Power-Feed System for the 

 Newfoundland-Nova Scotia Link 



By J. F. P. THOMAS* and R. KELLYf 



(Manuscript received September 22, 1956) 



Design engineers now have available the results of many years of operat- 

 ing experience with submerged-repeater systems supplied from electronic, 

 electromagnetic and rotary -machine power equipments. To meet the very 

 high standards of reliability required for the transatlfintic telephone system, 

 a scheme has been evolved that is a combination of new developments and the 

 best features of previous methods. Electronic-electromagnetic equipment 

 forms the basis of an automatic no-break system requiring very little routine 

 maintenance. 



INTRODUCTION 



The operating power for the submerged repeaters of the Clarenville- 

 Sydney Mines Hnk is derived from a constant current suppHed over the 

 central conductor from power equipments located at the two terminal 

 stations. In order to protect the electron tubes in the repeaters the cur- 

 rent must be closely maintained at the design value, irrespective of 

 changes in the mains supply voltage or ground potential differences be- 

 tween the two ends of the link. Automatic tripping equipment must be 

 provided to disconnect the cable supply should the current deviate be- 

 yond safe limits, but otherwise there must be a minimum of interrup- 

 tions due to power-equipment and primary -source failures. 



Earlier British Post Office schemes have been powered by electron- 

 ically controlled units feeding from one end only.t Manual change-over 

 to standby units has been provided at the end feeding power and at the 

 distant end — a method which has satisfactorily met the economic 

 requirements of short schemes. 



* British Post Office, f Standard Telephones and Cable Ltd. 



X Walker, D. C, and Thomas, J. F. P., The British Post Office Standard Sub- 

 merged-Repeater System for Shallow-Water Cables (with special reference to the 

 England-Netherlands System), Proc. I.E.E., 101, Part I, p. 190, Feb., 1954. 



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