TM 1-1500-204-23-9 (b) Electrically-operated.    This  type  of hoist  is  similar  to  the  manually-operated  hoist  in  lifting capacity  and  lifting  distance.    However,  it  requires  an outside   source   of   power,   typically   28   vdc   to   run   the electrically-operated winch. (3) Principles    of    operation.        The    topmost pulley  is  positioned  over  the  object  to  be  lifted.    The block which contains a pulley and hook is lowered to the object   and   connected   by   means   of   a   lifting   adapter, sling,  or  chain.  The  cable  is  wound  up  on  the  winch, which   in   turn   raises   the   block   through   a   system   of pulleys.  As the lifted object clears the aircraft, the hoist must be moved away from the aircraft before the object can be lowered. (4) Safety   practices   and   procedures.      The following  special  precautions  should  be  observed  when using hoists: ·  Do    not    exceed    the    lifting    capacity    of    the structure, the cable, or the winch. ·  Never stand under a loaded hoist. ·  Do not leave a loaded hoist unattached. ·  Always  use  enough  people  to  safely  move  and control a loaded hoist. ·  If   using   hand   signals,   be   sure   each   person knows and understands the signals. (5) Operating procedures. Consult the applicable    equipment    maintenance    manual,    aircraft maintenance manual, and local operating instructions or procedures for detailed guidance.  The following general procedures pertain to the operation of hoists. (a) Move the hoist into position. (b) Stabilize    the    unit    by    setting    the caster brakes, lowering the leveling pads. (c) Lower  the  block  to  the  object  to  be lifted. (d) Connect the hook to the object and lift it. (e) Release   the   brakes   or   raise   the leveling  pads,  carefully  move  the  hoist  away  from  the aircraft, and lower the object. (f) Reinstallation  of  the  object  using  a hoist requires completion of steps (a) through (d) and (f), except move the hoist toward the aircraft. (g) On    job    completion,    release    the caster  brakes  or  raise  the  leveling  pads  and  move  the hoist away from the aircraft. (6) Inspection. The following general operator inspections apply to hoist.  Detailed inspection requirements are contained in the applicable maintenance manual. (a) Cable.    Look  at  exposed  cable  for knots, kinks, corrosion, and broken wires. (b) Casters.    Check  for  flat  spots  and swiveling. (c) Hook.        Check    safety    latch    for serviceability. (d) Pulleys.    Check  that  the  cable  is  in the groove. l. Pre-Oiler and Pickler.  The pre-oiler and pickler, shown in figure 9-19, is capable of delivering a constant supply of corrosion preventive compound (pickling) at 3 gpm and a temperature between 150 and 230 °F (66 and 110°C)   with a pressure that should not exceed 250 psi. It is also capable of delivering pre-oiling fluid at 3 gpm and   a   temperature   between   150   and   175 °F   (66   and 79C) with a pressure of 175 psi.  The servicing hose is 25 feet long. m. Lubricating  Equipment.    Lubricating  equipment, shown  in  figure  9-20,  is  commonly  called  grease  guns. Grease guns are used to lubricate various moving parts on an aircraft.  This paragraph will cover hand operated grease guns. (1) Purpose.    Grease  guns  are  designed  to inject    a    lubricating    substance    between    two    metal surfaces that move against each other.  The lubricant is injected  through  a  fitting,  designed  with  a  check  ball  to prevent   the   lubricant   from   coming   back   through   the fittings. (2) Type.  The most common type of grease gun  is  the  lever  operated.    This  type  of  grease  gun  is cylindrical,  holds  14  ounces  of  lubricant,  and  requires two  hands  to  operate.    The  lubricant  is  spring-primed and is delivered at 6,000 psig. 9-48