11 drive dimensioning – Lenze DSD User Manual
Page 356
11
Drive Dimensioning
11.6
Inverters
356
Lenze · Drive Solution Designer · Manual · DMS 4.2 EN · 12/2013 · TD23
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k
ol
Set inverter operation with increased continuous power.
Frequency inverters can be operated with rated power
(100 %) and increased rated power (120 %).
• During operation with increased rated power, an in-
creased permanent power but only a few overload re-
serves are provided. Possible limitations for this
operation: limited temperature range, use of a mains
choke, lower switching frequency.
f
ch
kHz
kHz
Switching frequency range
M-n
M-n characteristic of the motor
: saved characteristic
-: equivalent characteristic
A
th
~
%
%
Previously calculated thermal utilisation of the inverter
• Monitoring of the continuous current
Relevant topics:
Thermal utilisation (Ixt) ( 348)
Possible messages:
Max. thermal utilisation >100 % ( 466)
A
~
(I
max
)
%
%
Previously calculated utilisation of the inverter relative
to the max. output current
• Ratio of the required current to the max. output cur-
rent of the inverter.
Relevant topics:
Determination of the utilisation values of the inverter
Possible messages:
Max. output current exceeded ( 465)
A
~
(I
max,I
/I
N,M
)
Utilisation of the inverter calculated in advance with ref-
erence to the ratio of the rated output current of the in-
verter and the rated motor current
• An overdimensioning that is too high, due to an unfa-
vourable current resolution will possibly result in con-
trol-oriented problems and an insufficient behaviour
with regard to smooth running.
Relevant topics:
Determination of the utilisation values of the inverter
Possible messages:
Current resolution is not adapted to the motor
I
rated
A
A
Rated output current of the inverter
I
max
A
A
Max. output current of the inverter
• The maximum output current depends on the mains
voltage and the heatsink temperature and is reduced
at low output frequencies.
Relevant topics:
Current derating for inverters ( 352)
Possible messages:
Max. output current exceeded ( 465)
Parameter
Unit
Description
Metric
Imperial