Vertiv Liebert EXM2 User manual

Vertiv™ Liebert® EXM2
User Manual
100kVA to 250kVA UPS

Vertiv™ | Liebert® EXM2 UPS User Manual
Technical Support Site
If you encounter any installation or operational issues with your product, check the pertinent section of this
manual to see if the issue can be resolved by following outlined procedures.
Visit https://www.vertiv.com/en-us/support/ for additional assistance.
The information contained in this document is subject to change without notice
and may not be suitable for all applications. While every precaution has been
taken to ensure the accuracy and completeness of this document, Vertiv
assumes no responsibility and disclaims all liability for damages resulting from
use of this information or for any errors or omissions. Refer to other local
practices or building codes as applicable for the correct methods, tools, and
materials to be used in performing procedures not specifically described in this
document.
The products covered by this instruction manual are manufactured and/or sold
by Vertiv. This document is the property of Vertiv and contains confidential and
proprietary information owned by Vertiv. Any copying, use or disclosure of it
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Vertiv™ Liebert® EXM2 UPS User Manual

TABLE OF CONTENTS
1 Im portan t Safety In structions 1
2 O verview 7
2.1 Features 7
2.2 Design Concept 8
2.2.1 System Design 8
2.2.2 Bypass 9
2.2.3 System Control Principle 10
2.2.4 UPS Power Supply Switch Configuration 11
2.2.5 Battery Circuit Breaker (BCB) 13
2.3 Parallel System 13
2.3.1 Parallel System Features 13
2.3.2 Parallel System Requirements 13
2.4 Operation Modes 14
2.5 Battery Management 20
2.5.1 Normal Function 20
2.5.2 Advanced Function 21
2.5.3 Battery Temperature Compensation 21
2.6 Battery Protection 22
3 M echanical Installation 23
3.1 Precautions 23
3.2 Transportation 24
3.3 Tools 25
3.4 Unpacking 27
3.5 Initial Inspection 29
3.6 Environmental Requirement 29
3.6.1 UPS Location Selection 29
3.6.2 Battery Location Selection 30
3.6.3 Storage 30
3.7 Mechanical Requirement 30
3.7.1 Composition 30
3.7.2 Moving Cabinet 30
3.7.3 Clearance 31
3.7.4 Cable Access Mode 31
3.8 Installation Drawings 32
4 Electrical Installation 35
4.1 Wiring of Power Cable 35
4.1.1 System Configuration 35
4.1.2 Maximum Steady State AC and DC Currents 36
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Vertiv™ Liebert® EXM2 UPS User Manual

