IM02602002E
Page 5-2
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MP-3000
LRC is set to the locked-rotor current, which is the current the motor
draws when stalled, in percentage of (see P1L1). Use the motor
nameplate or manufacturer’s data.
LRT species how long a locked-rotor or stall condition can be main-
tained before the motor is damaged, in seconds, for a cold start. Use
motor nameplate or manufacturer’s data.
LRC and LRT combine to specify a point on the motor damage curve
(Figure 9.4) which, when reached during a start, causes a locked-rotor
trip. Refer to Subsection 9.1.3 for a detailed explanation.
UTC sets the current level above which a trip eventually occurs when
no RTD stator temperature data is available, in percentage of FLA.
This value represents the limit line on the running (upper) portion of
the non-RTD motor damage curve shown in Figure 9.4.
This UTC setting is where the User considers the service factor
rating of the motor. Never adjust the setting P1L1 accord-
ing to the service factor (see Subsection 9.1.3.3).
For normal use, set UTC to the service factor times 100%. The avail-
able range is 85% to 150%. The service factor is found on the motor
nameplate or in manufacturer’s data.
Note that the relay does not trip at the moment the current goes above
UTC during motor running. Instead, it models the gradual stator
heating for currents above UTC, and trips only after some time has
passed. The trip time depends on a variety of setting and operating
factors, including motor nameplate data contained in other setting values.
Use a conservative, or lower, value of UTC than that dictated by the
service factor if motor ambient temperatures rise above 40ºC (104ºF)
and the optional URTD Module is not used (see Subsection 9.1.1).
Also, consider lowering the UTC value if the motor is suitably rated,
yet additional safety is critical for the application.
-
PCT species the numerator of the turns ratio of the main phase current
transformers. Obtain the value from the current transformer (CT) name-
plate or from the installation drawings
. PCT is not the CT rating, but
the actual turns ratio, which may depend on a CT ratio tap.
The MP-3000 motor relay is available in multiple styles designed
for use with current transformers (CTs) having a nominal or rated
secondary current of either 5 amperes or 1 ampere. Check the relay
labeling or the catalog number and the CT secondary rating to conrm
a match.
All displayed information is the same for either of the two types of MP-
3000 relays. When CT ratios are to be set, the value entered is the
numerator of the main CT ratio. The denominator is assumed to be
either 5 or 1 depending on the style of MP-3000 used.
For example, a set of three 400:5 phase CTs might be used with an
MP-3000 specied for 5 A CTs. The phase CT ratio is then set to 400.
Alternatively, a set of three 400:1 CTs could be used with an MP-3000
rated for 1 A CTs. Use a setting of 400 in this case as well.
Display Complete Help Messages
FLA CT L
THE RATIO OF FLA TO CT RATIO IS BELOW 0.25 - INCREASE FLA OR DECREASE CT RATIO - PRESS PROGRAM
TO CONTINUE
FLA CT H
THE RATIO OF FLA TO CT RATIO IS ABOVE 1.5 - DECREASE FLA OR INCREASE CT RATIO - PRESS PROGRAM
TO CONTINUE
IOC OUT
IOC SETTING IS OUT OF RANGE - DECREASE IOC OR DECREASE FLA OR INCREASE CT RATIO - PRESS PRO-
GRAM TO CONTINUE
JAMT OUT
AM TRIP SETTING IS OUT OF RANGE - DECREASE JAM TRIP OR DECREASE FLA OR INCREASE CT RATIO
- PRESS PROGRAM TO CONTINUE
MA OUT
JAM ALARM SETTING IS OUT OF RANGE - DECREASE JAM ALARM OR DECREASE FLA OR INCREASE CT
RATIO - PRESS PROGRAM TO CONTINUE
ULT LOW
UNDERLOAD TRIP SETTING IS LESS THAN STOP CURRENT LEVEL - DECREASE STOP CURRENT LEVEL OR
INCREASE UNDERLOAD TRIP LEVEL - PRESS PROGRAM TO CONTINUE
ULA LOW
UNDERLOAD ALARM SETTING IS LESS THAN STOP CURRENT LEVEL - DECREASE STOP CURRENT LEVEL OR
INCREASE UNDERLOAD ALARM LEVEL - PRESS PROGRAM TO CONTINUE
STP HIGH
STOP CURRENT LEVEL IS ABOVE THE START LEVEL - DECREASE STOP CURRENT LEVEL - PRESS PROGRAM
TO CONTINUE
TRNS LOW
STOP CURRENT LEVEL IS ABOVE THE TRANSITION LEVEL - DECREASE STOP CURRENT LEVEL OR
INCREASE TRANSITION LEVEL - PRESS PROGRAM TO CONTINUE
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