| 摘要 |
PROBLEM TO BE SOLVED: To provide a feed line cutoff device which controls cutoff of a feed line in such a manner that a fuse is prevented from being fused or a protection object component is prevented from being damaged, and an overcurrent prevention method.SOLUTION: The feed line cutoff device comprises: a switch 12 which is inserted into the feed line and electrifies or cuts off the feed line; a current discrimination part 31 for comparing a current that flows in the feed line with a plurality of overcurrent thresholds and discriminating whether the current exceeds each of the overcurrent thresholds; and a switch control part 32 for turning off the switch after the lapse of a preset OFF time threshold that is different for each of the overcurrent thresholds and shorter than a time for a protection object to be damaged, with respect to a current that flows in the feed line while exceeding the overcurrent thresholds. The OFF time threshold which is different for each of the overcurrent thresholds and shorter than the time for the protection object to be damaged, is preset to an overcurrent/time threshold setting part 33. The OFF time threshold is set shorter than a time for a fuse 13 to be fused in all current regions.SELECTED DRAWING: Figure 1 |
