Liebert UPS System User Manual page 106

Table 8-3 Fault and fault process methods of parallel operation system
No. Fault description
Overload of parallel
1
operation system
Single module UPS
system requires to
2
transfer to bypass
mode
3 Load sharing fault
Parallel operation
4
board fails
C hapter 8 Parallel System
Reasons
Overload occurs and the
redundancy is not available
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
bypass mode
The load current of each
UPS unit is noticeably
unbalanced, thus the system
loading ability is affected.
The board is damaged.
100
Fault processing
Disconnect the load of low priority,
maintain the power supply to important
load
If the parallel operation
transfers to bypass mode, and the
operation condition enables, all the
UPS units can recover to normal mode
synchronously.
to
Notify the service dept for repairing
Notify the service dept for repairing
system