ENGINE AR 4N2238 - Caterpillar

All SR4 GeneratorsReference: Service Manual, SR4 Generator With VR3 or VR4 Voltage Regulator, SENR3985. Service Manual, SR4 Generator (Three Phase Full Wave Excitation & Regulation), SENR2180. Operation & Maintenence Manual SEBU6150. This article supersedes a similar article in Engine News, August 1990, page 5, "Bearing Information For SR4 Generators".
Presently Caterpillar is using double shielded bearings on all 807 frame generators and smaller. The part numbers for the double shielded bearing are 108-1761 for 800 frame units, 108-1760 for 680 frame units, and 109-7687 for 580 and smaller. The double shielded bearing prevents overgreasing and protects the rolling elements from large particles of contamination. The shielded ball bearing uses 1.8 oz. of the 2S-3230 grease at an interval of every 2000 hours.
The 2L-4444 Spherical Roller Bearing is used on some two bearing generators, some 807 frame generators along with all 808 frame generators and larger. The spherical roller bearing provides higher load capability and the advantage of a larger diameter rotor shaft. The spherical roller bearing uses the 1 oz. of the new 108-8611 Grease at an interval of every 1000 hours. The new grease if properly used will reduce bearing temperatures and increase bearing life.
The following maintenance procedure for generator bearings should be followed:
1. Remove bearing bracket. Inspect bracket bore and bearing outer race and rolling elements. Generator bearing and bracket should be inspected at every major engine overhaul. Standby Power units should have the bearing inspected and the grease replace every 3 years. Bearing bracket bore should be inspected for out of roundness, excessive wear, and a bracket step greater than 0.0762 mm (.003 in). Double shielded bearings prevent visual inspection of the ball bearing elements. Bearings being removed for failure analysis should not be cut off with a torch.2. 2L-4444 Spherical Roller Bearing should be cleaned and re-packed with 108-8611 Grease. Pack the bearing and cavity to one-third to one-half of the cavity volume. (Approximately 4 - 5 oz. in the bearing and 5 - 6 oz. in the cavity.) Refer to the chart that follows.3. All ball bearings should be cleaned and the bracket cavity re-packed with 2S-3230 Grease. The cavity should be filled to one-third to one-half of the cavity volume. Refer to the chart that follows.4. Make sure the grease supply tube to the bearing is filled with grease.5. Remove the bracket drain plug and operate generator for one hour. This allows the grease to expand, forcing the excess grease out of the cavity relieving the internal pressure. The generator should continue to operate until the grease stops purging. Grease may not purge until later grease intervals.6. For future greasing intervals follow the recommendation on the lubrication plate (if equipped) or the procedure in the service manual. After each greasing interval step 5 should be followed. The grease amounts are not given in number of grease pumps due to the differences in quantity each grease gun delivers. DO NOT MIX GREASES.Some two bearing generators have spherical roller bearings in the front bracket and