6 Electrical Connection
SMA America, LLC
48
SI4548_6048-US-TB_en-13
Technical description
6.3.3 AC2 (Generator/Grid)
The sub-distribution of the generator or utility grid is to be connected at input AC2 of the Sunny Island.
Cable lengths in single-phase, parallel, split-phase, double split-phase and
three-phase systems
The AC cables between all Sunny Island and the generator/grid in a system must have the
same size and length.
Single-phase parallel system
In the case of single-phase parallel systems, also connect the generator or the grid to all slaves
on AC2. The cable cross-sections and cable lengths used must be identical.
Distribution of loads and AC feed-in generators in multi-phase systems
Distribute the feed-in power and consumption power of the loads as well as the AC feed-in
generators as equally as possible across all line conductors of the system.
Split-phase system
In a split-phase system, connect the master to line conductor L1 and the slave 1 to line
conductor L2 (see Section 2.2 "At a Glance", page 22).
Double split-phase system
In a double split-phase system, connect the master and slave 2 to line conductor L1.
In a double split-phase system, connect slave 1 and slave 3 to line conductor L2.
Three-phase system
Always install the master on line conductor L1, slave 1 on L2 and slave 2 on L3. This installation
has a right-hand rotating magnetic field.
Additional fuses in the system
If there are no additional fuses installed between the generator or utility grid and the
Sunny Island, the Sunny Island knows whether it has a connection to the utility grid/to the
generator. The Sunny Island can then draw current from the utility grid/from the generator.
If there are additional fuses or switches installed between the Sunny Island and the utility grid/
the generator, the Sunny Island cannot determine whether fuses or switches are separated or
whether there is no voltage available from the utility grid/the generator. In either case the
Sunny Island cannot charge its battery and the loads that are in operation will discharge the
Sunny Island battery.
Check the additional fuses and switches regularly in order that the Sunny Island battery only
discharges when there is no voltage available from the utility grid/the generator.
Summary of Contents for Sunny Island 4548-US
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