Outback FX-R Series Installation Manual

Commissioning
900-0166-01-01 Rev A 33
Stacking Configurations
Series Stacking (Dual-Stack)
In series stacking, two inverters create two separate 120 Vac
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output phases. One phase is the
master. The second inverter is a subphase master. It creates a 120 Vac output that is intentionally
180° out of phase with the master. Each of these outputs can be used to power a separate set of
120 Vac loads. Collectively they form a “split-phase” configuration. This configuration produces
240 Vac, which can be used to power 240 Vac loads when both inverters work together.

The two outputs operate independently of each other. The 120 Vac loads on each output cannot exceed
a given inverter’s size. One inverter cannot assist on the opposite phase.

Both inverters must be the same model.

See page 37 when stacking in series with more than two inverters (series/parallel stacking).
Figure 23 Example of Series Stacking Arrangement
When installing a series inverter system, observe the following rules.

Series stacking requires both the system display and the communications manager. See the HUB10.3
literature for any required jumper configurations.

The master must be connected to communications manager port 1. It is programmed as
Master
.
Other inverters must not be assigned as the master.

The second inverter must be programmed as
L2 Phase Master
. It must be connected to port 7.

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 circuit breakers to be
located at the bottom of the main panel. This prevents overloading of the AC bus.
NOTE
: The FW-X240 and similar transformers are not used for load balancing of stacked FXR inverters.
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Output voltages may vary with regional voltage standards.
2.0 kVA
120 Vac
4.0 kVA
240 Vac
2.0 kVA
120 Vac
2.0 kVA 120 Vac
2.0 kVA 120 Vac
LOAD PANEL
OR
Master
L2 Phase Maste
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