Usage:
All SR4 And SR4B Generators
Reference: Operation And Maintenance Manual, SEBU6150, SR4 Generators And Control Panels.
Reference: Operation And Maintenance Manual, SEBU6918, SR4B Generators And Control Panels.
Reference: Operation And Maintenance Manual, SEBU7050, SR4B Generators And Control Panels.
Reference: Service Manual Module, SENR5359, SR4B Generators.
Improved maintenance procedures have been released for SR4 and SR4B Generators. Properly following the procedures and recommendations listed here, as well as adherence to the procedures found in the references listed above, will result in increased long term performance.
1. Periodic insulation resistance (megger) checks must be performed as recommended in the Operation and Maintenance Manuals.
2. The correct grease must be used on all applicable components of the generator.
3. The bearing inspection and replacement procedures presented here should be followed.
Insulation Resistance (Megger) Checks
The SR4 and SR4B Operation and Maintenance Manuals recommend that the main rotor and main stator winding be checked before the initial startup of the generator, and at 3 or 6 month intervals depending on the environment. Caterpillar will request evidence that these checks were performed when warranty claims are filed.
Proper Grease For Generator Bearings
The correct grease part number is stamped on the grease plate on all 3500 series generators. The 2L-4444 Roller Bearing used on some 800 frame or larger generators must be lubricated with 28.3 grams (1 oz) of 108-8611 Grease every 1000 hours. All other bearings (ball bearings) are to be greased with 51 grams (1.8 oz) to 57 grams (2 oz) of 2S-3230 Grease every 2000 hours. The new 154-3032 Ball Bearings used on some 800 frame or larger generators do not need to be greased. Early production bearing support brackets (housings) did not have holes for grease fittings because the bearings are greased for life. Holes for grease fittings are now provided for customers who would prefer to add grease. In this case, 51 grams (1.8 oz) to 57 grams (2 oz) of 2S-3230 Grease is recommended every 2000 hours.
Bearing Installation
When installing a bearing on the shaft, it must be heated to 107 °C (225 °F) using an oven or induction heater. Do not use a torch. Do not use an oil bath because it will wash the grease out of the bearing. Be sure that the bracket bore is in good condition. The bore diameter is published in the Operation And Maintenance Manual for the SR4B generators. The bore diameter in the bracket for the new 154-3032 Ball Bearings is 280.007 ± .015 mm (11.024 ± .0006 in). Pack the bearing bracket with grease as specified in the Operation And Maintenance Manual for SR4B generators. When installing the 154-3032 Ball Bearing, use approximately 57 grams (2 oz) of 2S-3230 Grease to coat the bracket bore.
Bearing Inspection Procedure
The Operation And Maintenance Manuals contain a procedure for inspecting bearings and measuring wear. The following is an alternative method of performing the inspection: Bearing clearance (lift) is measured by installing a dial indicator within 3 inches of the bearing. The shaft must then be lifted using a jack or pry bar. The lift reading on the dial indicator must not exceed .25 mm (.01 in). If the reading is greater, replace the bearing.
When replacing the bearing, ensure that the bore in the bearing support bracket is in good condition. Some bearing brackets have sleeves that can be replaced. Check the sleeve condition and replace if needed. The bore should not have a "wear step" and should not exceed the diameter specified in the Operation And Maintenance Manual.
Bearing Monitoring
The 2L-4444 Roller Bearing should be monitored continuously using a temperature detector and/or vibration monitors. If monitoring is not done, the bearings should be inspected using the previous procedure every 2500 hours. It is also recommended that ball bearings be monitored using temperature or vibration monitors. If monitoring is not done, the bearings should be ispected using the previous procedure every 5000 hours.
Bearing Replacement
Caterpillar recommends that all bearings be replaced at or before 10000 hours.