UPSB220 Uninterruptible Power Supply Caterpillar

AC Capacitor Replacement Procedures

Overview

Use the following instructions to perform AC capacitor assembly replacement. The instructions involve the following:

• Removal of the cables and hardware

• Removal the AC capacitor assembly

• Installation of the AC capacitor assembly

• Installation of the cables and hardware

Removal Procedure

Note: The following procedure provides instruction to remove the capacitor assembly through the front side of the UPS.

The AC capacitors (3) are located in the upper right corner of the UPS cabinet.

Note: The date of manufacture will determine if the AC capacitors (4) are assembled in a vertical orientation or a horizontal orientation.

Illustration 1	g02552264
(1) Rectifier/charger module (CHDI) (2) Inverter module (DTQI) (3) Static switch module (CSDI-1) (4) C3, C4, and C5 AC capacitors (5) RFI/EMI filter and attenuation board (CIMI) attached to UPOZ shield

1. The UPSB220 must be de-energized for the following procedure. Confirm that the Mains 1 and Mains 2 upstream breakers are tagged out and locked out.

2. The required PPE must be put on.

3. Use the Fluke meter to verify that no AC or DC voltage is present.

   1. Verify that the Fluke meter is working properly with a known AC source. Use the AC scale.

   2. Verify that the Fluke meter is working properly with a known DC source. Use the DC scale.

   3. Measure for AC voltage at Q1. Measure for voltage phase-to-neutral and phase-to-phase.

   4. Measure for DC voltage plus-to-minus at the DC capacitors.

4. After no voltage is confirmed, the PPE can be removed, except for safety glasses.

5. Ensue that all cables and components are appropriately labeled before removal.

6. Removal of the RFI/EMI filter and attenuation board (5) depends on the model of the UPS. If needed, remove the RFI/EMI filter and attenuation board (CIMI) that is attached to UPOZ shield.

7. Removal of the output static switch module (3) depends on the model of the UPS. If needed, remove the output static switch module (3). The static switch module is also referred to as the CSDI-1 board.

8. Removal of the UPOZ board (5) depends on the model of the UPS. If needed, remove the UPOZ board.

9. Disconnect any necessary cables or wires from the AC capacitor assembly.

Show/hide table



Illustration 2	g02552577
AC capacitors assembled in a horizontal orientation

10. Remove the AC capacitor assembly mounting bolts.

AC Capacitor Bank Disassembly

Note: All of the capacitors must be replaced at the same time with new capacitors.

1. Ensure that all components are appropriately labeled before disassembly. Labeling the components will help avoid assembly problems.

2. Remove the copper plate that is attached to all of the capacitors.

3. Remove the mounting bolts (6). Remove the mounting bracket (7) .

Illustration 3	g02552603

AC Capacitor Bank Assembly

Note: Before beginning the installation, verify that all of the capacitors have the same date codes and are all from the same supplier.

1. Secure the new capacitors (8) to the mounting bracket (7). The mounting bolts (6) must be torqued to 7 N·m (5.2 lb ft).

2. Install the copper plate (9) that is attached to all of the capacitors.

Show/hide table



Illustration 4	g02552701

3. The mounting nuts (10) must be torqued to 7 N·m (5.2 lb ft).

AC Capacitor Bank Installation

1. Install the AC capacitor assembly mounting bolts.

2. Connect all cables or wires that were removed from the AC capacitor assembly.

3. If removed, install the UPOZ board (5), the static switch module ( CSDI-1 board) (3), and the RFI/EMI filter and attenuation board (5) .

4. Connect any remaining power cables or control cables that were removed to access the AC capacitor assembly.