Liebert FPX930 User Manual
POWER PROTECTION
Series 600T™ UPS
Multi-Module Three Phase
65 kVA to 750 kV A; 60 Hz
Operation & Maintenance
Manual
TABLE OF CONTENTS
1.0 INTRODUCTION
1.1 System Description . . . ..............................................................3
1.2 Reliability . .......................................................................7
1.3 Safety Precautions..................................................................8
1.4 Modes of Operation. . . ..............................................................9
1.4.1 Normal(LoadonUPS)...............................................................9
1.4.2 InputPowerFailure..................................................................9
1.4.3 Recharge..........................................................................9
1.4.4 Overload..........................................................................9
1.4.5 Redundant . . . ......................................................................9
1.4.6 Bypass(Internal)....................................................................9
1.4.7 MaintenanceBypass.................................................................9
1.4.8 Off-Battery ........................................................................9
1.5 Operator Controls .................................................................10
1.6 Options..........................................................................12
2.0 THEORY OF OPERATION
2.1 General Component Descriptions . ....................................................13
2.2 Detailed C omponent Descriptions. ....................................................15
2.2.1 Controls..........................................................................15
2.2.2 Rectifier/Charger...................................................................16
2.2.3 BatteryChargingCircuit.............................................................17
2.2.4 Inverter ..........................................................................18
2.2.5 StaticBypass......................................................................19
2.2.6 Redundant Mode ...................................................................22
3.0 OPERATION
3.1 DisplayScreenandOperatorControls.................................................23
3.1.1 MasterMenuScreen................................................................29
3.1.2 Monitor/MimicDisplayScreen........................................................31
3.1.3 Walk-InDisplayScreen..............................................................40
3.1.4 StatusReportsScreens ..............................................................41
3.1.5 SystemConfigurationScreens ........................................................48
3.1.6 AlarmLimitSettingsScreen..........................................................55
3.1.7 LoadTransferProceduresScreen......................................................57
3.1.8 Start-UpProceduresScreen...........................................................58
3.1.9 ShutdownProceduresScreen.........................................................60
3.1.10 Battery Time Screen (Module Only)....................................................62
3.1.11 MeterCalibrationScreen ............................................................65
3.1.12 BatteryEqualizeScreen .............................................................66
3.1.13 AlarmandStatusMessages...........................................................67
3.1.14 CommunicationInterfaces ...........................................................75
3.2 Modes of Operation. . . .............................................................78
3.2.1 LoadOnBypass ...................................................................78
3.2.2 OKToTransfer....................................................................79
i
3.2.3 MomentaryOverloads..............................................................81
3.2.4 InputPowerFailure(LoadOnBattery).................................................82
3.2.5 OneModuleOff-Line...............................................................83
3.2.6 OffBattery.......................................................................84
3.2.7 Emergency Modules Off . ...........................................................85
3.2.8 EmergencyPowerOff ..............................................................86
3.2.9 SystemShutdown..................................................................87
3.2.10 MaintenanceBypass................................................................88
3.3 ManualProcedures................................................................90
3.3.1 Start-UpProcedure.................................................................91
3.3.2 LoadTransferProcedures............................................................97
3.3.3 ShutdownProcedures...............................................................99
3.4 Automatic Operations ............................................................103
3.4.1 Overloads(WithoutTransfer)........................................................103
3.4.2 AutomaticTransferstoBypass.......................................................104
3.4.3 AutomaticRetransferstoUPS.......................................................104
3.4.4 Automatic Module Off-Line.........................................................105
3.4.5 Automatic Emergency Modules Off...................................................105
4.0 MAINTENANCE
4.1 Safety Precautions ...............................................................106
4.2 LiebertCustomerServiceandSupport...............................................108
4.3 Routine Maintenance .............................................................109
4.3.1 RecordLog......................................................................109
4.3.2 AirFilters.......................................................................109
4.3.3 BatteryMaintenance ..............................................................110
4.3.4 TorqueRequirements..............................................................115
4.4 Detection of Trouble .............................................................115
4.5 ReportingaProblem ............................................................. 116
4.6 Corrective Actions ...............................................................116
4.7 Recommended Test Equipment ..................................................... 116
5.0 SPECIFICATIONS AND RATINGS
5.1 Rating.........................................................................117
5.2 Environmental Conditions ........................................................ 118
5.3 Adjustments . . . .................................................................119
5.4 BatteryOperation................................................................ 119
5.5 ElectricalSpecifications ..........................................................120
ii
FIGURES
Figure 1 Multi-Module UPS, 65-80 kVA (left) and 100-500 kVA (right) ...................................3
Figure 2 Multi-Module 500-750 kVA UPS ..........................................................5
Figure3 SystemControlCabinets(SCCs) ..........................................................6
Figure4 SCCControlsandDisplayScreenwithExampleoftheMonitor/MimicScreen .....................10
Figure5 ModuleControlsandDisplayScreenwithExampleoftheMonitor/MimicScreen...................11
Figure6 UPSModuleBlockDiagram.............................................................14
Figure7 SystemControlCabinet(SCC)BlockDiagram ..............................................19
Figure8 OperatorControls,65to80kVA(left)and100to500kVA(right) ...............................24
Figure9 SystemControlCabinetOperatorControls(SCCBPictured) ...................................25
Figure10 Series600TUPSandSCCOperatorControlPanels ..........................................26
Figure11 SwitchesBehindSCCControlPanelDoor ..................................................27
Figure12 MenuTree ...........................................................................28
Figure 13 Master Menu Screens, SCC (above) and Module (below).......................................29
Figure14 SCCMonitor/MimicDisplayScreen ......................................................31
Figure15 ModuleMonitor/MimicDisplayScreen ....................................................33
Figure16 Monitor/MimicDisplayScreenExamples:NormalPowerFlowe.................................35
Figure17 Monitor/MimicDisplayScreenExamples:UtilityFail.........................................36
