| 摘要 |
PURPOSE:To obtain an overcurrent protecting circuit by a low voltage and a small current, by connecting semiconductor switching elements connected in series, to the driving circuit of a solid-state contactor connected to a power source circuit in parallel through a quick interruption type overcurrent protecting device. CONSTITUTION:When an interlocking circuit generates a malfunction due to a noise and output signals of NOR circuits 23, 24 become '1' simultaneously, this signal '1' turns on output transistors TR21, TR22, and simultaneously, turns on a TR23 and a TR24 connected in series. When these TR23, 24 become ON, the output side of a fuse 28 is short-circuited to an earth, and before solid- state contactors 25, 26 become ON, the fuse 28 of a quick interruption type is interrupted. Accordingly, the driving circuit of the solid-state contactors 25, 26 is interrupted and the short circuit of a power source in the main circuit of the contactors 25, 26 is prevented.
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