Liebert EMERSON NX 1+1 User Manual

Liebert Corporation

1050 Dearborn Drive
P.O. Box 29186
Columbus, OH 43229

Telephone: 1-800-877-9222
Facsimile: 1-614-841-6022
www.liebert.com

ject to change without notice.

® Liebert and the Liebert logo are registered trademarks of

Liebert Corporation. All names referred to are trademarks or

registered trademarks of their respective owners.
SL-25246 (10/04) Rev. 0

if they get failure during operation. For 1+1 sys-

tems, this settings needs to be set to 1.

System Startup

1. Start each UPS normally as described in Liebert

NX installation manual. SL-25215.

2. Turn on the inverter of each UPS module one at a

time.

3. Apply the load after the last UPS module transfers

to inverter. The total load can be determined

through the LCD of either UPS.

4. Verify the load rate of each UPS module. If the

load rates are roughly the same, then the parallel

system may be assumed to be operating normally.

Emergency Power Off (EPO)

The external emergency stop facility is identical to

that described for the single unit installation — that

an individual emergency stop button is provided for

each unit. Note that this is a Normally Open switch.

Figure 3

Connecting EPO push button

NOTE
The settings should be the same for all

modules within the parallel system, except

the UPS ID No.

NOTE
If one module cannot transfer to inverter

mode long after its inverter is on, its output

connection may not be good or its output

phase rotation may not be coincident with

other modules. At this time, the LCD for the

UPS module will display “inverter

asynchronous” and the inverter indicator

will flash continuously. If either UPS

module makes abnormal noise after it

transfers to inverter, its parallel cables may

be incorrectly connected.

EPO-H

EPO

Monitor board

EPO-L

UPS1

UPS2

EPO-H

Monitor board

EPO-L