Technical data
Instruction handbook bmaXX 5000
Document No.: 5.09021.19
77
of 346
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3.4.3 Output frequency-dependent current derating
All Baumüller devices have been developed so that the rated output current, as stated,
are only continuously permitted (i. e. in S1 operation) with an electrical output frequency
of 15 Hz or higher. If the static inverter output frequency is smaller than 15 Hz and the
frequency is between 0 and 15 Hz for more than 5 seconds, then the continuously per-
missible output current must be reduced according to the following characteristic curve.
These are affected, for example, but not exclusively:
n Applications with rpm control but without positioning, or
n Applications in which a current is required to assure a torque / a force at standstill or
n Applications in which blocking of the mechanical parts can occur, e.g. when starting up
cold extruders.
Thus, typically, the following applications are not affected:
n Generally, typical positioning applications
n Applications with motors that use a service brake when at standstill.
n Applications in which the higher-level control unit has standstill and blocking monitor-
ing.
Insofar as the derating range has been cycled through with sufficient speed, the applica-
tion of I
rated
is permitted. Here, cycled through with sufficient speed means that the fre-
quency change corresponds to 15 Hz/s.
Derating of the motor-side inverter output current I with respect to the rated output current
I
rated
as a function of the static inverter output frequency f.
Static inverter output frequency f
Figure 32: Derating with a static inverter frequency < 15 Hz
I
I
rated
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