4.1.3 Recommended CSA of UPS Cable 36
4.1.4 Selection of UPS I/O and Battery Switch 37
4.1.5 Distance Between the UPS Connection Point and The Floor 37
4.1.6 Notes 37
4.1.7 Power Cable Connecting Terminal 37
4.1.8 Protection Ground 38
4.1.9 External Protective Device 38
4.1.10 Power Cable Connection Steps 40
4.2 Wiring of Signal Cable 46
4.2.1 Overview 46
4.2.2 Dry Contact Port J6 47
4.2.3 Dry Contact Port J7 48
4.2.4 Programmable Dry Contact Port J8 52
4.2.5 REPO Port 53
4.2.6 Host Communication Port 54
4.2.7 Parallel and LBS Communication Ports 54
4.2.8 Intellislot Port 54
4.2.9 Signal Cable Connection Steps 54
5 O p era tor C o ntro l an d D is play P an el 57
5.1 Introduction 57
5.2 Navigating Through the Vertiv Liebert EXM2 Touchscreen Control Panel 59
5.2.1 Access Level Log-In 59
5.2.2 Vertiv Liebert EXM2 Touchscreen Control Panel Components 60
5.3 Operation 66
5.3.1 Log In to the Vertiv Liebert EXM2 Touchscreen Control Panel 66
5.3.2 Customizing the Display 67
5.3.3 Operator Controls 74
5.4 Viewing UPS Status 80
5.4.1 Viewing UPS Data with the Status Gauge 80
5.4.2 Viewing UPS Data with the Status Panel 84
5.4.3 Logs—Alarms and Events 90
5.5 Viewing UPS Component Status 92
5.6 Status Bar Component 95
5.6.1 Status Bar Messages 95
5.7 Alarm List 99
6 S ing le U P S O p era tion Intro du ctio n 10 3
6.1 Brief Introduction 103
6.1.1 Precautions 103
6.1.2 Power Switch 104
6.2 UPS Startup Procedures 106
6.2.1 Startup Procedures in Normal Mode 106
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6.2.2 Startup Procedures in ECO Mode 109
6.2.3 Startup Procedures in Battery Mode (Battery Cold Start) 110
6.3 Procedures for Transfer between Operation Modes 111
6.3.1 Transfer from Normal Mode to Battery Mode 111
6.3.2 Transfer from Normal Mode to Bypass Mode 111
6.3.3 Transfer from Bypass Mode to Normal Mode 111
6.3.4 Transfer from Normal Mode to Maintenance Mode 112
6.3.5 Transfer from Maintenance Mode to Normal Mode 113
6.4 Battery Test Procedures 114
6.5 UPS Shutdown Procedures 116
6.5.1 Procedures for Completely Powering Down UPS 116
6.5.2 Procedures for Completely Powering Down UPS while Maintaining Power to Load 116
6.6 EPO Procedures 116
6.7 UPS Reset Procedures after EPO 117
6.8 Automatic Restart 117
6.9 Selecting Language 118
6.10 Changing Current Date and Time 119
6.11 Control Password 120
7 Battery 121
7.1 Introduction 121
7.2 Safety 121
7.3 UPS Battery 123
7.4 Precautions for Installation Design 123
7.5 Battery Installation Environment and Number of Batteries 125
7.5.1 Installation Environment 125
7.5.2 Number of Batteries 126
7.6 Battery Protection 126
7.7 Battery Installation 127
7.8 Design of Battery Room 128
7.9 Common Battery String 129
7.10 Connections between battery compartments and UPS 130
7.11 BCB Box (Optional) 130
7.12 Battery Ground Fault Detector (Optional) 134
7.13 BCB Reference Current and Connection 135
7.14 Battery Maintenance 136
7.15 Disposal of Used Battery 137
8 Parallel S ystem and LB S System 139
8.1 General 139
8.2 System Installation Procedures 139
8.2.1 Preliminary Checks 139
8.2.2 Cabinet Installation 139
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8.2.3 External Protective Device 141
8.2.4 Power Cable 141
8.2.5 Parallel Cable 142
8.2.6 Remote EPO 143
8.3 Operation Procedures for Parallel System 144
8.3.1 Startup Procedures in Normal Mode 144
8.3.2 Maintenance Bypass Procedures 145
8.3.3 Procedures for Isolating One UPS Module from Parallel System 146
8.3.4 Procedures for Inserting One Isolated UPS Module in Parallel System 147
8.3.5 Procedures for Completely Powering Down UPS 147
8.3.6 Procedures for Complete UPS Shutdown while Maintaining Power to Load 147
8.4 LBS System 148
8.4.1 Cabinet Installation 148
8.4.2 External Protective Device 149
8.4.3 Power Cable 149
8.4.4 LBS Cable 150
9 O p tion s 15 3
9.1 Option List 153
9.2 Option Introduction 154
9.2.1 Optional Side Cabinet 154
9.2.2 Bypass Short-circuit Withstand Option 157
9.2.3 Battery Temperature Sensor 158
9.2.4 Battery Ground Fault Kit 158
9.2.5 Seismic Anchor Kit 159
9.2.6 IS-UNITY-DP Card 162
9.2.7 IS-UNITY-LIFE Card (Available in Specific Regions only) 162
9.2.8 SIC Card (Available in Specific Regions only) 163
9.2.9 UF-RS485 Card 164
9.2.10 IS-Relay Card 165
9.2.11 BCB Box 166
9.2.12 Parallel Cable 166
9.2.13 LBS Cable 166
9.2.14 Back-feed Contactor Option 166
9.2.15 Top Fan Kit 167
9.2.16 Input/output Switch Kit 168
9.2.17 IP21 Option 169
9.2.18 IP31 Option 170
9.2.19 Transformer 171
9.2.20 C2 Electromagnetic Shielding Option 172
9.2.21 CPSS Model Option 172
9.2.22 LBS Adapter 173
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Vertiv™ Liebert® EXM2 UPS User Manual

