Lenze 8400 - Manual (Page 165)

Lenze · 8400 protec HighLine · Reference manual · DMS 3.0 EN · 03/2013 · TD05
165
5 Motor control (MCTRL)
5.4 V/f characteristic control (VFCplus)
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5.4.4 Remedies for undesired drive behaviour
Drive behaviour Remedy
Inadequate smooth running at low speeds, especially in
the case of operation with a long motor cable
 Automatic motor data identification ( 134)
Problems in case of high starting duty (great mass
inertia)
 Adapting the Vmin boost ( 157)
Drive does not follow the speed setpoint. 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: Accel. time - main setpoint
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)
For operation without speed feedback ( C00006 = 6):
Insufficient speed constancy at high load (setpoint and
motor speed are not proportional anymore)
• 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 C00021 (possibly negative values).
Note: The slip compensation is only active for operation
without speed feedback.
"Clamp operation active" error message (OC11):
Controller cannot follow dynamic processes, i.e. too
short acceleration/deceleration times in terms of load
ratios.
• Increase the gain of the I
max
controller ( C00073/1 )
• Reduce the reset time of the I
max
controller
( C00074/1 )
• Prolong the acceleration time ( C00012 )
• Prolong the deceleration time ( C00013 )
Motor stalling in the field weakening range
(adaptation especially required for small machines)
• Reduce the override point of field weakening
( C00080 )
• If motor power < inverter power:
Set C00022 to I
max
= 2 I
rated motor
• Reduce dynamic performance of setpoint generation