The value of
Alarm thermal value
is set to a level which allows the use of the full
thermal capacity of the motor without causing a trip due to a long overload time.
Generally, the prior alarm level is set to a value of 80 to 90 percent of the trip level.
4.1.10.7 Signals
MPTTR Input signals
Table 478: MPTTR Input signals
Name Type Default Description
I3P SIGNAL - Three-phase currents
BLOCK BOOLEAN 0=False Block signal for acti-
vating the blocking
mode
START_EMERG BOOLEAN 0=False Signal for indicating
the need for emer-
gency start
AMB_TEMP FLOAT32 0 The ambient temper-
ature used in the cal-
culation
MPTTR Output signals
Table 479: MPTTR Output signals
Name Type Description
OPERATE BOOLEAN Operate
ALARM BOOLEAN Thermal Alarm
BLK_RESTART BOOLEAN Thermal overload indicator,
to inhibit restart
TEMP_RL FLOAT32 The calculated temperature
of the protected object rela-
tive to the operate level
4.1.10.8 MPTTR Settings
Table 480: MPTTR Group settings (Basic)
Parameter
Values (Range) Unit Step Default Description
Overload factor 1.00...1.20 0.01 1.05 Overload factor (k)
Alarm thermal value 50.0...100.0 % 0.1 95.0 Thermal level above
which function
gives an alarm
Restart thermal Val 20.0...80.0 % 0.1 40.0 Thermal level above
which function in-
hibits motor re-
starting
Table continues on the next page
1MRS759142 F Protection functions
REX640
Technical Manual
421
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