Inverter Stop-Active Eco Mode; Overload-Active Eco Mode; Emergency-Due To Source Supply Failure Or Variance Beyond Tolerance Limits, Active Eco; Mode - Vertiv Liebert NX Operation And Maintenance Manual

2.6.4 Inverter Stop—Active Eco Mode
If the inverter is stopped for any reason, there will be no transfer to the conditioned line and the load will continue
to be supplied by the bypass source. The source voltage and frequency values must be within the tolerance
limits specified.
2.6.5 Overload—Active Eco Mode
If an overload lasting longer than the maximum capacity specified for the bypass static switch, the load is
maintained on the bypass source and a message will appear on the LCD to warn about the potential risk related
to this condition. This default behavior can be changed (via a service-accessible firmware setting) to force a load
transfer to the conditioned line (similar to that described below), even if the bypass source is available. In the
event of an overload in conjunction with an unsuitable bypass source supply, the Liebert NX will transfer the load
from the bypass source to the conditioned line (assuming that the UPS was operating from the bypass source)
and the inverter will continue to supply the critical load for a period that depends on the degree of the overload
and the UPS rating. Visual and audio alarms alert the user to the problem.
2.6.6 Emergency—Due to Source Supply Failure or Variance Beyond Tolerance Limits, Active Eco Mode
If the Liebert NX is supplying the load via the bypass source and the bypass source supply varies beyond
tolerance levels (adjustable using the software), the load will be transferred from the bypass source to the
conditioned line. The load is powered from the source via the rectifier and inverter, (provided the input source
remains within the specified tolerances). Should the input source fall below the lower limit, the batteries will be
used to power the load via the inverter. The user is alerted to the battery discharge by visual and audio alarms
and the remaining autonomy is displayed on the LCD. During this process, it is possible to extend the remaining
autonomy by switching off nonessential loads.
2.6.7

Return to Normal Conditions-Active Eco Mode

When the source supply returns to within tolerance limits, the Liebert NX will continue to supply the load via the
conditioned line for a period that depends on the bypass source failure rate (the conditioned line draws power
from the source, not the battery). When the bypass source has stabilized, the Liebert NX resumes powering the
load from the bypass source. At this time the battery charger automatically begins to recharge the battery so
that maximum autonomy is available in the shortest possible time.
2.7 M O
ANUAL PERATIONS
The Liebert NX UPS is designed to function unattended by an operator. The system control logic automatically
handles many important functions, as explained in 2.8 - Automatic Operations. Other procedures must be
performed manually.
Manual procedures available to the operator include startup, load transfers and shutdowns. These are performed
with the touchscreen and some manually operated circuit breakers and switches.
This section lists typical step-by-step instructions.
• Startup—Including initial startup, recovering from input power failure, recovering from DC source shutdown and recovering
from shutdowns for emergencies or maintenance.
• Load Transfers—Including transfers from UPS to bypass and retransfers from bypass to the UPS system.
• Maintenance Bypass Load Transfers—Including transfers from internal bypass to maintenance bypass and transfers from
maintenance bypass to internal bypass.
• Shutdowns-Including module shutdowns for maintenance and emergency shutdowns.
Figures 34 through 39 illustrate the possible maintenance bypass configurations for Liebert NX systems.
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Vertiv Liebert NX 225-600kVA Operation Manual
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Operation
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