The lighting distribution system installed in this type vessel corresponds in general to the distribution system installed in current U.S.N. design.  However, the number of different components used is less than on U.S.N. submarines.  This factor has contributed to the relatively low level of illumination throughout the vessel.  
          Regulated 110 volt D.C. power supply for the system is obtained from the battery voltage of 110-170 volt D.C. by means of a voltage sensitive relay actuated regulator.  
          Upon complete loss of 110 volt D.C. power supply, the permanently installed emergency relay operating lighting is cut in.  
          Low level illumination for dark adaptation is not provided.  Control instruments have been treated with relatively long persistence phosphorescent material.  
          Except for the regulator and distribution panels no shock mounting of any kind is employed.  Reference should be made to the separate Bureau reports on voltage regulators, rotary snap switches and emergency lighting fixtures when they become available.  
May, 1946
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A. Introduction 3
B. Description 3
  Voltage Regulators 3
  Distribution 5
  Component Design 5
  Emergency Lighting 7
  Non-Electric Illumination 8
  Low Level Illumination 8
  Running Lights 8
C. Conclusions 9
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          The scope of this report is concerned primarily with presenting in a general way the lighting installation incorporated in this type vessel.  
          For detailed information with regard to circuit layout and component design and dimensions reference should be made to the following German instruction books.  
          1.  Beschreibung und Betriebsvorschrift für E-Maschinen, Haupt und Hilfschalttafeln (Description and Operation Data for Electric Machines, Main and Auxiliary Switchboards).  
          2.  Skizzenbuch für die Maschinenmannschaft für U-805, Band E, Allgemeine E Anlagen (Sketch Book for the Machinery Installations for U-805, Band E, General Electrical Systems).  
          3.  Sander und Verbrauschsstoffsoll für Elektrische Anlagen (Special and Necessary Material for Electrical System).  
          A lighting voltage regulator and several sizes of rotary snap switches have been sent to BuShips, Code 660, for detailed study and reference should be made to this report when it has been written.  In addition, the physical description of the lighting switchboard has been incorporated in Report 2G-9C-S62-1 and reference should be made to that report.  
          Voltage Regulator  
          The battery voltage of 110-170 volts is manually or automatically regulated to attain a voltage of 110 volts D.C. for various purposes as enumerated in Report 2G-9C-S60.  
          A brief description of the voltage regulator is presented here and may be used in conjunction with the detailed report by BuShips, Code 660, when it has been written.  
          The unit is similar in operation to the lighting voltage regulators installed in U.S.N. submarines subsequent to SS313.  
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          It is rated at 11 K.W. 100 Amps, 110 Volts, continuous duty.  Allowable variation from 110 volts is + 3%.  German instruction books emphasize that it is not to be overloaded.  The load requirements appear to be within the capacity of the regulator.  
          A rough survey indicates that on a unit space, weight and power comparison with the USN "HIR" regulator that the USN unit has a slightly favorable balance in these factors.  It is assumed these comparisons will be contained in detail in the report to be written by the Bureau.  
          The German regulator is mounted in the lighting switchboard and consists of the following separate components.  
          1.  Voltage sensitive relay, usually mounted in a dust proof phenolic case.  
          2.  An assembly built on an angle iron framework which is readily removed from the switchboard for maintenance.  Removal requires disconnecting the various leads and cables.  This assembly consists of the following components.  
                  a.  Two control relays which govern the direction of flow of current in the drive motor armature, hence its direction of rotation.  
                  b.  Drive motor and associated gearing which cut in or out as necessary the regulating resisters.  Maximum length of continuous operation of motor is specified as being 5 minutes.  The time required to travel from limit to limit at 170 volts is 5.5 to 6 seconds.  
                  c.  Shaft extension and handwheel for manual operation.  
                  d.  Necessary resistors, face plates and connections.  The material on which the resistors are wound appears to be porcelain.  
          There are two voltage regulators installed, one in the lighting panel, No. 2 located in the Control Room as part of the auxiliary power switchboard.  The second in lighting panel #1 in the Maneuvering Room as part of auxiliary power switchboard #1.  Provision is made to  
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  energize the regulators from either battery by means of separate transfer switches, both of which are located in the Control Room.  
          The lighting power is distributed as follows.  From the #2 panel in the Control Room, the normal lighting from the Engine Room forward is obtained.  In addition, several fixtures in each compartment from the Engine Room aft are energized through this regulator.  
          A similar arrangement exists from the #1 lighting panel to the Engine Room and compartments aft with regard to normal lighting.  In addition several fixtures in each compartment from the Control Room forward are energized from this regulator.  
          Thus in the event of a casualty to one regulator, limited illumination can be provided in those compartments whose normal lighting power comes from the regulator which has become inoperative.  
          The lighting circuits are generally set up in groups based on compartmentation.  On the lighting panel, 25 ampere rotary snap switches are provided to energize or deenergize a given group.  Between the bus and the group switches fuses are installed.  From the switch the power is led to quick opening fuse boxes located in the various compartments.  Frequently the fuse boxes contain both lighting and auxiliary power circuits.  Individually fused circuits are connected to the lighting bus in the fuse box, these circuits are then led to switches usually located adjacent to the passage way hatch.  Each switch controls two or more lighting fixtures in that particular compartment.  Only in special cases are the switches located near the fixture controlled.  
          Component Design  
          The circuit components are described as follows:  
          1.  Group switches on lighting panels are usually the 25 ampere rotary snap switches of the type used throughout the vessel.  (Note:  Several of the rotary snap switches up to 600 ampere capacity have been sent to BuShips, Code 660 for detailed exploitation).  
