Matsushita Electric Industrial Co., Ltd.

Seigo Hagiwara

Kazuo Kimoto

Yoshiaki Tanaka

Naoki Kawai

Norikazu Osaki

Akihiko Kitajima

Hidetoshi Ooyama

An arc welding and arc plasma cutting machine having a dc high-voltage generator is provided. The dc high-voltage generator includes a first dc power source, a second dc power source, an one-way rectifier, and a voltage clamping circuit. The first dc power source applies a dc voltage through the one-way rectifier across an electrode and a work piece. The second dc power source is connected across the first dc power source and superimposes a dc voltage on the power produced by the first dc power source for developing an arc discharge across the electrode and the work piece. The voltage clamping circuit connected in parallel to the one-way rectifier to restrict a high-voltage applied to the one-way rectifier below a given level for protecting the one-way rectifier from breakage due to application of the high-voltage.

Arc welding and arc plasma cutting machines having improved DC

In an arc welding machine and a plasma cutting machine, by connecting the output of a second DC power supply unit to a circuit fed by a first power supply unit, a DC high voltage from the second DC power supply unit is applied, during start, across an electrode and a base metal which are not in contact with each other, so that radiation noise can be reduced considerably and leakage of high frequency power from an extension cable can be eliminated to attain steady arc start.

ARC welding machine and plasma cutting machine

Arc welding machine and plasma cutting machine

An arc welding machine includes a transformer a diode for rectification connected to the secondary winding of the transformer, two capacitors connected in series with each other and in parallel with the diode, and the first and second switching elements connected in series with each other and in parallel with the diode. This machine also includes an electrode having one end connected at a location intermediately of the two switching elements and the other end opposed to an object to be welded, first and second drive circuits connected to the first and second switching elements, respectively, an oscillating circuit for determining the width of pulses of the first and second drive circuits, and a timer circuit for inputting to the oscillating circuit signals required to make the oscillating circuit periodically repeat oscillating and stop operations. The object is connected at a location intermediately of the two capacitors. The second drive circuit outputs inverted signals of the first drive circuit. By this construction, an alternating current and a direct current alternately flow between the electrode and the object during welding.

Arc welding machine and method

Growing community of inventors

Kawanishi, Japan

Seigo Hagiwara