Monitoring
Parameter manual
b maXX
BM5800
Document No.: 5.16029.03
Baumüller Nürnberg GmbH
716
3.11
3.11.5 Overload monitoring of the motor (I
2
t)
3.11.5.1 General information
I
2
t model
The overload monitoring protects the motor from thermal overload. Thereby, the thermal
load of the motor is emulated and monitored by an l
2
t model.
l
2
t monitoring is no replacement for the motor temperature monitoring.
Figure 186:
Time curve of the motor l
2
t actual value in the nominal operating point
The time curve of the l
2
t model during nominal current is presented in
standardization of the l
2
t model corresponds to 40°C
0% (maximum value of the en-
vironmental temperature) and the maximum thermal load of the motor
100%. The
maximum thermal load of the motor corresponds to the maximum continuous load of the
motor (e.g. motor nominal current at motor nominal speed)
5000_0087_rev03.cdr
T
107.28
t
t
6.28
= 100 %
40°C = 0 %
|I
|
[A]
Motor
I
N
t
max.
thermal load
63.2 %
NOTE!
The overload monitoring applies to motors used for continuous operation (S1) at a
maximum environmental temperature of 40°C and set up under 1000 m altitude. If
these motors should be used within an environmental temperature of more than 40°C
or in heights over 1000 m altitude, then the motor nominal power
and the
motor nominal current
must be accordingly reduced. For this purpose the
motor manufacturers provide the accordant derating factors.
