Outback FX-R Series Installation Manual

Commissioning
900-0166-01-01 Rev A 37
Series/Parallel Stacking (Quad-Stack or Larger)
In series/parallel stacking, inverters create separate 120 Vac
6
output phases and 240 Vac
collectively, as in series stacking. However, in this configuration, each output uses inverters in
parallel. One output contains the master; the other uses a subphase master. Each output has at
least one slave.

The 120 Vac loads on each output can exceed the size of a single inverter. They can be powered by all
the inverters on that output.

The slave outputs are controlled directly by their respective master inverters. They cannot operate
independently. The slaves can go into Silent mode when not in use.

Up to eight inverters may be installed in series/parallel. All inverters must be the same model.
Figure 27 Example of Series/Parallel Stacking Arrangement (Four Inverters)
When installing a multiple-inverter series/parallel system, observe the following rules.

Series/parallel stacking requires both the system display and the communications manager. See the
HUB10.3 literature for any required jumper configurations.

The inverter that is mounted physically lowest is always master and is programmed as
Master
.
Mounting below the other inverters allows the master to avoid heat buildup and remain relatively cool as it
sees the greatest duty cycle.

The master must be connected to port 1 of the communications manager. Other inverters must not be
assigned as master.

Any other inverter on the L1 output (parallel with the master) should be assigned as
Slave
during
programming. These can be connected to ports 2 through 4. L1 inverters cannot use other ports.

The subphase master for the L2 output must be assigned as
L2 Phase Master
. It must be connected
to port 7.

Any other inverter on the L2 output (parallel with the subphase master) should be assigned as
Slave
during programming. These can be connected to ports 8 through 10. L2 inverters cannot use other ports.

All wiring and circuit breakers must be sized appropriately for loads and inverter power.

The AC input (generator or utility grid) must be a split-phase source of the proper voltage and frequency.

When wiring the AC source to the inverters, local codes may require the inverter circuits to be located at
the opposite end of the panel from the main circuit breaker. This prevents overloading of the AC bus.
NOTE
: The FW-X240 and similar transformers are not used for load balancing of stacked FXR inverters.
6
Output voltages may vary with regional voltage standards.
3 kVA 120 Vac
3 kVA 120 Vac
12 kVA
240 Vac
6 kVA
120 Vac
6 kVA
120 Vac
3 kVA 120 Vac
3 kVA 120 Vac
LOAD PANEL
OR
L2 Phase
Master
Slave
Master Slave