Patent GB-539551-A (GB)
Title: Improvements in remote control and supervisory systems
IPC: H02J13/00
Filed: 1940-03-13
Abstract: 539,551. Distant control systems. AUTOMATIC TELEPHONE & ELECTRIC CO., Ltd., and BURNS, G. A. March 13, 1940, No. 4681 [Class 40 (i)] In a system for the control and supervision of circuit-breakers &c. over a carrier or voice frequency channel, different frequencies are employed for the signals in the two directions, the control and indicating operations both involve the transmission of a constant number of impulses from the control station. For control the impulses are broken up into two trains in accordance with the circuit-breaker to be selected, and for indicating a switch at the sub-station is stepped to connect up the circuitbreakers in succession. Selection and control.-The control station, Figs. 1, 2, is provided with a selection key for each circuit breaker at the sub-station, Figs. 3, 4, only a typical one 3SK being shown. Assuming this key and the common start key STK are operated, the switch S rotates under the control of stepping relay CE until a marking over key 3SK is picked up, whereupon relay PT responds and transfers the control to the switch M, which rotates in a similar way until a further marking is encountered, when KR pulls up. During these operations CE sends impulses to the sender CRS which transmits A.C. impulses to the sub-station, an inter-train pause being introduced after the oneration of PT until the switch M reaches position 4. T,he markings are applied by the selecting keys to the switches S, M in reverse order so that the total number of impulses is constant. At the sub-station, the impulses are repeated by relay A to set the switches AS, BS, relays C, D being operative during the successive trains. Provided the full number of impulses have been received relay H energizes over cross-connected contacts of AS, BS and connects up the sender SSS to transmit a check signal. Relay AR responds and operates OP momentarily to send the executive signal, which is repeated by A to the appropriate interposing relay ITR. The switches AS, BS restore on the relapse of sluggish relay SR, which holds throughout the control operations, while the switches S, M at the control station restore on the replacement of the start key STK. Supervision.-Any change at the sub-station, whether caused automatically or by remote control, brings about the application of positive to lead 13 to operate relays RSR, SE, and a start signal is sent to the control station by the sender SSS. If, however, a control operation is taking place, the supervisory condition is registered by RSR and the start signal is sent when SR relapses. Relay AR responds and connects up RVR to start the switch DC rotating under the control of stepping relay CEX, and impulses are sent to rotate the switch DS at the control sub-station in synchronism. Indicating contacts AC are connected up in turn, and relay RV energizes over those that are closed and returns a supervisory signal to operate RVR which reverses the potentials extended over DC 2, 3. A set of relays, only one 3CC of which is shown, are connected alternatively to these banks by two-position locking relays such as 3CON. A change of condition of circuit-breaker No. 3 for example brings up 3CC which locks under the control of a reset key ARK and connects up 3 CON to reverse its contacts. The indicating lamp 14 or 15 is flashed and a bell AB sounds until key ARK is actuated. If the switch DS does not finish in its home position the operation of RP sends a fresh start signal and the cycle is repeated. Similarly, if a change takes place while a cycle is in progress, RSR pulls up and causes the cycle to be repeated.