Figure 18 Monitor/Mimic Display Screen Examples: Load on Bypass, UPS Modules On and Charging Battery . . . . 37
Figure 19 Monitor/Mimic Display Screen Examples: Load on UPS, One UPS Module Off Line ................38
Figure20 Monitor/MimicDisplayScreenExamples:LoadonBypass,AllUPSModulesOffLine..............39
Figure21 Walk-InDisplayScreenDuringStart-Up ...................................................40
Figure22 StatusReportsScreen ..................................................................41
Figure23 PresentStatusReportScreens ............................................................42
Figure24 EventHistoryReportScreen.............................................................43
Figure25 HistoryStatusReportScreens............................................................44
Figure26 BatteryCycleMonitorScreen ............................................................46
Figure27 BatteryCycleMonitoringSummaryScreen .................................................47
Figure28 TypicalDataonDischargeCyclesof91to240SecondsDuration................................47
Figure29 SCCSystemConfigurationScreen ........................................................48
Figure30 DateScreen ..........................................................................49
Figure31 TimeScreen..........................................................................50
Figure32 AutoDialSettingScreen................................................................51
Figure33 ModemBaudRate.....................................................................52
Figure34 MaximumAuto-RetransferAttemptsScreen ................................................53
Figure35 ModuleAlarmLimitSettingsScreen ......................................................55
Figure36 LoadTransferProceduresScreen .........................................................57
Figure37 SCCStart-UpProceduresScreen .........................................................58
Figure38 ModuleStart-UpProceduresScreen ......................................................59
Figure39 SCCShutdownProceduresScreen ........................................................60
Figure40 ModuleShutdownProceduresScreen......................................................61
Figure41 BatteryTimeScreenExample-15MinuteDischarge .........................................62
Figure42 BatteryTimeScreenExample-45MinuteDischarge .........................................63
Figure43 RangeofValuesforCalculatedBatteryTimes ...............................................64
Figure44 MeterCalibrationScreen................................................................65
Figure45 BatteryEqualizeScreen ................................................................66
Figure46 SCCStatusandAlarmMessageAreas .....................................................67
Figure47 LoadonBypass(UPSNotAvailable) ......................................................78
Figure48 LoadonBypass(UPSAvailable) .........................................................79
Figure49 LoadonUPS(BypassAvailable) .........................................................80
iii
Figure50 MomentaryOverload(PulsedStaticBypassSwitch)..........................................81
Figure51 InputPowerFail(LoadonBattery) .......................................................82
Figure52 OneModuleOff-Line(LoadonUPS) .....................................................83
Figure53 LoadonUPS(BatteryNotAvailable) .....................................................84
Figure 54 Emergency Modules Off ................................................................85
Figure55 EmergencyPowerOff .................................................................86
Figure56 SystemShutdown .....................................................................87
Figure57 LoadonMaintenanceBypass(TwoBreakers)...............................................88
Figure58 LoadonMaintenanceBypass(ThreeBreakers)..............................................89
Figure59 SCCStart-UpProceduresScreen .........................................................93
Figure60 ModuleStart-UpProceduresScreen ......................................................95
Figure61 LoadTransferProceduresScreen.........................................................97
Figure62 SCCShutdownProceduresScreen........................................................99
Figure63 ModuleShutdownProceduresScreen ....................................................101
Figure64 Current-Versus-TimeCurveofModuleOverloadCapacity....................................103
TABLES
Table1 AlarmMessages-MeaningandCorrectiveAction ...........................................70
Table2 AlarmMessages-Summary.............................................................74
Table3 Series600TTerminalCommands.........................................................77
Table4 TorqueSpecifications(UnlessOtherwiseLabeled) ..........................................115
Table5 RecommendedTestEquipmentandTools..................................................116
iv
IMPORTANT SAFETY INSTRUCTIONS
Save These Instructions.
This manual contains importantinstructionsthat should be followed during installation and maintenance of your
Series 600T UPS and batteries.
WARNING
!
EXERCISE EXTREME CARE WHEN HANDLING UPS CABINETS TO
AVOID EQUIPME NT DAMAGE OR INJURY TO PERSONNEL. REFER TO
SEPARATE INSTALLATION MANUAL FOR EQUIPMENT HANDLING
INFORMATION AND INSTALLATION PROCEDURES.
FOLLOW ALL BATTERY SAFETY PRECAUTIONS IN 4.0 MAINTENANCE WHEN INSTALLING, CHARGING, OR SERVICING
BATTERIES. IN ADDITION TO THE HAZARD OF ELECTRIC SHOCK,
GAS PRODUCED BY BATTERIES CAN BE EXPLOSIVE AND SULFURIC
ACID CAN CAUSE SEVERE BURNS.
IN CASE OF FIRE INVOLVING ELECTRICAL EQUIPMENT,USE ONLY
CARBON DIOXIDE FIRE EXTINGUISHERS, OR OTHERS APPROVED
FOR USE IN ELECTRICAL FIRE FIGHTING.
EXTREME CAUTION IS REQUIRED WHEN PERFORMING
MAINTENANCE.
BE CONSTANTLY AWARE THAT THE UPS SYSTEM CONTAINS HIGH
DC AS WELL AS AC VOLTAGES. WITH INPUT POWER OFF AND THE
BATTERY DISCONNECTED, HIGH VOLTAGE AT FILTER CAPACITORS
AND POWER CIRCUITS SHOULD BE DISCHARGED WITHIN 30
SECONDS. HOWEVER, IF A POWER CIRCUIT FAILURE HAS
OCCURRED, YOU SHOULD ASSUME THAT HIGH VOLTAGE MAY
STILL EXIST AFTER SHUTDOWN. CHECK WITH A VOLTMETER
BEFORE MAKING CONTACT.
AC VOLTAGE WILL REMAIN ON THE SYSTEM B YPASS (SBB) AND UPS
OUTPUT CIRCUIT BREAKERS, AND THE STATIC BYPASS SWITCH,
UNLESS ASSOCIATED EXTERNAL CIRCUIT BREAKERS ARE OPENED.
CHECK FOR VOLTAGE WITH BOTH AC AND DC VOLTMETERS PRIOR
TO MAKING CONTACT.
WHEN THE UPS SYSTEM IS UNDER POWE R, BOT H THE OPERATOR
AND ANY TEST EQUIPMENT MUST BE ISOLATED FROM DIRECT
CONTACT WITH EARTH GROUND AND THE UPS CHASSIS FRAME BY
USING RUBBER MATS.
SOME COMPONENTS WITHIN THE CABINETS ARE NOT CO NNEC TED
TO CHASSIS GROUND. ANY CONTACT BETWEEN FLOATING
CIRCUITS AND THE CHASSIS IS A LETHAL SHOCK HAZARD.
EXERCISE CAUTION THAT THE TEST INSTRUME NT E XT E RIOR DOES
NOT MAKE CONTACT EITHER PHYSICALLY OR ELECTRICALLY
WITH EARTH GROUND.
1
OVERVIEW OF THIS MANUAL
The manual is organized so that information can be found quickly. Each major topic is separated by sections, and
the Table of Contents contains major headings within each section. The names of the sections and their contents
are described below.
1.0 - Introduction is a summary of the Series 600T UPS System. It describes some of the unique features and
benefitsof the S eries 600T,as well as the design principles and standardsthatLiebert follows in the manufacture
of each system. Descriptions of the Series 600T system and an overview of its functions are also included.
2.0 - Theory of Operationis an explanation of the major circuit groups of the Series 600T UPS. This section is
for individuals who want to know both the basics and the specifics of each major component. The text explains
how the UPS handles electrical disturbances and interruptions.
3.0 - Operation is written for facility personnel responsible for the operation of the system. It details the procedures required to s tart-up each module and the system, to transfer the load between the available s ources, and to
shut down each module and the system. Both manual and automatic operations are described. Operator controls
and displays, including the solid state liquid crystal display (LCD) screen, are illustrated and explained for the
UPS Module and for the Sys tem Control Cabinet (SCC).
4.0 - Maintenance lists routine maintenance checks and helps the user pinpoint and quickly resolve problems if
they arise.
5.0 - Specifications a nd Ratings gives detailedspecifications a bout the Series 600T UPS System. This technical
information is of use to installing contractors, engineers, and service personnel.
