discharge   pressure   are   related   to   the   pump   speed. Decreasing   the   engine   speed,   and thus   the   pump   speed,   will   decrease   the   water   discharge   volume   and   pressure.   If operating   at   less   than   maximum   volume   and   pressure,   increasing  the  engine  speed will   increase   the   pump   output. The   pumping   assembly   has   controls   that   sense   the suction   and   discharge   pressures. When   operated   in   an   automatic   mode,   the   controls adjust  the  engine  speed  as  needed  to  regulate  the  pump  output. 1.14.1     Source or Lead Pump. When  operated  as  a  source  or  lead  pump,  the  pumping assembly   draws   water   from   a   large   source, such  as  a  lake  or  stream  or  a  storage facility   that   is   supplied   by   wells,   water   purification   units,   or   desalination operations. If   operated   singly   as   a   source   pump,   the   water   is   fed   to   another storage   facility. If  operated  as  a  lead  pump,  the  water  is  fed  downline  through  a hoseline   or   pipeline   to   a   boost   pump. 1.14.2    Boost Pump. When  operated  as  a  boost  pump,  the  pumping  assembly  draws  water from   a   hoseline   or   pipeline   and   feeds   it   downline   to   the   next   boost   pump   or   to   a storage    facility. Operated   manually   during   startup   and   can   then   be   switched   to   an automatic   mode   for   sustained   operation. In  automatic  mode,  engine  speed  is regulated    automatically. 1.14.3       Engine and Control Electrical System. The   engine   starter   and   engine   controls   are supplied   with   direct   current   (de)   electric   power   by   the   pumping   assembly   battery   or batteries   and   engine   alternator. 1.14.4     Trailer Lights. The  trailer  lights  are  supplied  with  24  volts  dc  through  an electrical   cable   connected   to   the   towing   vehicle. 1.14.5   Trailer  Hydraulic  Brake  System. The  pumping  assembly  trailer  is  equipped  with  an inertial   hydraulic   brake   system. The   inertial   hydraulic   brake   system   automatically applies  the  brakes  when  the  vehicle  SlOWS  or   stops   or   when   the   trailer   accidentally uncouples   from   the   towing   vehicle. The   brake   system   includes   a   drawbar   ring   or lunette,    a   hydraulic   brake   actuator,   a   master   cylinder,   a   breakaway   lever   and chain,   brake   lines,   wheel   cylinders,   brake   shoes,   and   brake   drums. 1.14.5.1    Lunette. The  lunette  attaches  to  the  towing  vehicle. It   is   connected   to   the hydraulic   brake   actuator,   which   controls   the   master   cylinder. When  the  towing vehicle   moves   forward   the   lunette   is   pulled   and   the   brakes   are   released. When  the towing   vehicle   slows   down,   the   trailer   pushes   the   lunette   against   the   towing vehicle,    which   causes   the   brakes   to   be   applied. 1.14.5.2    Hydraulic  Brake  Actuator. The   hydraulic   brake   actuator   connects   the   drawbar ring/lunette   to   the   master   cylinder. It   transmits   mechanical   motion   from   the drawbar   ring/lunette   to   the   master   cylinder. 1.14.5.3  Master Cylinder. The   master   cylinder   receives   mechanical   motion hydraulic   brake   actuator   and   from   the   breakaway   lever. It   changes   the motion   into   hydraulic   pressure. The  hydraulic  pressure  is  transmitted brake   lines. 1.14.5.4   Breakaway Lever and Chain. The  breakaway  chain  is  attached  to  the from  the mechanical through  the breakaway lever  and  to  the  towing  vehicle. It  will  pull  the  breakaway  lever  up  if  the trailer   accidentally   uncouples   from   the   towing   vehicle. When  the  breakaway  lever is   pulled   up,    it   transmits   mechanical   motion   to   the   master   cylinder   and   applies brakes. 1.14.5.5   Brake Lines and Wheel Cylinders. The   brake   lines   transmit   hydraulic   pressure from   the   master   cylinder   to   the   wheel   cylinders. When  pressurized,  the  wheel cylinders   engage   the   brake   shoes. 1.14.5.6    Brake Shoes and Drums. When  wheel  cylinder  pressure  causes  the  brake  shoes  to be   engaged,   the   brake   shoes   press   against   the   brake   drums. This   causes   friction that   slows   and   stops   the   trailer. The  brake  shoes  disengage  from  contact  with  the brake  drums  when  the  pressure  is  released. 1-15/(1-16   Blank) TM  10-4320-344-10