Abstract: An arc welding system including an electric circuit including a power source, a welding torch with a consumable welding wire, a workpiece and a control system including a computer, memory and elements for tuning the arc welding system.

Abstract: An electric switching device for alternating current comprises two branches (2, 3) connected in parallel in a current path and having each at least two contact members (4–7) connected in series. A semiconductor device (8) is adapted to interconnect the midpoints between the two contact members of each branch. When opening the current path a first contact member (5) of one, first branch located before said midpoint as seen in the current direction existing is controlled to open and a second contact member (6) of the second branch located after the midpoint as seen in the current direction is controlled to open for transferring the current to a temporary current path through the semiconductor device. The current path through the switching device is then broken when the semiconductor device is in a blocking state by opening a contact member (4, 7) of the switching device arranged in the temporary current path.

Abstract: A robot for movement of a moveable element (2) relative to a base element (1) comprises at least two link devices (4, 5, 6) coupled between the elements. These link devices comprise each at least two mutually articulated link units (7, 8; 9, 10; 11, 12) and power exerting arrangements (13, 14, 15) adapted to pivot the link devices for changing the relative position of the elements. A first (4) of the link devices is connected with the moveable element (2) via a hinge connection (16) so that there are, on consideration of the robot in its entirety, at least two degrees of freedom in the form of relative pivotability about two pivot axes, real or imaginary, extending at an angle relative to each other between the first link device (4) and said element (2).