10 C om m un ication 175
10.1 SNMP Protocol Communication 175
10.2 Modbus Protocol Communication 175
10.3 Dry Contact Communication 175
10.3.1 Communication Through IS-Relay Card 175
10.3.2 Communication Through Dry Contact Port 176
11 Service and M aintenance 177
11.1 Safety 177
11.2 Service Procedures of Power Module and Bypass Module 177
11.2.1 Service Procedures of Power Module 177
11.2.2 Service Procedures of Bypass Module 178
11.3 Key Components and Service Life of UPS 179
11.3.1 Life Parameters and the Proposed Replacement Time of Key Components 180
11.3.2 Replacement of Air Filter 180
11.4 Maintenance of UPS and Options 181
12 Specifications 183
12.1 Conformance and Standards 183
12.2 Environmental Characteristics 183
12.3 Mechanical Characteristics 184
12.4 Electrical Characteristics (Input Rectifier) 184
12.5 Electrical Characteristics (Intermediate DC Circuit) 185
12.6 Electrical Characteristics (Inverter Output) 185
12.7 Electrical Characteristics (Bypass Input) 186
12.8 Efficiency and Loss 187
Appendices 189
Appendix A: Technical Support and Contacts 189
Appendix B: Glossary 190
Appendix C: Hazardous Substances and Content 191
Appendix D: Declaration of Materials and Components 192
Appendix E: Disposal After End of Product (Applicable for India) 193
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Vertiv™ Liebert® EXM2 UPS User Manual

1 Important Safety Instructions
Personnel Safety
1. This product must be installed and commissioned by professional engineers of the manufacturer or its
authorized agent. Failure to observe could result in product malfunction or personal safety risk.
2. Take the time to read this product manual and the safety precaution thoroughly before installing and
commissioning this product. Failure to observe could result in product malfunction or personnel safety risk.
3. This product is not intended for life support equipment application.
4. Never dispose of the internal or external battery of this product in fire, as it may explode and jeopardize
personnel safety when exposed to flame.
Product Safety
1. If this product will be stored or remain de-energized for a long period, it must be placed in a dry and clean
environment within specified temperature range.
2. This product should be used in an appropriate operating environment. For details, refer to the section on the
environmental requirement in this manual.
3. This product is not designed for application in an environment:
•Where the temperature and relative humidity are outside the specifications
•Subjected to vibrations or shocks
•Where conductive dusts, corrosive gases, salts, or flammable gases are present
•Near heat sources or strong electromagnetic interferences.
Disclaimer
Vertiv disclaims any and all responsibility or liability for the defects or malfunction caused by:
•Application range or operating environment outside the specifications
•Unauthorized modification, improper installation or operation
•Force majeure
•Other actions not in compliance with the instructions in this manual.
Safety Precaution
This manual contains information concerning the installation and operation of the Vertiv™ Liebert® EXM2 100kVA~250kVA
UPS.
Read this manual thoroughly before installing, using and servicing the UPS.
IM PO R TA NT ! The U PS w ith stan dard con figu ration is a category C 3 p rod uct for com m ercial and
indu strial a pp lica tion in th e seco nd e nviron m ent. Installation re striction s or ad dition al m easures m ay
be needed to p reven t disturbances.
IM PO RTA NT ! The UPS adding C 2 EM C op tion b ased on th e stan da rd configu ration is a ca teg ory C 2
prod uct for a reside ntial en vironm ent o r co m m erc ial and industrial application in the second
env iron m ent.
1 Important Safety Instructions 1
Vertiv™ Liebert® EXM2 UPS User Manual

