Description of the Software Modules and Parameters
Parameter manual
b maXX
BM5800
Document No.: 5.16029.03
723
3
3.11.5.3 Monitoring of the single phases
The introduced standard solution referring to the monitoring of the total current is insuffi-
cient for a lot of applications, during low speed and with zero speed. Therefore, an imple-
mentation solution is introduced considering the effect of an output frequency having a
period not significantly smaller than the thermal time constant of the motor.
It must be considered that in the motor data sheets neither the specification of the stand-
still current nor the current characteristics are not to be interpreted literally. A minimum
speed for the standstill current can be mentioned in the data sheets. Please, contact the
motor manufacturer for more detailed information if the output frequencies are as low as
described above.
The output frequencies described above load the three phases unequally. By l
2
t monitor-
ing mode
bit 3 set to 1 instead of the l
2
values of the total current the l
2
values
can be evaluated separately for every phase (
to
). The "Motor l
2
t actual
includes the value of the most strongly loaded phase. By default this option
is not activated.
Figure 194:
Motor-I
2
t, monitoring of the single phases
5000_0363_rev01.cdr
N
D
PT
1
N
D
max
Ref
I
6.28
T
t
Iu-,Iv-,Iw Actual values
47.32, 47.33, 47.34
Initialization
Motor I t actual value
2
