| 摘要 |
<p>PURPOSE:To mark a position having troubles by flowing a current in the direction reverse to a supply power current when the function of a basic group PCM relay transmission line is stopped, operating a relay in an intermediate relay, measuring a current value flowed from a constant voltage power source and comparing it with the current value previously measured when the transmission line is normal. CONSTITUTION:When a transmission line is normally functioning, a supply power current flows to a middle point (b) of an output transformer 1-5 from a middle point (a) of an input transformer 1-4. Consequently relays 2-3, 3-3... on each relay board are reversely biased not to act, and nodes 2-4, 3-4... of relays are opened. When the function of the transmission line stops, a current reverse to the supply power current is flowed in the transmission line, but this current will not flow to an upstream part of the point where a main circuit is disconnected. As a result, the relay will not act and the node remains opened. Then, since a current flows from a constant voltage power source 1-3 through a monitor/consultation circuit and the acting relay, the current is measured and compared with a previously measured current; therefore the position having troubles can be easily marked.</p> |
