A welding system includes an engine-driven welder generator that produces welding power. A welding torch receives the welding power and applies it to a stick electrode to initiate and maintain a welding arc. A parameter of the welding power, such as voltage, is monitored, such as to determine whether spikes occur during a short time after arc initiation. Based upon the monitored parameter, the engine speed is controlled. The engine speed may be increased or maintained at an elevated level if the monitored parameter indicates that particular types of electrode are being used, such as XX10 or cellulose electrodes.

A pressure welding method and a pressure welding device (1) are provided. The pressure welding device (1) includes a plastification device (7), an upsetting device (8) and component mountings (34,35,36,37) for the components (2,3,3′,4) to be welded together and a machine frame (12). The pressure welding device (1) further includes a plurality of machine heads (13,14), each having a component mount (34,35), which machine heads are movably arranged on the machine frame and are connected to respective upsetting drives (22). The machine heads (13,14) and respective upsetting drives (22) can be independently driven. An upsetting head or support head (27), which is preferably secured on the frame, is arranged between the machine heads (13,14).

An arc-welding method in welding by repeating a short circuit and an arc. When the sign of opening of the short circuit is detected, the welding current is reduced from a first current value at the detection of the sign to a second current value, which is lower than the first current value. When the opening of the short circuit is detected, a pulse current having a peak value higher than the first current value is supplied at a plurality of times in the arc period. This suppresses porosities and spatters when galvanized steel sheets are welded.

An arc-welding method in welding by repeating a short circuit and an arc. When the sign of opening of the short circuit is detected, the welding current is reduced from a first current value at the detection of the sign to a second current value, which is lower than the first current value. When the opening of the short circuit is detected, a pulse current having a peak value higher than the first current value is supplied at a plurality of times in the arc period. This suppresses porosities and spatters when galvanized steel sheets are welded.

A passive arc control system for a motor control center 60 includes an arc attenuating box having sides separating adjacent vertical bus bar phases 54, providing a physical barrier to arc flash energy. The box is open at its top and bottom forming a chimney 55. A shutter assembly for each box includes an insulator cap 62 on a free end of the bus bar and an independently moveable, box-shaped shutter 64 that slides along the bus bar away from the insulator cap, when a device is connected to the bus bar. The shutter has an opening 65 through which the bus bar passes when the device is connected to the bus bar and an opening 55′ aligned with the box's chimney. The arc control system provides a high degree of arc protection for personnel working around open motor control centers and is highly modular and easy to construct.

A passive arc control system for a motor control center 60 includes an arc attenuating box having sides separating adjacent vertical bus bar phases 54, providing a physical barrier to arc flash energy. The box is open at its top and bottom forming a chimney 55. A shutter assembly for each box includes an insulator cap 62 on a free end of the bus bar and an independently moveable, box-shaped shutter 64 that slides along the bus bar away from the insulator cap, when a device is connected to the bus bar. The shutter has an opening 65 through which the bus bar passes when the device is connected to the bus bar and an opening 55′ aligned with the box's chimney. The arc control system provides a high degree of arc protection for personnel working around open motor control centers and is highly modular and easy to construct.

In control applying a gradient to a command voltage value during an arc period, although stable welding can be performed even in a case where a protrusion length of a welding wire becomes long, when the disturbance such as sudden change in the protrusion length is generated, a current waveform of the arc period is undershot, the short circuit period is disturbed, and it took time to return to the stable state, and the amount of sputter generation is also increased. Therefore, it is possible to suppress a change in current such as undershoot or the like when the disturbance is generated, stabilize short circuit cycle, perform welding with a strong resistance to disturbance and a small amount of sputter generation by changing an inductance value a plurality of times during the arc period.

In control applying a gradient to a command voltage value during an arc period, although stable welding can be performed even in a case where a protrusion length of a welding wire becomes long, when the disturbance such as sudden change in the protrusion length is generated, a current waveform of the arc period is undershot, the short circuit period is disturbed, and it took time to return to the stable state, and the amount of sputter generation is also increased. Therefore, it is possible to suppress a change in current such as undershoot or the like when the disturbance is generated, stabilize short circuit cycle, perform welding with a strong resistance to disturbance and a small amount of sputter generation by changing an inductance value a plurality of times during the arc period.

In a consumable electrode-type arc welding in which pulse welding and short-circuit welding are alternately repeated, a welding current is controlled such that a welding current immediately before shifting from the pulse welding to the short-circuit welding is lower than a base current in a pulse.

There is provided an arc welding control method for performing a forward/reverse feeding control of alternating a feeding rate of a welding wire between a forward feeding period and a reverse feeding period, and generating short-circuiting periods and arc periods to perform welding. The welding wire is fed forwardly upon starting the welding. The forward feeding is continued during a transient welding period from a time point at which the welding wire comes in contact with a base material and conduction of welding current is started to a time point at which convergence on a steady welding period is performed. The transient welding period is terminated at the short-circuiting period. The forward/reverse feeding control is started from the reverse feeding period after the termination of the transient welding period.