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Eaton 93PS UPS 8–40 kW
5.6
The outputs of multiple 93PS UPS systems can be connected in parallel. Up to
4 units can be paralleled. The UPS static bypass power rating needs to be
identical among all the paralleled units. However, paralleled UPS cabinets can
be housed with different number of UPM power modules.
The outputs are paralleled to increase the load capacity of the power system
and for redundancy. The system is paralleled for (N+1) redundancy as long as
there is always one or more UPS online than required to support the load. The
system is paralleled for capacity if all UPSs in a system are required to support
the load.
Communication between the UPSs is required for system metering and mode
control. The system level communication and control are accomplished using a
Controller Area Network (CAN). A pull-chain signal in each UPS, connected to
the other UPSs in parallel and tied to the bypass status relay in each UPS, is
used for a secondary communication path. This arrangement ensures bypass
control even if the CAN bus is lost.
Do not connect units equipped with an internal Maintenance Bypass Switch
(MBS) or internal transformers in parallel.
5.6.1
See Section
installation practices.
Input feed
The input feed is defined as the power source connected to the UPS rectifier.
The feed to all UPS's inputs must be derived from the same source.
Bypass feed
The bypass feed is defined as the power source connected to the UPS bypass.
The feed to all UPS's bypass must be derived from the same source. The
shortest length of power wire from the source to the UPS must be a minimum of
95% of the length of the longest wire.
Output
The neutrals of all the UPSs must be connected. The shortest length of wire
from the source to the UPS must be a minimum of 95% of the length of the
longest wire. The measurement is with respect to where the UPS's outputs are
tied.
Dual source
©
Eaton Corporation plc 2016. All rights reserved.
Wiring parallel 93PS UPS systems
Power wiring overview
4.3.2
for the recommended cable and external fuse sizes and
WARNING
Revision: 003
Document ID: P-164000493
User's and installation guide
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