If you require assistance for any reason, c all the toll-free Liebert Global Services number: 1-800-543-2378. For
LGS to assist you expediently, please have the following information available:
Part Nu mbers:
Serial Nu mbers:
kVA Rating:
Date Purchased:
Date Installed:
Location:
Input Voltage:
Output Voltage:
BatteryReserve Time:
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
2
1.0 INTRODUCTION
1.1 System Description
The role of the parallel-redundant multi-module UPS system is to supply uninterruptible, clean power to the critical load. It maintains a full-voltage, low-distortion output, even if the utility source power sags or becomes distorted.
If there is an outage of the source power, the UPS m aintains power to the load until an alternate source of power
is activated, or until the original power source is restored. If input AC power is not restored, the UPS maintains
the load (with the battery plant) long enough that the critical e quipment can be shut down in an orderly manner.
The Series 600T UPS module displays the rate of battery discharge and calculates the amount of battery time
remaining based on the actual connected load. T he time that the battery will maintain the load depends on the
capacity of the battery backup plant and the size of the load.
The system control logic automaticallymanages critical bus operation. System logic is resident in Application
Specific Integrated Circuits (ASICs) for precise control and improved reliability.
If the critical load current exceeds the rated load of the S eries 600T UPS system, the control logic determines the
magnitude of the ove rload and reacts appropriately. Overloads are usually the result of inrush current requirements. The UPS system supports loads that are 150% of the rated load for up to 30 seconds and 125% of the
rated load for up to ten minutes. If the system is operating in the non-redundant mode (e.g., a UPS module is off
line), the overload limits are automatically adjusted.
Figure 1 Multi-Module UPS, 65-80 kVA (left) and 100-500 kVA (right)
If the load surpasses the overload capacity of the UPS, the load is automatically transferred to bypass without
interruption. When the load returns to within the UPS rating, it is either automatically or manually returned
Introduction 3
(retransferred) to the UPS. How and when the load is returned to the UPS depends on several factors: how long
the overload lasted, how many overload conditions occurred before transfer, whether there is an imminent failure
of any part of the UPS, etc. Refer to 3.4 - Automatic Operations.
In the unlikely event of a fault within the UPS, the SCC control logic, which continuously monitors all c ritical
circuitswithinthe UPS system, t ransfers the load to bypasswithoutinterruption and simultaneously sets off local
and remote a larms. If a fault is detected in an individual UPS module, that module is automatically disconnected
from the critical bus and shut down. A Mo dule Off Line status message will appear at the SCC display. The
module can be manually returned to service when the fault has been corrected.
If the multi-module UPS system is operating in the redundant mode (at least one extra module is available for the
connected critical load), t he load will remain on the UPS s ystem if one individual module is disconnected from
the critical bus (off line). If the UPS system is operating in the non-redundant m ode, the load will be automatically transferred to bypass if a module goes off line.
The Series 600T UPS display system provides precise monitoring of the UPS, fast alarm response, and quick
troubleshooting. For easy manual operations, menu-driven software provides access to several step-by-step help
screens. All operator functions are performed using menu-prompted displays and a minimum number of operator
controls. The System Control Cabinet includes external communication capability with both automatic dial-out
and dial-in features for early warning and diagnosis of abnormal conditions.
The system software allows the operator, or L iebert Global Services, to enter application specific information.
Overload, overvoltage, battery discharge, and shutdown limits can be set by the operator. In effect, the software
is tailored for each site.
The UPS system protects critical equipment from source power disturbances and outages, load faults, and UPS
malfunctions. This triple protection virtually eliminates computer and computing equipment downtime as a
result of utility source power problems.
4Introduction
Figure 2 Multi-Module 500-750 kVA UPS
Introduction 5
Figure 3 System Control Cabinets (SCCs)
Types of System Control Cabinets (SCCs)
• SCCT -- A stand-alone cabinet containing system control logic for up to six UPS modules, a static bypass
switch, manually operated disconnects for the static bypass switch, and two motor-operated system circuit
breakers.
• SCCB -- Similar to the SCCT, except that external sheet metal matches that of the UPS modules.
• SCCP -- Similar to the SCCB, except narrower and designed for two UPS modules.
• SCCI -- System controllogic and static bypass switch are integrated into a switchboard cabinet manufac-
tured by others, which also includes the system circuit breakers.
• SCCC -- An integrated configuration like the SCCI, but with a static switch rated for continuous duty.
6Introduction
1.2 Reliability
Reliability is the most importantdesign goal for Uninterruptible Power Systems. Liebert Series 600 UPS systems
have demonstrated reliability by achieving a field-proven critical bus MTBF in excess of one million hours. In
addition, our Quality Assurance program is certified to the requirements of ISO 9001 standards.
Liebert Large UPS systems are ETL listed to the requirements of UL 1778. All equipment and components are
manufactured to applicable UL, NEC, NEMA, ANSI, IEEE, and CSA standards and guidelines.
Designed for Success
The keys to reliability in the design of the UPS system are using conservatively rated components, minimizing
transfers to bypass, making operator controls understandable, and providing easy access for maintenance and
repair. Liebert UPS systems lead the industry in all these areas.
For example, the Series 600T can clear substantial overloads through the solid state static bypass switch without
transferring to the bypass source. By minimizing transfers to bypass, the Series 600T minimizes operation of circuit breakers and enhances system reliability.
As another example, the system control logic has been packaged into Application-Specific Integrated Circuits
(ASICs) to eliminate the failure-prone discrete logic boards used in other brands of UPS products. Furthermore,
these ASICs are isolated from heat-generatingcomponents to ensure optimal operating temperatures.
Other Factors to Consider
Reliability depends on more than just UPS module design. Improper installation can c ause any system to fail. To
prevent this, Customer Engineers from Liebert Global Services thoroughly inspect the installation of all our systems to ensure they are installed properly and operating within performance specifications.
Once a UPS is properly installed, you—the on-site equipment operator—are the most important factor in preventing critical bus failures or unplanned transfers to bypass. To make your task easier,the Series 600T UPS provides easy-to-follow, prompted instructions on the industry’s largest operator display screen.
If you ever need help, call Liebert Global Services (24 hours a day at 1-800-543-2378). Your attention to proper
installation, operation, and periodic maintenance will ensure that your mission-critical operations receive the
best possible protection from electrical disturbances and outages.
Introduction 7
1.3 Safety Precautions
Read this manual thoroughly, paying special attention to the s ections that apply to you, before working with the
UPS. Also read the battery manufacturer’s manual before working on or near the battery.
Under typical operation and with all UPS doors closed, only normal safety precautions are necessary. The area
around the UPS system a nd Battery should be kept free from puddles of water, excess m oisture, or debris.
Special safety precautions are required for procedures involving handling, installation, and maintenance of the
UPS system or the battery. Observe precautions in the separate Installation Manual before handling or installing
the UPS system.Observeprecautions in 4.0 - Maintenance, before as well as during performance of all maintenance procedures. Observe all battery safety precautions in 4.0 - Maintenance before working on or near the
battery.
