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

Illustration 1	g01269094
Bypass Static Switch Assembly (1) "K4" Contactor (2) Line Disconnect or Fuse Disconnect (3) Fuses "F22, F23, F24" (4) Snubber Assemblies (5) Thyristor (6) Bypass Cabinet Controller (7) Line Disconnect or Thyristor Disconnect

Description

The optional Bypass Static Switch Assembly is located behind the door in the middle of the cabinet and connected to the right panel.

Fuses

Refer to Systems Operation, Testing and Adjusting, RENR9988, "System Fuses (SMS Bypass Cabinet)" for information of the fuse, installation, and removal procedures.

Contactor for the Bypass Static Switch "K4"

The contactor for the Static Bypass "K4" is located on the rear of the Static Bypass panel.

Board for the Bypass Cabinet Controller (BCC)

The BCC (6) is located on the front of the Static Bypass assembly. The BCC (6) acts as an interface between the UPS and the Static Bypass. The BCC (6) is the controller for the Static Bypass option in Single Module System (SMS). The BCC (6) receives logic signals. The BCC (6) drives the gate signals of the bypass static switch.

Removal Procedure for the Board

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

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Illustration 2	g01269152
Board for the Bypass Cabinet Controller

1. Disconnect all connectors. Verify the labeling of the wires for subsequent installation. Refer to Illustration 2.

2. Disconnect the four screws that connect the board to the standoffs on the right panel.

Installation Procedure for the Board

1. Position the board in the cabinet over the white standoffs that are connected to the right panel.

2. Attach the board to the standoffs with four screws.

3. Connect the wire connectors into the correct connectors on the board. Check the labels on each connector for proper placement.

Thyristors

Three thyristors (5) are located on the static bypass for each of the following phases: A, B and C.

The thyristors (5) act as a static switch. Also, the thyristors (5) allow a rapid changeover when you change between the bypass and on-line states.

Snubber Assemblies

"Snubber assemblies" (4) are connected between the input and the output on each of the three static bypass thyristors (5).

The snubber assemblies (4) prevent false turn-ons of the thyristor that are caused by voltage transients.

Removal Procedure for the Assembly

All parts of the Static Bypass Assembly are removed as a unit and installed as a unit.

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

2. Unplug the line disconnect or fuse disconnect (2) at the top of the assembly.

3. Unplug the line disconnect or the thyristor disconnect (3) at the bottom of the assembly.

4. Cut the tie-wrap for the cable "J15" on the BCC board. Cut the tie-wrap for the cable "J7" on the BCC board.

5. Unplug the "J1" connector from the BCC board. Unplug the "J15" connector from the BCC board. Refer to Illustration 1.

6. Unplug the wire for the "F22 NC" fuse sensor. Unplug the wire for the "F24 COM" fuse sensor.

7. Remove the sense and control wires for the "K4".

8. Loosen the two bolts at the bottom of the assembly that hold the assembly to the right panel.

9. Unscrew the two bolts at the top of the assembly that hold the assembly to the right panel.

10. Remove the assembly out of the cabinet.

Installation Procedure for the Assembly

1. Position the Static Bypass panel in the cabinet by sliding the lower slotted tabs on the bolts on the right panel. Tighten the bolts.

2. Attach the top of the Static Bypass panel to the right panel with two bolts.

3. Install the sense and control wires for the "K4" contactor (1).

4. Connect the wire for the "F22 NC" fuse sensor. Connect the wire for the "F24 COM" fuse sensor.

5. Connect the "J1" connector to the BCC board. Connect the "J15" connector to the BCC board.

6. Connect the line disconnect or the thyristor disconnect (3) at the bottom of the assembly.

7. Connect the line disconnect or the thyristor disconnect (3) at the top of the assembly.

8. Tie-wrap the "J15" to the right panel. Tie-wrap the "J7" cable to the right panel.