Plus™ and
PM™
Units
2.
Mode
Instantaneous Pickup
Instantaneous overcurrent protection, with Trip Unit
display illustrated in Figure 19, causes an immediate
breaker trip when the chosen current level is
reached. The pickup value may be set in steps of 0.5
xln
from 1 .5
xln
to a maximum dependent on the
frame size and the presence of the short-time
function, as listed in Table 13.
Note the difference from short-time pickup, which is
based on a multiple of
xLT.
The time-current charac
teristic is shown in Figure 20.
SETUP
xln
INST
PICKUP
Figure
19.
Trip Unit display for instantaneous pickup.
Q)
E
f.=
Current
Instantaneous
Pickup Setting
Figure
20.
Instantaneous overcurrent protection set point.
Frame Max.
Setpoints
Setpoints
Amp Rating
Without ST
With ST
2000
1 .5-1 0.0
xln
1 .5-15.0
xln
3200
1 .5-10.0
xln
1 .5-1 3.0
xln
4000
1 .5-9.0
xln
1 .5-9.0
xln
5000
1 .5-7.0
xln
1 .5-7.0
xln
Table
13.
Instantaneous pickup settings for various frame sizes
with and without the short-time function.
18
On Trip Units with the user-selectable switchable
instantaneous overcurrent and ground-fault option,
X, an additional value of
O F F
appears at the end of
the listing of numerical values. Choose this setting to
disable instantaneous protection. The instantaneous
OFF
selection is interlocked with short-time pickup,
so that only one function can be turned off at a time.
High-Range Instantaneous Overcurrent
Protection
High-range instantaneous overcurrent protection
has a fixed trip setting equal to the breaker frame's
short-time withstand rating,
H,
with pickup tolerance
+0%, -20%. When this option is installed, skip pro
gramming of instantaneous pickup and go on to the
next function by pressing
SELECT .
Ground-Fault Pickup
The trip unit display for ground-fault pickup is
shown in Figure 21 . This function sets the pickup
current for ground-fault protection. The available
settings are listed in Table 1 4 as multiples of
xCT
the
current sensor rating, in steps of 0.01
xCT.
The maxi
mum value is limited to 1 200 A. Figure 22 illustrates
the time-current curve for ground-fault pickup.
, .,
.C Lf
GF
PICKUP
SETUP
xCT
Figure
21.
Trip Unit display for ground-fault pickup.
Sensor, A
Set Points
1 50-2000
0.20-0.60
2500-3200
0.20-0.37
4000
0.20-0.30
Table
14.
Ground-fault pickup settings, as a function of sensor
rating.
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