| 摘要 |
In order to improve the quality of seam welding, an inverter seam resistance welding electric power supply apparatus reliably determines local weldability (conforming/defective) of seam welding by simply monitoring welding current. In a seam welding operation, when a current monitor time interval has elapsed, a CPU reads, from storage, measured current values [I1], [I2], etc., of each inverter cycle obtained during the current monitor time interval and computes an average current value [IM1] thereof, according to an averaging method such as an arithmetic mean method. Then the CPU compares the average current value [IM1] with a preselected monitoring value or range. If the average current value [IM1] falls within the monitoring range, the CPU determines the occurrence of a conforming local welding whereas it determines the occurrence of a defective local welding if the average current value goes out of the monitoring range. For successive determinations of defective local welding for a preselected number of times, for instance, three, the CPU determines that a defective seam welding has occurred, and takes appropriate action immediately, for instance, by stopping the seam welding operation.
|
