Abstract: The capacitor module includes a capacitor, in which a screw hole is arranged on an outer bottom wall surface of a capacitor case housing a capacitor element, and a heat dissipater, on which a plurality of capacitor cases are fixated by screwing fixation screws in the screw holes of the capacitors. As a result, for example, the capacitor can be fixated with reliability and durability secured even under a condition where very strong vibration is continuously applied, for example, when the capacitor module is mounted on construction machinery. Further, because, an adherence of the outer bottom wall surface of the capacitor case on a fixation surface of the heat dissipater is strengthened by screwing the fixation screw in the screw hole, the capacitor can be cooled down by transferring heat produced by the capacitor to the heat dissipater as needed.

Abstract: The capacitor module includes a capacitor, in which a screw hole is arranged on an outer bottom wall surface of a capacitor case housing a capacitor element, and a heat dissipater, on which a plurality of capacitor cases are fixated by screwing fixation screws in the screw holes of the capacitors. As a result, for example, the capacitor can be fixated with reliability and durability secured even under a condition where very strong vibration is continuously applied, for example, when the capacitor module is mounted on construction machinery. Further, because, an adherence of the outer bottom wall surface of the capacitor case on a fixation surface of the heat dissipater is strengthened by screwing the fixation screw in the screw hole, the capacitor can be cooled down by transferring heat produced by the capacitor to the heat dissipater as needed.

Abstract: A plasma arc welding for effectively letting gases of low boiling point substances for coating a steel sheet escape, ensuring the escape of a molten metal into gaps between the steel sheets and eventually accomplishing satisfactory plasma arc welding. A hole (31) is first bored in an upper sheet (21)(or both upper and lower sheets (21 and 22)) quickly by using a plasma arc (20) having greater power than an appropriate welding value, and a vapor of coating substances is allowed to escape through the hole (31). Subsequently, power of the plasma arc (20) is lowered to the appropriate welding value, and the upper sheet (21) and the lower sheet (22) are welded together while a filler (9) is being supplied to fill the hole (31) and the gap (23). While boring is made or immediately after boring is finished, the size of the gap (23) is measured on the basis of the plasma arc voltage, and the feed quantity of the filler (9) is controlled in accordance with the size of the gap (23).

Abstract: A plasma arc torch is provided which has a very long electrode lifetime, even if the number of times that an arc is generated and stopped is great. Improper electric discharge can be effectively prevented, and the lifetime can be increased due to the excellent resistance to heat. For this purpose, a metallic layer is provided in the portion where a pilot arc is generated, and the metallic layer contains at least one metal selected from the group consisting of gold and silver. The metallic layer is provided on the surface of the electrode holder, or on both of a surface of the electrode holder and a surface of the nozzle. Further, at least one of the electrode holder and the nozzle can be formed of aluminum or an aluminum alloy, and after the formation, an anodic oxide film can be formed on the surface thereof.