TM 5-6115-365-15 CHAPTER 13 GENERATOR SETS PU-253/U AND PU-253A/U Section I.  DESCRIPTION AND DATA 13-1. Description a. General.          The     PU-253/U     and     PU-253A/U Generator  Sets  consist  of  either  two  PU-107/U  or  PU- 107A/U gasoline Engine Generator sets (one in use, one standby), mounted on a 2-wheeled, box type, steel body, 11/2-ton capacity, model M-105A1 or M-105E3 trailer. Note There  is  no  switch  gear  assembly  to transfer  the  load  from  the  operating generator set to the standby generator set.  The load is connected directly     to     the     generator     output terminals     For     location     of     output terminals refer to applicable technical manuals  (PU-107A/U  generators)  and (PU-107/U generators). b. Interchangeability. The gasoline engine Generator Sets PU-107/U and PU-107A/U are interchangeable, and can be mounted as a mixed pair. c. Function.          The     PU-253/U     and     PU-253A/U Generator  Sets  are  a  source  of  power  for  the  Electronic Search   Control   AN/GS]S-1   and   for   various   types   of electronic and communication equipment. d. PU-107/U. For description and further information   about   PU-107/U,   Generator   Sets,   refer   to applicable  technical  manual,  as  shown  on  generator  set nameplates or in DA Pam 310-4. e. PU-107A/U. For description and further information     about     units     equipped     with     PU-107A/U Generator Sets, refer to applicable technical manual, as shown on generator set nameplates or in DA Pam 310- 4. f. Generator. For description and further information about the O'Keefe and Merritt, permanent magnet  type,  28  pole,  120/208-volt,  one-or  three-phase, 400-cycle generator, Signal Corp stock number 3H2441- 4,   refer   to   applicable   technical   manual,   as   shown   on nameplates  or  in  DA  Pam  310-4.    Applicable  technical manuals, as shown on nameplates or in DA Pam 310-4, will provide description and additional information on the John R.  Hollingsworth Corporation model APG-H-11636 Generator. g. Engine.        Applicable    technical    manuals    will provide   description   and   maintenance   instructions   for Continental  Motors  Corporation  model  FS-162  gasoline engine.      Applicable   technical   manuals,   as   shown   on nameplate  or  in  DA  Pam  310-4,  will  contain  description and  maintenance  instructions  for  Willys-Overland  model 807532 gasoline engine. h. Trailer.    For  further  trailer  information,  refer  to applicable    technical    manuals,    as    shown    on    trailer nameplate or in DA Pam 310-4. i. Lubrication.    Lubricate  the  trailer  in  accordance with instructions given in applicable lubrication order, as shown  in  DA  Pam  310-4.    Applicable  lubrication  order, as   shown   in   DA   Pam   310-4,   contains   instructions   for lubricating   the   PU-107A/U   Generator   Set.      Lubricate Willys-Overland    gasoline    engine    model    807532    per applicable lubrication order, as shown in DA Pam 310-4. Lubricate  Continental  model  FS-162  gasoline  engine  as instructed  by  applicable  lubrication  order,  as  shown  in DA  Pam  310-4.   Applicable  technical  manual,  as  shown in DA Pam 3104, contains instructions for lubricating the PU-107/U Generator Set. 13-1