Vertiv Liebert Load Bus Sync Controller User manual

Brand: Vertiv

Model: Liebert Load Bus Sync Controller

Type: User manual

Liebert®

Load Bus Sync™ Controller for Liebert® NX™ 225-600kVA 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.VertivCo.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 without the written permission of

Vertiv is strictly prohibited.

Names of companies and products are trademarks or registered

trademarks of the respective companies. Any questions regarding

usage of trademark names should be directed to the original

manufacturer.

Vertiv™|Liebert

® Load Bus Sync™ Controller Installation Manual | i

TABLE OF CONTENTS

IMPORTANT SAFETY INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

SAVE THESE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.0 INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.1 Installation Kit - 10B14515G1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.2 Mechanical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.0 TYPICAL CONFIGURATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.1 Two Systems with Separate Utility Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.2 Two UPS Units With Common Bypass Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.3 Liebert® Systems and Electrical Generating Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.4 Liebert® NX™ and Third-Party Brand UPS in the Same Installation. . . . . . . . . . . . . . . . . . . . . . 8

3.0 INSTALLATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

3.1 Installation Kit - 10B14515G1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3.2 Installation Tips. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3.3 Appendix C - Liebert® NX™ 225-600kVA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3.3.1 Setting Parameters - Enable External Synchronization Control . . . . . . . . . . . . . . . . . . . . . . . . . 10

3.3.2 Offset Compensation Tuning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3.3.3 Procedure complete for UPS1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

3.4 Installation Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

FIGURES

Figure 1 Rear panel reference supply input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Figure 2 Front panel UPS sync. outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Figure 3 Two separate utility supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Figure 4 Common bypass line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Figure 5 Liebert® NX™ systems and electrical generating devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Figure 6 Liebert® NX™ and third-party brand UPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Figure 7 Installation example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Figure 8 Offset compensation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Figure 9 Synchro Error 88,56 [°] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Figure 10 Synchro Error 0 [°] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Figure 11 Installation example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

TABLES

Table 1 Installation Kit - 10B14515G1 components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Table 2 Electrical Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Table 3 Installation Kit - 10B14515G1 components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Vertiv™|Liebert

® Load Bus Sync™ Controller Installation Manual | ii

Vertiv™|Liebert

® Load Bus Sync™ Controller Installation Manual | 1

IMPORTANT SAFETY INSTRUCTIONS

SAVE THESE INSTRUCTIONS

This manual contains important instructions that should be followed during installation of your

Liebert® Load Bus Sync™ Controller. The Liebert® Load Bus Sync™ installation must be performed

only by properly trained and qualified personnel.

Read this manual thoroughly, paying special attention to the sections that apply to your

installation, before working with the UPS. Retain this manual for use by installing personnel.

Before beginning to install the Liebert® Load Bus Sync™ Controller verify that:

• The Liebert® NX™ UPS and the Liebert® Load Bus Sync™ Controller are switched Off (all front-panel

indicators are extinguished)

• The UPS and the Liebert® Load Bus Sync™ Controller and related installations are isolated from all local and

remote power supplies.

• All power supplies upstream of the UPS are switched Off. Should the UPS be switched On, carry out the

shutdown procedure as described in the unit’s user manual.

NOTICE

Risk of improper electromagnetic shielding. Can cause radio communication interference.

This unit complies with the limits for a Class A digital device, pursuant to Part 15 Subpart J of the FCC

rules. These limits provide reasonable protection against harmful interference in a commercial

environment. This unit generates, uses and radiates radio frequency energy and, if not installed and used

in accordance with this instruction manual, may cause harmful interference to radio communications.

This unit is not designed for use in a residential area. Operation of this unit in a residential area may cause

harmful interference that the user must correct at his own expense.

WARNING

Risk of electric shock. Can cause injury and death.

Under typical operation and with all UPS doors closed, only normal safety precautions are

necessary. The area around the UPS system should be kept free of puddles of water, excess

moisture and debris.

Special safety precautions are required for procedures involving handling, installation and

maintenance of the UPS system and the batteries. Observe all safety precautions in this

manual before handling or installing the UPS system. Observe all precautions in this

manual, before as well as during performance of all maintenance procedures. Observe all

battery safety precautions before working on or near the battery.

