TM5-6115-593-34 NAVFAC P-8-631-34 TO-35C2-3-463-2 (4) Insulation resistance shall be at least 1 megohm at 77xF (25xC).  If this value is not met, clean or dry out the winding and repeat test.  Replace rotor if defective. NOTE Low insulation resistance may be caused by dirt or excessive moisture.  Insulation failure may be caused by wrong voltages, induced voltages caused by opening field circuits too quickly, oil and grease, high temperatures, or excessive vibration. (5) Perform a growler test on the rotor as follows: (a) Place the rotor on the growler and energize. (b) Hold a thin piece of metal, such as a hacksaw blade, directly over the top slot of the rotor and along the length of the slot.  If the coil is shorted the blade will vibrate rapidly and cause a growling noise. (c) If the above test is not met, proceed with the removal and repair procedures. c. Replacement.  For removal and replacement of the generator rotor assembly, the generator must be removed from the generator set.  (See paragraph 11-5b).  After generator has been removed from the generator set, locate it in a suitable maintenance area affording sufficient accessibility for maintenance and sufficient unobstructed flow of coolant air.  Move the generator to the maintenance location either by attaching an overhead hoist to the eyebolts installed in the generator frame or by lifting the generator from underneath the base with a fork lift. Determine that the hoist, when used, is of sufficient strength to adequately support the weight of the generator. Hoist and hoist cables and slings should have a rating of not less than 6,000 pounds (2,727 kg).  when moving unit with a fork lift, make certain it is completely onto and balanced on the fork lift tines. WARNING OVERHEAD OPERATIONS HAVE INHERENT HAZARDS THAT CANNOT BE MECHANICALLY SAFEGUARDED.  HARD HATS AND SAFETY SHOES ARE REQUIRED. CAUTION Always    make    certain    care    is    taken    when moving  the  generator  to  prevent  its  striking other   objects   or   personnel.      Never   apply   a lifting   force   to   structural   points   other   than those provided for that purpose. NOTE Avoid  maintenance  locations  which  would subject the generator to excessive moisture,   dust,   steam   or   the   fumes   from acids, alkalines, or other corrosive chemicals. (1) Removal.  Remove the rotor from the generator as follows: (See figure 11-3.) (a) Remove cover (30) by removing screws (26 and 28), washers (29), and nuts (27). WARNING USE EXTREME CARE WHEN REMOVING ROTOR TO PREVENT INJURY TO HANDS DUE TO MAGNETIC ATTRACTION BETWEEN THE PMG ROTOR AND THE PMG STATOR OR GENERATOR SHAFT. (b) Remove PMG rotor (37) by removing pin (36), screw (35), and washer (34). NOTE Do not subject PMG rotor to severe mechanical shock. (c) Loosen setscrew (52) in exciter rotor (38). 11-30