Outback Power Systems GFX International Series Installation Manual - Manual (Page 33)

Installation
900-0111-01-00 Rev B 31
Three-Phase Stacking
In three-phase stacking, inverters are stacked to create three separate 230 Vac output legs in a wye
configuration.
¾ The output of each inverter is 120° out of phase from the others. Any two outputs produce 400 Vac
between them. The outputs can be used to power three-phase loads when all inverters work together.
¾ Only three inverters, one per phase, may be installed in a three-phase arrangement.
Figure 22 Example of Three-Phase Stacking Arrangement (Three Inverters)
When installing a three-phase system, the following rules must be observed.
¾ Three-phase stacking requires a system display and a HUB.
¾ The inverter that is mounted physically lowest is always the master and is programmed as Master. (See the
system display manual for programming.) Mounting below the other inverters allows the master to avoid
heat buildup and remain relatively cool as it sees the greatest duty cycle.
¾ The master must be connected to port 1 of the HUB. Other inverters must not be selected as master.
¾ One slave inverter must be programmed as 3p Classic B. The other must be programmed as 3p Classic C.
(See the system display manual for programming.)
¾ The inverters should be wired to the loads and to the AC sources in phase order. The master should be
phase A, the first slave should be phase B, and the second slave should be phase C.
¾ All overcurrent devices must be sized for 30 Aac or less.
¾ All wiring must be sized for 30 Aac or more.
¾ All output circuit breakers must be sized appropriately for loads and inverter wattage.
¾ All inverters must be of the same model.
¾ The AC input (generator or utility grid) must be 230/400 Vac at 50 Hz (a three-phase wye configuration).
¾ 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.
IMPORTANT:
Although the HUB manual states that it is necessary to move the HUB’s jumper to the
three-phase position, that statement is not applicable for this model. The jumper must
be left in its original position.
1.3 kVA 230 Vac
1.3 kVA 230 Vac
1.3 kVA 230 Vac
1.3 kVA
230 Vac
3.9 kVA
400 Vac
1.3 kVA
230 Vac
1.3 kVA
230 Vac