Eaton MP-3000, Instruction Leaflet

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IM02602002E
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MP-3000
2.2 Motor Starting and Control functions
The MP-3000 Motor Protection relay includes logic to control the num -
ber of starts that can occur on the motor in a given time period for cold
and hot motor conditions. Settable timers are provided to control the
time between starts and to restart a motor after a stop. Additional logic
is included for transition control of reduced-voltage starters.
2.2.1 Start Control Timers
Motors typically have limits on 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
of the motor.
2.2.2 Reduced Voltage Starting
The MP-3000 provides transition and incomplete sequence detection
function for reduced voltage starting. The User can select to transi -
tion 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 does not 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 pushbutton 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 tim -
ing feature that holds off thermal tripping during the long acceleration.
This should be used this with a zero-speed switch input.
2.2.7 Motor Starting Profile
The MP-3000 records the average current and voltage versus time for
the last four starting cycles. This information is available via the com -
munications port. The PowerNet host plots the motor current versus
the motor cold-start protection curve, as shown 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 set-
ting changes. LEDs provide visual indication of display mode. The
pushbutton access scheme is easy to learn, and quickly accesses the
large volumes of setting, monitoring, logging, and historical
information.
The User may also access settings via the front panel RS-232 port.
The JTAG port is for factory use only.
figure 2.1 Motor Starting Profile.