Outback Power Systems GFX International Series Installation Manual - Manual (Page 30)

Installation
28 900-0111-01-00 Rev B
Multiple-Inverter AC Installations (Stacking)
Installing multiple inverters in a single AC system allows larger loads than a single inverter can handle.
This requires stacking. Stacking inverters does not refer to physically placing one on top of another. It
refers to how they are wired within the system and then programmed to coordinate activity. Stacking
allows all units to work together as a single system.
Examples of stacking configurations include “parallel” and “three-phase” configurations.
Stacking Connections
Stacking requires an OutBack HUB product, as well as a system display, such as the OutBack MATE or
MATE3. (If the MATE is used, it must have firmware revision 4.1.6 or above.) A system using four or
fewer units may use the HUB4. Systems using up to ten units require the HUB10. All interconnections
are made using CAT5 noncrossover cable.
Figure 19 OutBack HUB4, MATE3, and MATE
Each inverter must be assigned a status — “master” or “slave”. The master is the primary and most
heavily used unit. The master inverter’s MATE/HUB port must connect to port 1 on the HUB.
Slave inverters provide assistance when the loads are more than the master can handle alone. Slaves
plug into ports 2 and above on the HUB. In general, it does not matter which slave connects to which
port. However, it is always important to keep track of units and ports for programming purposes. See
the system display manual for more information.
Programming involves using the system display to assign a status and stacking value to the inverter
on each port. Each inverter is assigned to power a specified phase of the system. These assignments
can be changed at any time as long as the master is plugged into port 1.
IMPORTANT:
¾ The master inverter must always be connected to port 1 on the HUB. Connecting it
elsewhere, or connecting a slave to port 1, will result in backfeed or output voltage
errors which will shut the system down immediately.
¾ Installing multiple inverters without stacking them (or stacking them incorrectly) will
result in similar errors and shutdown.
¾ Although stacking allows greater capacity, the loads, wiring, and overcurrent devices
must still be sized appropriately. Overloading may cause circuit breakers to open or
the inverters to shut down.
HUB4
MATE
Additional Ports Port 1 MATE Port
MATE3