TM 55-4920-328-13 5.    Pressure  transmitter  MT3.    The  pressure transmitter   (177,   figure   7-24)   is   installed   in   the   data acquisition   assembly   for   use   in   sensing   compressor discharge air pressure.  This unit is identical to pressure transmitters   MT1   and   MT2   except   for   input   pressure range and pressure circuit function.  The input range of the unit is 0 to 100 psig with an analog output of 0 to 5v dc     full     scale.          The     pressure     transmitter     senses compressor discharge air pressures and converts these values to analog signals displayed on the TORQUE/PRESSURE   digital   indicator   (4,   figure   122) after signal conditioning. 6.    Pressure  transmitter  MT4.    This  pressure transmitter   (178,   figure   7-24)   is   identical   to   pressure transmitter  MT3    except  for  the  input  pressure  range. This unit is installed in the data acquisition assembly to sense   compressor   discharge   air   pressures   from   the engine under test.  Input pressure range of the unit is 0 to  200  psig  with  an  analog  output  range  of  0  to  5v  dc with  an  excitation  voltage  of  28v  dc.    The  unit  senses compressor  discharge  air  pressure  and  converts  these values  to  analog  signals  to  the  TORQUE/PRESSURE digital indicator (4, figure 1-22) after signal conditioning. 7.    Pressure    gage    transmitters    MT5,  MT6, MT9,   and   MT10.      These   pressure   gage   transmitters (193, figure 7-24) are identical in design and differ only in pressure circuit function.  The 0 to 200 psig pressure range    and    the    analog    voltage    output    ranges    are identical.    Pressure  gage  transmitter  MT5  is  used  to sense  torque  oil  pressures  through  a  range  form  0  to 200 psig.  The excitation voltage required for each unit is 26v, 400 Hz.  The voltage output of this unit is analog ac   and   is   displayed   on   the   TORQUE   PRESSURE synchro  indicator  on  the  operator's  panel,  and  is  also conditioned  to  be  displayed  as  gage  pressures  on  the TROQUE/PRESSURE  digital  indicator  (4,  figure  122). Pressure    transmitter    MT6    senses    engine    outlet    oil pressure    with    the    same    pressure    range    as    MT5. Pressure  switch  S2,  connected  to  the  same  engine  oil pressure   sense   line   as   MT6,   is   used   to   provide   an engine  low  oil  pressure  signal.    The  analog  output  of MT6     is     also     conditioned     and     displayed     on     the TORQUE/PRESSURE digital indicator. Pressure transmitter  MT9  senses  scavenge  oil  pump  pressures over the same input pressure range.  The analog output of  this  unit  is  conditioned  to  be  displayed  on  the  same indicator.      Pressure   transmitter   MT10   senses   torque boost   oil   pressure   and   operates   through   the   same pressure   range   as   the   preceding   units.      Selection   of pressures to be displayed on the TORQUE/PRESSURE digital indicator is made by depressing the TM 55-4920- 328-13      appropriate   pushbutton   switch   on   the   data selector assembly (7, figure 1-22). 8.    Pressure    transmitters    MT7    and    MT8. Pressure  transmitters  MT7  and  MT8  (192,  figure  724) are used to sense oil pressures in an engine under test. Input  pressure  ranges  from  0  to  25  psig  are  sensed  by each  transmitter.    Output  signals  in  the  form  of  analog ac    voltages    are    conditioned    and    displayed    on    the TORQUE/PRESSURE  digital  indicator  (4,  figure  1-22) as gage pressure values which vary in direct proportion to the input analog signals.  Excitation for each pressure transmitter  is  provided  by  the  system  26v  ac,  400  Hz power supply.  Each unit is a synchro type of transmitter similar to a transformer with a movable core.  The core (rotor)  is  positioned  by  varying  input  pressures  through internal   linkage.      Changing   the   position   of   the   rotor varies    the    coupling    between    the    windings    of    the transformer  (stator)  to  vary  the  induced  voltage  across the stator output leads. 9.    Pressure        gage        transmitter        MT11. Pressure gage MT11 (194, figure 7-24) is used to' sense engine    inlet    fuel    pressure.        This    pressure    gage transmitter  is  identical  in  design  and  function  to  other transmitters except for the pressure circuit in which it is installed.    The  input  pressure  range  is  0  to  100  psig. Output  analog  ac  signals  are  displayed  on  the  digital indicator (4, figure 122).  Selection of the pressure to be displayed on the digital indicator is made by depressing the  applicable  pushbutton  switch  on  the  data  selector assembly (7).  Excitation voltage for the pressure gage transmitter   is   provided   by   system   26v   ac,'   400   Hz power.    The  unit  is  a  synchro  transmitter  similar  to  a transformer with a movable core.  The core is positioned through   internal   linkage   by   varying   input   pressures. Changing  the  position  of  the  rotor  varies  the  coupling between the winding of the transformers (startor) to vary the   induced   voltages   across   the   stator   output   leads. The   synchro   output   is   then   fed   to   a   synchro   to   DC converter,  the  output  of  which  is  conditioned  through zero  and  span  potentiometers  and  then  routed  to  the digital indicator. 10.    Pressure  gage  transmitters  MT12,  MT13, and   MT14.      These   pressure   gage   transmitters   (195, figure   7-24)   are   used   to   sense   engine   fuel   manifold pressure, engine fuel pump No.  1 pressure, and engine fuel pump No. 2 pressure, respectively. The transmitters    are    identical    in    design    and    function; therefore,  only  one  will  be  described.    The  unit  is  a synchro   transmitter,   similar   to   a   transformer   with   a movable   core.      The   core:   (rotor)   is   connected_   to   a diaphragm  through 1-61