Baumuller b maXX BM3000 User Manual

Description of the Software Modules and Parameters
Parameter manual b maXX BM3000
Document no.: 5.12001.07
729
of 820
4
If the output value of the I
2
t-sub-model (PU-I
2
t-actual value) reaches 105% of Z175.8–
the warning 206 is set and the apparent current is limited to the maximum PU continuous
current
Z175.7–.
If the PU-I
2
t actual value reaches 95%, the current limit is canceled on the part of the I
2
t-
sub-model.
If a current limit is additionally activated by the power electronics sub-model, the warning
206 remains. The warning and the limit is disabled not before the current limit is canceled
from both sub-models.
Power electronics sub-model:
The temperature of power electronics is emulated and is standardized using the tempera-
ture threshold 
Sempu
(temperature actual value = 
Sempu
corresponds to 105% load),
which was defined in the characteristics of the device. Thus, the load value is compatible
to the I
2
t-sub-model.
If the value reaches 105%, warning 206 is set and the apparent current is limited to the
maximum PU continuous current
Z175.7–.
The power electronics sub-model cancels the current limit after 
Sempu
falls below the
value 105% within 30
s. The 30 s time slice is an empirical value, which is great enough
so that all devices can recover thermally.
However, the current limit still can be activated by I
2
t-sub-model.
Protective function PWM reduction
In order to avoid current limiting, the switching frequency can be automatically reduced
(i.e. PWM frequency
Z130.15– is halved). Thereby, the switching losses in the IGBTs are
reduced.
If the temperature of the power electronics exceeds the temperature threshold

SemLimRed
, the PWM frequency is halved and warning 216 is triggered. The tempera-
ture threshold 
SemLimRed
is lower than the threshold 
Sempu
, which triggers the cur-
rent limit.
The PWM reduction doesn't change the value of the PWM frequency Z130.15–, which
was set.
NOTE!
m As long as the safety function current limit is active and the output frequency is
Z47.49– < 15 Hz (current derating dependent of output frequency is active), the
apparent current is limited to the lowest existing value of the maximum PU contin-
uous current Z175.7–. This means, that during this time the current limit can be
lower, if the output frequency drops. However, the current limit cannot become
greater, if the output frequency increases.
m At the protective function current limit the "Max. drive current available" Z19.5– is
reduced, whereat the settable limit of the apparent current "Max. drive current"
Z19.6– isn't changed. The reduction of the apparent current takes place via the
current torque, i. e. via the "Max. available torque current" Z19.8–.

Baumuller b maXX BM3000 Specifications

General

Brand	Baumuller
Model	b maXX BM3000
Category	Measuring Instruments
Language	English