This equipment contains circuits that are energized with high voltage. Only test equipment

designed for troubleshooting should be used. This is particularly true for oscilloscopes.

Always check with an AC and DC voltmeter to ensure safety before making contact or

using tools. Even when the power is turned Off, dangerously high electric charges may exist

within the UPS or Liebert® Load Bus Sync™ Controller.

All power and control wiring should be installed by a qualified electrician. All power and

control wiring must comply with the NEC and applicable local codes.

ONLY qualified service personnel should perform maintenance 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 should wear

insulating shoes for isolation from direct contact with the floor (earth ground).

Never work alone, even if all power is removed from the equipment. A second person

should be standing by to assist and summon help in case an accident should occur.

Vertiv™|Liebert

® Load Bus Sync™ Controller Installation Manual | 2

1.0 INTRODUCTION

The Liebert® Load Bus Sync™ Controller is an option designed for use in complex power source

systems consisting of different distributions and static switches supplied by Vertiv™ and other

manufacturers. It provides synchronization between the Liebert® NX™ 225-600V and third-party

UPS systems when synchronization cannot be guaranteed by the system configuration or when

temporary conditions prevent it (e.g., during battery operation).

The Liebert® Load Bus Sync™ Controller is available as an option with the Liebert® NX™ 225-600V,

either as a factory-installed option or as a kit that is installed and configured by Vertiv™-trained

and certified personnel.

Examples of configurations where the Liebert® Load Bus Sync™ Controller can be used:

• Installation consisting of two Liebert® NX™ 225-600V units

• Installation consisting of a Liebert® NX™ 225-600V and electrical generating devices

• Installation consisting of a Liebert® NX™ 225-600V and third-party UPS systems.

The Liebert® Load Bus Sync™ Controller option consists of an electronic unit housed in a metal

box that can be mounted near the UPS or inside the electrical distribution panel.

The Liebert® Load Bus Sync™ Controller requires a 480V input reference supply and can be used

to supply two units. When installing the unit inside a distribution panel or UPS, ensure that the

metal box is secured so that it cannot fall or touch metal parts containing hazardous voltages.

Vertiv™ recommends that the unit not be installed behind the second access panel or in front of

the Liebert® NX™ air inlet vents.

The device operates by identifying one of the connected units as the master and using its

frequency as a reference for the other units (slaves). While a non-Liebert® UPS can be used as

the master, only Liebert® UPS’s can be used as slave units. Depending on their configuration, the

slave units will follow the reference frequency all the time, or only when their reserve utility supply

is out of tolerance. The reference frequency will be generated only when the master utility supply

line is within acceptable limits.

The Liebert® Load Bus Sync™ Controller can drive up to two separate units. These units may be

independent of each other or connected in a parallel system. Where the installation consists of

more than two slave units, or the master/slave configuration is not the preferred option, Vertiv™

suggests using Liebert® MultiBus Synchronization Module™ (MBSM), Part No. 10B14545G1.

The Liebert® Load Bus Sync™ Controller does not affect the system’s mean time between failure

(MTBF)—it is not a single point of failure for the system). The individual units will ignore this

signal if it is outside the acceptable limits.

1.1 Installation Kit - 10B14515G1

The equipment is supplied with the following components:

Table 1 Installation Kit - 10B14515G1 components

Item Description Part # Quantity

1 Circuit Board 10B10877G1 1

2 Metal Enclosure — 1

3 RJ-45 Short Cable 10H54910P15 1

4 Installation Manual 10H92873 1

5 Female IEC 10 A plug 10H46776P01/02 1

Vertiv™|Liebert

® Load Bus Sync™ Controller Installation Manual | 3

The Liebert® Load Bus Sync™ Controller has the electrical characteristics detailed in Table 2.

1.2 Mechanical Characteristics

The Liebert® Load Bus Sync™ Controller has these dimensions:

• Length = 7.1" (181mm)

• Width = 3.7" (94mm)

• Height = 2.5" (64mm)

Figure 1 Rear panel reference supply input

Table 2 Electrical Characteristics

Minimum Nominal Maximum

Supply voltage (50/60 Hz sinusoidal), volts 180 480 250

Supply current, mA — 14 —

Output current (per channel), mA 25 — 30

Working temperature °F (°C) 14 (-10) — 104 (40)

Phase stability error — 0.18 —

Phase shift within voltage tolerance range, degrees * — 1.5 °

* Voltage within ±10% of nominal value.

