- Uninterruptible Power Supply:
- UPS 250 (S/N: BEE1-UP; CNM1-235; APZ1-274 and 276-282)
- UPS 300 (S/N: CNJ1-292 and 294-304; CPZ1-349)
- UPS301 (S/N: CSY1-199)
- UPS 500 (S/N: CSE1-128)
- UPS 600 (S/N: CTX1-259)
- UPS 750 (S/N: CPM1-159)
- UPS 900 (S/N: CRY1-329)
The upper and lower flywheel bearings in the UPS product line have recently been upgraded to an improved bearing design. The development of a new bearing design was prompted by reports of UPS flywheels having audible bearing noise (along with the associated nuisance vibration alarms).
This new bearing design is called Elastomeric Vibration Damping (EVD). EVD institutes two identifiable component changes. The first change increases the clearance between the flywheel bearing cartridge bore and the outer bearing race. The second change adds a special elastomer type o-ring between the bearing cartridge bore and the outer bearing race. The main purpose of the o-ring in the second change is that of a vibration dampener.
The new EVD style bearing has been incorporated into all Caterpillar UPS products and is currently available as a service item in Caterpillar parts stocking facilities. The Caterpillar parts stocking facilities have purged their inventory of the original non-EVD style bearing.
The new EVD style bearings will carry the same Caterpillar part number as the original non-EVD style bearing. This will also apply for Caterpillar Reman bearing part numbers. When replacing the UPS flywheel bearings, ensure that you use bearings of the same type. Always replace the upper and lower bearings as a matched set.