| 摘要 |
PURPOSE:To prevent the occurrence of an open communication line at the reverse breakdown state by operating a relay due to a current flowing there to connect the other terminal of the 2nd arrestor to an output terminal via a resistor. CONSTITUTION:The 1st arrestor 2 is connected in series with the parallel circuit comprising a relay 4 and a diode 7 and the result is connected between an output terminal of an information transmitter 1 and a station protection ground 8, the 2nd arrestor 3 whose one terminal is connected to a remote ground 9, a resistor 6 whose one terminal is connected to the other terminal of the 2nd arrestor 3 and a contact 5 connecting the other terminal of the 2nd arrestor 3 to the output terminal via the resistor 6 by the operation of the relay 4 by a current flowing there via its own normally closed contact are provided. If a reverse arcing takes place, the relay 4 is activated by the reverse arc current, the reverse arc current route passes through the circuit protection resistor 6 by its contact 5 and the current is limited by the resistor 6.
|
