Patent GB-302937-A (GB)
Title: Improvements in and relating to electrical supervisory signalling systems
IPC: H02J13/00
Filed: 1928-12-22
Abstract: 302,937. Compagnie Francaise pour l'Exploitation des ProcedÚs Thomson-Houston, and Toulon, P. Dec. 22, 1927, [Convention date]. Tell-tale apparatus.-Photo-electric sound-reproducing apparatus is used for indicating at a place of observation the condition of apparatus situated at a distant point or points. The invention is particularly applicable in connection with electric supply and transmission systems, means being provided whereby a breakdown or fault in the working at a. substation sets the sound-reproducing apparatus in action and causes an appropriate record to make the necessary announcement. Another use to which the invention may be put is to indicate the condition of apparatus at distant meteorological stations. Fig. 1 (Cancelled) shows the construction of a sound-reproducing apparatus which may be used. This Figure is substantially the same as Fig. 2 of the Specification as accepted. A translucent rotary drum 1 carries a number of films a - - l, each bearing a photographic' sound record such as a verbal announcement. Light is transmitted from an elongated lamp 2 within the drum, through the records, and is reflected by a mirror 5, on to a photo-electric cell 6. The cell is connected with a sound-reproducer comprising an amplifier 7 and loud-speaker 8. Interposed between the films a - - l and the mirror are a number of shutters 0', O<2>, O<3>, &c., one for each film, and each shutter normally closes a slit through which light transmitted through the record may pass. Fig. 1 shows how such a sound-reproducing apparatus may be used to transmit indications of the conditions of apparatus such as electrical machines at a sub-station. In this case, the films a, b, c, &c. each bear a photographic record of sentences relating to the working of the apparatus to be supervised, and each shutter O<1>, O<2>, O<3>, &c. is adapted to be operated by a relay R<1>, R<2>, R<3>, &c. These are connected across. a pair of conductors L<1>, L<2>, and in series with. each relay is a make-and-break device, C<1>, C<2>, &c., and a contactor V<1>, V<2>, &c. The devices C<1>, C<2>, &c. are all rotated at the same speed as the recordbearing drum 1, and are so arranged that no two pairs of contacts are closed at the same time. Associated with each relay, and in series with the line L<1>, is a switch A, B, D, &c. The switches normally remain in their lower position (as B and D), and each is associated' with, and moved when necessary by the action of a particular device of whose condition an indication is required. For example, if the switch A is associated with a circuitbreaker, then when a fault occurs on the line the current which operates the circuit-breaker will move the switch A into its uppermost position. This causes the relay R1 to operate the shutter O<1> and the words " short-circuit " are uttered by the loud-speaker. At the same time, the relay R<1> breaks the circuit through the conductor L<1> at Ra, and the contactor V<1> is moved so as to cut out the relay R<1> when it has functioned once. The operation of the indicating apparatus may be initiated by a relay placed, together with a bell, in the line L<1>. The relay may light the lamp. 2, start the drum 1, complete the battery circuit of the sound-reproducer, and operate one of the switches A, B, &c. to cause an announcement to be made as to which station is transmitting an indication. The Specification, as open to inspection under Sect. 91 (3) (a) states also that the shutters O, O<2>, &c. may be operated by mechanical means, such as cams, instead of electrical devices, and that the film records may be arranged concentrically on a disc. This subject-matter does not appearin the Specification as accepted.