C on form ity an d stand ards
This product conforms to the following European directives and UK Regulations:
2014/35/EU
Directive of the council for adapting the legal regulations of member states on electrical equipment for use within specific
voltage limits.
Electrical Equipment (Safety) Regulations: 2016
Regulations implemented according to EU Directive (2014/35/EU) on electrical equipment designed for use within specific
voltage limits approved on the GB market.
2014/30/EU
Directive of the council for adapting the legal regulations of member states on electromagnetic compatibility.
Electromagnetic Compatibility Regulations: 2016
Regulations concerning the aspects on electromagnetic compatibility approved on the GB market.
Conformity is established through compliance with the following standards:
• IEC/EN/BS 62040-1:2008+A1:2013
• IEC/EN/BS 62040-2:2018
Additional information regarding adherence to these directives and regulations is included in the appendices NSR and EMC
to the Declarations of Conformity. If needed, the Declarations of Conformity can be requested to Vertiv.
2011/65/EU
Directive of the council for adapting the legal regulations of member states on the restriction of the use of certain hazardous
substances that can be used in the manufacture of electrical and electronic equipment.
The Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment Regulations 2012.
The restriction of the use of certain hazardous substances that can be used in the manufacture of electrical and electronic
equipment approved on the GB market.
W A R N IN G ! H igh e arth lea ka ge cu rre nt: E arth co nn ectio n is critic al b efo re c on ne ctin g th e
inpu t su pp ly (in clud in g b oth m a in s su pply an d ba ttery ).
T his e qu ipm e nt is insta lle d w ith a n E M C filter.
Earth leaka ge cu rrent is less than 30 00 m A .
T ran sien t a nd s tea dy sta te e arth le ak ag e c urre nts , w hic h m a y o cc ur w h en th e eq uip m en t is
started, should be taken into account in the selection of instantan eous RCC B s or R C D devices.
RC CB w hich is sensitive to unidirectional DC pulse (class A ) and insensitive to transient state
curre nt p ulse m ust b e selected .
N ote also that the earth leakage curren ts of the load w ill be carried b y the R C C Bs or RC D s.
The eq uipm ent m u st b e e arthed in acco rdan ce w ith the local electrical c od e of practice.
1 Important Safety Instructions
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Vertiv™ Liebert® EXM2 UPS User Manual

W A R N IN G ! T he s elec tion o f th e u ps tre am d is trib utio n p ro tectio n e qu ip m e nt o f th e U P S s hall
b e s ele cte d in a cco rd an ce w ith th e d eta ils an d sh all c om p ly w ith th e lo ca l electrica l
reg ulations.
W A R N IN G ! B ac kfe ed ing p ro tec tion
T his U P S is fitte d w ith a d ry con tac t clos ure s ig na l for u se w ith an e xtern al a uto m atic
disconnect d evice (supplied by others) to protect against b ackfeeding voltage into the
incom ing te rm ina l through the re ctifier o r byp ass static sw itch circu it. A label m ust be ad de d
at all exte rnal incom in g prim ary su pply disconnec t de vice to w arn se rvice p erson ne l that the
circuit is co nn ected to a UPS. The text of the label has th e follow ing m eaning: Risk of voltage
b ac kfe ed ! Isolate th e U P S, th en c he ck fo r h aza rdo us vo lta ge b etw e en all term in als inc lu ding
th e p rote ctive ea rth b efo re w o rk in g o n th is circ uit.
U ser service ab le com po nen ts (F or se rvice p erson ne l)
All equipment maintenance and servicing procedures involving internal access requires the use of a tool and should be
carried out only by trained personnel. There are no user-serviceable parts behind covers requiring a tool/key for removal.
Battery voltage exceeds 400 V dc (For service perso nn el)
All physical battery maintenance and servicing procedures requires the use of a tool/key and should be carried out only by
trained personnel.
Take special care when working with the batteries associated with this UPS. When connected, the battery terminal voltage will
exceed 400 Vdc and is potentially lethal.
Battery manufacturers supply details of the necessary precautions to be observed in working on, or in the vicinity of, a large
bank of battery cells. These precautions should always be followed implicitly. Particular attention should be paid to the
recommendations concerning local environmental conditions and the provision of protective clothing, first aid and fire-
fighting facilities.
General safety (For u sers)
Like other types of large power equipment, the UPS and battery circuit breaker box/battery cabinet have high voltage inside.
Because the components with high voltage can be accessed only when the front door is opened, the risk of contacting high
voltage has been minimized. This equipment meets the IP20 standard, and other safety shields are provided inside the
equipment.
There will not be any risk when operating this equipment according to the general instructions and the steps recommended
in this manual.
M u ltiple p ow er in pu ts (F or u se rs)
This UPS system receives power from more than one source. Disconnection of all AC source and the DC source is required
before servicing.
This UPS has several circuits that are energized with high AC as well as DC voltages. Check for voltage with both AC and DC
voltmeters before working within the UPS.
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Vertiv™ Liebert® EXM2 UPS User Manual

