CONFIDENTIAL REPORT 2G-9C
S62
     
 
FORMER GERMAN SUBMARINE TYPE IX C
  
 
 
 
ELECTRIC POWER DISTRIBUTION
 
     
 
SUMMARY
  
     
          In general, the auxiliary power distribution circuit layout installed in Type IX-C vessels corresponds with the present USN system.  However, the application of protective, switching and isolating components making up these circuits differs appreciably from current USN practices.  Creepage clearances and insulation values are at lower levels.  External shock protection is more widely employed.  
          Individual cases of particularly good and bad workmanship and design are evidenced throughout the system although the installations are reasonably uniform with respect to German practices.  
     
     
     
     
     
     
     
     
     
 
March, 1946
 
 
 
 
PORTSMOUTH NAVAL SHIPYARD, PORTSMOUTH, N. H.
 
     
 
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9C-S62
     
 
TABLE OF CONTENTS
 
     
 
A. DESCRIPTIVE
Pages
  (a) Introduction
3
  (b) Description
3
  (c) Conclusions
4
  (d) Report 2G-9C-S62-1
5-8
  (e) Report 2G-9C-S62-2
9-21
  (f) Report 2G-9C-S62-3
22&23
  (g) Report 2G-9C-S62-4
24&25
 
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
 
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9C-S62
     
  A.  DESCRIPTIVE  
          (a)  Introduction  
          The scope of this report is to present the type of auxiliary power distribution circuits employed and the components installed in those circuits on type IX-C vessels.  In order that the report may be more effectively utilized, it is divided into the various subgroups, S62-1, S62-2, S62-3, and S62-4, in conformance with the Navy Filing Manual.  Each subgroup is written as a separate report and incorporated as an integral part of the overall S62 group.  
          For detail information regarding the circuit layout with regard to the compartmentation localization of the various components reference should be made to the German Instruction Book "Skizzenbuch für die Maschinenmannsachaft für U-Boote Typ IX-C40, Band E, Allgemeine E Anlagen" (Sketch book for the Machinery for U-boats Type IX-C40, Volume E, General-Electrical Systems).  
          (b)  Description  
          The auxiliary power distribution system installed in Type IX-C vessels corresponds in general to current USN system layout with the following noted exceptions:  
                  (1)  Instead of using a bus tie switch mounted on the after switchboard to provide for connecting both switchboards to the same battery, the German uses separate transfer switches, one for each switchboard to provide for connecting the switchboard to the desired battery.  Both of these transfer switchboards are located in the control room, which is considered a poor practice due to the fact that a casualty in the control room jeopardizes the safety of the entire vessel since a possibility of losing all auxiliary power exists.  
                  (2)  Air circuit breakers are not used in any auxiliary power circuits for protective devices.  
                  (3)  The auxiliary power load is connected to the batteries ahead of the battery breaker.  Disconnect switches are not provided, the circuits being fused only.  Since the total auxiliary load can be connected to one battery, the protective value of the fuse is rather dubious when operating under normal conditions of auxiliary load being divided between both batteries.  
                  (4)  Feeder circuits at the distribution boards are not provided with disconnect switches, the circuits  
     
 
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9C-S62
     
  being fused only.  These circuits usually feed branch distribution boxes which in turn are fused to protect the given auxiliary equipment.  Disconnect switches are not installed in the branch distribution boxes.  
                  (5)  Creepage clearances between polarities and ground and polarity are frequently found to be 50% of the required values for comparable USN design.  
                  (6)  External shock mounting in form of bonded rubber mounts used in compression, tension, and shear are employed throughout on the various components.  It is possible that this secondary means of shock protection was employed so extensively because of the Germans' inability to develop high shock components to the satisfactory level attained by USN designers.  
          (c)  Conclusions  
                  There is nothing to recommend complete adoption of the German distribution system installed in this type vessel for installation in American submarines.  USN specifications require an installation engineered at a much higher level with respect to circuit protective devices and safety of the vessel as a whole.  
     
     
     
     
     
     
     
     
     
     
     
     
     
 
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