TM 1-1500-204-23-9 (2)    Principles of operation.  A dc motor drives an ac generator.    A  solid  state  voltage  regulator  controls  the voltage    output    while    the    speed    of    the    generator determines the hertz of the ac output. (3)    Safety practices and procedures.  The following special  precautions  should  be  observed  when  using  an inverter: ·   Turn    the    inverter    before    connecting    or disconnecting a plug to or form the receptacle. ·    Keep  liquids,  such  as  coffee  or  soda, away from the unit to avoid spilling them on or in the unit. ·  Do  not  override  or  try  to  defeat  built-in  safety devices. (4)   Operating   procedures. The   following general procedures pertain to the operation of the inverter: (a)    Connect the plug to the receptacle. (b)    Turn the inverter power switch on. (c)    After use, turn the power switch off. (d)    Disconnect plug from receptacle. (5)    Inspection.  General operator inspections for the inverter    are    contained    in    the    following    paragraphs. Detailed    inspection    requirements    are    found    in    the applicable maintenance manual. (a)    Input  cord.    Check  for  cuts  or  cracks  in rubber covering. (b)    Case.  Look for obvious damage, such as dents, which may indicate internal damage to components. (6)    Maintenance. Consult the applicable maintenance manual for    scheduled    and    preventive maintenance requirements. g.    Oxygen    Servicing    Unit.        The    oxygen servicing unit, shown in figure 9-24, will provide oxygen at a maximum pressure of 3,000 psig.  Each of the eight   bottles   will   hold   224   cf   of   oxygen.      The   flow capacity  of  the  regulator  is  1,500  scfh  at  2,300  psig delivered. (1)    Purpose.  The oxygen servicing unit is designed to  provide  a  means  of  carrying  standard  high  pressure oxygen  bottles  and  of  interconnecting  them  to  provide regulated    single    output    which    can    be    adjusted    for pressure.      It   is   used   to   service   aircraft   and   other equipment which requires pressurized oxygen. (2)    Principles  of  operation.    The  oxygen  servicing unit consists of eight cylindrical tubes, each of which can house  a  standard  high-pressure  oxygen  bottle  lying  on its    side.        Pigtails    and    a    manifold    are    used    to interconnect   the   oxygen   bottles   to   provide   a   single output.    Each  pigtail  is  connected  to  a  check  valve  to prevent backflow. A manual control valve, connected to the manifold, is used to supply the oxygen directly from the   oxygen   bottles   to   the   receiving   equipment.      An adjustable,  dual  indicator  regulator  controls  the  oxygen output  at  the  desired  pressure.    The  oxygen  supply  is transferred   through   a   25   foot   flexible   output   service hose. (3)    Safety practices and procedures.  The following special precautions should be observed when using the oxygen servicing unit: ·  Personnel  operating  the  unit  must  be  familiar with the safety regulations regarding the handling of oxygen. ·  Do   not   smoke   within   50   feet   of   the   oxygen servicing unit. ·  All   open   connectors   must   be   protected   with plastic    protectors    (dust    covers)    to    prevent contamination. (4)   Operating   procedures. The   following general procedures   pertain   to   the   operation   of   the   oxygen servicing unit: (a)     Connect  the  filler  line  to  the  equipment being serviced. (b)    Open the bottle pressure outlet valve. (c)    Open  the  regulator  pressure  outlet  valve to the desired amount of pressure. (d)    Open the receiving vessel input valve and transfer oxygen. (e)    When  the  desired  amount  of  oxygen  has been transferred, close the receiving vessel input valve. 9-54