Emerson Liebert NX 10-30kVA User Manual

Page 90

Operating Instructions

9.12 Shutting Down a Multi-Module System Without System Bypass Switch

1. Open the UPS door to gain access to the main power switches, SW1 and CB1of a UPS in the

system.

2. Turn the rotary switch to BYPASS position. Rotating any UPS Rotary Switch (SW1) to the

Bypass position will force all UPS modules to Static Bypass

3. Repeat Steps 1 and 2 for the rest of the units in the system.

4. Turn the rotary switch of each unit in the system to TEST. The load is now on maintenance

bypass.

5. Turn the rotary switch of each unit in the system to MAINT.

6. Open system output breaker. The load will now be disconnected.
7. Open rectifier switch CB1. All operator indicators and messages will turn off as the utility-driven

internal power supplies decay.

8. To isolate a module:

a. For systems that have UPS input breakers in paralleling cabinet, open the UPS input breaker

for the unit you want to isolate.

b. For systems that do not have UPS input breakers in paralleling cabinet, the utility source to

the UPS will need to be opened.

9.13 Shutting Down a Multi-Module System With System Bypass Switch

1. In the Bypass Cabinet, rotate the system bypass switch to the Bypass position. This will force the

UPS's in the system to Static Bypass.

2. Open the UPS door to gain access to the main power switches, SW1 and CB1of a UPS in the

system.

3. Turn the UPS SW1 to BYPASS position for each module in the system
4. Repeat Steps 2 and 3 for the rest of the units in the system.
5. Turn the rotary switch of each unit in the system to TEST.
6. Turn the rotary switch of each unit in the system to MAINT.
7. Open rectifier switch CB1. All operator indicators and messages will turn off as the utility driven

internal power supplies decay.

8. To isolate the UPS(s) from the bypass cabinet, open the module input and output isolation

breaker(s).

NOTE
Before beginning this procedure, shut down the connected load to prevent the possibility of

damage. This procedure will shut off power to the load.

NOTE
If this operation will be performed on multiple units, the procedures should be performed on

each unit with as little delay as possible.

NOTE
The following step will shut off power to the connected load.