This equipment contains several circuits that are energized with high voltage. Only test equipment designated for troubleshooting should be used. This is particularly true for oscilloscopes. Always check with an AC
and DC voltmeter to e nsure safety before making contact or using tools. Even when the power is turned Off, dangerously high potentials may exist at the capacitor banks. Observe all battery precautions when near the battery
for any reason.
ONLY qualified service personnel should perform m a in tenance on the UPS system. When performing
maintenance with any part of the equipment under power, service personnel and test equipment should be standing on rubber mats. The service personnel s hould wear insulating shoes for isolation from direct contact with the
floor (earth ground).
Unless all power is removed from the equipment, one person should never work a lone. A second person should
be standing by to assist and summon help in case an accident should occur.This is particularly true when work is
performed on the battery.
Three types of messages are used throughout the manual to stress important text. Carefully read the t ext below
each Warning, Caution, and Note and use professional skills a nd prudent care when performing the actions
described by that text.
A Warning signals the presence of a possible serious, life-threatening condition. For example:
WARNING
!
LETHAL VOLTAGES MAY BE PRESENT WITHIN THIS UNIT EVEN
WHEN IT IS APPARENTLY NOT OPERATING. OBSERVE ALL
CAUTIONS AND WARNINGS IN THIS MANUAL. FAILURE TO DO SO
COULD RESULT IN SERIOUS INJURY OR DEATH. DO NOT WORK ON
OR OPERATE THIS EQUIPMENT UNLESS YOU ARE FULLY QUALIFIED
TO DO SO!! NEVER WORK ALONE.
A Caution indicates a c ondition that could seriously damage equipment and possibly injure personnel. For
example:
CAUTION
!
Make sure you understand the proper sequence before operating any c ircuit
breaker. Operating a Maintenance Bypass circuit breaker out of sequence could
cut off power to the critical lo a d.
A Note emphasizes important text. If the note is not followed, equipment could be damaged or may not operate
properly. For example:
NOTE
If the UPS system has a blown fuse, the c ause should be determined before you
replace the fuse. Contact Liebert Global Services.
8Introduction
1.4 Modes of Operation
Refer to 2.0 - Theory of Operation and 3.0 - Operation for more details.
1.4.1 Normal (Load on UPS)
The utility AC source provides power to the rectifier/charger in each UPS module. Each rectifier/charger c onverts the utility AC power to DC and supplies DC power to the UPS module inverter while simultaneously float
charging the battery plant. Each UPS module inverter converts DC to AC and furnishes AC power to the critical
bus. The System Control Cabinet (SCC) is the tie point for the paralleled modules and monitors a nd controls the
critical bus performance.
1.4.2 Input Power Failure
If the utility source power fails or is outside the acceptable range, the battery plant becomes the primary supplier
of DC power to the inverter.
1.4.3 Recharge
After the utility source power is restored, or an alternate power source becomes available, each rectifier/charger
slowly walks-in to once again power the inverters a nd recharge the battery plant.
1.4.4 Overload
Overloads in critical systems may be caused by inrush currents during connected equipment start-up or by faults
in the critical load. The Liebert Series 600T UPS system can maintain full output voltage regulation while sustaining the following overloads:
• Up to 150% for 30 seconds
• Up to 125% for 10 minutes
• Up to 104% for an indefinite period of time
Also, for clearing momentary faults above 155% of rated SCC current, the static switch turns on for 40 milliseconds to supply power from the bypass source. Up to 1000% of the rated current can be supplied for less than one
cycle, while up to 500% of rated load can be sustained for the full 40 milliseconds of pulsed-parallel operation.
The critical load remains on the UPS modules for the a bove conditions. If the UPS system overload capacity is
exceeded, an automatic transfer to bypass is initiated, which closes the system bypass circuit breaker (SBB) and
opens the UPS output c ircuit breaker.
Whenever you have an overload condition, you should determine the cause of the overload.
1.4.5 Redundant
If the multi-module UPS system includes one more module t han the number re quired to supply the critical load,
the UPS system can operate in the redundant mode. This means that the load will remain on the UPS system if
one of the modules is disconnectedbecause of an overload, an internalfault, or for maintenance.If the additional
module is not included in the s ystem design, or if the additional module is disconnectedfrom the critical bus, the
UPS system operates in the non-redundant mode.
1.4.6 Bypass (Internal)
The SCC control logic initiates a n automatic transfer to the bypass source if the overload-current-versus-time
curve is exceeded or if specified UPS system faults occur. You can also manually transfer the load to the bypass
(without interruption) if you must take the UPS module out of service for maintenance.
The SCC internal maintenance bypass will allow most key componentsand operating m odes to be checked without disturbing the critical bus. However, certain key power-carrying components, such as the output and bypass
circuit breakers, w ill require c omplete system shutdown or isolation through an external maintenance bypass
cabinet for 100% service.
1.4.7 Maintenance Bypass
The installation of a Maintenance Bypass Cabinet, Panelboard or Switchboard is recommended to allow you to
totally isolate the UPS from all power sources. Use of the Maintenance Bypass is described in 3.0 - Operation.
1.4.8 Off-Battery
The battery plant can be disconnected from the rectifier/charger by using an external Module Battery Disconnect
(MBD circuit breaker). The UPS module continues to function normally, though it does not have power outage
back-up capabilityuntil the battery plant is reconnected.
Introduction 9
1.5 Operator Controls
The Liebert Series 600T UPS System Control Cabinet (SCC) a nd each individual module are equipped with a
microprocessor-based Operator Display Screen and Control Panel designed for convenient and reliable operation.
The front panel location of the monitoring and control system enables the user to quickly identify the current status of the UPS and to perform most of the manual operations. The operator display screen is driven by an easyto-follow menu-prompted software program that controls and monitors the UPS system.
Figure 4 SCC Controls and Display Screen with Example of the Monitor/Mimic Screen
The operator controls and Monitor/Mimic screen for the System Control Cabinet (SCC) are shown in Figure 4.
The controls and display screen for e ach UPS module are shown in Figure 5. Each cabinet (SCC or module) has
the displays and controls required to monitor and perform its functions.
Figure 4 shows a three-module system designed for redundant operation. A multi-module UPS system m ay
include up to six (6) modules for each SCC.
Detailed instructions on how to interpret the displays and use the controls are in 3.0 - Op eration.
10 Introduction
Figure 5 Module Controls and Display Screen with Example of the Monitor/Mimic Screen
Introduction 11
1.6 Options
A number of standard pre-designedoptions are available from Liebert for your UPS system. De scribed below are
the most frequently provided options. Note that the battery items (1-3) are required to complete the UPS system.
The remaining options provide improved system performance or convenience.
1. Battery
The batteries provide power in the event of a power outage. The Liebert UPS can use a variety of battery
types, provided the battery plant is designed for the UPS DC voltage range and the load requirements of
your application.
2. BatteryRacks or Cabinets
The battery racks are specifically designed for stationary service batteries. They are painted with electrolyteresistant paint for corrosion resistance. Battery cabinets are available for 150 through 600 kVA modules.