W A R N IN G ! W h en th e in ter na l fu se o f th e U P S is d am a ge d, it m u st b e re pla ce d w ith fu se o f th e
sam e electric pa ram e ters by qualified p erson ne l.
IM PO R TA NT ! Be side th e com m u nica tion b oa rd is a static sensitiv e a rea, an E SD -pro of ac tion is
critical b efo re c on tac ting w ith th is a rea.
W A R N IN G ! T he u se r m u st s ele ct a n a pp rop riate M C C B to p ro tec t ag ainst s ho rt circ uit a nd
ove rloa d for th e b atte ry. It is rec om m en ded to adopt V ertiv B CB to p rovide a b etter so lu tion .
N OT E: T he U PS m e ets th e sta nd ard req uirem en t of sh ort tim e w ith stan d cu rren t of 10 kA w hen
ex tern al u ps trea m d istrib ution is e qu ip ped w ith a deq uate c ap ac ity o f fu se s/c ircu it b re ak er fo r fau lt
clearance. T he specified upstream fuses are required to obtain the cond ition al short circuit cu rren t
rating , Icc at 65 k A sym m etrica l rm s. It is re com m e nd ed to select the fu ses in com p lian ce w ith
voltage of 69 0 V , current of 80 0 A an d breaking of 20 0 kA . Th e specified upstream breakers should
co m ply w ith an IE C 6 0 26 9 s eries s tand ard .
N O T E: B yp ass S C R is o nly p ro tecte d a g ain st sh ort c irc uit w h en ad eq u ate c ap ac ity o f fu se s/circ uit
breaker are present in the upstream distribution.
1 Important Safety Instructions
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Vertiv™ Liebert® EXM2 UPS User Manual

T he M a nu al D e scribe s th e F ollow in g E qu ip m en t
P ro duc t M od el
100kVA EXM 0100kTG16FN02000
120kVA EXM 0120kTG16FN02000
150kVA EXM 0150kTG16FN02000
160kVA EXM 0160kTG16FN02000
200kVA EXM 0200kTG16FN02000
250kVA EXM 0250kTG16FN02000
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Vertiv™ Liebert® EXM2 UPS User Manual

Re vision Inform ation
V1.0 (November 11, 2020)
Initial release.
V1.1 (October 20, 2022)
Updated the manual for GHMI images in Chapter 5 Operator Control and Display Panel. Added 28-block battery in Table 7.4
BCB rated current and battery m ax. discharge current at full load (recommended). Added 9.2.13 LBS Adapter. Updated Table
12.1 European and international standards, Table 12-2 Environmental characteristics, Table 12.3 Mechanical Characteristics,
12.5 Battery, Table 12.6 Inverter output (to critical load), Table 12.7 Bypass input, and Table 12.8 Efficiency and loss.
1 Important Safety Instructions
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Vertiv™ Liebert® EXM2 UPS User Manual

2 Overview
This chapter briefly introduces the features, design concept, parallel system, operation mode, battery management and
battery protection of the Vertiv™ Liebert® EXM2 UPS 100kVA~250kVA (UPS for short).
2.1 Features
The UPS is connected between a critical load (e.g. a computer) and mains power to provide high quality power for the loads.
The UPS has the following advantages:
A ug m en t p ow e r q uality
The UPS protects its output against the input power change through the intelligent controller.
Prov id e m ains failure protection
If the input power fails, the UPS will work in battery mode, and the power supply to the loads will not be interrupted.
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Vertiv™ Liebert® EXM2 UPS User Manual

