UPS Multi-Module Installation

3.2.4Control Cables Intermodule Control

Shielded and double insulated control cables available in lengths of 5, 10 and 15 meters must be must be interconnected in a ring configuration between UPS modules as shown below. The parallel control board is mounted on the top, behind protective cover of each UPS module (refer to Figure 23). The ring configuration ensures high reliability of the control. Refer to Figure 16.

Figure 16 Connection of 1+N system parallel control cables

 

1

 

 

2

 

 

3

UPS

 

4

 

 

5

 

 

6

 

 

 

 

 

 

 

 

 

 

 

 

 

Parallel Board

Parallel Board

Parallel Board

Parallel Board

Parallel Board

Parallel Board

X3

 

P5

X3

 

P5

X3

 

P5

X3

 

P5

X3

 

P5

X3

 

P5

 

 

X4

 

 

X4

 

 

X4

 

 

X4

 

 

X4

 

 

X4

X2-2

X2-1

X2-2

X2-1

X2-2

X2-1

X2-2

X2-1

X2-2

X2-1

X2-2

X2-1

P2

 

P1

P2

 

P1

P2

 

P1

P2

 

P1

P2

 

P1

P2

 

P1

X1-1

X1-2

X1-1

X1-2

X1-1

X1-2

X1-1

X1-2

X1-1

X1-2

X1-1

X1-2

P3

 

P4

P3

 

P4

P3

 

P4

P3

 

P4

P3

 

P4

P3

 

P4

3.3Hot-Standby UPS Modules

3.3.1Cabinet Installation

Place the UPS modules side by side and interconnect as shown below.

The hot standby mode comprises two series connected UPS modules of the same rating. One module is designated as the hot standby master (downstream), and the other module is designated as the hot standby slave (upstream). Their roles are determined by power connection and configuration soft- ware. In normal operation, both slave and master operate in normal mode and the output from one upstream (slave) UPS feeds the bypass input to the other (downstream/master) UPS. The output of the downstream (master) UPS is connected to the critical load and is always synchronised to the out- put of the upstream (slave) UPS. If the inverter of the UPS connected to the load fails, the inverter of the upstream (slave) UPS supplies the load through the downstream (master) UPS bypass circuit. The system can be programmed to cycle the downstream (master) UPS between normal mode and bypass mode so that both ups are equally exercised.

NOTE

If it is a hot-standby system, the master (downstream) must be turned on first.

3.3.2External Protective Devices

Refer to the instructions in 1.0 - Single Module UPS Installation.

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Liebert NX UPS System user manual Hot-Standby UPS Modules, Control Cables Intermodule Control