Sansha Electric Manufacturing Company, Limited

Thermal Dynamics Corporation

Haruo Moriguchi

Kenzo Danjo

Toshikazu Fujiyoshi

Kunio Karino

Atsushi Kinoshita

Hideo Ishii

Tetsuro Ikeda

Takashi Hashimoto

Shigeru Okamoto

Masayuki Ono

Toru Arai

Masahiro Aoyama

Tetsurou Ikeda

Masao Katooka

Satoshi Hamada

Kunio Shikata

Takeshi Omura

Takashi Tsujii

Masataka Nishimura

Karino Kunio

Michael R Dumont

Kenzo Danjou

Nathaniel S Hansen

Atushi Kinoshita

Fumi Noda

A power supply apparatus useful for starting and driving a discharge lamp includes a DC-to-DC converter for converting a DC signal from a DC power supply to a second DC signal having a predetermined magnitude which is supplied to the lamp. A current detector develops a DC current representative signal representing DC current supplied to the lamp from the DC-to-DC converter. A combination of the current detector a DC voltage detector and a multiplier develops a DC power representative signal representing DC power supplied from the DC-to-DC converter to the lamp. An error amplifier develops a DC current error signal representing the difference between the DC current representative signal and a predetermined DC current reference signal. An error amplifier develops a DC power error signal representing the difference between the DC power representative signal and a predetermined power reference signal. For a predetermined time period following the start of operation of the power supply apparatus, a combination of a delay circuit a comparator and a clamping diode clamps the DC power error signal so that only the DC current error signal can be outputted. A driver unit controls the DC-to-DC converter in such a manner as to make the DC current error signal zero.

Power supply apparatus for lamp

One of commercial AC voltages is coupled to power supply terminals from one of commercial AC power supplies. The AC power supplies belong to either a first group providing higher voltages or a second group providing lower voltages. A rectifier rectifies the AC voltage applied to the power supply terminals, and a rectified voltage is developed between two rectifier output terminals. A switching unit operates to connect voltage-boosting converters selectively in series and in parallel between the rectifier output terminals. Inverters are connected in the output sides of and in association with the respective voltage-boosting converters for converting DC voltages from the associated voltage-boosting converters to high-frequency voltages. The high-frequency voltages are voltage-transformed by associated voltage-transformers, and the voltage-transformed high-frequency voltages are converted into a DC voltage by a rectifier circuit and a reactor. The DC voltage is developed between output terminals of the apparatus. A switching control unit controls the switching unit so as to connect the voltage-boosting converters in series between the rectifier output terminals when a commercial AC power supply of the first group is connected to the power supply terminals, while connecting the voltage-boosting converters in parallel between the rectifier output terminals when a commercial AC power supply of the second group is connected to the power supply terminals.

Power supply apparatus for arc-utilizing apparatus

A voltage from an AC power source is converted into a DC voltage in an input-side rectifier-smoother circuit. The DC voltage is then converted into a high-frequency voltage in an inverter, and the resulting high-frequency voltage is voltage-transformed in a transformer. The voltage-transformed high-frequency voltage is converted into a DC voltage in an output-side rectifier-smoother circuit, which is applied via output terminals to a load. The input-side and output-side rectifier-smoother circuits, the inverter and the transformer are enclosed in a casing having a plastic panel. The output terminal of the apparatus is mounted on the plastic panel. When a temperature sensing unit with a temperature sensor disposed on the panel near the output terminal senses that the temperature of the panel has risen above a predetermined temperature, which is lower than the heat deformation temperature of the panel, a gate signal ON-OFF circuit prevents a gate signal from a gate signal generating circuit from being coupled to the inverter. The gate signal ON-OFF circuit permits the gate signal to be coupled to the inverter when the temperature sensing unit senses that the temperature of the panel has decreased below the predetermined temperature.

Power supply apparatus

A power supply apparatus includes a power supply unit disposed within a casing. The power supply unit includes power semiconductor devices. A fan is provided in the casing for cooling the power semiconductor devices. The power supply unit is operated in a plurality of contiguous cycles each including a running and pausing modes of operation. Each cycle lasting a relatively short time period. The power supply unit operates in the running mode and the pausing mode, respectively in response to the closing and opening of a start switch. In association with the closing and opening of the start switch, a switch for the cooling fan causes the fan to rotate and stop, respectively, which results in minimizing the difference between the highest and lowest temperatures of the power semiconductor devices so that the lifetime of the power semiconductor devices can be prolonged.