2.2 Design Concept
2.2.1 System Design
This section introduces the working principle of the UPS single module. The UPS adopts AC-DC-AC converter (as shown in
Figure 2.1 below). The first stage conversion (AC-DC) adopts three-phase high frequency rectifier to convert the three-phase
input voltage into stable DC bus voltage.
Fig ure 2.1 B lo ck d iag ra m for w o rking p rinc ip le o f U P S sing le m o du le
N O . D e scrip tio n N O . D e scrip tio n
1 Input 9 Rectifier input switch
2 Output 10 Rectifier
3 Bypass input 11 Inverter
4 Maintenance bypass switch 12 Inverter switch
5 Maintenance bypass 13 Output
6 Static switch 14 UPS Battery
7 Bypass input switch 15 Battery charger
8 Mains input 16 Output switch
2 Overview
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Vertiv™ Liebert® EXM2 UPS User Manual

The UPS has its own battery charger and adopts advanced temperature compensation technology to effectively prolong the
battery service life. The inverter adopts three level T-type IGBT topology and uses advanced SVPWM control technology to
derive the stable AC voltage from the DC bus voltage. When the mains is normal, the rectifier and inverter work together to
supply the loads and charge the battery.
When the mains is abnormal, the rectifier stops working, and the battery supplies power to the loads through the inverter. If
the battery voltage falls to end of discharge (EOD) voltage and the mains still has not been recovered, the UPS will shut down
(if the system uses split bypass configuration and the bypass is normal, the system will transfer to bypass). The battery EOD
voltage is preset.
When the mains is abnormal, the rectifier stops working, and the battery supplies power to the loads through the inverter. If
the battery voltage falls to end of discharge (EOD) voltage and the mains still has not been recovered, the UPS will shut down
(if the system uses split bypass configuration and the bypass is normal, the system will transfer to bypass). The battery EOD
voltage is preset. When the mains is abnormal, the battery maintains the UPS operation till the battery voltage is reduced to
EOD voltage and the UPS shuts down, this time is called 'Backup Time'. The length of backup time depends on the battery
capacity and the loads.
2.2.2 Bypass
Through the intelligent control of the 'Static Switch' module (as shown in Figure 2.1 on the previous page) containing the
controllable electronic switch, the loads can be supplied by the inverter or the bypass. In normal situation, the loads are
supplied by the inverter, in this case the automatic inverter switch at inverter side is closed. In the case of overload (the
overload delay time expires) or inverter failure, the automatic inverter switch is opened, and the 'Static Switch' module will
automatically transfer the loads to the bypass.
In normal operating state, to realize the uninterrupted transfer between inverter and bypass, the inverter output must be
synchronized with the bypass.
Therefore, when the bypass frequency is within the synchronization range, the inverter control circuit will synchronize the
inverter output frequency with the bypass frequency and phase.
Besides, the UPS has a manual maintenance bypass switch for shutdown of the UPS upon maintenance. In this situation, the
bypass will directly supply the critical loads through the maintenance bypass.
N O T E: W he n th e lo ad is s up plied b y th e b yp ass or m a inte na nc e b yp ass, th e p ow e r su pp ly q ua lity w ill
be uncertain.
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Vertiv™ Liebert® EXM2 UPS User Manual

