Patent GB-382312-A (GB)
Title: Improvements relating to electric signalling systems
IPC: H02J13/00
Filed: 1931-07-24
Abstract: 382,312. Electric signalling and distant control systems. SIEMENS BROS. & CO., Ltd., Caxton House, Tothill Street, and HUMPHRIES, H. E., 61, Woodville Road, Blackheath, both in London. July 24, 1931, No. 21148. [Class 40 (i).] In a system for controlling and supervising apparatus at a remote station wherein step-bystep switches selectively associate control keys and supervisory signals at a control station with corresponding apparatus units, e.g. circuitbreakers at the remote station, the step-by-step switches are driven synchronously or at a fixed speed relationship by individual relay combinations which deliver stepping impulses at a predetermined rate. In the arrangement shown, stepping switches AM, BM at the control and remote stations respectively are adapted to associate keys such as OLS with corresponding control relays, viz. FAG, over the control line OL. The switches are driven synchronously and independently by relay combinations comprising interacting relays AZ, AY, BZ, BY, these relays being arranged as described in Specification 334,516, [Class 40 (iv),Telephones &c.], and adapted to deliver beat impulses at a predetermined rate to separate the respective switches. A similar system employing switches CM, DM is used for transmitting supervisory indications to the control station over line wire IL. Stepping arrangements. To initiate operation of stepping switch AM, " start " key CSK is depressed to energize slow-acting relays ES, AS, the latter being slow-acting by reason of the shunt condenser circuit AQC. After a delay AS pulls up and ES opens the circuit of AS but AS is held operated by the discharge current of the condenser. When AS is operated, relay AY and stepping magnet AM are energized, the relay AY opening the discharge circuit for condenser AQC through relay AS and preparing the circuit for relay AZ which is closed after a further interval due to the inherent slow-releasing characteristics of relay AS. Relay AZ is connected in series with a choke AZC and resistance AYA and is shunted by a condenser AQA, the choke and condenser effecting a delay in operation and the resistance governing the time of release. When relay AZ operates after its delay period the circuit of AY, AM is opened, the release of AM causing a stepping operation of the switch. Release of AY releases AZ which after a delay re-establishes the circuit of AY, AM over earthed banks of wiper amb, and the cycle of operations of the relays AY, AZ is repeated. In this manner stepping of the switch is produced under the control of relays AY, AZ until when wiper amb moves into engagement with the penultimate contact a self-drive circuit is closed through a second winding of relay AY which allows stepping to normal with further operation of relay AY. Stepping of the substation switch is initiated by the release of normally energized line relay BS when relay AY is first operated to energize relay BY and stepping magnet BM. BY operates BZ which deenergizes BY, BM and counteraction of relays BY, BZ is continued to operate the switch, the relays operating in a manner similar to that of the relays at the control station. In order that synchronous starting may be effected relays AZ, BZ must operate simultaneously and in consequence the releasing time of relay AS should equal the releasing time of BS plus the operating time of BY. Stepping of the receiving switch is continued under the control of relays BY, BZ until the wiper bmb engages the first contact multipled to the second winding of relay BY, self-drive then being effected without operation of relay BY. Since on selfdrive the switch BM operates through more steps than the switch AM and as such stepping is faster than stepping under the control of relays, the switch arrives at its home position before the switch AM in order that the receiving station may be ready for further 'signals from the control station. Control operation. Alternate contacts of the bank ama are connected to the keys. When a key is operated one or other of two contacts is marked so that when the wiper engages the marked contact during the stepping operation an impulse is transmitted to line relay BS and a circuit is closed over wiper bma for the appropriate control relay FAG, FAR. The operated relay energizes a corresponding power relay PR, which effects the desired operation. Supervisory signalling. When the controlled apparatus changes its position, auxiliary contacts AUX are operated to mark the bank cma in accordance with the new position of the associated apparatus and during the changeover to make temporary engagement with an intermediate contact to operate relay CS and initiate stepping of the switch CM. This switch and switch DM at the control station are driven independently by associated relays CY, CZ, DY, DZ in a manner similar to that already described, and during rotation an impulse is transmitted over lines IL to effect operation or release of relay EX dependent on the position of contacts AUX. Relay EX controls supervisory lamps G, R and also a " change " lamp which is under the control of a key RE. If during operation of switch CM, a switch associated with contacts in the bank cma over which the wiper has already passed, alters its position, relay CS is operated over bank cmd and locks over bank cma to store the signal and ensure that a second operation, of the switch is produced. When the switch arrives at normal relay CS is held operated by condenser CQC for a time sufficient to allow operation of relay CY and the initiation of a second cycle. Modifications. Instead of using alternate contacts in the switch banks, successive contacts may be utilized. The switches may be arranged to effect a test revolution prior to signalling or controlling and only a single pair of line wires may be employed, automatic switching being effected between the control and the supervisory apparatus. Moreover the control and signalling impulse may be of alternating current of voice frequency and the switches may be arranged to move at different speeds providing the ratio of speed is fixed and the connections to the bank contacts spaced accordingly.