Vertiv™|Liebert

® Load Bus Sync™ Controller Installation Manual | 4

Figure 2 Front panel UPS sync. outputs

Vertiv™|Liebert

® Load Bus Sync™ Controller Installation Manual | 5

2.0 TYPICAL CONFIGURATIONS

2.1 Two Systems with Separate Utility Supplies

When two UPS’s are connected to separate power sources, the inverters attempt to synchronize

with their respective bypass lines, but the lines may not be in phase, so synchronization cannot be

guaranteed. Even if the two units are supplied from a common line, when one or both is operating

on-battery there will be no common input signal, and the outputs will not be synchronized. When

the Liebert® Load Bus Sync™ Controller is installed, one of the UPS outputs must be chosen as the

master, all the other UPS (slave) outputs will then follow this reference: see Figure 3 for details.

Figure 3 Two separate utility supplies

N.B. fuses should be installed in the phase signal line, upstream of the Liebert® Load Bus Sync™

Controller to protect against the damage caused by short circuits. Installation tips: UPS B should

be configured so that it follows the external synchronization signal. This is achieved by setting

the main synchronization source to external signal. Otherwise, the UPS will be in phase with its

own bypass line and will follow external synchronization only when this is out of tolerance.

Power Source A Power Source B

SlaveMaster

UPS A UPS B

Source

Line B

Source

Line A Static Switch

To Others

Static Switch

To Load

To Others

Static Switch

Liebert

Load

Bus Sync

™

Controller

Vertiv™|Liebert

® Load Bus Sync™ Controller Installation Manual | 6

2.2 Two UPS Units With Common Bypass Line

When two UPS’s are connected with a common bypass line, the bypass line synchronizes the two

inverters. Synchronization can be lost because of protection upstream of the bypass line. Using

the following solution, the two systems will be always synchronized, even if one of the two bypass

lines is out of tolerance. These units will usually be capable of synchronous operation.

Figure 4 Common bypass line

N.B. fuses should be connected at the beginning of the signal line to avoid fires in case of short

circuit in the wires.

2.3 Liebert® Systems and Electrical Generating Devices

The Liebert® Load Bus Sync™ Controller can be used to provide phase reference to the Liebert®

NX™ UPS in installations with alternative power sources, such as diesel generators, see Figure 5.

NOTE

UPS A and UPS B should be configured with main synchronization source to bypass. Otherwise

the UPS’s won’t be capable of synchronous transfer to bypass.

Power

Source B

UPS B

Power

Source A

UPS A

Source

Line B

Source

Line A

UPS A

L1 -Phase Signal

Neutral

L1 -Phase Signal

Common Bypass

Line

Static Switch

To Load To Others

Static Switch

UPS

To Others

Static Switch

Liebert

Load Bus

Sync

™

Controller

Liebert

Load Bus

Sync

™

Controller

Slave

Master

Vertiv™|Liebert

® Load Bus Sync™ Controller Installation Manual | 7

Figure 5 Liebert® NX™ systems and electrical generating devices

N.B. fuses should be installed in the phase signal line, upstream of the Liebert® Load Bus Sync™

Controller, to protect against the damage caused by short circuits.

Source

Line B

Source

Line A

Power Source

UPS

Liebert

Load

Bus Sync

™

Controller

Static Switch

To Load

Master Power Source

L1 -Phase Signal

Neutral

To Others

Static Switch

To Others

Static Switch

Vertiv™|Liebert

® Load Bus Sync™ Controller Installation Manual | 8

2.4 Liebert® NX™ and Third-Party Brand UPS in the Same Installation

The device can also be used to synchronize a Liebert® NX™ UPS with other manufacturer’s UPS

systems. The Liebert® NX™ units must be configured as slave devices so that they follow the phase

reference signal derived from the non-Liebert® master UPS. UPS #1 and UPS #2 may be

configured as parallel or single units, see Figure 6.

Figure 6 Liebert® NX™ and third-party brand UPS

Installation Tips: UPS #1 and UPS #2 should be configured to follow the external

synchronization signal. This is achieved by setting the main synchronization source to external

signal. If UPS #1 and UPS #2 are not set to follow the external synchronization signal, the UPS will

be in phase with its own bypass line and will follow external synchronization only when the bypass

line is out of tolerance.

