IL17562BH04
Page 2-2
Effective 10/02For more information visit: www.cutler-hammer.eaton.com
2.2.1 Start Control Timers
Motors typically have limits to the number of cold starts, starts per time
period and time between starts that are permitted without damage. The
MP-3000 incorporates these checks to prevent excessive starting the
motor.
2.2.2 Reduced Voltage Starting
The MP-3000 provides a transition and incomplete sequence detection
function for reduced voltage starting. The user can select to transition
based on four logical combinations of starting current and time
sequence. The incomplete sequence function can be used indepen-
dently for feedback indication from the process, to trip the motor if
expected action doesn’t occur.
2.2.3 Antibackspin Timing
For certain applications, such as pumping a fluid up a pipe, the motor
may be driven backward for a period of time after it stops. The MP-
3000 provides an antibackspin timer (minimum time between stop and
restart) to prevent starting the motor while it is spinning in the reverse
direction. The relay displays the timer countdown from the moment a
stop is declared by the relay.
2.2.4 Load Shedding
The MP-3000 provides a mechanical load shedding feature that can be
used to control the driven process. The load shedding function closes
a contact on an overload condition to stop addition of load until the
overload condition subsides by a set amount. Then the load shedding
contact opens and the load is restored.
2.2.5 Emergency Override
The MP-3000 has a user programmable feature that lets the operator
reset certain trip conditions including the jogging timers and thermal-
model overload bucket. This function is for use in emergency condi-
tions only and may result in motor damage or failure. The override
action is logged with time-tag. The button is located behind a security
door. The function can be disabled.
2.2.6 Long Acceleration Motors
Large motors with high inertia loads, such as centrifuges and large
fans, may experience starting currents that greatly exceed the full load
current for greater than the locked rotor time. The MP-3000 has a
timing feature which holds off thermal tripping during the long
acceleration. Use this with a zero-speed switch input.
2.2.7 Motor Starting Profile
The MP-3000 records the average current versus time for the last four
starting cycles. This information is available via the communications
port. PowerNet host plots the motor current versus the motor cold-
start protection curve as in Figure 2.1.
2.3 User Interface
The MP-3000 Motor Protection Relay has a user-friendly interface that
makes it easy to retrieve important information or to make setting
changes. LED’s provide visual indication of display mode. The push
button access scheme is easy to learn, and quickly accesses the large
volumes of setting, monitoring, log, and historical information.
Fig. 2.1 Motor Starting Profile
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