Basic Operation - Xantrex XW4024-120 Operation Manual

Basic Operation

Multi-unit operation
975-0240-01-01
The XW Series Inverter/Charger is a modular "building block" sine-wave
inverter/charger that can be used for both residential and commercial stand-alone,
grid-backup, and grid-tie applications with battery energy storage. The XW
Inverter/Charger is a self-contained DC to AC inverter, battery charger and
integrated AC transfer switch. Up to three inverters can be installed together in a
120/240 V split phase configuration.
Inverting For multiple XW Inverter/Chargers, the master inverter/charger
broadcasts pulses on the Xanbus network to synchronize and arbitrate operation
between the other paralleled units. This coordination of multi-unit operation
results in reduced tare loss and improved efficiency—other paralleled units stay in
low-power mode until they are needed.
For paralleled XW Inverter/Chargers, only one inverter/charger operates, and
additional devices come on-line only when the load exceeds approximately 60 per
cent of the rated output of the master inverter/charger. In a three-unit system,
additional slave units come on sequentially if the load on the master does not drop
below 60 per cent about 3 to 5 seconds after a slave unit turns on to assist the
master. When the load drops below 20 per cent of the master's rated output, the
slave units turn off in reverse order; that is, the last slave unit to turn on will be
first to turn off.
The current sharing imbalance for a single inverter/charger does not exceed 10 per
cent of the rated maximum nominal output power. All non-utilized inverter/
chargers are off-line when no load is present.
Parallel charging When multiple XW Inverter/Chargers are charging in a
system, they synchronize charging stages to ensure efficient charging of the
battery bank. All units transition from bulk to absorption when a single unit does.
In absorption, all units must complete the absorption stage before transitioning to
the next stage. Note that units do not load share when charging. Each unit charges
batteries based on the Max Charge Rate setting and active internal (temperature-
based) deratings.
If equalize is enabled on one or more devices capable of equalization charging
(such as XW Inverter/Chargers or XW Series Solar Charge Controllers), only
those devices initiate and perform a equalize cycle after absorption. Other devices
will float (if three-stage charging is selected) or transition to AC pass-through (if
two-stage charging is selected).
When one or more XW Series Solar Charge Controllers are installed and
operating in the system, the XW Inverter/Chargers synchronize charging stage
(bulk, absorption, or float) with the charge controllers. In a similar fashion to the
XW Inverter/Charger charge behavior, charge controllers also harmonize charging
among themselves.
AC Transfer XW Inverter/Chargers monitor each other using a peer-to-peer
monitoring technique to determine the quality of AC input. If AC input is deemed
bad by any of the paralleled units, no transfer to AC occurs and the units may
Basic Operation
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