TM 5-3895-373-20 1.21.1.   Auger/Conveyor     Hydraulic     System.          The auger/    conveyor    drive    system    consists    of    electrical controls on both the left and right screed control panels, control switches on the operator switch panel, auger/conveyor  control  valve,  speed  control  valve,  left and   right   auxiliary   hydraulic   pumps,   and   feed    limit switches.      The   left   and   right   auger/conveyor   control circuits are identical.  The following description applies to both sides. Electrical  power  for  the  auger/conveyor  drive  system  is from CB6 to the screed control panel.  The feeder control switch on the screed control panel passes the current to the auger/ conveyor switch on the operator switch panel. The  three  position  switch  on  the  operator  switch  panel allows  for  manual  control,  automatic  control,  and  an  off position. When  the  feeder  control  switch  on  the  screed  control panel   is   turned   on,   and   the   auger/conveyor   reverse control    switch    is    in    normal,    power    is    sent    to    the auger/conveyor   switch   on   the   operator   switch   panel. With  MAN  selected  on  the  auger/  conveyor  switch,  the auger/conveyor control valve forward solenoid is actuated and positions the auger/ conveyor control valve. When the auger/conveyor switch on the  operator  switch panel is placed up, "AUTO" position, power is sent to the feed limit switch mounted on the end gate of the screed. When an insufficient amount of paving material is in the auger   chamber   the   limit   switch   will   be   closed.      This allows   power   to   pass   through   the   limit   switch   and energize    the    auger/conveyor    control    valve    forward solenoid.  The solenoid is energized and the valve shifts to   the   forward   position.      When   the   paving   material reaches   a   sufficient   level   in   the   auger   chamber,   the paving   material   actuates   the   feed   limit   switch.      The current path to the auger/conveyor control valve forward solenoid   is   broken.   The   auger/conveyor   control   valve forward solenoid is deenergized and the valve returns to the center, off, position. For reverse operation of the auger/conveyor system, the feeder  control  switch  on  the  screed  control  panel  must be in the center OFF position.  This removes power from the    auger/conveyor    control    valve    forward    solenoid. When   the   auger/conveyor   reverse   control   switch   is placed in the up, REVERSE position, power is sent to the auger/conveyor control  valve  reverse  solenoid.    The  solenoid  energizes and    repositions    the    valve    to    the    reverse    position. Hydraulic   oil   for   the   auger/conveyor   drive   system   is supplied  by  the  auxiliary  hydraulic  pumps.    The  left  and right   auxiliary   hydraulic   pumps   each   consist   of   two pumps, a 0.7 and a 0.58 cu in.  (11,5 and 9,5 cc) output, mounted  on  a  common  shaft.    The  0.7  cu  in.  (11,5  cc) pump    on    each    side    supplies    hydraulic    oil    to    the respective sides auger/conveyor drive system.  The 0.58 cu in. (9,5 cc) pump on the left auxiliary hydraulic pump provides  oil  to  a  50/50  flow  divider.    The  flow  divider splits the output of the pump and delivers half of the flow to  each  side  of  the  auger/conveyor  drive  system.    The hydraulic oil from the hydraulic pumps is sent to a speed control  valve  and  a  test  manifold.    The  test  manifold allows  the  measuring  of  pressure  on  the  outlet  of  the hydraulic    pumps.        The    speed    control    valve    is    an adjustable relief valve.  The valve regulates the speed of auger/conveyor drive motor by regulating the pressure of the hydraulic oil sent to  the  motor.    Excess  hydraulic  oil from  the  speed  control  valve  is  relieved  to  the  return manifold. The  output  of  the  speed  control  valve  is   sent   to   the auger/   conveyor   control   valve.      The   control   valve   is protected by a 2750 psi (18 961 kPa) relief valve internal to  the  control  valve.  The  control  valve  is  equipped  with two   solenoids   to   position   it   for   forward   and   reverse. When  neither  solenoid  is  energized,  the  control  valve  is in the center, off, position.  The input and return ports are cross connected allowing hydraulic oil entering the valve to   go   immediately   out   the   return   port   to   the   return manifold.    When  the  forward  solenoid  is  energized,  the control  valve  is  positioned  to  the  forward  position.    This position  sends  the  incoming  hydraulic  oil  to  the  forward port  on  the  auger/  conveyor  drive  motor,  causing  the motor   to   rotate   in   the   forward   direction.      When   the reverse  solenoid  is  energized,  the  valve  is  repositioned to  the  reverse  position.    The  control  valve  sends  the incoming hydraulic oil to the reverse port on the hydraulic motor, causing the motor to turn in the reverse direction. The  output  shaft  on  the  auger/conveyor  drive  motor  is attached to a drive sprocket wheel and chain.  The chain drive  system  allows  the  hydraulic  motor  to  provide  the mechanical   power   for   both   the   conveyor   and   auger systems. 1-42