UPS 120, UPS 150, UPS 250, UPS 300, UPS 301, UPS 500, UPS 600, UPS 750 and UPS 900 Uninterruptible Power Supplies Caterpillar

Description

Illustration 1	g01278148
Location of the assembly for the utility inverter (1) Utility inverter modules

The assembly for the utility inverter is located in the upper part of the cabinet for the flywheel in the middle.

There are two inverters in the system, the flywheel inverter and the utility inverter. The inverters are used for the following reasons:

• Developing the current that is necessary to rotate the flywheel

• Developing the voltage that is used during a discharge

• Charging and maintaining the DC bus voltage

Power is provided by one inverter at a time to the DC bus. The utility inverter maintains the voltages for the DC bus. The utility inverter regulates output voltage.

The utility inverter contains a three-phase insulated gate bipolar transistor (IGBT). The IGBTs perform the following functions:

• Rectifying the AC voltage from the filter node

• Converting the DC voltage back to AC voltage during discharge

Removal Procedure (MMS/SMS300)

Refer to Systems Operation, Testing and Adjusting, RENR9988, "Internal Component Preremoval Steps (Flywheel Cabinet)" in order to shut down the system and gain access to internal components.

1. Remove the two screws that attach the SKiiP interface board to the front of the assembly for the utility inverter. Place the SKiiP interface board in an anti-static bag. Refer to Systems Operation, Testing and Adjusting, RENR9988, "SKiiP Interface PWA".

2. Disconnect the input cable from the right side of the module (1).

3. Cut the tie-wrap that attaches the ribbon cable and the toroid to the assembly.

4. Disconnect the "18 AWG Red/Black" wires from the module (1).

5. Remove the ribbon cable from the module (1).

6. Remove the two mounting bolts from the positive connection of the DC bus.

7. Remove the two mounting bolts from the negative connection of the DC bus.

8. Loosen the two mounting bolts at the top of the assembly for the heat sink.
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   NOTICE
   The module for the flywheel inverter is heavy. Exercise caution upon removing the last bolt of the assembly in order to not damage components.

9. Remove the module (1) from the assembly.

Installation Procedure (MMS/SMS300)

1. Remove the hardware for mounting the cables and capacitors from the old module (1). Attach the hardware to the new module (1).

2. Install the new assembly in the cabinet.

3. Install the two mounting bolts for the negative connection of the DC bus. Tighten the bolts to 11.3 N·m (100 lb in).

4. Install the two mounting bolts for the positive connection of the DC bus. Tighten the bolts to 11.3 N·m (100 lb in).

5. Install the two mounting bolts at the top of the assembly for the heat sink. Tighten the bolts to 4.5 N·m (40 lb in).

6. Connect the ribbon cable to the module (1).

7. Connect the input cable to the right side of the module (1). Tighten the bolt to 9 N·m (80 lb in).

8. Attach the SKiiP interface board to the bottom of the module (1) with the two screws.

9. Connect the "18 AWG Reb/Black" wires to the module (1).

10. Energize the system.

Illustration 2	g01292923
Utility inverter module, DC bus, and DC capacitors (except SMS 150) (2) Mounting bolt (3) Heat sink and shroud (4) Capacitors (5) SKiiP interface board (6) DC bus (7) Fuses for DC bus (8) DC capacitors

Illustration 3	g01292927
Utility inverter module (SMS 150) (9) Location for mounting

Removal Procedure (SMS 150)

Refer to Systems Operation, Testing and Adjusting, RENR9988, "Internal Component Preremoval Steps (Flywheel Cabinet)" in order to shut down the system and gain access to internal components.

1. Remove the six bolts from the 3 DC bus bars.

2. Remove the three bus bars that connect the following assemblies:

   • Flywheel Inverter

   • Utility Inverter

3. Disconnect the cables from the assembly for the Utility Inverter. Disconnect the wires from the assembly for the Utility Inverter. Verify the labeling of the cables with the location of the cables.

4. Remove the bolt at the front right side of the assembly that connects the assembly to the ceiling of the cabinet.

5. Loosen the three bolts at the top of the assembly that hold the assembly to the ceiling of the cabinet.

6. Slide the assembly forward. In order to remove the assembly, slide the assembly downward.

Installation Procedure (SMS 150)

1. Remove the old assembly.

   1. Remove the capacitors.

   2. Remove the SKiiP interface board. Refer to Systems Operation, Testing and Adjusting, RENR9988, "SKiiP Interface PWA".

   3. Remove other parts from the old assembly that do not come with the new assembly. Attach the parts to the new assembly.

2. Position the assembly on the three bolts at the top of the cabinet. Install the new assembly in the cabinet.

3. Install the mounting bolt that is located at the top front left of the module to the ceiling.

4. Install the three bus bars to the following assemblies:

   • Flywheel Inverter

   • Utility Inverter

5. Tighten the bolts to 11.3 N·m (100 lb in).

6. Tighten the two mounting bolts at the top of the assembly to 4.5 N·m (40 lb in).

7. Connect the wires to the module.

8. Connect the three-phase cables to the left side of the module. Tighten the bolts to 9 N·m (80 lb in).

9. Energize the system.