Emerson Liebert NXL 250 kVA, Operation And Maintenance Manual

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3.6.2 Intelligent Paralleling Target Area
The Intelligent Paralleling Target Area is the Number of Redundant Modules that fall between the
Minimum System Redundancy setting and the internal Maximum System Redundancy (Minimum
System Redu 1.25).
• The Maximum Number of Redundant modules is designed to provide hysteresis so that modules
are not started and stopped when the load oscillates a few percentage points.
• When the Number of Redundant Modules goes above the Target Area, the system puts one or
more modules into standby operation until the Number of Redundant Modules is inside the
Target Area.
• When the Number of Redundant Modules goes below the Target Area, the system puts one or
more modules back into normal operation until the Number of Redundant Modules is inside the
Target Area or all available modules are supporting the load.
3.6.3 Conditions to Activate Intelligent Paralleling
All of the following conditions must be true for the system to activate Intelligent Paralleling
• Intelligent Paralleling is enabled.
• The Number of Redundant Modules is above the Intelligent Paralleling Target Area for longer
than the Shutdown Delay setting.
• The Critical Load is on UPS.
• The module is part of the collective.
• No modules are on DC source.
• The module is selected as the next module to activate Intelligent Paralleling.
• Input Contact Interface 2 (Channel 7) event is not active
3.6.4 Conditions to Suspend Intelligent Paralleling
Suspend Intelligent Paralleling for a Module
At least one of the conditions below must be true for the module to terminate Intelligent Paralleling
at a module and return the module to normal operation:
• Intelligent Paralleling is disabled.
• The Number of Redundant Modules is below the Intelligent Paralleling Target Area.
• One or more modules is on DC source.
• Module is removed or user has issued a UPS/System shutdown.
• All Module Termination is initiated.
• Maximum Time Module In Standby has expired.
• Inhibit IP Standby (Input Contact Interface 2, Channel 7) event active.
Suspend Intelligent Paralleling for the system
Any of the following conditions will terminate Intelligent Paralleling and place all modules in normal
operation:
• All modules transfer to bypass
• System overload
• One or more modules go on DC source
3.6.5 Intelligent Paralleling Module Selection
Intelligent Paralleling Module Activation
The next module chosen to activate Intelligent Paralleling and put into standby operation will be
done by cycling through the Module Numbers, starting with Module 1.
• The module chosen to be next must be a part of the collective (load on UPS). Otherwise, this
module will be skipped.
• When the last Module Number is chosen, the next module will be Module 1 (start cycle over).
Intelligent Paralleling Module Termination
The next module chosen to terminate Intelligent Paralleling normally and put back into normal
operation will be done by selecting the module that has had Intelligent Paralleling active the longest.