36 Operation principle and hardware description
Descriptions of symbols
Symbol Terminal/Component Description/Operation
1 DC input terminals The solar generator is connected to the inverter DC input terminals
with busbars and fuse links.
2 AC output The AC output terminals connect the inverter to the low-voltage AC
power system.
3 Auxiliary control
voltage input
The customer supplies 230 V AC 1-phase auxiliary control voltage to
the inverter circuit boards, cooling fan(s) and contactor control
circuits. For other voltages, see section External 100 V AC,
115 V AC or 200 V AC auxiliary power supply (options +G396,
+G397 and +G398) on page 39.
4 Transformer The transformer connects the inverter AC side to the low-voltage or
medium voltage distribution network.
5 Junction box power
supply (option +G410)
The inverter supplies power to the junction box through terminal
X21. Max 6 A. Fault current protected.
A20 Grounding board (with
options +F282 and
+F283)
Provides fuse protection and current monitoring. See section
Positive or negative pole grounding (options +F282 and +F283) on
page 42.
A50 Varistors For overvoltage protection
C11
C16
EMC filter capacitor Reduces electromagnetic interference.
F1.1
F1.4
AC fuses Protect the inverter module and main circuit components.
F2.1
F2.3
Inverter DC fuses Protect the inverter module.
F3.x Input DC fuses Protect the DC input connections. The exact number of the fuses
depends on the number of the DC input connections.
F50
F51
F52
Overvoltage protection
devices (F50 with
option +F263 only)
Devices for overvoltage protection against for example climatic
overvoltages caused by lightning strikes.
K1.1
K1.2
AC contactors The inverter controls the AC contactor according to the operational
state.
K2.1
K2.2
DC contactors The inverter controls the DC contactor according to the operational
state. The solar generator is disconnected from the inverter when
needed.
K19.1
K19.2
R1.1
R1.2
F19.1
F20.1
F20.3
Charging circuit The inverter controls the charging contactors after receiving a start
command.
K20 Grounding contactor
(with options +F282
and +F283)
The inverter software controls the disconnection of the
positive/negative pole grounding. See section Positive or negative
pole grounding (options +F282 and +F283) on page 42.