Patent GB-723038-A (GB)
Title: Improvements in or relating to electrical supervisory control systems
Inventor: BURNS GEORGE ARTHUR
IPC: B61L7/06
Filed: 1952-05-14
Abstract: 723,038. Electric selective signalling systems. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd. May 14, 1953 [May 14, 1952], No. 12248/52. Class 40 (1) A circuit for effecting the successive operation of a selected plurality of circuit breakers or like devices at a sub-station is completed in response to the transmission from a control station and correct reception at the substation of a single train of impulses of fixed total number but selectively different polarities. As shown, the impulses, of which Fig. 2 shows a possible series, are transmitted in a loop circuit including in series at each sub-station, Fig. 1, two polarized relays N, R which respond to normal and reverse impulses respectively. The first impulse is always reverse, impulses 2 to 13 are code impulses for selecting the sub-station and the group of circuit breakers therein, and impulses 14 to 25 select the required circuit breakers in the selected group of twelve. Relay R responds to the first reverse impulse, brings up relay BX, followed by BB and BH, and causes switch S to step to position 2. Switch S steps at each impulse, and the impulse train shown in Fig. 2 brings up relays CA and CC at the second and fourth impulses, thereby selecting the second group of circuit breakers 13-24. The first group 1-12 would be selected by the operation of relays CA and CB. Positions 5-13 on switch S are unused in the sub-station shown, but are wired in other sub-stations. Each of the impulses 14-25 brings up one of the O relays over wiper Sl or one of the NO relays over wiper S2 according to its polarity. In the present example, relays 10, 120 and 2NO-11NO are operated, selecting the first and twelfth circuit breakers in the second group. At the end of the impulse train, switch S is back in its home position and relay BX releases slowly, completing a circuit over a chain of contacts of the O and NO relays to start a switch Q stepping. Wiper Q6 finds positive potential on its multipled contacts 2-13, due to the operation of relays CA and CC, so that switch Q steps to position 14. Relay A then operates, followed by B, and since relay 10 is operated a circuit is completed over wiper Q2 for either the close relay 13C or the trip relay 13T of circuit breaker 13, according to the condition of the associated magnetic locking relay 13ML (not shown). The operation of circuit breaker 13 changes over auxiliary contacts 13aux1 to release relays A and B, and switch Q. steps to its next position. In the present example the operation of relays 2NO- 11NO causes wiper Q3 to encounter positive potential at positions 15-24, so that switch Q is driven to position 25. Circuit breaker 24 is operated, and switch Q then steps to its home position where wiper Q7 completes a circuit for a relay RSR which initiates the operation of an indicator circuit IC, which may be of the type described in Specification 591,043. If a circuit breaker fails to operate when required, switch Q is enabled to step on by the operation of a relay KO after a delay during which a condenser C1 is charged.