- Uninterruptible Power Supply:
- UPS 250 (S/N: CNM1-UP; APZ1-UP)
- UPS 300 (S/N: CNJ1-UP; CPZ1-UP)
- UPS 301 (S/N: CSY1-UP)
- UPS 500 (S/N: CSE1-UP)
- UPS 600 (S/N: CTX1-UP)
- UPS 750 (S/N: CPM1-UP)
- UPS 900 (S/N: CRY1-UP)
- UPS 300 (S/N: CNJ1-UP; CPZ1-UP)
Introduction
This Special Instruction contains MOV / surge protector removal procedure for uninterruptible power supply.
Important Safety Information
Work safely. Most accidents that involve product operation, maintenance, and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs.
A person must be alert to potential hazards. This person should also have the necessary training, skills, and tools in order to perform these functions properly.
Safety precautions and warnings are provided in this instruction and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard.
Therefore, the warnings in this publication and the warnings that are on the product are not all inclusive. If a tool, a procedure, a work method, or operating technique that is not recommended by Caterpillar is used, ensure safety for you and other people to use.
Ensure that the product will not be damaged or the product will be made unsafe by the operation, lubrication, maintenance, or the repair procedures that are used.
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Do not operate or work on this machine unless you have read and understand the instructions and warnings in the Operation and Maintenance Manual. Failure to follow the instructions or heed the warnings could result in injury or death. Contact any Caterpillar dealer for replacement manuals. Proper care is your responsibility. |
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High voltage may be present. The power source must be disconnected before working on the equipment. Failure to disconnect the power source could result in injury or death. Verify that the equipment is not energized before performing any maintenance. This work must be performed by trained personnel with correct tools and procedures. |
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Risk of electric shock or energy hazard. Parts inside this UPS are energized by the flywheel even when the AC power is disconnected. |
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Reference
ReferenceTesting and Adjusting, RENR9988, "UPS120, UPS150, UPS250i, UPS250iE, UPS300, UPS300E, UPS301, UPS500, UPS600, UPS750, and UPS900 Uninterruptible Power Supply"
Required Parts
| Quantity | Part Number | Description |
|---|---|---|
| 3 | 416-8824 | Varistor Assembly |
Rework Procedure
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| Illustration 1 | g03069416 |
Isolate MMU electrically or switch off power from the entire system before replacement of 261-1004 Varistor Assembly (1) and then follow the below steps:
Note: Begin work only after verifying MMU is de-energized.
- Remove the six 9/16" nuts (2) and six washers (3) to remove the fuses located in front of the 261-1004 Varistor Assembly (1). Refer to Illustration 1 and Illustration 2.
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| Illustration 2 | g03088579 |
- Remove 7/16" nut (4) and bolt (5) and associated washers (6) connecting the DC cables to the MOV blocks. Refer to Illustration 3.
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| Illustration 3 | g03088662 |
- Remove two Phillips head screws (7) from both 261-1004 Varistor Assembly (1) and retain the screws. This will allow the 261-1004 Varistor Assembly (1) to be removed. Refer to Illustration 3.
- Each new 416-8824 Varistor Assembly contains one replacement block (8), two 1.25" studs (9), two 7/16" nuts (10). Refer to Illustration 4.
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| Illustration 4 | g03069420 |
- Install 1/4" stud (11) into MOV replacement block (8) and thread the two 7/16" nuts (10) onto the 1/4" stud (11). Refer to Illustration 5.
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| Illustration 5 | g03069422 |
- Tighten both 7/16" nuts (10) together on stud (11) which creates a point to tighten the stud (11) into the replacement block (8). Refer to Illustration 5.
- Repeat the Step 5 - Step 6 for the installation of second stud.
- Use the same Phillips head screws (7) used to secure the 416-8824 Varistor Assembly to the side panel to secure the replacement blocks (8) .
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| Illustration 6 | g03069423 |
- Using the pre-existing MOV hardware, use one flat washer and one lock washer with supplied 7/16" nut and connect cables (12) to the corresponding stud locations on the new replacement blocks.
- Repeat Step 9 for connecting the remaining cables.
- Return armature fuses to original locations and connect corresponding armature cables.
- Return MMU to the original state.