continuously conductive. Further, the control circuit () and the drive signal generating circuit () simultaneously render the IGBT () and the IGBT () nonconductive and conductive, respectively, at least once during the DC period, and, thereafter, simultaneously render the IGBT () and the IGBT () conductive and nonconductive, respectively.

Welding method and welding power supply apparatus

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

Casting apparatus

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

A power supply apparatus for a welder includes a rectifier ( ) and a smoothing reactor ( ) 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 ( ), which, in turn, is voltage-transformed by a voltage-transformer ( ). The voltage-transformed, high-frequency voltage is converted to a DC voltage by a rectifying diode ( ) and a smoothing reactor ( ), and the resulting DC voltage is applied to a workpiece ( ) and a torch ( ). A current detector ( ) develops a load current representative signal, and a control circuit ( ) so controls a drive circuit ( ) which drives the inverter ( ) that the load current representative signal becomes equal to a reference current signal provided by a reference source ( ). When a small load current is used, a pulse forming switch ( ) is repetitively turned on and off to produce a pulse current from a pulse current setting source ( ). The pulse current is superposed on a control signal from the control circuit ( ).

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Osaka, Japan

Hideo Ishii