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

5.7.5

Remedies for undesired drive behaviour

Drive behaviour
Deviation between no-load current and magnetising
current or bad speed or torque accuracy.
Insufficient speed constancy at high load: Setpoint and
motor speed are not proportional anymore.
Caution: Overcompensation of the settings mentioned
under " Remedy" may result in unstable behaviour!
Unstable control with higher speeds.
"Short circuit" (OC1) or "Clamp operation active" (OC11)
error messages at short acceleration time (C00012) in
proportion to the load (controller cannot follow the
dynamic processes).
Mechanical resonance at certain speeds.
Speed variations in no-load operation for speeds > 1/3
rated speed.
Drive runs unstable.
Setpoint speed and actual speed differ strongly.
The torque required is not generated at standstill.
Current overshoots occur when heavy loads are
accelerated from standstill (OC1 or OC11 error).
The machine runs uneven.
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8400 StateLine C | Reference manual
Remedy
Adapt the motor magnetising inductance (C00092) for
no-load operation.
• If the no-load current is greater than the magnetising
current (C00095) at 0.5-fold rated motor speed, the
magnetising inductance must be reduced until the
no-load current and the magnetising current have the
same values.
• Otherwise, the magnetising inductance must be
increased.
Tendency of the correction of
+15 %
0
-15 %
0,37
PN: Rated motor power
Via the slip compensation (C00021), the speed stability
under high loads can be affected:
• If n > n
act slip
• If n < n
act slip
• Check the setting of the magnetising inductance
(C00092) by comparing the current consumption in
no-load operation with the rated magnetising current
(C00095).
• Optimise oscillation damping (C00234).
• Increase the gain of the torque controller (C00073/2).
• Reduce the reset time of the torque controller
(C00074/2).
• Increase the acceleration (C00012)/deceleration (
C00013) time.
The L_NSet_1 function block masks out those speed
ranges that include resonance.
Minimise speed oscillations with oscillation damping
(C00234).
Check set motor data (nameplate data and equivalent
circuit diagram data).
Motor selection/Motor data ( 107)
Increase motor magnetising current (C00095).
L
Motor control (MCTRL)
Sensorless vector control (SLVC)
C00092:
P [kW]
22 90
N
, reduce the value in C00021
, increase the value in C00021
173