Manual 7SJ45 Settings
C53000-K1174-C001-7 54
chanical relays. In case several faults occur successively it is en-
sured that the "prehistory" is taken into consideration due to the
inertia of the disk and that the time behavior is matched. The
7SJ45 divides the operation range of the disk emulation into an
incrementing zone (1.1 to 20
⋅ I/I
P
) and a decrementing zone
(< 0,9
⋅ I/I
P
).Thezoneinbetweeniscalledidlestatezonesince
this is the zone where the virtual disk is in idle state.
The current transformer supply of 7SJ45 conditions that the de-
vice is unable to operate with single-phase supply and currents
smaller than 0.8 ⋅ I
N
. The device and the virtual disk are reset.
The operation zones of the reset characteristics therefore de-
pend on the setting value selected for I
P
and the supply condi-
tions. If, for instance, I
P
= 4.0 is selected, the disk emulation (with
single-phase supply and I/I
P
= 0.2) is reset due to a device reset.
When the disk emulation is picked up again, the time counter
starts at zero.
If you press the "ENTER" key, the disk emulation will also be
reset.
The disk emulation offers its advantages when the grading coor-
dination chart of the time overcurrent protection is combined (on
electromechanical base) with other devices connected to the sys-
tem.
The current thresholds relating to the rated device current are set
on the device. These thresholds include:
All parameters are set on an additive basis. Some parameters
have fixed upper and lower thresholds.
Current transformer I
NP
/I
NS
100 A / 5 A
Rated device current I
N
5A
Maximum load current 120 A
Safety factor (assumed) 1.25
Ip
120A
100A
--------------
I
NS
I
N
--------
1⋅ 25,⋅ 15 I
N
⋅,==
.
.
Setting value,
Switch values,
å
=
To Next Page
Loading...
Need help?
General