Source

Line B

Source

Line A

Power

Source B2

UPS 2

Power

Source B1

UPS 1

To Load To Others

Static Switch

Power

Source A

UPS 1

UPS 2

L1 -Phase Signal

Neutral

To Others

Static Switch

Liebert

Load

Bus Sync

™

Controller

Vertiv™|Liebert

® Load Bus Sync™ Controller Installation Manual | 9

Figure 7 Installation example

Third-Party

UPS

(not by

Vertiv™)

Liebert

Load

Bus Sync

™

Controller

Liebert

™

UPS Parallel

System

Short connection

between UPS’s and

Liebert

Load Bus

Sync

™

Controller

Long connection between

Master source and

Liebert

Load Bus Sync

™

Controller

Fuse

Floor 1

Supply

Floor 2

Supply

Floor X

Supply

Vertiv™|Liebert

® Load Bus Sync™ Controller Installation Manual | 10

3.0 INSTALLATION

3.1 Installation Kit - 10B14515G1

The equipment is supplied with the following components:

Connect the PE, and master phase and neutral signals to the Liebert® Load Bus Sync™ Controller

reference signal input (see Figure 1) using the female IEC 10 A plug and a suitable power cable.

Connect the slave UPS to the Liebert® Load Bus Sync™ Controller UPS output (see Figure 2)

using the RJ-45 short cable.

3.2 Installation Tips

• Connect the Liebert® Load Bus Sync™ Controller input earth cable to a protective earth terminal.

• Position the Liebert® Load Bus Sync™ Controller near the slave units.

• Use shielded RJ-45 cables.

• Connect the RJ-45 cable (10H54910P15) directly to the control board; do not use terminals to extend

connections.

• Position the Liebert® Load Bus Sync™ Controller in a suitable location, protected from harmful conditions

such as: vibration, dust, corrosive atmospheres and high humidity.

• Install a 2A slow-blow fuse on the phase signal line as close as possible to the master unit

• If the Liebert® Load Bus Sync™ is mounted on top of a UPS, ensure that it does not obstruct air outlets.

NOTICE

Risk of improper electrical connections. Can cause equipment damage.

The Liebert® Load Bus Sync™ Controller must be supplied from L1 and N.

3.3 Appendix C - Liebert® NX™ 225-600kVA

3.3.1 Setting Parameters - Enable External Synchronization Control

Once all connections are completed, switch on QS1 on the first UPS and set the following

parameters:

1. In PPVis, click on “Service Tools” and select “Parameter.”

2. Set “Access level” to “Superservice”: PNU 51=4.

3. Set “Function Selection” to “HW-In it”: PNU 52=2.

4. Set “External synchronization control” to “Enable:” PNU 700=1.

5. Set “Function selection” back to “Return”: PNU 52=0.

6. Set “Access level” back to “Normal operation:” PNU 51=1.

7. Once back in normal operation, open QS1 and the electronics will shut down.

Table 3 Installation Kit - 10B14515G1 components

Item Description Part # Quantity

1 Circuit Board 10B10877G1 1

2 Metal Enclosure — 1

3 RJ-45 Short Cable 10H54910P15 1

4 Installation Manual 10H92873 1

5 Female IEC 10 A plug 10H46776P01/02 1

NOTE

Once the connections above have been completed, follow the procedure related to the UPS

model in 3.3 - Appendix C - Liebert® NX™ 225-600kVA

Vertiv™|Liebert

® Load Bus Sync™ Controller Installation Manual | 11

Follow these steps for ALL the units connected to the Liebert® Load Bus Sync™ Controller.

