| 摘要 |
PURPOSE:To detect the short circuit on the upper or down stream side of the fuse of a load circuit by outputting a breaking command signal when either the short circuit on the upper side of the fuse of the load circuit or fusing is detected. CONSTITUTION:The voltage at a detection point 15 increases to increase the voltage of a gate G of a thyristor 13 to operate the thyristor 13 when the upper stream side of the fuse 3 of load circuit is short circuited. A coil C1 of a circuit breaking relay 11 is energized to break the load circuit and an alarm lamp 19 is lighted. On the other hand, the fuse 3 is blown when the down stream side of the fuse of the load circuit is short circuited but the coil C2 of a fusing detection relay 25 is de-energized and the both contacts 25a and 25b of a normally closed relay 25 are short circuited. The thyristor 13 is thereby operated and the coil C1 of a circuit breaking relay 11 is energized. The relay 11 breaks the load circuit. |
