Eaton MP-4000, Instruction Bulletin For Installing, Operating, And Maintaining

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MP-4000 IB02602002E
CT Ratio Selection
Check the following criteria to ensure a suitable current transformer ratio.
For a 5 ampere CT set:
For optimum metering accuracy at low loads, the CT should deliver
between 3.5 and 4 A at 100% FLA. Attempt to achieve 3.75 A.
For reliable motor protection, the CT must deliver between 2.5 and 4 A
to 5 A MP-4000 at 100% FLA.
For example, if the motor has an FLA value of 300 A, a 400:5 CT will sup
-
ply:
300 × 5/400 = 3.75 A, an ideal value.
For a 1 ampere CT set:
For optimum metering accuracy with low loads, use a 1 A MP-4000.
The primary of the CT should deliver between 0.7 A and 0.8 A at
100%percent FLA. Attempt to achieve 0.75 A.
For reliable motor protection, the CT should deliver between 0.5 A and
0.8 A at 100% FLA.
For example, if the motor has an FLA of 300 A, a 400:1 CT will supply:
300 × 1/400 = 0.75 A, an ideal value.
Note that Fla/PCt
must lie between 0.25 and 1.5 for successful pro
-
gramming - the User will not be able to exit Program Mode until one or
the other value is adjusted. Refer to Subsection 5.0.1.
CaUTION
BE CaREFUl WhEN DETERMINING CT TURNS RaTIO. aN
IMPROPER ValUE CaN CaUSE ThE MP-4000 TO RECEIVE
INCORRECT MOTOR CURRENT DaTa. MOTOR DaMaGE COUlD
RESUlT.
5.1.6 Setting P1l6, Ground Fault CT Ratio (GCT)
GCT specifies the numerator of the turns ratio of the single ground cur
-
rent transformer used only for ground fault protection and ground current
metering. The User should obtain the GCT from the CT nameplate or
from the installation drawings, watching for the use of taps on CTs that
have tapped windings.
Typically, the three-phase power conductors pass through the single
window of a ground fault CT, whose ratio is usually much lower than
that of the phase CTs for good ground fault sensitivity. A very common
type of ground fault CT has a ratio of 50:5 or 50:1, but the User should
check the CT in use.
Ground fault protection by the residual connection of phase CTs is
possible, but it does not give high sensitivity. Refer to Subsection
9.1.10 .
5.1.7 Setting P1l7, Frequency (FREQ)
FREQ sets the MP-4000 for either a 60 Hz or 50 Hz ac supply
frequency. The device assumes the supply and phase currents are
at the same nominal frequency. No hardware settings are neces
-
sary. The MP-4000 can protect the motor during the limited frequency
excursions of a power system in emergency conditions, but it is not
intended for use with variable-frequency motor drives
.
5.1.8 Setting P1l8, Reversing or Non-reversing Starter (REV/
NONREV)
REV/NONREV specifies whether or not the starter for this motor is
designed to reverse phase sequence and make the motor run in either
direction.
Setting to REV indicates that starting with a reversed phase sequence
is an acceptable operating condition. The MP-4000 accepts either
sequence at the time of a start, and assigns the role of a positive
sequence to the larger of the two sequence components. When the
motor runs in reverse, any phase current unbalance is displayed with
a negative sign. This is not a negative number; it should be viewed
as a notation that the unbalance was measured on a motor running in
reverse.
If set to NONREV, the MP-4000 checks the phase sequence at the
beginning of the START cycle only, and accepts only a positive phase
sequence (ABC). It trips the motor for a reversed sequence of ACB
and displays the message “PH REVRS”.
5.1.9 Setting P1l9, Stop Current Threshold
This setting controls the current magnitude threshold in which the
MP-4000 declares a stop state if the actual current is below the
threshold for at least 280 milliseconds. If a stop state occurs, the jog
-
ging functions Starts per Time Allowed (
ST/T P5l1, T/ST P5l2 ), Time
Between Starts ( TBS P5l3 ), and Anti-Backspin ( aBK, P5l12 ) are en-
forced. All phases of the current must be below this level before a stop
will be declared. The setting is programmed as percentage of the CT
ratio numerator (
PCT P1l5
). For example if 400:5 CTs are used and
the setting is programmed as 5%, all phase currents must be below
20 A before a stop is declared. It is possible that if power factor cor-
rection capacitors are used, a high inertial motor may generate current
after the motor contacts open. Make sure to set the stop current level
to be above the level of current generated by the motor free spinning.
The Stop Current Threshold must be below the current that causes
a starting condition to be declared, which is 30% of FLA. In addition,
the Stop Current Threshold setting must be below the Underload trip
( UlT P3l9 ), Underload alarm ( Ula P3l5 ), and Motor Start Transition
Current Level (
TRNC P5l5
). The User should be mindful that the Stop
Current Threshold is programmed as a percentage of
PCT . To convert
this setting to be a percentage of Fla
, multiply the Stop Current
Threshold by PCT/Fla .
5.2 Page 2, SP RTD, Settings P2l1 to P2l10
This page contains all of the settings needed to use the RTD temperature
inputs from the optional URTD accessory module
.
NOTE
: For direct temperature tripping, alarming, and displays to func
-
tion, a URTD module must be connected and communicating
with the MP-4000. However, the settings for temperature can be
viewed or adjusted with or without a URTD module connected.
Pay attention to the specific labeled assignments of the 11 URTD input
channels. The first six are specifically intended for up to six RTDs em
-
bedded in the motor stator winding. Inputs 7 and 8 are specifically for
motor bearing RTDs. Inputs 9 and 10 are specifically for load bearings.
Input 11 is an auxiliary general-use input.
All RTD inputs have alarm and trip values set below. But, note that
only the maximum of the values read via stator RTD channels 1
through 6 is used by the MP-4000 motor thermal modeling algorithm.
CaUTION
ThE MP-4000 CaNNOT COMMUNICaTE WITh ThE URTD IF ThE
SETTING “RS-232 MODE” IS ENaBlED (ON).