Product Manual

Operation
40 900-0145-01-01 Rev B
depending on the inverter’s stacking designation.

Master Power Save Level
appears on an inverter which is set as master (the default setting). In a stacked
system, this selection should only appear on the inverter using Port 1 of the communications manager.
The range of rank numbers is 0 to 31. The default value is 0. The master is normally left at this value.

This heading also appears on an inverter which is set as the B phase or C phase master. The range of rank
numbers is 0 to 31. The default value is 0.

Slave Power Save Level
appears on an inverter which is set as slave. The range of rank numbers is 1 to 31.
(The default value for all ports is 1.)

The ranks are prioritized so that lower-numbered ranks turn on sooner and higher ranks turn on later.
The lowest-ranked unit will not go silent and will remain on unless ordered otherwise. The lowest-ranked
unit is expected to be the master. The priorities are the same across both screens; thus, if P01 (master) is set
at 0 and P02 (slave) is set at 1, the slave will turn on later. Since the
Master
item is the only one that goes to
0, it is easy to ensure that all other units besides the master go silent.
IMPORTANT:
Set the master rank at 0 and arrange the slave ranks in order (1, 2, 3, 4, etc.). Another
order may defeat the purpose of Power Save mode. Leaving the master at 0 makes 4
kW of power available from the master; the other inverters should not be active. If a
slave is ranked lower (prioritized higher) than the master, that slave will not go silent.
NOTE:
Disregard this rule if the installation requires some of the slaves to be
continuously active.
IMPORTANT:
Do not give slave inverters the same rank numbers. If, for example, multiple slaves
were all ranked at 1, they would all come on at the same time. Once they came on, the
divided load would cause the master to detect a minimal load on its output, so it
would shut off all the slaves, at which point the master would read a high load again.
This could quickly escalate into a rapid on/off cycling of inverters and could cause
long-term system problems.
Figure 12 shows a system of four GS3548E inverters (the master and three slaves) in a parallel system
with a common load bus. The labels at the top indicate the ranking of each unit. The notations at the
bottom show how the units are activated in sequence as loads of approximately 2.5 kW are applied.
Figure 12 GS3548E Power Save Priority
The last line indicates that loads of approximately 7 to 8 kW are present on the system, causing all four
inverters to be activated.
Minimal Load On Off Off Off
approx. 2.5 kW (12 Aac) On On Off Off
approx. 5 kW (24 Aac) On On On Off
approx. 7 to 8 kW (36 Aac) On On On On
Master
Slave 1 Slave 3 Slave 2
Master Power Save
=
0
Slave Power Save
= 1
Slave Power Save
= 3
Slave Power Save
= 2