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8. OPERATING PROCEDURES FOR PARALLEL SYSTEMS
8.1. Introduction
PDSP PREMIUM UPS Systems are designed according to high MTBF figures with increased reliability.
To increase the output power or the UPS system availability a second (or more) PDSP PREMIUM UPS can be
connected in parallel redundant/power. Maximum of 4 identical power PDSP PREMIUM power unit can be
connected in parallel.
You may see the block diagrams of Parallel Systems in
Appendix-6: Description of UPS and Block Diagram
.
There are two paralleling modes you may choose via Front Panel.
You may reach this menu with service
password, only.
8.1.1. Redundancy
The UPS parallel system is redundant when one or more UPS units can be stopped by failure or maintenance
operation without affecting the load supply by the remaining operating UPS units.
N+1 redundancy means than one UPS unit can be stopped without affecting secured load supply.
N+2 redundancy means than up to two UPS unit can be stopped without affecting secured load supply.
Maximum Load per parallel UPS unit to keep redundancy:
Number of Parallel UPS Units
2
3
4
Red
u
n
d
an
cy
N+1
50%
66%
75%
N+2
---
33%
50%
8.1.2. Power Increase
If Power Increase Mode is selected, the total capacity of the system is N times the capacity of each UPS unit.
Maximum load per unit can reach 100% in normal operation. All running UPS units in parallel share the load
equally.
In case of any problem on one of the units, the remaining units may operate in overload and the loads
supplied through bypass after certain time.
Parallel configuration must only be activated by INFORM UPS Technical Service Personnel.