GE Industrial Solutions WavePro Low-Voltage Power Circuit Breakers - Manual (Page 22)

MicroVersaTrip Plus™ and MicroVersaTrip PM™ Trip Units
Chapter 2. Setup Mode
14
Long-Time Pickup
The first setup-mode display is always the long-time pickup
setpoint, as illustrated in Figure 7. This set point
establishes the breaker’s nominal ampere rating, 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 7. Trip Unit display for long-time pickup.
The choices are 0.50 to 1.10 times xIn, in steps of 0.05. The
pickup value is defined for
−1 0% to +10% of the set point.
Figure 8 illustrates the long-time pickup settings.
Figure 8. Time-current curve illustrating long-time pickup.
Long-Time Delay
The Trip Unit display for long-time delay is illustrated in
Figure 9. This function allows normal momentary over-
loads 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 10. Figure 10 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 9. Trip Unit display for long-time delay.
Band Delay, sec
1 2.4
2 4.9
3 9.8
4 20
Table 10. Lower-limit delays for long-time delay bands.
Figure 10. Time-current curve illustrating long-time delay.
Short-Time Pickup
The short-time pickup function establishes the current 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 11. The time-current curve for short-time pickup is
shown in Figure 12.
Figure 11. Trip Unit display for short-time pickup coupled with long-
time pickup.