Product Manual

Operation
900-0198-01-00 Rev A 31

The fourth line shows that loads of 36 Aac or more (approximately 4 to 4.5 kW) are present on the system. This
load causes all four inverters to be activated.
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The last line shows that the loads are reduced to 16 Aac. Since this load is distributed among four inverters, the
master reads 4 Aac, the lower threshold for Power Save. This causes one slave to enter Silent mode. The 16 Aac are
distributed among the remaining three inverters. If the loads decreased to 12 Aac, a second slave would go silent.
Figure 15 shows a system of six FX2012MT inverters. In this example the inverters are stacked in an
OutBack series/parallel system with FW-X240 transformers. The master inverter is on the L1 output with
two slave inverters. The L2 output has three slave inverters.
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The captions at the top indicate the ranking of each inverter.

The captions also show the port assignments on the HUB10.3 Communications Manager. The L1 inverters use
ports 1, 2, and 3. However, the HUB10.3 requires the L2 inverters to use ports 7, 8, and 9.

The notations at the bottom show how the inverters are activated in sequence as loads are applied.
 The first line shows a load handled by the master alone.
 The second line shows a total load of 15 Aac, even though the load on the master has not changed. (This load is visible
to the master due to the balancing transformers.) The master turns on the first slave, L2 Slave 1 (Power Save Level 1).
 The third line shows an increasing load of 28 Aac. The master turns on two more inverters (Power Save Levels 2 and 3).
 The fourth line shows that loads of 36 Aac or more (approximately 4 to 4.5 kW) are present on both L1 and L2. This load
causes all six inverters to be activated.
 The last line shows that the total load is reduced to 25 Aac. The master turns off three inverters (Power Save Levels 3, 4,
and 5) and leaves three active.
Figure 15 Power Save Priority (Split-Phase)
L1 Master L1 Slave 1 L2 Slave 1L1 Slave 2
Port 1
Master Power
Save = 0
Port 2
Slave Power
Save = 2
Port 7
Slave Power
Save = 1
Port 3
Slave Power
Save = 4
L1 Load L2 Load
9 Aac On Off Off 0 Aac Off Off Off
9 Aac On Off Off 6 Aac On Off Off
15 Aac On On Off 13 Aac On On Off
36 Aac On On On 36 Aac On On On
16 Aac On On Off 9 Aac On Off Off
L2 Slave 2 L2 Slave 3
Port 8
Slave Power
Save = 3
Port 9
Slave Power
Save = 5