TM 5-3895-374-24-2 SECTION IV OPERATION OPERATING CHECKS Satisfactory   operation   of   any   piece   of   mechanical equipment  depends,  to  a  large  degree,  upon  adherence  to  a preventive maintenance schedule. To   obtain   optimum   performance   at   minimum   cost, observe the "Maintenance" guide on page 15. COMPRESSOR LUBRICATION FRAME OIL CHANGE Oil changes should be made every 500 hours  of  operation  or every 90 days, whichever occurs first.  If XL-T30 lubricating oil is  used,  oil  change  may  be  extended  to  1500  hours  or  12 months.  Important: For maximum removal of impurities, drain only when frame oil is hot.  After the operator has observed the condition  of  the  oil  from  a  number  of  changes,  the  length  of time   between   changes   may   be   extended   if   so   warranted. Frame oil capacity for Model 7100 is 2½h quarts (2.37 liters), and the Model 3000 is 41/2 quarts (4.25 liters). LUBRICATING OIL RECOMMENDATIONS I Ingersoll-Rand    recommends    the    use    of    XL-T30 lubricating oil after a 200 hour break-in on petroleum based oil. The   petroleum   lubricating   oil   should   be   a   non-detergent, containing only rust, oxidation, and anti-foaming inhibitors with either a naphthenic or paraffinic base. The viscosity should be selected for the temperature immediately surrounding the unit when it is in operation. OIL VISCOSITY TABLE Viscosity at 100F (37.8C) Temp. Range SUS Centistokes 40F & Below (4.4C & Below) 150 32 40F to 800F (4.4C to 26.7C) 500 10 80F to 125F (26.7 to 51.7C) 750 165 The  viscosities  given  In  the  table  are  intended  as  a general  guide  only  Heavy-duty  operating  conditions  require heavier viscosities and where borderline temperature conditions are encountered    the    viscosity    index    of    the    oil    should    be considered.  Always refer your specific operating conditions to your industrial lubricant supplier for recommendations. MOTOR LUBRICATION & CARE Depending  upon  the  type  of  electric  motor  driving your unit, the following lubricating schedule should be observed. BALL BEARING MOTORS WITH GREASE FITTINGS Ball   bearing   motors   that   have   grease   fittings   and plugs near the    bearings are to be repacked with grease once a year.  Use a very good grade of ball bearing grease. BALL BEARING MOTORS PRELUBRICATED FOR LIFE These  motors  have  no  grease  fitting  or  plugs  near the bearing and do not require lubrication. Several   major   points   contributing   to   proper   motor operation and care are given in the following paragraphs. For more detailed instructions, refer to the manufacturers' specific recommendations. It  is  also  a  good  practice  to  monthly  blow  off  the motor windings with a jet of air to prevent an accumulation of dirt.    An  occasional  revarnishing  of  the  windings  will  greatly prolong the life of the motor. If  the  motor  is  located  in  an  atmosphere  where  it  is exposed to appreciable quantities of water, oil, dirt or fumes, it must be  specially constructed. AIR INLET FILTER/SILENCER It  is  very  important  that  the  air  inlet  filter/silencer  be kept clean at all times.  A dirty inlet filter reduces the capacity of the compressor. The  filtering  element  should  be  taken  out  at  least once a month  and  cleaned  by  vacuuming  or  washing  in  mild detergent and water.  Allow to dry and then reinstall. Figure 4-1.Air inlet Filter/ Silencer Check the oil level in the bare    compressor    before    each use by removing the oil filler plug and  wiping  clean.    Place  the  oil gauge with the writing up into the filler  hole  until  the  threads  touch (DO NOT ENGAGE THE THREADS.)  Remove  the  gauge and read the oil level.  II oil level drops  below  the  safe  point,  add oil to bring level back to the FULL mark.    Do  not  over  fill.    Replace oil plug HAND TIGHTEN ONLY. Flushing compressor frame with gasoline, kerosene or flammable fluid can cause severe injury or death. Use a regular flushing oil to flush out compressor frame. page 3-836