Emerson NX manual Detecting Trouble, Reporting a Problem, Items to check include

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Maintenance

4.5Detecting Trouble

It is important that the operator check the instrument readings if abnormal equipment performance is suspected. Any metered value that differs appreciably from normal could mean an impending malfunction and should be investigated.

4.5.1Items to check include:

•If the UPS has not operated on battery power during the last 10 hours, the batteries should require little charging current. Battery mimic should indicate normal DC voltage with the battery charge current no more than 1% of maximum discharge current.

•Input current on each phase should be within 10% of the average input current.

•Alarm messages indicate malfunction or impending malfunction. A daily check of the Display Screen will help to provide an early detection of problems.

•Tracing a problem to a particular section is facilitated by alarm messages and the metered parameter indications.

NOTICE

Risk of recurring problem. Can cause degraded performance and equipment damage.

If the UPS system has an open fuse, the cause should be determined before replacing the fuse. If the cause is not corrected, it could recur. Contact Liebert Services for assistance.

4.6Reporting a Problem

If a problem occurs within the UPS, review all alarm messages along with other pertinent data. Contact Liebert Services at 1-800-LIEBERT to report a problem or to request assistance.

4.7Upstream Feeder Circuit Breaker Setting Inspections

During normal UPS operations, short-term overload current demand from the bypass source may reach 10 times the UPS output current rating. This overload current demand may be caused by the magnetizing inrush current of one or more downstream transformers (i.e., power distribution units) or faults on downstream branch circuits. The instantaneous trip point(s) of the upstream bypass feeder breaker(s) must be set to support these temporary overloads. The magnitude of short-term overload bypass current demand is typically six to eight times the UPS current rating, but must be determined by analysis on a per-site basis. This analysis, generally known as an End-to-End Fault Coordination Study, must be done by a registered professional engineer experienced in this activity and familiar with local codes and related requirements.

Liebert strongly recommends periodic inspections of the bypass feeder breaker instantaneous trip settings, as well as the module input (rectifier) feeder breaker trip settings, to ensure that they are correct. For a variety of reasons, although typically during circuit breaker maintenance procedures by others, trip settings have been known to be inadvertently left improperly set. Correct trip setting of these circuit breakers is most important to achieving high-availability from your Liebert UPS system.

For further information regarding proper trip settings for your feeder breakers, call 1-800-LIEBERT.

NOTE

The instantaneous trip setting of the breaker feeding the UPS bypass input should be high enough to accommodate short-duration overloads. The bypass static switch power path inside the UPS can draw up to 10 times the system’s rated current for up to three cycles.

NOTE

While Emerson can provide typical guidelines, the responsibility for the proper breaker trip settings outside the Emerson-manufactured UPS equipment resides with the owner. Contact Liebert Services at 1-800-LIEBERT for further information.

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Liebert®NX™

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Contents Liebert NX Product Warranty Registration Table of Contents Specifications MaintenanceOptions Figures Page Important Safety Instructions Battery Cabinet Precautions General Description Typical single module UPS system one-line diagramMaintenance Bypass Normal ModeBypass Mode Battery ModeOptions Main component locations-225 to 300kVA Liebert NX FeaturesFront Doors Removed Main display screen, typical Main Display Screen Touchscreen NavigationSystem Status Measures Menu Rectifier Bypass Inverter Chg/Boost Battery LoadStatus Events Log MenuBattery Status Battery MenuBattery Test Battery parameters Battery MeasuresLife menu Life MenuAbout Menu Settings MenuAnimated One Line Mimic Rectifier Functional BlockLoad on bypass, UPS available Load on BypassOff DC Source Input Power Failure-Load on DC SourceManual Operations-All Systems Remote Emergency Power OffStartup-Single Module System Startup-1+N System Retransfer Procedure Transfer ProcedureLoad Transfer and Retransfer-Single Module System 6 1+N System Transfer load from UPS to Bypass Shut Down-Single Module UPS System 7 1+N System Transfer load from Bypass to UPS9 1+N System Shutdown Load Transfer-1+N System Add a UPS to the System Collective Load Transfer-1+N System Remove a UPS from System CollectiveOverloads Without Transfer Automatic OperationsCurrent-versus-time curves of overload capacity Automatic Transfers to Bypass Overload Condition Automatic Transfers to Bypass, UPS System FaultsAutomatic Retransfers to UPS MopUPS Shutdown and Monitoring Software Remote Alarm UnitConnectivity Manage UPS AdapterConnectivity combinations Available Selectable Output Contacts Available Selectable Input ContactsSafety Precautions Training Liebert ServicesMaintenance Agreements The Signature Program Professional StartupRecord Log Routine MaintenanceAir Filters Component Expected Life Replace Battery MaintenanceUPS component service life Limited Life ComponentsBattery Safety Precautions Number of Cells Nominal Float 240 480 527 Matching Battery Cabinets-OptionalBattery voltage, nominal and float Battery Voltage, VDCRetorque Value Battery retorque valuesBattery Mfr Battery Model # In-lb N-m Other DC SourcesItems to check include Reporting a ProblemUpstream Feeder Circuit Breaker Setting Inspections Detecting TroubleOther DC Sources Battery OperationEnvironmental specifications DC SourcesPhysical specifications Electrical specificationsSpecifications LiebertNX Page Care Ne tIs t Twor k
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