Patent GB-605732-A (GB)
Title: Improvements in or relating to remote metering arrangements
IPC: G08C19/00
Filed: 1945-12-28
Abstract: 605,732. Telemetering. GUNNING, P. F. Dec. 28, 1945, No. 35028. [Class 40 (i)] The transmission of meter readings is determined by the condition of a relay chain counter adapted to be set under the control of the meter movement which comprises two coils, one of which produces a torque proportioned to the quantity concerned, while the other is energized in opposition in accordance with the condition of the relay chain so as to maintain the meter movement in a normal position. As shown, the measuring and balancing coils SC, TBC are mounted on the meter spindle normally positioned to maintain contacts CA1, CS1, CA5, CS5 open. On an increase in current through SC, the spindle rotates and contacts CA1 close, thereby energizing relay coil ADD through contacts RVC4. Contacts ADD1, ADD2 prepare relay chains A, B respectively, the relays 1A-7A of the counter chain corresponding to successive powers of two. Contacts ADD3 open to de-energize relay ST, the release of which is delayed by condenser CA to prevent response to momentary signals. Relay ST as it falls off applies positive through contacts' ST1 to operate magnetic locking relay ML. Simultaneously, positive is applied to the lefthand coil of relay 1B over contacts GU1, ADD2, FC3, 1A1. Thereupon, relay 1B operates and contacts 1B1 and 1B2 cause, respectively, the locking of relay 1B through its righthand winding in series with relay GU and the energization of the right-hand winding of relay 1A through contacts ST1, GU1, SO2, ADD1, 1B2. The energization of relays 1A and SO which has a delayed operation is completed to the positive supply by the movement of contact GU1. Contacts 1A1, 1A2, 1A3, 1A4 respectively prepare circuits for relays 2B, 1B, connect resistor 256K in series with the balancing coil TBC and make positive connection to the common signalling lead representing 1 unit. When relay SO operates, contacts SO1 separate to de-energize relays 1B, GU and contacts SO2 open to de-energize relay 1A which, however, remains closed, being magnetic locking. The de-energizing of relay GU effects the return of contacts GUl to their original position, to de-energize relay SO, the contacts SO1, S02 of which return to their normal settings. The operation of contact 1A3 to insert resistor 256K in the circuit of coil TBC raises the D.C. current drawn from lines 10, 11 by coil TBC and if the resulting rise of balancing torque is sufficient to restore the spindle to its normal position the contacts CA1 will open. If the torque due to coil SC remains predominant, however, the contacts CA1 are kept together, the contacts ADD3 remain open and in the restoration of contact GU1 the lefthand winding of relay 2B is energized. As with relay 1B, the right-hand winding effects " lock-up " in series with relay GU so that contact GU1 moves to energize relay SO and relay 1A is released by current flow in its lefthand winding, and relay 2A operated to insert resistor 128K in the circuit of coil TBC. If further adjustment is necessary, as indicated by the state of contacts CA1, the relay 1A will close in addition to relay 2A at the next pulse rod contacts ST1, the next adjustment comprising the closure of relay 3A, together with the opening of relays 1A, 2A, and so on. Upon balance being achieved, relay ADD releases to energize relay ST when positive is removed from marking lead UM and connected to common start lead US to initiate the shunting operation of a distributer which in its rest position, with its wipers associated with the particular meter concerned causes start relay CST to initiate operation of the common transmitter. Simultaneously, relays MCA, MCB, MCC are operated to connect the leads associated with this particular meter to the 11 common leads connected to the indicator point, these leads including three to control the transmission of a code corresponding to the meter in question. After the completion of the transmitting cycle, relay ML is released by energization of its lower winding, whereupon condenser CA charges over ML1 and marking potential is again applied to line UM over ML2. If the meter reading alters in a downward direction, the contacts CS1 close, the relay SUB is energized and the effect of the resultant current distribution in the A relays is to release the A relay operative in the balanced state and substitute the relays below it in the series. If the opposing torque remains too high, the relevant relays 1A, 2A, &c. are de-energized to decrease successively the balancing torque of coil TBC. For large instrument readings changes, the contacts CA5 or CS5 close in addition to the respective contacts CA1, CS1 and the action of the transmission is speeded up first by the disconnection of the condenser CA from relay ST and secondly by commencing the modification of the B-relay chain at relays 3B, 4B, thus dispensing with the intermediate steps, both of these effects being initiated by relay FC. In order to distinguish between an import or export power reading of coil Sc, the relays RVA, RVB, RVC are provided. If the meter torque changes through the zero point, the relay RVA is energized and prepares relays RVB and RVC for operation. The latter reverses the connections from the D.C. source to coil TBC and from the moving contacts CSI &c. to the relays ADD and SUB. Relay RVB operates and prepares the circuit for the restoration of relay RVA. The import of power is indicated at the distant point by the application of the positive supply to the liue IMP over contacts RVA2. Under export conditions the original conditions are restored.