
7.3.3
Optimising the stalling behaviour
Motor stalling due to torque overload in the field weakening range in all characteristic-based
motor control types (VFCplus) is prevented by means of an inverter-internal stalling current
monitoring. In the field weakening range, hence at frequencies above the base frequency, it
reduces the maximum current to prevent the motor from stalling. The reduction depends on
the current field frequency, the base frequency, the DC-bus voltage, and the maximum cur-
rent. Generally, a higher field frequency causes a stronger limitation of the maximum current.
The response in the field weakening range can be adapted via the override point of field weak-
ening
0x2B0C (PAR 319)
.
DANGER!
Danger by incorrect parameterisation.
Possible consequences: damage to material assets and injury to persons
▶
Only change the Lenze setting (0 Hz) in
0x2B0C (PAR 319)
after consulting the motor manu-
facturer!
▶
Recommendation: maintain Lenze setting (0 Hz).
Details
With the override point of field weakening
0x2B0C (PAR 319)
, the frequency-dependent maxi-
mum current characteristic can be shifted.
Override point of field weakening > 0 Hz:
•
The maximum current characteristic is shifted to higher field frequencies by the frequency
entered.
•
The maximum permissible current and the maximum torque increase in the field weakening
range.
•
The risk of motor stalling increases.
Override point of field weakening < 0 Hz:
•
The maximum current characteristic is shifted to lower field frequencies by the frequency
entered.
•
The maximum permissible current and the maximum torque are reduced in the field weak-
ening range.
•
The risk of motor stalling is reduced.
Parameter
Name / value range / [default setting]
Info
0x2B0C
(PAR 319)
Override point of field weakening
(Overr. point of field weak.)
-599.0 ... [0.0] ... 599.0 Hz
Offset of the override point for field weakening.
0x2B01:002
(PAR 303/002)
V/f characteristic data: Base frequency
(V/f char. data: Base frequency)
0 ... [50]* ... 599 Hz
•
Default setting depending on the size.
Frequency in the reference point of the V/f characteristic.
•
The V/f base frequency is usually set to the rated motor frequency
0x2C01:005 (PAR 320/005)
.
Motor control
Optimisation of motor control
Optimising the stalling behaviour
86
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