PURPOSE: To measure welding speed automatically and accurately by giving command to starting and finishing of work later than the time of detection of arc light detector installed in the welding start and welding finishing sections.
CONSTITUTION: When a welding arc arrives at a distance l1 from the installed position of arc light detectors 5a, 5b, if voltage is raised to power source voltage, the start and terminal of the distance L1 is detected by detectors 5a, 5b. This differs from detection of start and terminal of distance L0 between the positions of the detectors 5a, 5b. The first delay relay or second delay relay is operated according to output voltage of the detectors 5a, 5b. In this case, delay time of the delay relay corresponds to, for instance, the time in which the arc 4 moves the distance la. Accordingly, it can be brought sufficiently close to the time in which the arc moves the distance L0, and detection error due to raidal spreading of arc light can be compensated substantially.
HANEDA TAKUJI
MASUDA KOUTAROU
KISHIDA HITOSHI
