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7.1.2 Design Concept
This option is composed by:
Parallel Board (Part no. # 100216120028)
1 flat 60-poles, to connect to UPS Board (connector X7)
1 screened flat 34-poles, to connect signals of the two modules in
parallel.
WARNING
Installing and connecting parallel option must be performed
by trained personnel. Operation of modules from single to 1
+ 1 requires a new commissioning: also this operation must
be performed by trained personnel.
The 7400-M UPS manufactured before this series have different serial
numbers: they can be upgraded in field to accept Parallel Option: An
upgrading kit s.n. 7464103005 is allowable - consult Emerson
Network Power Sales Office or Emerson Network Power's Customer
Service & Support.
Maintenance Bypass
The load can be supplied by the Maintenance Bypass switch of each
module or both.
An electronic interlock prevents the module itself and the other to
supply the load with its own inverter.
Bypass Supply
The load can be supplied by the static switch of each module or both.
The conditions to operate static switch are the same than the single
module. An electronic interlock prevents the module itself and the
other to supply load with its own inverter.
Normal Operation
The load is normally supplied by both inverters; an electronic control
share equally the load separately for the 3 phases. In normal
conditions the synchros of the two inverters are the same and their
oscillators are locked together: they may be phase-locked to mains
frequency if present and that's allowed by the system. If synchro with
mains is not allowed the two oscillators run at their set centre
frequency (50.0 or 60.0 Hz).
The presence of mains at the input of one of the two modules is
enough to synchronise both modules
.
Note:
In parallel configuration the microprocessor PLL on UPS
Board is Inactive: setting of slew rate of synchronisation in Hz/sec
is fixed and is not possible to change it from panel of UPS: PLLs
working are on Parallel Boards and they are totally analogic.
7400M - Series UPS User Manual
Single Module and 1+N Parallel System