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© 2010 Magnum Energy, Inc.
3.0 Setup
02E Parallel Threshold:
This setting programs when the slave inverters
turn on as a result of the power being provided by the master inverter.
In order to keep from overcurrenting the master inverter before the
slave inverters can turn on and provide more power to run loads, the
master inverter should not be allowed to reach the full output capacity.
This setting is expressed in a percentage of power being provided by
the master inverter.
Info:
When the
Parallel
Threshold
setting is reached, all
connected slave inverters turn on at the same time to deliver
maximum power to the loads. After approximately 30-seconds
running to stabilize the AC current, the slave(s) that are not
needed will shut down and the units that are still inverting will
share the AC current equally.
Example:
There are 3 MS4024PAE units in parallel (1- Master, Slave #1,
and Slave #2) with a total capacity of 12kW and the
Parallel
Threshold
default is set to 60%. The master inverter is running a 2000W load which
is below the 60% threshold (4000W x .6 = 2400W). A 1000W load is
added so the total load on the system is now 3000W, which exceeds
the
Parallel
Threshold
setting of 2400W. Slave #1 and #2 inverters will
turn on, delivering up to 12000W total power. Within approximately 30-
seconds, the system will shut down Slave #2, and the master and Slave
#1 will each run 1500W (sharing the 3000W load equalling between
them). Now the 1000W load is turned off so the total system load is
2000W. Slave #1 will now turn off and the master inverter will be running
the 2000W load.
Default setting
-
60%
Should I use the Parallel Threshold feature?
This depends on the
application. Most applications set a threshold level such that the connected
slave inverters come on only when they are required to power the loads. This
reduces the power drain on the batteries because the slave inverters that are
not actively powering the loads are in standby.
If you have a load larger than the capacity of the Master inverter and the
startup current is needed very quickly, you may need to turn the threshold
setting OFF. This will ensure all the stacked inverters are always on to meet
the fast startup current requirements of this large load.
Where should I set Parallel Threshold?
Where you set the threshold
depends on your typical AC loads and how much time you would like the
master inverter to run (versus the slaves). If you want the master inverter
to run as much of the loads as possible before the slave(s) turn on, then set
the threshold at a higher setting. If you want the slave(s) to share more of
the load, then set the threshold to a lower setting.
Example:
Your loads are typically under 4000W and you have a 3-
inverter parallel system. You want the master to run loads up to 3000W
before the slave inverters turn on. You would set the
Parallel Threshold
to 75% (4000W x .75 = 3000W). The master inverter will now run any
load up to 3000W before the slave inverters turn on. In this scenario,
if a 5000W load was turned on the slave inverters would turn on, and
then Slave #2 would turn off, and the master and Slave #1 would each
run at 2500W.
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