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.
4.1.11.6 Signals
Table 366: MPTTR Input signals
Name Type Default Description
I_A SIGNAL 0 Phase A current
I_B SIGNAL 0 Phase B current
I_C SIGNAL 0 Phase C current
I
2
SIGNAL 0 Negative sequence
current
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
Table 367: MPTTR Output signals
Name Type Description
OPERATE BOOLEAN Operate
ALARM BOOLEAN Thermal Alarm
BLK_RESTART BOOLEAN Thermal overload indicator,
to inhibit restart
4.1.11.7 Settings
Table 368: 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 val-
ue
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
Negative Seq fac-
tor
0.0...10.0 0.1 0.0 Heating effect fac-
tor for negative se-
quence current
Weighting factor p 20.0...100.0 % 0.1 50.0 Weighting factor
(p)
Table continues on the next page
1MRS757644 H Protection functions
620 series
Technical Manual
373
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