MicroVersaTrip Plus™ and MicroVersaTrip PM™ Trip Units
Chapter 2. Setup Mode
16
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,
xLT
, as a fraction of the rating plug value,
xIn
(
xLT
= LT multiplier x
xIn
). Press the VALUE key to
scroll through the available choices. Press
ENTER to
store the desired set point.
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 1.10 times
xln
, in steps of 0.05. The pickup value is defined for
−10% to +10% of the set point.
Figure 11 illustrates the long-time pickup settings.
Figure 11. Time-current curve illustrating long-time pickup.
Long-Time Delay
The Trip Unit display for long-time delay is illus-
trated in Figure 12. 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,
xLT
, are listed
in Table 11. Figure 13 illustrates the effect of this
delay on trip time. Press the
VALUE key to cycle
through the four choices of time-delay bands. Press
ENTER to store the desired value.
Figure 12. Trip Unit display for long-time delay.
BB
BB
aa
aa
nn
nn
dd
dd
DD
DD
ee
ee
ll
ll
aa
aa
yy
yy
,,
,,
ss
ss
ee
ee
cc
cc
1 2.4
2 4.9
3 9.8
420
Table 11. Lower-limit delays for long-time delay bands.
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,
xLT
, in steps of 0.5
xLT
. The
Trip Unit display is illustrated in Figure 14.
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