Abstract: A relative weaving motion of a welding torch relative to a weld line is given to a welding torch, by way of composing a weld main path vector for a relative movement of the weld torch along the weld line and a swing vector for a relative movement of the weld torch. And by detecting the amount of an electrical parameter of an arc of the weld torch, the amount of correction is calculated based upon the deviation between the detected amount and a predetermined reference amount. The direction of the amount of correction is determined based upon the swing vector. The relative movement of the weld torch relative to the weld line is performed by a vector composed of the weld main path vector, the swing vector, and the correction vector. In other words, the present invention features the direction of the amount of correction being definitely determined based upon the basis of the swing vector.

Abstract: A memory system has a first memory such as a magnetic bubble memory and a second memory such as a RAM having a faster access time than the first memory. The first memory is divided into a plurality of blocks each of which has program steps stored therein. The second memory has a plurality of unit chains which correspond to the blocks of the first memory respectively and in each of which step information representative of the number of steps stored in the corresponding block and pointer information indicative of a connection to a next block are stored. The step information in the unit chains are successively read in accordance with predetermined start block information and the pointer information to count the total number of steps on the basis of the read step information. From the first memory is read information in the block corresponding to the unit chain of the second memory with respect to which the counting is made when the counted number of steps reaches or exceeds a program step number to be detected.

Abstract: A system and method for weld line profile control wherein an electrical quantity corresponding to the arc of a welding torch is detected and the deviation between the electrical quantity and a reference quantity is monitored so that correction movements of the welding torch relative to the weld line can be limited if the deviation exceeds a predetermined value. In more detail, an electrical quantity corresponding to the arc of one side waveform of a welding torch operating under the influence of a wave signal is detected and a reference quantity corresponding to the arc of the other side waveform of the welding torch is detected, and the deviation between the electrical quantity and the reference quantity is monitored to provide a signal limiting the correction movements of the welding torch relative to the weld line when the deviation exceeds a predetermined value.

Abstract: In welding effected by weaving an electrode, welding current or voltage is applied to a frequency analyzer, for deriving a frequency component having the same period as a weaving period and a doubled frequency component having a period which is half the weaving frequency. The center of weaving motion is corrected in relation to the two frequency components to thereby effect tracer control for the electrode.

Abstract: A control apparatus for an induction motor wherein an inverter is connected between a power source and the induction motor so as to energize the induction motor through the inverter, characterized in that when an input voltage of the inverter has lowered, a magnetizing current component command is decreased, while a torque current component command is increased.