Power Feed Equipment for the 

 North Atlantic Link 



By G. W. MESZAROS* and H. H. SPENCER* 



(Manuscript received September 20, 1956) 



Precise regulation of the direct current which provides power for the 

 undersea repeaters in the new transatlantic telephone cable is necessary to 

 maintain proper transmission levels and to assure maximum repeater 

 tube life. The highest possible degree of protection is needed against excessive 

 currents and voltages under a wide variety of possible faidt conditions. 

 Furthermore, to minimize the dielectric stresses, a double-ended series-aiding 

 power feed must be used and the balance of these applied voltages must be 

 maintained in spite of substantial earth potentials. This paper describes the 

 design features which were employed to attain these objectives simulta- 

 neously, while eliminating, for all practical purposes, any possibility of 

 even a brief system outage due to power failure. 



INTRODUCTION 



The principal objectives in the power plant design for the Trans- 

 atlantic cable system were as follows: 



1. To stress reliabilit}^ in order to guarantee continuous dc power to 

 the electron tubes that form an integral part of the submerged repeaters. 

 This is essential, not only to be able to maintain continuous service, 

 but to prevent cooling and contraction of the repeater components, 

 especially the tubes. 



2. To provide close dc cable current control to ensure constant 

 cathode temperature and regulated plate and screen potentials for the 

 repeater tubes. These operating conditions are essential both for ob- 

 taining maximum life from these tubes and for maintaining constant 

 transmission level. 



3. To control and limit the applied dc cable potentials in order to 

 minimize the dielectric stresses. The life of certain capacitors in the re- 

 peaters is critically dependent upon these stresses. Moreover, momen- 



* Bell Telephone Laboratories. 



139 



