P/usTM and
PM™
Units
2.
Mode
Long-Time Pickup
The first setup-mode display is always the long-time
pickup setpoint, as illustrated in Figure
10.
This set
point establishes the breaker's nominal ampere rat
ing,
x.LT,
as a fraction of the rating plug value,
xln
( x.LT
=
LT multiplier
x
xln ) .
Press the
VALU E
key to
scroll through the available choices. Press
ENTER
to
store the desired set point.
LT
.� ,,
.=- Lf
PICKUP
SETUP
xln
Figure
10.
Trip Unit display for long-time pickup.
The choices for UL breakers are
0.50
to
1 .00
times
xln
in steps of
0.05.
The pickup value tolerance band
is
0%
to
+20%
of the set point.
The choices for ANSI breakers are
0.50
to
1 . 1 0
times
xln,
in steps of
0.05.
The pickup value is defined for
-1 0%
to
+10%
of the set point.
Figure
1 1
illustrates the long-time pickup settings.
Q)
E
i=
Pickup Settings
Current
Figure
1 1.
Time-current curve illustrating long-time pickup.
Long-Time Delay
The Trip Unit display for long-time delay is illus
trated in Figure
1 2.
This function allows normal
momentary overloads without nuisance tripping.
The time delays at the lower limit of the bands at
600%
of the long-time current setting,
x.LT,
are listed
16
in Table
1 1 .
Figure
13
illustrates the effect of this
delay on trip time. Press the
VAL U E
key to cycle
through the four choices of time-delay bands. Press
ENTER
to store the desired value.
LT
'
'
SETUP
DELAY
Figure
12.
Trip Unit display for long-time delay.
Band Delay, sec
1
2.4
2
4
.9
3
9.8
4
20
Table
1 1.
Lower-limit delays for long-time delay bands.
Q)
E
i=
Time-Delay
/ Bands
Current
Figure
13.
Time-current curve illustrating long-time delay.
Short-Time Pickup
The short-time pickup function establishes the cur
rent at which short-time trip is activated. Short-time
pickup is coupled with long-time pickup and the
choices of pickup settings are from
1 .5
to 9.0 times
the long-time setting,
x.LT,
in steps of
0.5
x.LT.
The
Trip Unit display is illustrated in Figure
14.
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