Eaton MP-4000, Инструкция по установке, эксплуатации и техническому обслуживанию

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MP-4000 IB02602002E
SECTION 2 - PRODUCT OVERVIEW
2.0 General Overview
The MP-4000 Motor Protection Relay is available in either a fixed
mount, semi-flush case, or in a semi-flush, Quick Release drawout
case. Both housings are compact and fit a standard IQ cutout.
The optional Quick Release drawout case features 2-stage contact
disconnects and self-shorting current transformer (CT) circuit terminal
blocks. The optional communications modules (PONIs) are exter
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nally mounted on the fixed mount case and internally mounted in the
drawout case.
The MP-4000 has 3-phase current inputs and one ground current
input. Both 5 A and 1 A versions are available. The ground protection
and metering functions are best used with a zero-sequence ground CT,
rather than from the residual connection of the phase CTs. The zero-
sequence ground CT provides greater ground fault sensitivity. The unit
is User-programmable for 60 Hz or 50 Hz operation.
The MP-4000 has 3-phase voltage inputs and one ground voltage
input. The ground input must be earth-grounded. The voltage inputs
are User-programmable for 50 or 60 Hz.
The MP-4000 has two discrete inputs, four form C (1 N.O. and 1 N.C.)
output contacts, and one 4 to 20 mA analog output. The relay lets the
User program the operation of all the I/O points, except for the trip out
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put. In addition, the relay has ten LEDs for the indication of protection
on, program mode, monitor mode, view setting mode, history mode,
log mode, trip, alarm, and Aux 1 and Aux 2 output relay operation. A
test page in the program mode provides a display indication of the
discrete input states and testing of the output relays, target LEDs, and
analog output circuit.
A User-friendly operator interface provides quick access to the set
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tings, monitored values, motor history, and operational logs. A large
LED alphanumeric display provides easy viewing from any angle.
Simple keypad operations provide quick and easy navigation through
all settings and stored data. The program mode and emergency over-
ride buttons are access restricted via a seal and latched cover. An
integrated context-sensitive help button provides an online descriptive
display of functions, abbreviations, and operations.
2.1 Optimum Motor Protection
The MP-4000 Motor Protection Relay has been designed for maximum
motor utilization and protection. It is desirable to run the motor as
close as possible to its design limits, while protecting it against exces-
sive heating and damaging overload conditions. The MP-4000 has
field-proven protection algorithms developed from basic motor design
principles and operating parameters.
The MP-4000 protects against rotor and stator overheating, short
circuits or insulation faults, excessive starting duty, and abnormal
operating conditions.
2.1.1 Intel-I-Trip (adaptive I 2 t Motor Overload Protection)
Motor operation is typically limited by the rotor thermal capabilities, but
the measuring quantities are stator currents. This requires accurate
measurements and good motor thermal models to provide maximum
utilization and reliable protection.
The MP-4000 uses the field-proven Intel-I-Trip overload measure
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ment and motor thermal protection model that uses the manufacturer’s
nameplate data to develop an overload protection curve specifically for
the motor being protected. When RTDs are used, the Intel-I-Trip over
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load protection curve becomes adaptive. The overload trip times will
change based on the modeling impact of the motor’s internal tempera-
ture data. It also trips directly for high stator temperature.
The relay samples the current waveforms 36 times per cycle provid
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ing accurate measurements of the positive and negative sequence
currents, as well as harmonic components that add to rotor and stator
heating. The negative sequence component of current causes far
greater heating effect on the rotor and has a greater impact on the
thermal model in the relay, as compared to the balanced or positive
sequence component.
2.1.2 Instantaneous Overcurrent Protection
The MP-4000 has an instantaneous phase overcurrent function to trip
the motor for fault currents, sometimes saving the fuses for medium-
current faults. This function can be disabled and has an adjustable
start time delay on starting to avoid nuisance tripping on inrush.
2.1.3 Phase Current Unbalance Protection
Motor supply circuits are often fed through fuses and may be ener
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gized with one fuse blown, causing single phasing of the motor. The
MP-4000 measures the current unbalance and can be used to alarm
or trip the motor before heating and a thermal-model trip. Pickup, start
and run timers, and separate alarm settings are provided.
2.1.4 Ground Fault Protection
A separate monitoring circuit is used to measure ground current. A
zero sequence ground CT is recommended for more sensitive protec
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tion against winding insulation failure to ground. The relay ground CT
input can be connected residually from the three phase CTs, but with
much inferior protection sensitivity. The ground fault protection has
adjustable pickup and time delay setpoints, and it can be disabled.
2.1.5 jam Protection
The User-selectable Jam function protects motors that are running
against a sudden mechanical jam or stall condition. The common
application is on motors used on crushers, chippers, or conveyors. It
detects an increase of motor current to a level above full load. Pickup,
start and run timers and a separate alarm setting are provided.
2.1.6 Underload Protection
The User-selectable underload function is used to detect the loss of
load on the motor. Coupling failure is a common cause for loss of load.
Pickup, start and run timers, and a separate alarm setting are provided.
2.1.7 Remote and Differential Trip
One of the discrete inputs can be programmed to accept a contact
input from a separate differential relay or other device to trip the motor.
This provides local and remote target (logging) information, and utilizes
the trip contacts of the MP-4000. It also records and logs the motor
information at the time of the trip. For differential tripping, the Eaton
MD-3000 is recommended.
2.1.8 Zero Speed Switch Trip
One of the discrete inputs can be programmed to accept a contact
input from a zero speed switch connected to the motor shaft. This pro
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vides faster tripping for a motor that remains completely stalled when
energized for a start. It provides backup protection for motors with long
acceleration timing.