| 摘要 |
PURPOSE:To make it possible to immediately analyze an abnormal cause, by allowing a memory device to store the voltage drop of the connection wires between an AC power source and a plurality of windings, which are arranged along a moving path, through a low band pass filter and stopping memory renewal when abnormality is generated to detect a moving state. CONSTITUTION:When a control rod begins to fall, a control rod driving shaft 2 being a magnetic body induces electromotive force in winding elements 1a-1e to generate voltage drop in connection wires 13. The output obtained by amplifying said voltage drop by an amplifier 7 and voltage drop due to an AC power source 3 in a normal state wherein the control rod is not fallen are separated by a low band pass filter 8. In addition, the output of the filter 8 is converted to a digital signal by an A/D converter 9 and this signal is stored in a memory device 10 in the relation with time under the control of a control circuit 11 and renewed at every definite time T. In this case, the renewal of the memory of the memory device 10 is stopped by the trip signal of an atomic reactor and the whole of the memory content is allowed to reappear by a recording needle 12 and used in analysis. |
