Lenze DSD - Manual (Page 432)

17 Restrictions of the drive dimensioning
17.10 Displacement of the M-n characteristic
432
Lenze · Drive Solution Designer · Manual · DMS 4.2 EN · 12/2013 · TD23
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
17.10 Displacement of the M-n characteristic
If the max. available output voltage on the inverter is lower than the rated motor voltage, field
weakening already starts below the rated motor speed.
• The output voltage on the inverter depends on the mains voltage.
• Depending on the max. output voltage on the inverter, the available torque decreases.
• In overboost operation (M > M
N
), this effect is particularly distinctive.
• Possible causes are:
• Mains undervoltage
• Voltage drop on filters, chokes. The components are only considered in DSD if they are man-
datory for operation.
• Voltage drop on long motor cables
• The operating voltages of the inverter and motor (U
mot
> U
mains
) are not optimally assigned,
e. g. 460 V motor on the inverter with 400 V mains supply.
[17-4] Maximum and continuous torques

Note!
Only relevant for inverter-motor combinations which are not adjusted to each other as
regards voltage (output voltage of inverter < motor voltage).
 Motor characteristic 360 V mains voltage
 Motor characteristic 400 V mains voltage
 Motor characteristic 440 V mains voltage