3. Module Battery Disconnect
The UPS system utilizesa separate Module Battery Disconnect for remotely located batteries.A sensing circuit in the UPS module, set at the battery low voltage limit, trips the Module Battery Disconnect to safeguard the battery from excessive discharge.The Module Battery Disconnect has an undervoltage release
mechanism designed to ensure that during any shutdown or failure mode all battery potential is removed
from the UPS system
4. Input Distortion Filter
This filter reduces rectifier input current reflected harmonic distortion to less than 7% THD, and less than
4% THD for m odules with the optional 12-pulse rectifier. The filter is factory installed within the UPS. This
filter also improves the input power factor to better than 0.92 lagging.
5. 12-Pulse Rectifier
Certain models may be ordered with the optional12-pulse rectifier section.Thisprovides input isolation and
reduces reflected input current THD to less than 9%, or less than 4% with optional input filter.
6. Isolation Transformers
An optional rectifier input isolation transformeris available in a matching transformer cabinet. A bypass isolation transformer is also a vailable.
7. Three Breaker M aintenance Bypass
This switchboard provides make-before-break maintenance bypass. It includes: UPS Bypass Input Breaker
(BIB), Maintenance Bypass B reaker (MBB), and Maintenance Isolation Breaker (MIB).
8. Two Breaker Maintenance Bypass
This switchboard provides make-before-break maintenance bypass. It includes: Maintenance Bypass
Breaker(MBB) and Maintenance Isolation Breaker (MIB).
9. Load Bus Synchronization (LBS)
The Load Bus Sync (LBS) option keeps two independent UPS systems (and therefore their critical load
buses) in sync, even when the modules are operating on batteries or asynchronous AC sources. This means
that critical loads connected to both load buses through a Static Bus Transfer Switch can be switched seamlessly between the two.
10. SiteScan CentralMonitoring System
Liebert manufactures a central monitoring system that automaticallydisplayskey UPS measurements and
alarms, as well as data from a variety of sensors. This monitoring system signals alarms so corrective action
can be taken. Events and data can be printed in hard c opy. Data can be logged for analysis.
11. Remote Monitor Panel
The UPS system may also be provided with an optional Remote Monitor Panel. This P anel provides eight
LED indicators and may be placed at a convenient location near the critical load. A functionaldescription of
the Remote Monitor Panel is provided in 3.0 - Operation of this manual.
12. Customer Alarm Interface
This optional interface board allows the input and display of 8 alarms from customer-suppliedc ontacts, each
with a customer-selected name of up to 16 characters. The following attributes can be user programmed for
each alarm: latching, summary,freeze history, sound horn, auto-dial, and time delay (0 to 999.9 seconds).
12 Introduction
2.0 THEORY OF OPERATION
2.1 General Component Descriptions
The UPS system includes all of the equipment necessary to c ontinuously provide computer-grade AC power to a
critical load, even when there is an interruption of the utility line power. It consists of a System Control C abinet
(SCC), UPS modules, and a back-up battery plant. Refer to Figure 6 and Figure 7. Except where otherwise
noted, the configuration is presumed to be parallel-redundant (with at least one more UPS module than required
to support the rated load).
System Control Cabinet
The System Control Cabinet (SCC) includes system controls, static bypass switch, load transfer control, protective devices, and other accessories. The system controls simultaneously monitor two or more parallel UPS modules sharing a critical load for increased capacity and/or redundancy. T he two (2) motor-operated system circuit
breakers (system bypass breaker—SBB and UPS output breaker) may be contained within the SCC, depending
on the configuration designed for your installation.
System Controls: The system control logic automatically manages critical bus operation and monitors performance of the UPS modules. Microprocessor technology and dedicated firmware provide advanced logic control
and a comprehensive display of information. The system control logic s ynchronizes the output of the UPS system to the bypass source. The SCC includes ports for communicating with external devices. Liebert Multi-Module Units do not require an SCC for load sharing. Automatic, parallelmodule load sharing is a function built into
the modules themselves; however interconnection through the SCC enables the modules to share data for more
precise control. Modules do not require master clocks or controls in order to load share or free-run at 60.0 Hz.
Static Bypass Switch: The static (solid-state) bypass switch immediately transfers the load from the inverter to
the bypass AC power source in the event of a severe overload on the system or a failure within the UPS. This
transfertakes place without any interruption of the power supplied to the load. The system includes redundant
circuits to detect and isolate shorted SCRs in the static switch.
Fuses are installedin series with the static bypass circuit to ensure reliable overload protection in the unlikely
event of a catastrophic output condition (e.g., a dropped wrench) electrically close to the output of your UPS system. The static switch SCRs themselves are rated to easily handle the fuse-blowing current.
Bypass Circuit: The bypass circuit consists of electrically operated circuit breakers and associated synchronizing and control circuitry to transfer the load to/from the bypass source.
Theory of Operation 13
Figure 6 UPS Module Block Diagram
MULTI-MODULE UPS SYSTEM
CONTROL POWER
Control
Wiring
To SCC
Controls
Utility
Input
Power
Input
CB
Rectifie r/
Charger
Inverter
Output
CB
Battery
MBD
CB - Circuit Breaker
MBD - Module Battery Disconnect
SCC - SystemCon tro lCabinet
Output
Power
To SCC
UPS Module
The UPS module consistsof module controls, a rectifier/charger, an inverter, protectivedevices, and other accessories.
Module Controls: The module control logic monitors performance of the UPS module. The UPS module status
is displayed locally and is also sent to the System Control Cabinet.
Rectifier/Charger: The rectifier/charger converts utility power from AC to DC to charge the ba ttery and provide the DC input to the inverter. Its design limits reflected harmonic current distortion to source power and provides low-ripple DC power for charging batteries. Multiple rectifier/chargers can share a common battery plant,
if that configuration is preferred for your application.
Inverter: The inverter converts DC power into the precise AC power required to supply a sensitive critical load.
The i nverter converts DC power into a pulse-width-modulated (PWM)/six-step waveform that is easily filtered
into a clean sine wave output. The PWM/stepwave also minimizes the harmonic voltage distortion caused by
typical switching power supplies and other non-linear load components used in computers and related electronics.
Battery Plant
The battery is used as the alternate source of power to supply DC power to the inverter if the AC supply voltage
is outside the acceptable range. The battery supplies power to the inverter until the utility power is restored or
untilan alternate power source is available. If AC source power is not restored or an a lternate power source is not
available, the ba ttery can be sized to provide power long enough for an orderly shutdown of the load.
14 Theory of Operation
2.2 Detailed Component Descriptions
2.2.1 Controls Hardware
The Series 600T UPS Operator Interface Display System is designed to provide all of the information that is
required for the operation of each UPS cabinet (the System Control Cabinet and each m odule). The following is
a list of the hardware features:
1. The control l ogic performs automatic operations with minimal operator interface. The limited number of
manual controlsare easy-to-use.
2. EachSeries 600T UPS cabinetis equipped with an easy-to-read640 x 200 pixel liquid crystal display (LCD)
screen. It presents information in a way that is easy to understand at an eye-level front panel location.
3. The display is controlled by a dedicated microprocessorwith a non-volatile (EPROM) program and a
battery-backed event memory.
