| 摘要 |
<p>PROBLEM TO BE SOLVED: To certainly and rapidly judge abnormality corresponding to the resistance irregularity or temp. change of the heater of a joint. SOLUTION: The current supplied to the heater of a joint 2 is detected and a welding current estimate function is operated from the presently detected welding current value and the past welding current value to calculate a welding current value after a predetermined time and the deviation between this estimated welding current value and an actually detected welding current value detected after a predetermined time is calculated and it is judged whether this deviation is within a normal current irregularity range and, when the deviation is out of a range of irregularity, a welded state is judged to be abnormal. By this constitution, the abnormality of a welded state can be rapidly and certainly detected at every predetermined time corresponding to the resistance irregularity or temp. change of the heater of the joint.</p> |
