Considerations For Multiple-Shelf Systems - ABB 827E Product Manual

Considerations for Multiple-Shelf Systems

Up to four inverter shelves may be installed as a system with their AC outputs paralleled to provide
higher current capacity. In creating such a system there are several aspects to recognize and
consider.
• Each shelf must be complete with a System controller, a Distribution Disconnect Module (with Distribution
Monitor), and at least one Inverter.
• Each shelf needs to contain the same (or similar) number of inverters. This is to balance the load current
across all of the shelves.
• Each shelf must have its SHELF # setpoint set to a unique value (1-4).
• Each shelf operates independently, as far as setpoints, control, alarms and remote communications are
concerned. The System Controller in each shelf
The Plant Status values shown on the LCD of a System controller apply only to that shelf.
•
The setpoint values entered into a System controller apply only to that shelf. This includes the setpoints
•
for "# REDUNDANT IMs" and "% of CAPACITY."
• The AC output of all inverters in a multi-shelf system must be connected together for the shelves to be able to
supply AC power to the same distribution and have their output waveforms phase-synchronized. To prevent
damage to inverters the proper power-up sequence must be followed. See Shelf Turn On and Operational
Checkout.
• The alarm setpoints for AC voltage, AC current and DC voltage must be set the same on all shelves.
• Each System controller must be equipped with its optional modem and phone line for remote communication
to take place with that shelf.
WARNING: AC power will feed back to all shelves and to loads from any operating inverter via the
parallel connection of shelf outputs. Extreme caution must be exercised in installation
and maintenance of multiple shelf systems.
CAUTION: Damage to inverters may occur if a shelf in a multi-shelf configuration does not have a
functioning System controller module or if an improper power-up sequence is followed.
Follow the sequence in the Shelf Turn On and Operational Checkout section when
turning on a shelf. Never close a shelf's output breaker with the shelf already powered
unless there is a functioning System Controller in the shelf and the shelf's inverters are
indicating STANBY mode (amber LED is on).
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