IV386 Rev.000 SIEL S.p.A.
Data di emissione: 2015-10-02
Pag. 76 di 263 + FR
P
ROTECTIONS
S
HORT
-
CIRCUIT PROTECTION
In the presence of a fault on the load, the UPS limits the value and duration of the output current (short circuit current) for
protection. These values are also functions of unit status at the time of the fault. Two different cases can be distinguished:
§
UPS in NORMAL OPERATION: the load is instantly switched to the bypass line (I
2
t=432000A
2
s): the input line is
connected to the output without any internal protection (it locks out after t>0.5s)
§
UPS in BATTERY-LED OPERATION: the UPS protects itself by sending a 2.7 times nominal current to the output for
the first 0.2s, which is then reduced to 1.5 times nominal for 0.3s. After this time (>0.5s) it switches off.
P
ROTECTION AGAINST BACK
-
FEED
The UPS is equipped with a device to prevent voltage backfeed to the input line when internal faults occur. During inverter
operation, if an internal fault occurs which causes backfeed on the bypass line, the protection switches off the inverter and
switches the load to the bypass. If the fault occurs with the UPS in battery operation, the load remains unpowered.
To prevent the inverter switching off and hence keep the load powered by the inverter even if a double fault occurs (mains
power failure and internal fault), the system can be customised to control the opening coil of an upline switch by reprogramming
one of the relays on the comms board.
The control logic allows you to reconfigure the relays, for example for a backfeed alarm, and use the no voltage contact to
actuate a switch upline of the UPS itself.
I
NPUT LINE THERMAL MAGNETIC SWITCHES
Install a trip switch with C (or D, depending on the type of load) trip curve on the power supply line upstream of the UPS.
FOR FURTHER INFORMATION, REFER TO THE INCLUDED "INSTALLATION INSTRUCTIONS"
B
ATTERY LINE
A surge protector and a cut-off device must be provided on the UPS external battery line.
The size and type of fuses must be selected on the basis of the capacity of the installed battery box, referring to the table in the
included "
Installation Instructions
".
