Patent GB-628568-A (GB)
Title: Improved means for effecting remote-control by means of superposed electric currents differing in frequency from the network currents
IPC: H02J13/00
Filed: 1946-07-31
Abstract: 628,568. Electric setective signalling over power circuits. LANDIS & GYR SOC. ANON. July 31, 1946, No. 22797. Convention date, Aug. 3, 1945. [Class 40 (i)] [Also in Group XXXIX] In an electric supply system wherein three or more consumer networks are arranged to be switched into circuit with their respective supply stations, sequentially, the initial station also functions to send control impulses of a different frequency over the network to the next station where the control impulses are stored, operate selected apparatus, e.g. circuit-breakers, and are subsequently sent to the next station to perform a similar control function, and so on for succeeding stations. The control impulses may be sent whether the various networks are energized or not from their supplies. As shown, transformer stations I, II, III, &c., Fig. 1, feed respective lighting circuits 4, 5, 6, &c. over switches 1, 2, 3, &c. the switches 2, 3, &c. at stations other than station I being operated respectively over the lighting circuit extending from the preceding station in known manner. At the control station 1, a signal transmitter (not shown), closes a contact 9 to inject signal pulses of audio frequency, corresponding to a desired switching operation, from the generator 7 into the network 4 through a transformer 8, whether or not the network is energized by switch 1. At the station II a receiving relay 10, responsive only to the audio signal frequency, operates a contact 11 to register the signal impulses on a storage device 12 which effects the desired control operation in network II and at contact 13 subsequently re-transmits the reconstituted signal pulses derived from a generator 14 over transformer 15 and network 5 to the station III where in a similar manner the signal is stored and subsequently transmitted to the next station, and so on. Impulse storage and re-transmission, Fig. 2. The receiving relay 10, Fig. 1, is'shown at E, Fig. 2. The first energization thereof by the starting impulse closes at contacts e the circuit of a synchronous motor M which drives the three arms d1, d2, d3 of a rotary selector switch I, II, III, in synchronism with a similar switch at the transmitter (not shown). The motor circuit is maintained for one revolution of the selector at motor operated cam contacts m2. During the rotation of the selector the signal impulses transmitted operate, over bank I, one or other of the two windings of one or more of the self-holding relays K1, K2 ... K50, dependent on the position in the cycle at which the impulses are sent. The two windings. of the relays K1, K2, &c. correspond respectively to the " on " and " off positions of circuitbreakers associated respectively therewith and operated, e.g. by relays in parallel with the K1, K2, &c. windings. The circuit-breakers to be operated at station II are thus selected and switched " on " or " off " according to the timing of the impulses transmitted thereto. All of these relays K1, K2, ... &c. at contacts k11, k12, k21, k22, &c. prepare corresponding markings on the contacts of the selector bank II. When contact 51 is reached a further " end-of-signal " impulse is transmitted from station I to energize a self-holding relay KU, contacts ku1 of which maintain the motor circuit through the normal position of the selector which then makes a second revolution during which the transmitter selector is stationary. Contacts ku2 apply marking potential to the contacts 1, 2 ... of selector bank II corresponding to the condition " on " or "off," of the relays K1, K2, &c. so that during the second selector revolution the relay S operates contacts s to inject impulses from the audiofrequency generator TG into the next lighting network 5, to operate the similar storage device at station III. Impulses are sent to station III corresponding to the condition of all the circuit-breakers at station II, but the only operative impulses are those corresponding to those transmitted to station II from station I. These operate the selected circuit-breakers at station III as for station II. The remaining impulses have no effect as the corresponding circuit-breakers at station III are already in the appropriate " on " or " off position corresponding to these impulses. At contacts ku3 the contact 50 of bank III is energized so that on the selector reaching this position during its second revolution the right hand coil of relay KU is energized and the relay thereby returned to normal. A delay-action relay V energized over ku3 marks over its contact v1 the contact 51 of selector bank II for a sufficient time to permit retransmission of an impulse in this position of the selector to operate relay KU at the next station. A selfholding relay AR operated by the signalstarting impulse functions to operate the motor M1 driving the audio generator TG and is released simultaneously with relay KU, the circuit for motor M1 then being maintained at v2 for the retransmission of the impulse in position 51 of the selector.