SPACER 4S5719 - Caterpillar

SR5 Generators
The ball bearings that are used in LC5, LC6, and SR5 generators contain grease. This grease is subject to deterioration. If the generator is stored for more than 1 year, without rotating the rotor, new ball bearings may be required. These bearings are greased at the factory. These bearings do not require any additional greasing in the field. Remove any necessary covers to inspect the rear bearings of the generators. Front bearings may be inspected through the fan screen. Perform a visual inspection for obvious damage, for corrosion, or for an excessive amount of purged grease around the bearing sleeves. Small amounts of purged grease are expected. Grease that covers the brackets or the windings is excessive.Bearing inspection should include the collection of vibration data. Refer to this Operation and Maintenance Manual, "Generator Set Vibration - Test/Record" for further information concerning checking the vibration levels.Bearing temperature should also be measured and recorded as a part of this inspection. Refer to this Operation and Maintenance Manual, "Generator Bearing Temperature - Test/Record" for further information concerning checking the vibration levels.If inspection indicates that bearings are free of rust or corrosion, and no noise or excessive vibration occur on start-up, replacement is not necessary.SR4 and SR500 Generators
Remove the bearing bracket. Inspect the following items: bracket bore, bearing outer race and rolling elements. On standby power units, the bearing must be inspected and the grease must be replaced at 3-year intervals. The sleeve in the bearing bracket should be inspected for out of roundness, excessive wear, and a bracket step that is less than 0.0762 mm (0.0030 inch). If there is no sleeve in the bearing bracket, inspect the bore of the bearing bracket. The bearing should be inspected for damage to the outer race, severe fretting, and smoothness of operation. When possible, the bearing elements should be inspected. Some double shielded ball bearings prevent visual inspection of the elements of the bearing. Other double shielded ball bearings have a retaining ring. This retaining ring can be removed to allow access for a visual inspection of the elements of the bearing.On two-bearing generators, the front bearing can only be removed after the drive coupling is removed. Refer to the Systems Operation Testing and Adjusting Disassembly and Assembly, "Coupling - Remove" for the generator for instructions for removing the drive coupling.