- 8 -
THERMAL-MAGNETIC CIRCUIT BREAKERS
As previously explained, the CSS has protection devices for output faults as well as for internal faults.
In order to configure the power source, a thermal-magnetic switch must be installed upstream of the CSS.
Please follow the indications in the table below:
Automatic external protective devices
Table 3
CSS model Mains input Bypass Input (DI version)
10 40A (trip characteristic curve “C”) 40A (trip characteristic curve “C”)
15 – 20 50A (trip characteristic curve “D”) 50A (trip characteristic curve “D”)
If the protective device upstream of the CSS interrupts the neutral wire, it must also interrupt all of the phase wires at
the same time (4-pole breaker).
Please select the thermal-magnetic circuit breakers in accordance with the “SHORT CIRCUIT WITHSTANDING” below.
Output protections (recommended values for selectivity)
Table 4
Normal fuses (GI) In (Nominal current)/4
Normal switches (C curve) In (Nominal current)/4
Ultra-fast fuses (GF) In (Nominal current)/2
SHORT CIRCUIT PROTECTION
If a failure at the output occurs, the CSS protects itself by limiting the value and duration of the output current (short-circuit current).
These values also depend on the operating status of the CSS at the time of the failure; there are two different scenarios:
CSS in NORMAL OPERATION with a bypass supply: the load is instantly switched to the bypass line (I
2
t = 11250 A
2
s): the
input line is connected to the output without any internal protection (blocked after t > 500ms).
CSS in BATTERY OPERATION or in NORMAL OPERATION without a bypass supply: the CSS protects itself by supplying
2.7 times the nominal current to the output for the first 200ms, which is then reduced to 1.5 times nominal for 300 ms. After
this time (500 ms) it switches off.
SHORT CIRCUIT WITHSTANDING
This equipment is rated for use in a circuit capable of delivering no more than 6000 symmetrical amperes (6 kA), at 415V maximum.
INTERNAL PROTECTIVE DEVICES
The table below shows the sizes of the switch disconnectors of the CSS and the sizes of the battery fuses: these devices are accessible
from the front.
There is also data in relation to the rating of the internal fuses (not accessible) which protect the input and output lines, along with the
maximum input and rated output currents.
Fuses must be replaced with ones of the same size and the characteristics as indicated in the table below.
Switches and internal protective devices
Table 5
Disconnect switches and fuse holders Internal Fuses
CSS model SWIN / SWBYP SWOUT / SWMB SWBATT
(
*
)
Rectifier input fuses Battery stage fuses Output fuses
10 63A (4P) 63A (4P)
32A gR 500V
(10x38)
25A FF 500V
(6.3x32)
20A FF 500Vdc
(6.3x32)
20A FF 500V
(6.3x32)
15 63A (4P) 63A (4P)
50A gR 500V
(14x51)
2x25A FF 500V
(6.3x32)
32A gR 500V
(10x38)
2x20A FF 500V
(6.3x32)
20 63A (4P) 63A (4P)
50A gR 500V
(14x51)
2x25A FF 500V
(6.3x32)
32A gR 500V
(10x38)
2x20A FF 500V
(6.3x32)
(
*
)
Warning: SWBATT disconnect only the batteries contained in the CSS cabinet
To Next Page
Loading...
Need help?
General
