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Liebert NXL UPS
During start-up, power is supplied to the critical load through the UPS (internal) bypass
line while the UPS system is being energized. Depending on the reason for the UPS system
shutdown, power may be present in the bypass line. To determine this, check the
Monitor/Mimic Display screen after control power is available.
1) Before you apply power to the UPS modules, determine the position of the following
isolators and switches:
•
Input Isolator (Q1)—Verify that this breaker on the front of the UPS cabinet
(Figure 2) is in the Open position.
•
Module Battery Disconnect (BCB)—Verify that this external breaker is open or
tripped. If battery cabinets are used, verify that breakers on all the cabinets are
open.
•
Bypass Isolator (Q2)—This breaker (Figure 2) should be open.
NOTE
Power to the critical load may already be supplied through this breaker.
•
Output Isolator (Q4) — This breaker (Figure 2) should be open.
NOTE
If the system was shut down in response to an "Emergency Off", there may be alarm
messages on the touch screen that describe system conditions before (or at the time
of) the shutdown.
Some or all of the alarm conditions may have been resolved. To clear these alarm
messages, turn off control power (see Figure 2). Wait at least 10 minutes for the control
power circuitry to completely de-energize. After 10 minutes, turn control power back on
and wait two minutes before continuing.
Risk of electrical shock and high short circuit current. Can cause equipment
damage, personal injury and death. If the UPS has been shut down for
maintenance, verify that all of the UPS system doors are closed and latched. All
test equipment must be removed from the system. All electrical connections
2) Power must be provided to the UPS controls so the operator can use the display touch
screen and so the system logic can function properly. The display touch screen may be
used to monitor UPS system status, even when the UPS modules are not operating.
This will be the usual condition unless you are recovering from a maintenance
shutdown.
Page 40
Operation and Maintenance Manual
WARNING
WARNING
WARNING
WARNING
must be secure.
250-300-400-800kVA
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