226 THE BELL SYSTEM TECHNICAL JOURNAL, JANUARY 1957 



With this arrangement the Unk requires a total supply voltage of 

 about 2,300. The power-feeding equipment^^ at each terminal station is 

 designed to feed a constant current of 316 ma at this voltage, and it is 

 permissible to energize the system from one end only, if necessary. The 

 repeater capacitors — the limiting factors in respect of line voltage — 

 are rated very conservatively at 2,500 volts, so that a single-ended 

 supply of 2,300 volts, with the possibility of superimposed ground-po- 

 tential differences, is near the desirable maximum. The two terminal 

 power units are therefore designed to operate in series and to share the 

 voltage. 



With access to the cable provided at Terrenceville it is possible to 

 operate the power system on the following bases: 



(a) No ground at Terrenceville, power from both ends on a master- 

 and-slave basis (to ensure that the constant-current units do not build 

 up an excessive voltage) ; this is the normal arrangement. 



(6) No ground at Terrenceville, power from one end only. 



(c) Ground at Terrenceville, with the Clarenville and Sydney Mines 



SYDNEY MINES 



FROM 



CARRIER 



EQUIPMENT 



HIGH 

 PASS 



FILTER 



LOW 



PASS 



FILTER 



POWER 



UNIT 



GROUND PLATES 

 IN SEA 



1 



X" 



(a) 



CLARENVILLE 



TO 



CARRIER 



EQUIPMENT 



HIGH 



PASS 



FILTER 



LOW 



PASS 



FILTER 



POWER 

 UNIT 



ANODES 

 I 



CATHODES 



PF 



m^xJi^^^v^^^ 



0.5V 



6 HEATERS 

 33V 



PF 



0.5V 



(b) 



Fig. 6 — Power-feeding arrangements, (a) General schematic, (b) Repeater 

 power circuit. P.F. — Power filter. 



