| 摘要 |
The invention concerns welding techniques, especially a machine for resistance butt welding. The machine contains welding transformers 1, in whose primary winding circuit are connected controllable gates 13, which are connected to respective phase shift elements 14. The secondary winding of each welding transformer 1 is connected in a welding current circuit, which is provided with a large number of elements 2 for supplying current to the work piece being welded. One input of the phase shift element 14 is connected to a programming arrangement 12, which is designed to put out a command signal which enables the checking of the melt continuity for a measurement circuit which is constructed from a welding current pickup 4, a pickup 5 for detection of short circuit, a preset pickup 6 for presetting a controlled short circuit interval of time that is provided with a comparison unit, and a display unit 9. Each current supply element 2 is provided with an individual measuring circuit and connected to its own welding current pickup 4. The controllable gates 13 are provided with a feedback circuit, based on an OR gate 7, for feedback with regard to the occurrence of a short circuit. The welding machine furthermore contains an OR gate 8, an AND gate 10, and a flip flop circuit 11, which is designed to preset the corresponding logical relation among the signals in the machine. The welding machine according to the invention can preferably be used for welding of work pieces with large cross sectional surface with great length. <IMAGE> |
