UPSB220 Uninterruptible Power Supply Caterpillar

Note: Work should be carried out in accordance with applicable safety regulations. To avoid interrupting the load, the various switching operations must be carried out in the correct order. Operations are explained in diagrams placed next to the switches. The system cabinet is only partially powered down. The load is still supplied via the bypass AC source and switch Q3BP (23) .

ReferenceRefer to Operation and Maintenance Manual, "UPS Isolation".

Single UPS Unit

Illustration 1	g02364722
Start up After Isolation Procedure is Completed (7) Inverter ON button (8) Inverter OFF button (23) "Q3BP" (24) "Q5N" (25) "Q4S" (26) "QF1" (27) "Q1"

Perform the following steps after servicing is completed.

Refer to Illustration 1.

1. Close switch Q1 (27) .

2. Wait approximately 10 seconds.

3. Close switch QF1 (26) .

4. Close switch Q5N (24) .

5. Close switch Q4S (25) .

6. Open switch Q3BP (23) .

7. Press the Inverter ON button (7) to start the inverter.

Parallel UPS Unit

Illustration 2	g02364843
Star-up After Isolation Procedure is Completed (7) Inverter ON button (8) Inverter OFF button (23a) "Q3BP" (24) "Q5N" (24a) "Q5N" (25) "Q4S" (26) "QF1" (27) "Q1"

Perform the following steps after servicing is completed.

Refer to Illustration 1.

Note: Ensure Q4S (25) is closed in each UPS before continuing.

1. Close switches Q5N (24) on the UPS units.

2. Close switch Q5N (24a) in the external bypass unit.

3. Open switch Q3BP (23a) in the parallel-connection unit.

4. Close switches Q1 (27) and QF1 (26) on the UPS units.

5. Press the Inverter ON buttons (7) to start the inverters.