4. The Series 600T System Control C abinet (SCC) has communication ports (terminal board connections) for:
a. Transmission of present status information to remote terminals via resident auto-dial communications
program and an external modem. This port also responds to inquiries of the UPS system status and
history from the remote terminal.
b. ReportingUPS system status and history information in response to inquiries from a local terminal (no
modem required).
c. Reporting to a local monitor the information requested from the local terminal.
d. Reportinginformation to a Liebert SiteScan c entral monitoring system.
e. Relaying selected alarm messages to a Liebert Remote Monitor Panel and to a separate terminal board
for customer use.
f. Relaying performance and status information to your network monitoring system via SNMP interface.
NOTE
All external communication devices are optional equipment.
Firmware
The Operator Interface Display System software enables the operator to monitor the UPS system status,to control the power flow through the UPS, to monitor all of the meter readings, t o execute the start-up, shutdown, and
the load transfer procedures, to access the event history files, and to make adjustments to the programmable
parameters. The following is a list of the firmware features:
1. The menu-driven software prompts the operator for input.
2. Step-by-step instructions assist the operator during start-up, shutdown, and load transfer procedures. This
helps to eliminateoperator errors.
3. Graphics-based m imic diagrams illustrate circuit breaker status and the power flow through the UPS system.
4. The Present Status screen reports information about the system’s present status. The History Status screen
chronicles the events leading up to and immediately after a fault. The Event History s creen lists all of the
alarm messages that have been logged over a period of time.
5. The Battery Cycle Monitor records information on up to 132 battery discharge events. Information includes
date, time, length of discharge, highest current demand, lowest battery voltage, and cumulative battery amp
hours discharged.
Refer to 3.0 - Operation for a description of the controls and indicators located on the Operator Control Panel.
2.2.2 Rectifier/Charger
The UPS module rectifier/charger consists of an input circuit breaker, optional input isolation transformer, AC
current limiting circuit, battery equalize charge circuit, DC filter, battery charge current limiting circuit, and
bridge rectifiers.
Operation
The rectifier/charger converts the AC input power to DC power. This conversion is accomplished by 3-phase
bridge rectifiers using SCRs. All phases a re individually fused. Reflected input current THD is less than 7% at
Theory of Operation 15
full load with optional input filter. For modules 500 kVA and larger, the optional 12-pulse rectifier reduces
reflected THD to less than 4% with optional filter, or 9% without.
The filtered output of the rectifier/charger provides regulated DC power to drive the inverter and c harge the battery.
Input Circuit Breaker
The i nput circuit breaker (CB1) is sized to allow enough current to recharge the battery and supply a full rated
load at the same time. The circuit breaker contains a thermal magnetic trip mechanism and an undervoltage
release that interrupts power, preventing damage to the system, if there is an internal AC over-current condition
or a shortcircuit.The circuit breaker also opens during certainalarmed faults. This circuit breaker must be closed
manually.
Isolation Transformer
The optional input isolation transformer has a dry type core, and copper windings with class H insulation. The
transformeron modules with standard 6-pulse rectifier has w ye primary and delta secondary windings. For models w ith the optional 12-pulse rectifier, the transformer has a delta primary, with delta and w ye secondary windings. The isolation transformer provides the initial step of critical bus isolation. This re duces the AC shock
hazard at the battery and at other DC components, and prevents a DC fault from disrupting upstream AC circuitry.
The transformer has a nominal tap and one tap 6% below the rated nominal input voltage(normally used for 460
VAC input).
Input Current Lim it
AC input current-sensing transformers (CTs) are used to measure current levels. Control circuitry connected to
the CTsrestrictsthe AC current to less than 125% of the full input current rating by reducing the battery charging
voltage. This current limit is adjustable from 100 to 125% and is factory set at 115%. A second (optional) level
of input current limit can be initiated by an external contact closure (field supplied for use with back-up generator), and is adjustable from 85 to 100% (factory set at 100%).
During a start-up procedure, the current slowly ramps up (walks-in) from 20% of the rated input current to 100%
over a 15 to 21 second period. The maximum rate of change of the AC input current is 15% per second. The
input current walk-in reduces the start-up surge distortion effects on all other equipment c onnected to the same
source and prolongs the service life of internal components.
Input Current Inrush
The maximum sub-cycle of inrush current due to the optional input isolation transformer is less than 500-800%
of the rated input current for the first 1/2 cycle. Without the optional transformer, inrush current is typically less
than 2-3 times normal.
Input Power Factor
The rated input power factor is no less than 0.85 lagging at the nominal input voltage and the full rated UPS load.
The optional input filter will improve the power factor to better than 0.92 lagging at full load. Refer to published
specifications for your UPS model.
2.2.3 Battery Charging Circuit
The UPS module charging circuit is capable of recharging the battery plant to 95% of full capacity within 10
times the discharge time. Rechargingthe last 5% takes longer because of characteristics inherent in the battery.
DC ripple voltage is limited to less than 0.5% RMS to preserve battery life during long-term float chargingwhile
the UPS system is operating on utility source power.
Multiple UPS module rectifier/chargers can share a c ommon battery plant, if that c onfiguration is preferred for
your application.
Operation After Discharge
When commercial power is interrupted, the battery continues to supply DC power to the inverter without interruptionto the criticalload.If the AC source power is restored before the ba ttery has fully discharged, the rectifier
automatically restarts and resumes carrying the inverter and battery recharge load requirements.
16 Theory of Operation
Operation After E nd-of-Discharge
The battery time screen displayed on the control panel enables you to estimate when battery shutdown will occur.
You will have enough time to energize an alternate A C power source or to initiate an orderly shutdown of the
critical load. If the battery plant discharges to the shutdown point during an outage, the UPS automatically disconnects the load, the AC input, and the battery.After AC input power is restored, the rectifier can be manually
restartedbytheuser.
Battery Disconnect
The external module battery disconnect (MBD) circuit breaker is used to isolate the UPS module from the battery during maintenance and to automatically disconnect the battery from the inverter at the end of ba ttery discharge. The MBD circuit breaker can be opened or tripped automatically, from the control panel, or manually. It
must be closed manually.
Battery Charge Current Limiting
The battery recharge current, after a battery discharge, is limited to between 1 and 25% (adjustable) of the full
load discharge current. An additional (optional) charge-limiting circuit can be activated by external dry contact
closure (field supplied) for use whe n operating on a back-up generator. These two levels of control regulate the
amount of current that flows from the power source to the battery while the battery is re charging.
The battery charge current limit is factory set at 10% for normal operation and at 1% for alternate powe r source
recharge operation.
Battery Equalize Charge Circuit
The battery equalize charge feature can be manually initiated or it can be programmed to operate automatically.
Either can be selected from the battery equalize screen displayed on the control panel.
The battery e qualizing charge circuit increases the rectifier/charger output voltage to charge the battery any time
there is a power outage of 30 seconds or longer. The equalizingvoltage is slightly higher than the float voltage.
This decreases the time required to recharge the battery.
NOTE
Do not use equalize charging with valve-regulated lead-acid batteries
Consult the battery manufacturer's manual for specific information about equalize
charging.
