Overcurrent And Undervoltage Cut-Out; General; Functional Principle; Safety - Fronius 250/30 DCD DF Operating Instructions Manual

Overcurrent and undervoltage cut-out

General

The Fronius String Control 250/30 DCD DF has a cut-out function that interrupts the power
supply in the Fronius Solar Net:
-
-
Functional princi- The overcurrent and undervoltage cut-out does not depend on the current flow direction.
ple If the Fronius String Control 250/30 DCD DF measures a current flow of > 3 A or a voltage
of < 7 V while supplying Fronius Solar Net components, the power supply in the Solar Net
is interrupted.
The power supply can be restored automatically or manually.

Safety

Restoring the
power supply au-
tomatically
Jumper (1) must be set to position A in order to restore the power supply automatically.
-
-
-
If there is no short circuit and the 'PWROK' LED does not light up, the unit has cut out in
response to undervoltage.
In this case, the Fronius DATCOM components must be supplied externally from an exter-
nal power pack.
74
in response to overcurrent, e.g. in the event of a short circuit
in response to undervoltage
WARNING! An electric shock can be fatal. Danger from DC voltage in PV mod-
ules.
- Make sure that both the input side and output side of the device are de-ener-
gised before attaching any connections.
- All connections must be made by qualified electricians.
- Note the safety rules in these operating instructions.
(1)
(2)
After cutting out because of overcurrent or undervoltage, the Fronius String Control
250/30 DCD DF attempts to restore the power supply in the Fronius Solar Net every
5 seconds while the short circuit, for example, is still present.
The 'PWROK' LED (2) flashes briefly every 5 seconds.
When the power supply is restored, the 'PWROK' LED lights up green.
Jumper positions:
A Power supply is restored automati-
cally
(factory default)
M Power supply is restored manually