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          2.  Fuses are socket type, sand filled, blown indicator, porcelain body type installed in front of board retainers which are surface mounted in the fuse box or switchboard.  The fuse retainer is constructed on the same principle as the lamps described below, the securing cap being serrated in way of the threads to minimize the possibility of losing contact due to the ship's vibrational disturbances.  
          3.  The majority of the fixtures are of one type similar to our steam tight fixtures.  These were provided with a clear glass globe around which a metal wire guard is placed.  The base is of cast steel and is held rigidly in place by means of a 3/4" threaded stud which is an integral part of the casting.  These fixtures are mounted on short 1/4" thick clips welded at the hull, bulkheads, etc. giving a very rigid mounting.  
          4.  In the officers' and Crew's quarters shallow double bulb light diffusing water tight fixtures are used.  These are flush mounted in the pressed fiber sheathing.  
          5.  Reflectors are not used to improve compartment illumination.  (Note:  The above described fixtures are the only types used for compartment illumination.)  
          6.  None of the lamp bulbs appear to be designed for high shock usage and it is believed that the filament structure in this respect would be inferior to standard USN lamp bulb filaments.  The structure of the bulbs is otherwise similar to USN design except that the ferrule base is slightly longer than US design.  In addition, the threads on the lamp base are serrated so that a small spring pressure on the socket against the serration reduces the possibility of the lamp becoming lose under vibrational disturbance.  The spring pressure is obtained by a small crimping of the socket ferrule on the periphery.  
          7.  The fuse boxes are of the quick opening type, somewhat similar to those used on USN V class submarines, except that the operating mechanism and strongback are more ruggedly designed and provided a reasonably secure watertight seal.  The holding device will not maintain the cover in a raised position under shock conditions.  
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          8.  terminal packing consists of a circular rubber washer of rectangular cross section, the inner periphery of which is caused to deflect against the cable and the outer periphery against the tube terminal inner well when the gland nut is tightened.  
          9.  Cable and lead designations in form of cable tags and stamped terminals are not as widely used as in current USN practice, however, the designations are consistent with the German method of presentation to the operating personnel.  The German method of presentation is described in Report 2G-9C-S28.  
          10.  The German 10 Ampere 250 volt rotary snap switches used with the lighting system are identical to the USN 5 Amp. 250 volt rotary snap switch except for the operating mechanism.  Otherwise the parts are completely interchangeable.  
          11.  All armoured cable throughout the system is thoroughly grounded at each cable entrance.  
          Emergency Lighting  
          As has been previously described provision is made to provide some illumination in all compartments upon loss of power from one regulator.  In addition to this an emergency lighting system provides limited illumination in the event of a casualty to both regulators.  
          This system is designed to operate in the following manner:  Upon complete loss of lighting power from both regulators the relay operated, permanently installed lighting fixtures are automatically cut in.  These fixtures are located at strategic points throughout the vessel, being placed much in the same fashion as the battle lanterns in USN submarines.  
          These fixtures are provided with a 3 watt, 4 volt bulb which was energized from a 4 volt wet cell battery.  Two of these units have been sent to BuShips, Code 660F for detailed exploitation and reference should be made to the report by Code 660F when i has been written.  
          A charging panel is provided for the upkeep of these batteries.  This panel consists of a voltmeter, an ammeter and a regulating resistance.  The panel is energized from 110 volt D.C. regulated bus.  Provision is made for charging up to eight at one time, employing the constant potential method of charging.  
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          Non-Electric Illumination  
          In addition to the above the indicating face plates of practically all I.C. equipment, important gauges, meters, etc., particularly in the Control Room are treated with phosphorescent material so that they may easily be read in the event of a complete casualty to the lighting power supply.  The number of units so treated in the control room provides enough illumination to allow personnel to move about freely.  
          Low Level Illumination  
          Additional fixtures for low level illumination, either blue or red, are not provided for dark adaptation of the ship's personnel.  Use is made, however, of tightfitting red lens goggles.  
          Running Lights  
          The following running lights are provided:  
          1.  Port and starboard side lights.  
          2.  Mast head light (portable).  
          3.  High and low stern lights.  
  Inspections of the above running light installations reveal the following:  
          1.  The side lights are provided with appropriate red and green lenses.  These units are pressure proof, the leads being led from the conning tower by means of stuffing tubes and conduit.  In general, the vertical height above the deck is approximately 3 feet higher than on late design USN submarines.  The angle of opening of the light is identical with present USN equipment.  
          2.  The mast head light is a portable, sheet metal, drip-proof light which can be secured to the forward periscope when it is in a slightly raised position to provide a mounting surface.  The power supply is obtained from an outlet in the Conning Tower, the lead being run up through the Bridge Hatch.   
          3.  The High and Low Stern Light fixtures are designed as pressure proof fixtures, the leads being run from  
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  the Conning Tower through conduit and stuffing tubes.  The angle of illumination and physical size of the fixtures is approximately the same as USN fixtures.  
          4.  All running lights are energized from the regulated 110 volt D.C. bus and are controlled from a common switchbox in the Conning Tower.  
          5.  The stuffing tubes used with these circuits are provided with drains within the vessel.  In these drains are installed petcocks which allow the conduits to be drained to the bilge in the event the conduit leaks at any point.  
          6.  It is observed that the German has not developed a pressure proof receptacle for use on the Bridge.  
          The German lighting system indicates his need to conserve labor and material and offers nothing new or unique with regard to his distribution system of component design.  However, his use of compartment group switches would make it relatively easy to trace ground circuits and his persistence in minimizing the numbering of different fixtures is noteworthy.  
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