Theory of Operation 17
2.2.4 Inverter
The inverter is a solid state device that converts the DC output of the rectifier/charger or the battery to AC power.
Operation
The i nverter converts DC power—from either the battery or the rectifier/charger—into three pulse-width-modulated/six-step waveforms. These waveforms are filtered into low-distortion sine wave power.The inverteris controlled by an Application-Specific Integrated Circuit (ASIC). This integrated circuit controls the precise
synchronization, amplitude, and frequency of the output voltage.
In addition to the inverter efficiently supplying a regulated AC output from a DC source, the output isolation
transformer acts as a second stage of isolation between the critical load bus and the commercial source power.
The inverter is configured to handle most critical load inrush surges. It maintains output voltage Total Harmonic
Distortion (THD) within specifications even when handling non-linear c omputer loads. Refer to non-linear load
characteristics.
Output Regulation and Overload Performance
The inverter is capable of sustaining full output voltage ±2% of the nominal voltage) for up to 150% overload at
the output for as long as 30 seconds without reducing the output voltage. It can also handle at least 125% of the
rated current for up to 10 minutes and 104% of the rated current continuously. The System Control Cabinet
(SCC) will transfer the critical load to the bypass source if the overload exceeds the system capacity or the capacity of the modules on-line. The multi-module overload capacity (in terms of percent of rated full load current of
modules on-line) is 140% for 20 seconds, 108% for 10 minutes, and 104% continuously.
Note that in normal operation the SCC will transfer the load to bypass before a UPS module exceeds its overload
capacity. If a module overload condition is sustained (beyond inverter capacity) the UPS module is automatically
taken off-line (disconnected from the critical bus) and is shut down. If the UPS system is operating in the redundant mode, the load may remain on the UPS system. Refer to 3.4 - Autom atic Operations.
Non-Linear Load Characteristics
Computersand computer equipment with switching power supplies generate non-linear currents rich in fifth and
seventh harmonics.
The inverter pulse-width-modulated/six-step waveform, coupled with the output filter,provides a natural path
for reducing the fifth and seventh harmonic currents produced by the load. The inverter/filter limits the output
voltage THD to less than 5% with up to 100% typical electronic data processing (EDP) loads. EDP equipment
characteristically includes both non-linear and linear load components.
Unbalanced Load Characteristics
Unbalanced loads a re actively regulated. The phase-to-phase voltage balance is maintained to within 2%, even
with a 50% load imbalance.
The three-phase, root mean square (RMS—approximately 70% of the peak) average voltage is also regulated
through a separate c ontrol circuit (phase-to-phase sensing).
18 Theory of Operation
2.2.5 Static Bypass
A static bypass is an integral part of the UPS System Control Cabinet (SCC). R efer to Figure 7.Thestatic
bypass consists of solid-state s witching devices working in conjunction with the motor-operated System Bypass
Breaker(SBB). An automatic transfer control circuit senses the status of the operator controls, UPS logic signals
and alarm messages, and critical bus operatingconditions. If the UPS modules can no longer supply the critical
load, the static bypass switch (in conjunction with the SBB and UPS O utput Breaker) automatically transfers the
critical load to the bypass source without interruption.
Figure 7 System Control Cabinet (SCC) Block Diagram
BypassLine
Sync &
Transfer
Control
Power
UPS
System
Modules
Supply
System
Monitor
Voltage
Adjust
Static Bypass Breaker
Transfer
Control
Gate
Driver
Static
Bypass
Switch
Static Switch
Disconnects
Alarms
To Critica l
UPSOutput
Load
Fuse Protection
The static bypass switch path uses two back-to-back SCRs per phase. Each phase is individually protected by a
fuse sized to clear only in the event of a catastrophic fault. This is a more reliable method than depending on
external protection devices. The fuses are in the circuit to protect the critical bus distribution equipment against
catastrophic faults. The static switch SCRs are oversized to easily handle any current surges that may blow the
fuses.
Shorted SCR Monitoring
The static bypass system has redundant shorted SCR sensing circuits and disconnects. This w ill prevent UPS output power backfeed to the distribution system even if two component failures exist simultaneously. If a shorted
SCR is detected, the static bypass switch is isolated and annunciated at the SCC control panel, and the critical
load remains on UPS output power.
Static Switch Isolation
The motor-operated system bypass circuit breaker (SBB), wired in parallel with the static switch, automatically
closes in approximately 200 milliseconds after the load is transferred to the bypass power source, removing the
static switch from the power flow.
Theory of Operation 19
Also, if required for maintenance, the static switch can be isolated from the bypass line by opening (to the OFF
position)the Static Switch Disconnects.
Pulsed Parallel Operation
When an overload condition such as magnetic inrush current or a branch load circuit fault exceeds the overload
capacity of the connected modules, the static bypass switch pulses on for 40 milliseconds. This allows up to
1000% of the rated full load current from the bypass line to clear the overload without closing the bypass circuit
breaker. The bypass source is briefly in parallel with the UPS s ystem, permitting the bypass source to carry the
initialoverload current. If the overload clears before 40 milliseconds, a load transfer to bypass is not made. If the
overload condition continues, the automatic transfer is made (maintaining the load voltage within the specified
limits).
This pulsed static switch operation reduces nuisance operation of motor-operated c ircuit breakers for such shortterm conditions.
Load Transfers
Transfers to (transfer) or from (retransfer) the bypassmay be performed automatically or manually in a makebefore-break sequence. T his is accomplished through the overlapping operation of the UPS output and t he system bypass power switching devices.
Manual load transfers a nd retransfers are initiated by the operator from the S ystem Control Cabinet (SCC).
In a manual operation, or an automatic retransfer, the two motorized circuit breakers—UPS output and system
bypass—are both c losed simultaneously for a short period of time (overlap).
Automatictransfers are initiated by the SCC system control logic when an overload is beyond the specified capa-
bilitiesof the UPS system or when a fault occurs within a non-redundantUPS module. An automaticretransferis
initiated if this function is enabledand if system conditions for a retransfer are present.
In an automatic transfer, the circuit breakers do not overlap, but during the short time gap bypass power is supplied to the critical load through the solid state static switch.
20 Theory of Operation
Transfer and Retransfer Conditions
1. Automatic Transfers to Bypass
Criticalbus conditions that will initiate a n automatic transfer of the critical load from the UPS system to the
bypass source are:
a. System Overload: overcurrent condition in excess of the overload rating of the System Control Cabinet
(SCC).
b. Output Overload: overcurrent condition in excess of the current-versus-time overload capacity of UPS
modules ON LINE.
c. Over/Under Voltage (OV/UV): critical bus voltage is outside the allowable tolerance.
d. Non-redundant UPS Module Inoperative: an essential UPS module is taken OFF LINE for one of the
reasons below.
1. Battery discharged to the shutdown voltage.
2. Inverter overload capacity exceeded.
3. Inverteror rectifierfault condition (power, logic, or over-temperature) present or imminent.
4. Failure of UPS module logic or logic power.
e. SCC Logic:
1. Emergency Module Off (EMO) circuit activated.
2. Failure of UPS system logic or logic power.
2. Manual Transfers
Manual transfers may be initiated at any time provided no transfer inhibition conditions are present.
