American Power Conversion MX28B4800 System Management, System Output Capacity, System Current

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5.3. System Management

System Output Capacity

The power plant has two basic configurations:

The MX28B-1200/2400 supplies a maximum of 2400 amps or 2350 amps with N+1 redundancy. The housing for this configuration provides two rectifier bays with integrated DC output distribution, a control unit, and expansion bays for added DC output distribution.

The MX28B-1200/4800 supplies a maximum of 4800 amps or 4750 amps with N+1 redundancy. The housing for this configuration provides four rectifier bays with integrated DC output distribution, a control unit, and expansion bays for added DC output distribution. The difference between the MX28B-1200/2400 Main Bay and the MX28B-1200/4800 Main Bay is the size and configuration of the power bus and battery shunt. All other parts are the same for both configurations.

System Voltage Control

The PSCU monitors and adjusts the system voltage. It uses a voltage trim input to the rectifier to precisely control the DC output voltage. In the event of PSCU removal or failure, the shelf rectifier controller card will control the voltage at a programmed default level. In the event of shelf rectifier controller card failure, the individual rectifiers will default to the analog voltage level preset with the front panel “float’ adjustment pots.

System Current

The PSCU monitors individual rectifier currents and displays total system current as a sum of rectifier currents. Load current can be found by adding battery current to system current. Battery Current is positive when the battery is discharging.

Sys Current + Batt current = Load Current

For example, if the battery is charging the Batt Current reading could be (–) 40 A, Sys Current reading could be 120 A. Load Current would be:

Sys Current + Batt current = Load Current 120A + (-) 40 A = 80 Amps.

If the battery is discharging the Batt Current reading would be 40 A, Sys Current would reading would be 40 A. Load voltage would be:

Sys Current + Batt current = Load Current 40A + 40 A = 80 Amps.

MX28B1200/2400 MX28B1200/4800 –48 VDC User’s Manual

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Contents VDC Power Systems Table of Contents Commissioning and Preventive Maintenance APC Worldwide Customer Support Limited Product Warranty Revision History Revision Date DescriptionSafety First General PrecautionsGeneral Information How to Use This ManualIntroduction 1 MX28B-1200 -48 VDC Power Plant Rectifier Bay 2 MX28B Block Diagram Unpacking Equipment InstallationMechanical Installation Room / LocationPower Bus Connections Mounting2 MX28B-1200-2400 has a maximum Circuit Breaker/LVD Ribbon Cable Connections 5 Circuit Breaker / LVD Expansion BoardVentilation AC Power ConnectionsFuse Alarm Ribbon Cable Connections 1 AC Input Wiring Battery Connections Planning the Battery InstallationConnecting the Battery Cables 1 Battery Cable Connection Locations2 Battery Probe Connection DC System GroundingDC Power Output Over-Current Protection DC Plug-in Circuit BreakersBreaker Part Number Rating 2 Plug-in Circuit Breakers DC Bolt-in Circuit Breakers 4 Bolt-in Circuit BreakersTelecom Fuses 5 Telecom FusesInstallation of Circuit Breakers and Fuses Plug-in Circuit Breaker InstallationBolt-in Circuit Breaker Installation 2 Circuit Breaker Alarm WiringTelecom Fuse Installation GMT Fuse InstallationCircuit Breaker Connections 1 to 50 Amps Load ConnectionsCable Size Considerations Circuit Breaker Connections 60-100 AmpsFront Panel DB9 Connection Monitoring and Relay Output ConnectionsGMT Fuse Connections Smart Cable DB9 ConnectionRJ45 Ethernet Connector Relay Output ConnectionsExternal Alarm Input Connections NO-NC-CRectifier Module Installation Battery Visual and Safety Inspection Commissioning and Preventive MaintenanceElectrical Installation Pre-Commissioning InspectionInitial Set-up AC Power UpCommissioning Rectifier Test DC Power UpBattery Power Up LVD TestUser Inputs Battery Temperature CompensationCircuit Breaker/ Fuse Test Output RelaysFinal Inspection Rectifier Management OperationTechnical Description System Voltage Control System ManagementSystem Output Capacity System CurrentBattery Charging and Protection Battery ManagementSystem Status and Alarm Reporting DC DistributionFront Panel User Interface Controls and IndicatorsBattery/Load Low Voltage Disconnect Status Alarms System Modules Batt PIN OEM Parameter Locations, Descriptions, and Default ValuesAddress Alarm ItemNo Alarms Switzer70.0 C Batt HT AlmBatt HT Thr Batt HV AlmCir Bkr 72 Almm+ Cir Bkr 1 Alm m+Major Comp HkneeHw Batt C Almm+ Fuse 1 AlmFuse 16 Alm Minor48.00 LVD ResetLVD Option LVD TripOut-Rly 6 Dly m+ Out-Rly 1 Dly m+Sec Relay MajorMRF28H54 DisableRect 1 Desc Rect 1ofN Almm+Sys LT Alm Sys HV AlmSys HV Thr Sys LT ThrTime 90025SYS MS System Module SET-ALM Setup DA Control Unit Menu StructureV e l C o n d L e v e l I r d L e v e l U r t h L e v e l SYS Sysin Modrec AM Info Modfuse LM Alias Fuse MOD Modlvd Modlvd LM Param Section Alarm Outputs Output RelaysFront Panel LED Indicators External Alarm Inputs Input Relays Description Command and Monitoring ProtocolRemote Monitoring Physical ConnectionsEquipment Preventive MaintenanceSystem Visual and Safety Inspection InspectionRectifier Current Test TestSystem Voltage Test Battery Current Test Rectifier Alarm TestSystem Temperature Test Rectifier Current Share TestBattery Temperature Test Battery Preventive Maintenance ProcedureFinal Inspection 1MRF28H54BV Rectifiers SpecificationsAC Input 1MRF28H54BV50 RectifiersVDC RectifiersPower Shelf Control Unit Compliance MechanicalEnvironmental Toll Free APC Worldwide Customer SupportUS and Canada WorldwideLimited Product Warranty