Patent GB-433185-A (GB)
Title: Improvements in or relating to electrical submarine signalling cables
IPC: H03F1/54
Filed: 1935-02-18
Abstract: 433,185. Repeating systems. ELECTRICAL RESEARCH PRODUCTS, Inc., 195, Broadway, New York, U.S.A.-(Assignees of Jacobs, O. B.; 20, Hamilton Road, Morristown, New Jersey, U.S.A.) Feb. 18, 1935, No. 5144. Convention date, Feb. 27, 1934. Addition to 425,639. [Class 40 (iv)] [See also Groups XXXVII and XL] A repeater housed within the armouring of a submarine cable as in the parent Specification and comprising a plurality of thermionic tubes fed with direct current from a terminal station, is designed so that if the heating element of one valve fails, the repeater still continues to function. In one arrangement, Fig. 1, feed current normally flows over the cable from batteries 7, 13 in series via chokes 22, 26, resistances 23, 24, 25, and filaments of valves 20, 21 (which as shown are arranged in push-pull relationship but may alternately be in parallel), the fall of potential across the resistances supplying the anode and grid-biassing potentials. If the filament of valve 20, say, burns out, spark gap 45 breaks down and connects a resistance 46 across the burnt-out filament so that the other valve continues operative. As an alternative to spark gap 45 a heat-coil as shown in Fig. 1A, may be employed. On the failure of the associated filament the increased current through high-resistance heating winding 51 softens a solder connection between rod 53 and ring 54 so that rod 53 moves under action of spring 55 into engagement with terminal 52 thereby connecting resistance 46 across the filament. The engaging portions of member 52, 53 are tinned so that a soldered connection is established. In a modification, Fig. 1B, the heating winding 61 is connected in series with a rectifier 451 which breaks down under the increased voltage when the filament fails and the movement of rod 63 disconnects the heating circuit in addition to connecting up resistance 46. In a second arrangement, Fig. 2 (not shown), employing valves with indirectly-heated cathodes, the anode voltages are supplied in parallel from the resistances of the heaters, with, if necessary, an additional series resistance, and the grid-biassing potentials are obtained from anode resistances. In a third arrangement, Fig. 3, (not shown), pentode valves are employed and the negative grid-bias potentials are obtained from a common resistance in the main supply circuit. In a fourth arrangement, Fig. 4 (not shown), a group of four rectifiers is added to enable the valves to continue to operate if the direction of current supply is reversed. In a fifth arrangement, Fig. 5 (not shown), anode potential is obtained by connecting the anodes in parallel to ground through a relatively-large resistance. In a sixth arrangement, Fig. 6 (not shown), each anode circuit includes the two heaters of the associated valves, an auxiliary conductor to the next repeater, and the two heaters at that repeater. In a seventh arrangement, Fig. 7, when a filament of one of the valves 70, say, burns out, heat coil 161 causes plunger 163 to bridge the filament by resistance 146 and at the same time the repeater is connected to ground over resistance 150 to mark it as faulty. When both valves fail, a second connection to ground is made over resistance 250 and at the same time heat coils 132, 133 are operated to byepass the repeater over conductor 135.