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CENTRIC 3x480, User Guide, rel. 1.7
Number of UPS modules:
must be less than or equal to the number of modules currently in-place in the UPS.
Number of modules for redundancy:
Of the total number of UPS modules, you must indicate the number of modules that are intended to
provide redundancy.
Number of dc-to-dc converter blocks:
Each dc-to-dc
converter module
contains two
converter blocks
.
Each UPS module requires one converter
block
. So, the ideal number of dc-to-dc converter blocks is
the same as the number of UPS modules to be used. The Centric does not verify that the number of
dc-to-dc blocks
matches the number of
UPS modules
. No harm is done if the number of dc-to-dc
converter blocks installed is greater than the number of UPS modules.
Note: If the number of dc-to-dc blocks is less than the number of UPS modules, the UPS modules
which have no corresponding dc-dc block will not have backup power when the UPS goes into battery
mode.
Section 2.7 has more information about the dc-to-dc converter modules.
7.2.1.2.1
R
EDUNDANCY
"Redundant" modules are those above and beyond the minimum number of modules required to supply the
maximum expected UPS load. Each
Centric
module can supply 10 kVA / 10 kW. So, for example, if the
maximum expected load is 50 kVA, and there are six power modules installed, one of them can be
designated for redundancy. In the event one of the six modules fails, the redundant module ensures that
the UPS will continue to be able to accommodate the maximum expected load.
When all modules are operating normally, the redundant modules participate in the load sharing.
A redundant module is one in excess of the minimum number of modules required to meet the UPS’s
maximum expected load. If any module fails, the presence of the “extra” or redundant module(s)
guarantees that the maximum expected load can still be supported. The number of redundant modules can
be zero or greater, depending on the maximum expected load and the number of available module shelves.
When all modules are operating normally, the redundant modules share the load equally with the rest of the
modules.
Defining a redundancy of one or more modules affects the UPS’s perception of its maximum output
capability. The redundant module(s) is not taken into account in calculating the UPS’s maximum output
capability.
As an example, say we have a UPS system with five module shelves that can hold modules of 10 kW. The
maximum expected load is 35 kW. Four modules (40 kW) are required to supply the maximum expected
load. A fifth module can be installed and a redundancy of one module declared, giving the UPS a total
capacity of 40 kW. If any one of the five modules fails, the UPS will still be able to supply power for the
maximum expected load. If all of the modules are operating normally, and the load unexpectedly increases
to 45 kW, the system will indicated an overload condition, because the redundant module is not taken into
account in calculating the UPS’s maximum output capability.
Redundancy is not a property of any particular module. Redundancy is simply the presence of one or more
modules in excess of the number of modules required to meet the maximum expected load.
Note: When modules are added to the system or removed from the system, the value of total number of
modules must be adjusted. You may or may not at that time also want to change the number of redundant
modules.
7.2.1.3
SETUP > SYSTEM > NUMBER OF BATTERIES
Specify the number of battery strings connected to the UPS. You can specify 1, 2, or 3 battery strings. The
Centric
requires you to enter a password to change this setting.
(Note: A “battery string” or “battery set” is the basic number of batteries required to provide standard
backup capabilities. For the Centric, this is 60 x 12 V batteries. A battery string may be housed in one or
more battery cabinets. For extended backup time, multiple battery sets can be attached to the Centric.)
