CONFIDENTIAL TIBU4058-01

WARNING: Personal injury or death can result from high voltage.

When the flywheel is spinning, the following components are energized: the bus, the armature leads, and the flywheel armature fuses.

High voltage and current are present when the Uninterruptible Power Supply (UPS) equipment is in operation.

Improper test equipment can fail and present a high voltage shock hazard to its user.

Make sure that the testing equipment is designed for and correctly operated during high voltage and high current testing.

When servicing or repairing UPS equipment, make sure all capacitors are discharged.

It has been determined that the Static Drain Assembly Kit (Cat p/n) is subject to being installed incorrectly in the field, contributing to premature life expectancy and unwarranted RPS alarm errors.

There are two versions of the 180-6295 Static Drain Assembly Kit. This document will provide instructions for proper installation of both the original version (Rev. 00) and the later version (Rev. 03).

In the 180-6295 Rev. 00 design, a copper contact with a carbon tip makes direct contact with the center of the flywheel rotor retaining bolt. The force of the copper contact is very important. Excessive force will cause the carbon tip to wear a hole in the flywheel rotor retaining bolt. This will cause RPS Errors and the UPS will change to by-pass mode as a result.

In 180-6295 Rev. 03, the design changed the copper contact and the contact location with the flywheel rotor retaining bolt. The carbon tip was removed. The copper contact was repositioned for off center contact with the flywheel rotor retaining bolt.

Ensure that you have de-energized the UPS and the flywheel rpm is at zero prior to performing these installation procedures.

1. Thoroughly clean the flywheel retaining bolt (Cat p/n 240-1666) with a clean dry rag.
2. Using a depth micrometer, measure the depth of the polished surface of the flywheel retaining bolt to the lip of the bearing cartridge. This dimension will be "X" in figure 1. Refer to Figure 1.
3. To dimension "X" (from Step 2), add 0.010" and note this value that will be used to set the copper contact. This value provides the "preload or force" of the copper contact against the polished surface of the flywheel retaining bolt.
4. Measure from the Cover Plate to the top surface of the copper contact.
5. Adjust the tip of the copper contact such that the distance measured in Step 4 is equal to the value obtained in step 3. The allowable tolerance for this adjustment is +0.030"/-0.00".
6. Install the Static Drain Assembly.
7. Using an Ohm meter, verify continuity between the top sensing flywheel retaining bolt and any unpainted surface of the flywheel housing.

1. Thoroughly clean the flywheel retaining bolt (Cat p/n 240-1666) using a clean dry rag.
2. Using a depth micrometer, measure the depth of the polished surface of the flywheel retaining bolt to the lip of the bearing cartridge. This dimension will be "X" in figure 1. Refer to Figure 1.
3. To dimension "X" (Step 2) add 0.010" and note this value that will be used to set the copper contact. This value provides the "preload or force" of the copper contact against the polished surface of the flywheel retaining bolt.
4. Measure from the Cover Plate to the top surface of the copper contact.
5. Adjust the tip of the copper contact such that the distance measured in Step 4 is equal to the value obtained in step 3. The allowable tolerance for this adjustment is +0.030"/-0.00".
6. Install the Static Drain Assembly.
7. Using an Ohm meter, verify continuity between the top sensing flywheel retaining bolt and any unpainted surface of the flywheel housing.

The 180-6295 Rev. 00 Static Drain assembly can be converted to the 180-6295 Rev. 03 assembly. In order to perform the conversion you will need to use the following new components:

Description Part Number

Contact 242-5326

Bracket 242-5328

Retaining Bolt 240-1660

Replace the existing Contact, Bracket and Retaining Bolt with the new components. The mounting hardware is the same.

REFERENCE: For additional operational instructions and procedures, refer to the following publications:

RENR2476, Systems Operations, Testing and Adjusting, "UPS250, UPS300, UPS500, UPS750, and UPS900 Uninterruptible Power Supply"

SEBU7464, Operation and Maintenance Manual, "UPS250, UPS300, UPS500, UPS600, UPS750, and UPS900 Uninterruptible Power Supply"

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