Remedies For Undesired Drive Behaviour - Lenze 8400 StateLine C Reference Manual

5.4.4

Remedies for undesired drive behaviour

Drive behaviour
Inadequate smooth running at low speeds, especially in
the case of operation with a long motor cable
Problems in case of high starting duty (great mass
inertia)
Drive does not follow the speed setpoint.
For operation without speed feedback
Insufficient speed constancy at high load (setpoint and
motor speed are not proportional anymore)
"Clamp operation active" error message (OC11):
Controller cannot follow dynamic processes, i.e. too
short acceleration/deceleration times in terms of load
ratios.
Motor stalling in the field weakening range
(adaptation especially required for small machines)
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8400 StateLine C | Reference manual
Remedy
Automatic motor data identification ( 112)
Adapting the Vmin boost ( 134)
The current controller intervenes in the set field
frequency to limit the controller output current to the
maximum current (C0022, C0023). Therefore:
• Prolong acceleration/deceleration times:
C00012:
C00013: Decel. time - main setpoint
• Consider a sufficient magnetising time of the motor.
Depending on the motor power, the magnetising
time amounts to 0.1 ... 0.2 s.
• Increase the maximally permissible current:
C00022: Imax in motor mode
C00023: Imax in generator mode)
(C00006 = 6): • Increase slip compensation (C00021).
Important: Unstable drive due to overcompensation!
• With cyclic load impulses (e. g. centrifugal pump), a
smooth motor characteristic is achieved by smaller
values in
Note: The slip compensation is only active for operation
without speed feedback.
• Increase the gain of the I
• Reduce the reset time of the I
(C00074/1)
• Prolong the acceleration time (C00012)
• Prolong the deceleration time (C00013)
• Reduce the override point of field weakening
(C00080)
• If motor power < inverter power:
Set C00022
• Reduce dynamic performance of setpoint generation
L
Motor control (MCTRL)
V/f characteristic control (VFCplus)
Accel. time - main setpoint
C00021 (possibly negative values).
controller (C00073/1)
max
controller
max
to I = 2 I
max rated motor
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