| 摘要 |
626,970. Electric selective signalling. ALLMANNA SVENSKA ELEKTRISKA AKTIEBOLAGET. Sept. 12, 1946, No. 27390. Convention date, Sept. 24, 1945. [Class 40 (i)] The invention is concerned with a system in which sub-stations, e.g. 1 ... 5, Fig. 2, can signal to a central station C and has for its object the limitation of a fault in one substation to that substation alone. According to the invention, the substations are interconnected by repeaters, and a fault results in the faulty station being rendered incapable of operating the repeater immediately following it. As shown, station 3 acts as a repeater for stations 1 and 2, station 4 acts as a repeater for stations 1, 2 and 3 while stations 5 are connected to the central station C over repeaters M6, M7, Fig. 1. Substations signal by interruption of line current; thus stations 1, 2, Fig. 1, signal by opening contacts S1a, S2a, releasing relays M1, M2 in substation 3 to open contacts M1a, M2a to release relay S4 controlling contact S4a; similarly substation 4 acts as a repeater; relay M4 actuating contacts M4a, M4b to control relays S6s controlling contact S6a; stations 3, 4 signal by breaking contacts M3a, M5a, to interrupt the circuits of relays S4, S6; and station 5 signals by opening contact S7a. In the central station, relay M8 is released in accordance with the received signal. When relays S4, S6 and M8 de-energize, the circuits of delay release relays H1, H2 and V are broken, but the normal signal interruption is not long enough to cause them to fall away. However, a long interruption, corresponding to a fault, results in relay V first falling off, followed by release of relays H1, H2. Relay V releases to make contacts Va, Vb, actuating relays B6 and L which lock up over contacts B6a and Lb; relay B6 closes contact B6c to shunt contact M6a, thus temporarily preventing stations 1 ... 4 from controlling relay M8, and energizing relay M8 to re-actuate relay V. Assuming relay H1 releases next, relay B2 energizes to lock up and actuate relays M4, S6, before relay H2 releases, and relay M6 is energized to release relay B6 and break contact B6c, restoring relay M8 in the central station for actuation by all substations except substation 2; relays H1, H2 re-energize as soon as relays S4 and S6 are actuated. If relay H2 releases before relay HI, the same state is reached. Similarly, faults in stations 1, 3, 4 and 5 cause relays B1, B3, B5 and B7 to lock. The energization of relay L releases long delay relay T to actuate relay O which causes an asking signal to be sent to the substations and releases relay L; the substations reply and the one at fault is revealed by lack of reply. |
