Liebert UPS System - Manual (Page 106)

Chapter 8 Parallel System
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Table 8-3 Fault and fault process methods of parallel operation system
No. Fault description Reasons Fault processing
1
Overload of parallel
operation system Overload occurs and the
redundancy is not available
Disconnect the load of low priority,
maintain the power supply to important
load
2
Single module UPS
system requires to
transfer to bypass
mode
In parallel operation system,
some UPS unit may require
to transfer to bypass due to
surge or overload, other
units will transfer to bypass
after receiving the signal
sent by this UPS unit that
requires to transfer to
bypass mode
If the parallel operation system
transfers to bypass mode, and the
operation condition enables, all the
UPS units can recover to normal mode
synchronously.
3 Load sharing fault
The load current of each
UPS unit is noticeably
unbalanced, thus the system
loading ability is affected.
Notify the service dept for repairing
4
Parallel operation
board fails
The board is damaged. Notify the service dept for repairing