| 摘要 |
PURPOSE:To stably execute multielectrode are welding without being influenced by a temperature rise of a material to be welded, by measuring a temperature of the material to be welded, and executing the welding, controlling a welding condition of an electrode in accordance with its value. CONSTITUTION:A temperature signal measured by a temperature detector 17 constituted of a lens 18 and a detector 19 is sent to a temperature controlling circuit 21 through an amplifier 20. The circuit 21 stores a mean temperature within a specified time after welding is started, and sends a welding current drop signal corresponding to a temperature difference to a controlling circuit 13, when a temperature of a material to be welded 1 becomes higher than the mean temperature. The circuit 13 reduces a welding current to be supplied to a non- consumble electrode 5 in accordance with a signal value, and simultaneously, applies a switching signal to switching elements 9, 10, 11 and 12. As a result, an output from a DC power source 8 is switched to the electrode 5 and a wire 7 of a consumable electrode 3 alternately by the elements 9, 10, 11 and 12. A current of the electrode 3, however, is made to keep constant. |