1. In this case in PPVis click on “Service Tools” and select “Parameter” -> “Parameter set” -> “DIC1 - Service

commissioning”

2. Set PNU 51 “Access level” to “Superservice(4).”

3. Set PNU 52 “Function Selection” to “HW-Init(2).”

4. Set PNU 700 “External synchronization control” to “Enable(1).”

5. Set PNU 52 “Function selection” back to “Return(0).”

6. Set PNU 51 “Access level” back to “Normal operation(1).”

7. Click on “Send all set values” push button.”

8. Once back in normal operation open QS1 and the electronics will shut down.

NOTE

Since the DIC FW Rev. 1.10 users may change parameters through a graphic interface:

Vertiv™|Liebert

® Load Bus Sync™ Controller Installation Manual | 12

3.3.2 Offset Compensation Tuning

The parameter 731.32 has been designed to compensate the phase error, introduced by the UPS

control, between the frequency reference coming from the Liebert® Load Bus Sync™ Controller

and the inverter output signal. To carry out this procedure an oscilloscope between reserve input

and inverter output must be used. The Liebert® Load Bus Sync™ Controller must be installed and

interconnected to the UPS system. The PNU 700 must be set to 1. The PNU 731.32 calibration

must be done on each UPS in the system. Perform the following steps:

1. Connect an oscilloscope to the first UPS.

Connect “Channel 1" to “Bypass Input L1 and N” and “Channel 2" to “UPS Output L1 and N”, as shown in

Figure 8) Main BUS A.

Figure 8 Offset compensation

2. With NO LOAD connected, start the inverter.

3. Open the reserve input switch QS2.

4. Verify on the oscilloscope the phase error between inverter and bypass. The following figures show an

example of NO SYNC (Figure 9) and SYNC (Figure 10).

Figure 9 Synchro Error 88,56 [°]

Main Bus A

CH1 Oscilloscope

CH2

Fref

Liebert®

Load Bus

Sync™

Reserve Input

UPS An

Vertiv™|Liebert

® Load Bus Sync™ Controller Installation Manual | 13

Figure 10 Synchro Error 0 [°]

When there is NO SYNC we need to determine the offset between the two waveforms, in the

example Figure 9 there is a difference of 88.56°. To ensure a correct synchronization, enter a

value in PNU 731.32 (the offset).

To calculate the offset value:

PNU 731.32 = phase-error [°] * 65536 / 360 PNU 731.32 = 88,56° x 65536 / 360 PNU 731.32 = 16121

After calculating the new value for PNU 731.32, proceed with following steps to change it.

1. Close QS2 on the first UPS.

2. Wait for the Warning W1.1 - Bypass Switch Open - to be cleared.

3. Stop the inverter.

4. In PPVis click on Service Tools and select Parameter.

5. Set “Access level” to “Superservice”: PNU 51=4.

6. Set “Function Selection” to “HW-Init”: PNU 52=2.

7. Set PNU 731.32 “EXT_SYNCH_OFFSET” to “the new calculated value” (16121 in our example).

8. Set “Function selection” back to “Return”: PNU 52=0.

9. Set “Access level” back to “Normal operation”: PNU 51=1.

10. Start the inverter and open QS2 again, check that the SYNC is now according to example in Figure 10.

11. Close QS2 again.

NOTE1

If by using this formula you are not able to compensate the offset, try with the following formula:

PNU 731.32 = (360 - phase error [°]) * 65536 / 360

Vertiv™|Liebert

® Load Bus Sync™ Controller Installation Manual | 14

3.3.3 Procedure complete for UPS1

NOTE

This offset compensation procedure must be followed for ALL the units connected to Liebert®

Load Bus Sync™ Controller.

Vertiv™|Liebert

® Load Bus Sync™ Controller Installation Manual | 15

3.4 Installation Example

Figure 11 Installation example

Note the position of the Liebert® Load Bus Sync™ Controller. This unit’s location should be

selected so that the connections to the slave units are as short as possible. Install a 2A slow-blow

fuse on the phase signal line, as close as possible to the master unit.

Third-Party

UPS

(not by

Vertiv

™

)

Liebert

Load

Bus Sync

™

Controller

Liebert

™

UPS Parallel

System

Short connection

between UPS’s and

Liebert

Load Bus

Sync

™

Controller

Long connection between

Master source and

Liebert

Load Bus Sync

™

Controller

Fuse

Floor 1

Supply

Floor 2

Supply

Floor X

Supply

Vertiv™|Liebert

® Load Bus Sync™ Controller Installation Manual | 16

NOTES

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Vertiv Liebert Load Bus Sync Controller User manual

Vertiv Liebert Load Bus Sync Controller User manual

Vertiv Liebert Load Bus Sync Controller User manual

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