2.2.3 System Control Principle
N o rm a l op era tio n
Normal mode: It means that the UPS has normal input mains, the rectifier and inverter operate normally, the load is supplied
by the inverter, the battery circuit breaker is closed, and the battery is in stable floating charge state.
Parallel System As the UPS single module outputs are connected in parallel, the system checks that the inverter control
circuits are perfectly synchronized with one another and with the bypass in terms of both frequency and phase, and that they
have the same output voltages. Current supplied to the load is automatically divided among UPSs. A warning message
appears while synchronization is in progress.
M ains ab no rm al
When the mains fails or is abnormal, the rectifier will stop working automatically, and the load will be catered by the battery
output (through inverter). The length of the operation time in battery mode depends on the load and the battery capacity.
During this period, if the battery voltage falls to the EOD voltage and the mains still has not been recovered, the inverter will
stop working automatically, and the UPS operator control and display panel will display corresponding alarm messages. If the
system uses split bypass configuration and the bypass is normal, the system will transfer to bypass.
M ains recovery
When the mains resumes normal within allowable time, the rectifier will start automatically and supply the load and charge the
battery again. Therefore, the power supply to the load will not be interrupted.
Battery disconn ection
To disconnect the external battery from the UPS system for maintenance, use the external isolating switch. At this time,
except for the battery backup function upon mains failure, other functions and all the steady state performance of the UPS
will not be affected.
U PS m od ule failure
In case of inverter failure and output fuse blowout, the load will automatically transfer to the bypass, and the output power
supply will not be interrupted. In this situation, please contact the local customer service center of Vertiv for technical support.
Parallel System In the event of a fault in a UPS module, it will automatically exit from the parallel system. If the system is still
capable of providing the required load, the remaining modules will continue to supply the load with no interruption. If the
remaining modules are no longer capable of fulfilling the power requirements, the load will automatically transfer to the
bypass.
O ve rloa d
If the inverter is overloaded or the inverter current remains outside the specifications (refer to Table 12.6 on page185) longer
than the specified time, the load will automatically transfer to the bypass without power interruption. If both the overload and
the current are reduced to a level within the specified range, then the load will be transferred back to the inverter. In case of
output short circuit, the load will be transferred to the bypass, and the inverter will shut down. Five minutes later, the inverter
will start up automatically. If the short circuit is removed at this point, the load will be transferred back to the inverter. The
transfer is determined first of all by the features of the protective device of the system.
In the above two situations, the UPS operator control and display panel will display alarm messages.
2 Overview
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Vertiv™ Liebert® EXM2 UPS User Manual

Parallel SystemThe control logic system constantly monitors load requirements and controls the power supplied by each
UPS module. In the event that an overload condition is sustained for greater than a preset time, the load will transfer to the
bypass, when the number of active modules is unable to satisfy load requirements. The load returns to the inverter if the
power is reduced to a value that can be sustained by the number of active modules in the system.
M aintenance byp ass
The UPS has a second bypass circuit, i.e. maintenance bypass, which provides a safe working environment for the engineers
to provide regular maintenance or repair to the UPS system and at the same time provide unregulated mains supply to the
loads. The maintenance bypass can be manually selected through the maintenance bypass switch, and it can be
disconnected by turning the switch to OFF.
W A RN IN G! If th e U PS system is com po sed of tw o o r m ore U PS m od ules an d w hen the load
cap acity exceeds the sing le m odu le cap ac ity, d o no t use th e inte rnal m a in ten an ce by pa ss
sw itch .
2.2.4 UPS Power Supply Switch Configuration
The UPS has four switches: rectifier input switch Q1, bypass input switch Q2, maintenance bypass switch Q3, and output
switch Q5.
Figure 2.2 on the next page describes the block diagram of the UPS module. The UPS has split bypass configuration (i.e., the
bypass adopts independent mains input) and common input configuration. If the system adopts common input configuration,
the UPS has shorting copper bar of common input configuration, and the bypass input switch (Q2) and rectifier input switch
(Q1) would be linked together. If the system adopts split bypass configuration, just remove the shorting copper bar of
common input configuration of the UPS.
During the normal operation of the UPS, except for the maintenance bypass switch Q3, other switches shall be closed.
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Vertiv™ Liebert® EXM2 UPS User Manual

Fig ure 2.2 U P S po w er s up ply sw itc h co nfigu ratio n
N O . D e scrip tio n
1 Bypass input
2 UPS
3 Maintenance bypass switch Q3
4 Static switch
5 Shorting copper bar of common input configuration
6 Bypass input switch Q2
7 Mains input
8 Rectifier input switch Q1
9 Rectifier
10 DC bus
11 Inverter
12 Inverter switch
13 Output switch Q5
14 Charger
15 UPS output
16 Neutral line input
17 Battery
18 BCB
2 Overview
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Vertiv™ Liebert® EXM2 UPS User Manual