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	g01278077
Location of the Assembly for the Flywheel Inverter (1) Flywheel Inverter Modules

The assembly for the Flywheel Inverter is located in the upper part of the cabinet for the Flywheel on the right side.

During discharge, the flywheel inverter performs the following functions:

• rectifying the three-phase AC signals from the armature windings

• maintaining the voltages from the DC bus

• increasing the speed of the flywheel

During discharge, the assembly for the flywheel inverter converts the three-phase AC voltage from the flywheels. The DC bus is kept charged. This regulated DC voltage is used by the Utility Inverter. The voltage is converted back to AC voltage in order to supply the load for the customer.

Illustration 2	g01278108
(2) DC Bus (3) Mounting Bolt (4) Heat Shrink and Shroud (5) Fuses for the DC Bus (6) Capacitors (7) SKiip Interface Board

The assembly for the flywheel inverter consists of three inverter modules (1). Each inverter module (1) contains the following components: heat sink (4), IGBT module and DC capacitors (6). Refer to Illustration 2.

Removal Procedure

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.

Note: The module for the Field Coil Driver (1) needs to be removed in order to gain access to the module for the Flywheel Inverter.

Note: The "phase 1" module must be removed in order to access the "phase 2" module. In order to access the "phase 3" module, the "phase 1" module and the "phase 2" module must be removed.

1. Remove the assembly for the Field Coil Driver. Refer to Systems Operation, Testing and Adjusting, RENR9988, "Field Coil Driver".

2. Remove the two screws that attach the SKiipp Interface Board (7) to the front of the assembly for the flywheel inverter. Place the SKiip Interface PWA (7) in an anti-static bag. Refer to Systems Operation, Testing and Adjusting, RENR9988, "SKiip Interface PWA".

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

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

5. Disconnect 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

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 (7) to the bottom of the module (1) with the two screws.

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

10. Install the assembly for the field coil driver. Refer to Systems Operation, Testing and Adjusting, RENR9988, "Field Coil Driver".

11. Energize the system.