©
2013 Magnum Energy, Inc.
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Operation
3.11 Parallel Operation
This section provides information about operating the MS-PE Series inverters in parallel.
IMPORTANT: You must have a ME-RTR router to parallel stack multiple inverters. Refer
to the ME-RTR Owner’s Manual for info on setting up and turning on a parallel system.
WARNING:
The information is this section is meant to supplement the information
in previous sections. To prevent personal injury or equipment damage, you must
carefully read and follow all instructions and warnings in this owner’s manual.
3.11.1 Overview
A single MS-PE inverter produces 230VAC at its rated power (i.e., MS4124PE provides 4100 watts
of inverter power). Parallel stacking synchronizes multiple inverters to work together as a single
inverter/charger system that increases the inverters’ continuous and surge capacity, the charging
capability to the battery bank, and the AC pass-through capacity.
The ME-RTR router allows MS-PE Series inverters to operate in phase by having one of the inverters
operate as the “master” and the others as “slaves” (slaves are controlled by the master). When
fi
rst
turned on, all the stacked inverters are powered and then begin to monitor the power required by
the AC load. If the power requirement by the AC load decreases, the slave inverters power down
into Power Standby mode until needed. Power Standby mode allows the inverters to shut down
to reduce power consumption and to quickly begin inverting when the loads demand more power.
Because the paralleled inverters operate as a single unit, the total battery charging capability and
AC pass-through capacity are also increased. This helps with fuel consumption ef
fi
ciency and allows
available current to transfer to loads when using large generators. When the generator (or utility
power) is connected to the parallel system, the master inverter
fi
rst synchronizes, then connects.
Since the slave inverter(s) follow the master inverter, they are prevented from connecting until
the master inverter has synchronized and connected. After the full system has connected, battery
charging begins. This allows a smooth transition from Inverter mode to Charger mode since the
slave inverters are already synchronized when they transfer the loads and start battery charging.
3.11.1.1
Conditions for Parallel System
When connecting units in parallel, the following requirements must be met:
Info:
Magnum’s MP-E & MMP-E Series enclosures meet the requirements for parallel
stacking MS-PE inverters for a code compliant installation.
• Only MS-PE Series inverters are capable of being stacked in parallel. All inverters stacked
together must be the same model (i.e., MS4124PE with another MS4124PE).
• A maximum of four MS-PE inverters can be connected in parallel (must be same model).
• The ME-RTR router must be connected to communicate and synchronize with the other MS-PE
inverters for parallel operation, and must be within 1.8 meters (6’) of the stacked inverters.
• The Router Sync cable that is provided with the ME-RTR router must be used to connect
directly from the ME-RTR to each inverter. This cable is the only one that meets a parallel
system’s size, data, and insulation requirements.
• The inverters must be connected to the same battery bank.
• The DC connection cables from the battery to the inverter must be of equal length and size.
• The inverter’s negative terminals must be connected together either at the inverters or at a
location close to the inverters (within 45.7 cm/18 inches).
• The AC input/output cables to/from each inverter must be of equal length and size (length to
AC input may be different from length to AC output).
• Place the MS-PE inverters close to each other to allow the 6 ft router sync cable to connect to
each inverter—they should be no more than 15.2 cm (6”) from each other, but allow at least
7.6 cm (3”) for ventilation purposes under, above, and in front of each inverter.
• The AC input to every inverter must be from the same 230 VAC AC source.
• Each inverter must have appropriate AC and DC overcurrent protection.
• All negative connections (i.e., inverter, battery) must be permanently connected to each other.
No fuse or disconnect can be placed in the negative circuit.
