Lenze DSD - Manual (Page 456)

18 Drive dimensioning messages
18.5 Lenze motor
456
Lenze · Drive Solution Designer · Manual · DMS 4.2 EN · 12/2013 · TD23
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18.5.4 Motor is operated in the field weakening range
18.5.5 Max. mismatch is higher than permissible mismatch
18.5.6 Motor speed too low
Note!
The field weakening factor of the motor is xxx.
Hence, the limit value of yyy is exceeded. The motor is operated in the field weakening range.
During field weakening operation, larger reserves must be provided for the inverter.
Cause Effects Possible remedies
In the field weakening range, the ac-
curacy of the DSD current model is re-
stricted.
DSD cannot calculate correctly the
thermal utilisation of the inverter.
The inverter is thermally overloaded. Select inverter with higher thermal
reserves.
 Field weakening ( 426)
Note!
The max. mismatch of the motor is xxx.
Hence, the max. permissible mismatch of the motor of yyy is exceeded.
(only applicable to speed-controlled systems)
Cause Effects Possible remedies
The maximum mismatch exceeds
the limit value defined.
The drive is inclined to vibrations and
possibly is not controllable with re-
gard to feedback control (only for
speed control or position-controlled
systems).
For torque-controlled or VFCPLUS-
controlled systems this value has a
lower priority.
• Select gearbox with higher trans-
mission ratio.
• Select motor with higher inertia
(standard motor instead of servo
motor).
 Load-matching factor ( 321)
Tip!
The required max. motor speed is xxx rpm. Thus it falls below the limit value for low motor speeds of
yyy rpm.
Cause Effects Possible remedies
With regard to their size, inverters
are defined by the motor current. If
the motor is only operated in the
lower speed range with regard to its
rated speed, the voltage provided by
the inverter is not utilised.
A different motor that would be op-
erated more near its rated speed
would improve the utilisation of the
inverter.
Drive system possibly may not be at
optimal cost.
Use a gearbox with a higher ratio, so
that the motor at the same power is
better utilised with regard to speed,
and the inverter is better utilised
with regard to voltage.