A DC voltage resulting from rectifying and smoothing a commercial AC voltage is converted into a high-frequency voltage in an inverter which is operated in response to the closure of a start switch. A transformer transforms the high-frequency voltage, and the voltage-transformed high-frequency voltage is converted to a DC voltage by a rectifier and reactor for application between a torch and a workpiece with a gap disposed therebetween. In response to the closure of the start switch, an igniter operated from the voltage-transformed high-frequency voltage is enabled by an igniter driver to thereby apply a high-frequency voltage between the torch and the workpiece to generate an arc therebetween. A current detector detects current attributable to the arcing. A timer starts operating upon closure of the start switch and causes a disabling commander to disable the inverter when no current is detected by the current detector during a time period longer than a period required for an arc to be generated in the gap. This interrupts the supply of the operating voltage for the igniter, and the igniter stops operating.

Power supply apparatus for arc-utilizing machine

A DC power supply apparatus includes a rectifier circuit which rectifies an input commercial AC voltage. The rectifier output voltage is smoothed in a smoothing capacitor. The DC voltage from the capacitor is converted to a high-frequency voltage in an inverter. The high-frequency voltage from the inverter is voltage-transformed by a transformer into a voltage-transformed, high-frequency voltage, which is then converted back into a DC voltage in a high-frequency-to-DC converter circuit. When an input commercial AC voltage is applied to the DC power supply apparatus, a pre-charging circuit pre-charges the smoothing capacitor from the input AC voltage. If a voltage having a magnitude larger than a prescribed value is applied to the DC power supply apparatus, an overvoltage protection circuit renders the rectifier circuit and the pre-charging circuit inoperative.

DC power supply apparatus

An AC voltage applied among power input supply terminals is rectified by a rectifier, and the rectified voltage is adapted to be reduced in a voltage-reducing converter with a switch connected in parallel with it. A switching circuit connect smoothing capacitors in series or parallel to the voltage-reducing converter. Inverters are connected in parallel with the respective smoothing capacitors. The output voltages of the inverters are voltage-transformed by transformers. The transformed voltages from the transformers are converted to DC voltages by converters. A control unit renders the voltage-reducing converter operative and causes the switching circuit to connect the smoothing capacitors in series when a third AC voltage is applied among the power supply input terminals. When a second AC voltage lower than the third AC voltage is applied among the power supply input terminals, the control unit causes the switch connected in parallel with the voltage-reducing converter to be closed and causes the switching circuit to connect the smoothing capacitors in series. If a first AC voltage about one-half as high as the second AC voltage is applied, the control unit causes the switch to be closed and causes the switching circuit to connect the smoothing capacitors in parallel.

DC power supply apparatus for arc-utilizing apparatuses

A power supply apparatus for welders includes an input-side AC-to-DC converter for converting an input commercial AC voltage into a DC voltage, which is, in turn, converted to a high-frequency voltage in an inverter. The high-frequency voltage is transformed to a high-frequency voltage having a desired magnitude in a transformer. The transformed high-frequency voltage is then converted back to a DC voltage in an output-side high-frequency-to-DC converter. The DC voltage is developed between output terminals of the power supply apparatus. A current detector detects the current flowing through the output terminals and develops a detected-current representative signal. A voltage detector detects the voltage between the output terminals and develops a detected-voltage representative signal. A CPU has three control modes and controls, in a first mode, the inverter in such a manner that the current representative signal becomes equal to a reference-current representative signal. In a second mode, the CPU activates and, then, deactivates a high-frequency generator, which provides a high-frequency voltage between the output terminals, and, thereafter, performs the first mode of control. In a third control mode, the CPU controls the inverter in such a manner that the voltage representative signal becomes equal to a reference-voltage representative signal and also controls a wire feeder for feeding a wire to be connected to one of the output terminals.

Power supply apparatus for welders and method of manufacturing same

DC power from a smoothing capacitor is converted into high frequency power by an inverter, and then lowered by an output transformer. The lowered high frequency power is converted into DC power by an output rectifier and a DC reactor, and then supplied to a load. The load is short-circuited and then opened to initiate arcing. The short-circuiting and the arcing alternate. An auxiliary rectifier provides a load-voltage representative signal, and a current detector detects a load current. A load-current representative signal is differentiated by a differentiation circuit. The signals from the auxiliary rectifier, the current detector and the differentiation circuit, and a reference signal are applied to an operational amplifier. A control circuit controls the inverter such that the output of the operational amplifier can be zero. An integration circuit receives at least the load-voltage representative signal to detect a period of a cycle consisting of the arcing and the short-circuiting and provide an operation-cycle-period representative signal to the operational amplifier.

