MUTxT Module Removal and Installation
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Failure to connect the unit to a suitable grounding electrode creates an electrical shock hazard. An electrical shock will result in serious personal injury or death. |
Personal Protective Equipment (PPE) suitable to the work being performed must be worn when performing maintenance on the UPS.
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High voltage is present. Work on this equipment must be performed by authorized trained personnel. Personnel must be wearing Personal Protective Equipment that meets regulatory requirements to protect the body for the work that is being performed. Failure to use appropriate PPE to protect the body will result in serious personal injury or death. |
Refer to Operation and Maintenance Manual, SEBU8275, "Safety" section for more safety-related information.
Note: Do not remove heat pipes in order to access the IGBTs.
Note: Do not use power tools for disassembly.
Required Tools
The required tools include the following items:
- Installation kit
- Torque wrench
- Thermal grease kit
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| Illustration 1 | g02137576 |
355-8579 Grease As for thermal application | |
The kit contains the applicator for the thermal grease, the thermal grease, and a spatula to spread the grease properly.
Required Parts
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| Illustration 2 | g02137699 |
Typical thyristors | |
Removal Procedure
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High voltage may be present. Work on this equipment must be performed by authorized trained personnel. Failure to disconnect the power source before performing maintenance or removing modules exposes personnel to electrical potential. Bodily contact with electrical potential will cause serious personal injury or death. |
| NOTICE |
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Electrostatic discharge can damage integrated circuits or semiconductors if you touch the connector pins. When not in use, keep modules in static shielded bags. Follow these guidelines when you handle modules: Allow a minimum of 5 minutes for capacitors to discharge. Touch a grounded object to discharge static potential. Wear a wrist-strap grounding device. Do not touch the connector pins. Do not touch circuit components inside the module. If available, use a static-safe work station. |
Use the following instructions to disassemble the control.
- Remove power from the UPS by following the appropriate shutdown routine. Allow at least 5 minutes for the capacitors to discharge to remove any stored energy.
ReferenceOperation and Maintenance Manual, SEBU8575 for startup and shutdown procedures.
- Disconnect the wires (1) and the ribbon cable (2) from the circuit board.
- Remove the mounting bolts (4) for the snubber capacitors (5). Remove the snubber capacitors (5) .
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| Illustration 3 | g02607417 |
(1) Wire connection points (2) Ribbon cable connection (3) Bus bar (4) Snubber capacitor mounting bolts (5) Snubber capacitors (6) Ten mounting bolts that are to be removed | |
- Remove the ten mounting screws (6) .
- Remove the connecting bus bar (3) .
- Remove the mounting bolts (7) for the module. Remove the module.
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| Illustration 4 | g02609800 |
(7) Mounting bolts for module | |
Installation Procedure
- Clean any dirt or debris from the heatsink surface (8) .
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| Illustration 5 | g02609989 |
- Apply thermal grease (9) onto the thyristor base. Refer to Illustration 6.
- Use the edge of the spatula (10) to spread the thermal grease on the thyristor base (11). Refer to Illustration 6.
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| Illustration 6 | g02611036 |
(9) Thermal grease applied to thyristor base (10) Spatula edge to use to spread thermal grease evenly (11) Thermal grease evenly spread on thyristor base (12) Spatula edge to use to spread thermal grease (13) Technique to spread thermal grease (14) Final result if applied correctly | |
- Use the "SIXPACK" edge (12) to spread the thermal grease on the thyristor base (13) as shown in Illustration 6. The final result must resemble (14) .
- Install the guide rods (20) in the heatsink plate (8) .
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| Illustration 7 | g02611177 |
(8) Heatsink plate (20) Guide rods (21) Thyristors (22) Thyristor assembly | |
- Install the thyristor assembly on to the guide rods. Thread the thyristor mounting bolts in only a few threads. Do not tighten the mounting bolts.
Note: Do not at any time press or pry on the front of the thyristor assembly (22) .
- Remove the guide rods (20) .
- Thread the remaining thyristor mounting bolts in only a few threads.
- Press the thyristor assembly on to the heatsink plate. Torque the thyristor mounting bolts to 0.5 N·m (4.4 lb in) using the tightening sequence shown in Illustration 8.
- Torque the thyristor mounting bolts to 4.5 N·m (40 lb in) using the tightening sequence shown in Illustration 8.
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| Illustration 8 | g02611436 |
Front view of thyristor assembly. Torque pattern | |
- Install the power bar assembly (25). Do not tighten the mounting bolts (27) at this time.
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| Illustration 9 | g02611536 |
- Install the bolts (28) that attach the power bars (26) to the thyristors.
- Attach the three power cables to the power bars (26) .
- Install the two bus bar mounting bolts (29), but do not tighten.
- Install the bolts (30) that attach the snubber capacitors and the bus bar to the thyristors.
- Torque the mounting bolts (27), (28), (29), and (30) to 4.5 N·m (40 lb in).
- Connect ribbon cable to the connector (31) .
- Tighten the power bar cable connections.