3. Transfer Inhibited
A manual transfer to the bypass source shall be inhibited if any of the following conditions exist:
a. Bypass frequency deviates ±0.5 Hz from the nominal.
b. UPS system to bypass voltage difference ( V) exceeds a predetermined percentage (normally 5%).
c. Static switch disconnects (manual switches) open.
d. OK to Transfer signal from the control logic is not present.
NOTE
A load transfer to the bypass line will be completed whenever an automatic transfer
to bypass is initiated If the Static Switch Unable alarm message is present for any
reason(including a ±20° phase lock synchronization error), the automatic transfer
will be interrupted for 40 to 120 milliseconds. Because of the reliabilityof the UPS
components, an interrupted load transfer is a very unlikely occurrence.
4. Automatic Retransfers to UPS
Criticalbus c onditions that must be present to initiate an automatic retransfer (Auto-Rexfer) of the critical
load from the bypass source to the UPS system are:
a. The number of Auto-Rexfer Attempts selected must be greater than zero (0). If zero (0) is selected, no
automaticretransfer will occur.
b. Critical load was initially transferred to the bypass source due to a system overload only.
c. Overload has since dropped below 100% of the rated SCC current.
d. Enough UPS modules are ON LINEto supply the critical load.
e. OK to Transfer signal received from the control logic for at least 10 seconds, within 5 minutes of the
overload transfer. (A manually initiated retransfer from bypass is required for overloads lasting 5
minutes or more.)
f. Cyclic-type system overloads, which occur up to five (select range is 0 to 5) times in 60 minutes, are
automatically returnedto the UPS system for each event including the Nth overload. A manually
initiated retransfer from bypass is required for the N+1 overload.
Theory of Operation 21
5. Manual Retransfers
Manual retransfers may be initiated at any time provided no retransfer inhibition conditions are present.
6. RetransferInhibited
A re transfer from the bypass source to the UPS system shall be inhibited if any of the following conditions
exist:
a. Manual (and Automatic) Retransfer Inhibitions:
1. Bypassfrequency exceeds ±0.5 Hz of the nominal.
2. UPS system-to-bypass voltage difference ( V) exceeds a predetermined percentage (normally
5%).
3. System circuit breaker (UPS output or SBB) is inoperative.
4. OK to Transfer signal from the control logic is not present.
5. Not enough UPS modules are ON LINE to supply the connected critical load.
b. Automatic Retransfer Inhibitions (in addition to those above):
1. The load transfer to bypass was not caused by a system overload.
2. Excessive cyclical overloads within a one-hour pe riod.
3. Retransfer conditions are not satisfied within 5 minutes of the initial transfer.
2.2.6 Redundant Mode
The typical multi-module UPS system is configured with a back-up (redundant) UPS module, connected in parallel to share the critical load with the other module(s). This parallel redundant system includesone more module
than is required to supply the full c ritical load.
A pa rallel redundant system will always be in the Redundant Mode if all modules are ON LINE . In addition, if
the critical load is reduced so that not all ON LINEmodules are required, the UPS system can also operate in the
Redundant Mode with one or m ore modules OFF LINE. The critical load will remain on the UPS system—even
if one ormore of the modules is taken OFFLINEfor maintenance or because of an internal fault—as long as the
remaining ON LINE m odules can carry the full connected system load.
The system control logic monitors the connected critical load and t he number of UPS modules ON LINE. If the
UPS system is operating in the Redundant Mode, the REDUNDANT status message will be displayed at the
System Control Cabinet (SCC). If the UPS system is operating in the Non-Redundant Mode (redundant module
is OFF LI NE or was not included in the system configuration), the NON-REDUNDANT status message is displayed at the SCC. In the Non-Redundant Mode, the critical load will be transferredto bypass if any UPS module
goes OFF LINE and the remaining ON LINE module(s) cannot carry the connected load without being overloaded.
The system control logic, located in the SCC, automatically adjusts the allowable overload limits based on the
connected load and the number of modules ON LINE.
22 Theory of Operation
3.0 OPERATION
3.1 Display Screen and Operator Controls
Each Liebert Series 600T UPS cabinet is equipped with a microprocessor-based Operator Control Panel and Display Screen and System Control Panel designed for convenient and reliable operation. T he System Control Ca binet (SCC) performs different functions than the UPS modules. Each cabinet has the controls and displays
required to operate and monitor its functions. The locations of operator controls are shown in Figure 8 through
Figure 11.
The front location of the control panel enables the user to quickly identify the current status of the UPS system
and to perform most of the manual operations. The operator display screen is driven by an e asy-to-follow menuprompted software program.
Features
The Series 600T interface display system enables the operator to easily perform the following:
• Obtain a quick indication of operational status:
• Is the critical bus OK?
• Is the UPS system OK?
• Which UPS modules are available?
• Is the battery available?
• Is the bypass line available?
• Monitor the power flow through the UPS system a nd monitor all meter readings:
• Is the critical load being supplied power from the UPS system or bypass?
• Are input, battery, and output voltage, frequency, and current readings at nominal levels?
• How much battery time is still available during an outage?
• Is the battery recharging after discharge?
• Execute operational procedures:
• Perform critical bus transfer/retransfer between the UPS system and the bypass line.
• Start-up and shut down the UPS system and each module.
• Shutdown the system and all modules instantly in the event of an emergency.
• Access status reports and history files:
• Obtain a complete listing of the present status of the UPS system and all modules (input, output, and
battery voltage, frequency, and current readings, and any alarms that may be present).
• Review a complete history report of all events leading up to and immediately after a fault condition.
• Examine an archive listing of all alarm conditions that have occurred over a period of time.
• Make adjustments to programmable parameters (access limited by Security Access function):
• Set the date and the time functions.
• Change the auto-dial phone number and the modem options.
• Select the number of auto-retransfer attempts.
• Make adjustment to t he UPS output voltage before performing a manual load transfer.
Operation 23
Figure 8 Operator Contro ls, 65 to 80 kVA (left) and 100 to 500 kVA (right)
2
2
5
Item Description Function
1 Input Circuit Breaker
(behind door of 65-80
kVA) (CB1)
This manually operated circuit breaker provides power to the UPS module rectifier.
In 625-750 kVA modules and some 500 kVA modules, this breaker is located inthe
transformer cabinet.
5
2 Module Output Circuit
Breaker (behind door of
65-80 kVA) (CB2)
3 OperatorControl Panel Referto Figure 10 for controls available on this panel.
4 ControlDisconnect
(behind inner door)
5 Interlock Button
(on rear of Control Panel)
This manually operated circuit breaker connects the UPS module inverter output to
the UPS System Control Cabinet.
These two fuses provide power to the controls. They are normally closed (ON).
Turn Control Power OFF (by opening the two fuse holders) only for maintenance
procedures.
Press this button to make authorized changes to any parameter protected by the
Security Access function. This includes time, date, auto-dial phone numbers,etc.
24 Operation
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