Consumable electrode DC arc welder

An inverter includes a series circuit of two current conducting units connected between two input terminals adapted to be connected to a DC power supply. Two first capacitors are connected in series between the two input terminals. A primary winding of a transformer is connected between the junction of the current conducting units and the junction of the first capacitors. Each of the current conducting units includes a parallel circuit of an IGBT, a diode and a second capacitor. The IGBT has a collector, an emitter and a gate and is rendered conductive when a control signal is applied to the gate while a voltage of a predetermined polarity is applied between the collector and the emitter. The diode is connected in inverse parallel with the IGBT. An inverter control circuit applies alternately the control signals to the respective IGBTs with a predetermined quiescent period disposed between the respective control signals applied.

Inverter and DC power supply apparatus with inverter used therein

A DC power supply apparatus includes an input-side rectifier which rectifies an input AC voltage and supplies the rectified voltage to a voltage-boosting converter. The voltage-boosting converter converts the supplied voltage to a voltage of a predetermined magnitude. The predetermined magnitude voltage is, then, converted to a high-frequency voltage by an inverter and applied to a primary winding of a transformer. An output-side rectifier rectifies a high-frequency voltage induced in a secondary winding of the transformer. The inverter includes IGBTs and diodes, which are connected in a full-bridge configuration. A capacitor is connected in parallel with each IGBT. When the IGBTs are rendered conductive by the charging and discharging of the capacitors, no current flows through the IGBTs, and when the IGBTs are rendered nonconductive, the voltages applied to the IGBTs are made to become zero.

DC power supply apparatus includes an input-side rectifier for converting an AC signal from an AC power supply into a DC signal. A DC-to-high-frequency converter converts the DC signal into a high frequency signal in response to a control signal from a control unit. An output-side rectifier converts the high frequency signal into a DC signal and applies it to a load. An input current detector detects an input current flowing through the input-side rectifier and generates a signal representative of the input current. A load current detector detects a load current flowing through the load and generates a signal representative of the load current. The control unit receives the input-current and load-current representative signals, a reference input current signal and a reference load current signal, and provides the DC-to-high-frequency converter with the control signal such that the input-current representative signal can be equal to the reference input current signal and the load-current representative signal can be equal to the reference load current signal.

Power supply apparatus includes a converter which converts a commercial AC voltage into a DC voltage. An inverter converts the DC voltage into a high frequency voltage. The high frequency voltage is voltage-transformed by a transformer, and then rectified and smoothed by a rectifier and a smoothing reactor into a DC voltage. This DC voltage is applied between a workpiece and a torch. A high frequency voltage generator generates a high frequency voltage and applies it to a primary winding of a coupling transformer. A boosted high frequency voltage is induced in a first secondary winding and applied between the workpiece and the torch, so that arcing is initiated. The coupling transformer includes a second secondary winding in which another high frequency voltage is induced. The high frequency voltage induced in the second secondary winding is converted into a DC voltage by a diode and a smoothing capacitor for application between the workpiece and the torch, so that the arcing is sustained.

Power supply apparatus with initial arcing sustaining circuit

A power supply apparatus for a plasma arc utilizing equipment providing an output current nearly equal to an input current includes a first converter for converting an AC voltage to a DC voltage. The DC voltage is converted to a high frequency voltage by an inverter. The output of the inverter is converted through a second converter to a DC voltage which is applied between a torch and a workpiece. A current detector detects an output current flowing between the second converter and the workpiece. A voltage detector detects an output voltage between the torch and the workpiece. A multiplier multiplies the output current and the output voltage to provide a signal representative of an output power. A comparator compares the output power representative signal with a first preset value. A signal from the current detector is applied to an error amplifier when the output power representative signal is smaller than the first preset value, and, otherwise, the output power representative signal is applied to the error amplifier. The error amplifier controls the inverter such that the signal applied to the error amplifier can be equal to a second preset value set by a setting device.

Power supply apparatus for plasma arc utilizing equipment

A power supply apparatus includes a housing containing therein a component which generates heat when operating, a fan for cooling the heat-generating component, and a driving unit for driving the fan. The housing also contains therein a temperature detector for detecting the temperature in the housing and providing a detected-temperature representing signal. In response to the detected-temperature representing signal, a control unit provides the driving unit with a control signal to change the rotation speed of the fan.

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Itami, Japan

Haruo Moriguchi