Emerson Liebert NX 10-30kVA - Manual (Page 93)

Operating Instructions
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9.16 Parallel System Start Up
1. Start each UPS normally as described in 9.2 - UPS Start Up
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.
9.17 Replacing Dust Filters
1. Open the UPS door.
2. The dust filters are behind the door. For each filter, there is a bracket on either side holding the
dust filter in place, as shown in Figure 61.
3. Remove one bracket and loosen the other. The second bracket need not be removed.
4. Remove the old filter and replace with the new filter
5. Reinstall the bracket that was removed and tighten the other bracket.
Figure 61 Dust filter replacement
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.
Bracket Sems screw
Bracket