5 remedies for undesired drive behaviour, Remedies for undesired drive behaviour, 5motor control (mctrl) – Lenze 8400 BaseLine D User Manual
Page 92
5
Motor control (MCTRL)
5.5
Sensorless vector control (SLVC)
92
Lenze · 8400 BaseLine D · Reference manual · DMS 5.5 EN · 01/2014 · TD05
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5.5.5
Remedies for undesired drive behaviour
Drive behaviour
Remedy
Deviation between no-load current and magnetising
current or bad speed or torque accuracy.
Adapt the motor magnetising inductance (
) for no-
load operation.
• If the no-load current is greater than the magnetising
current (
) at 0.5-fold rated motor speed, the ma-
gnetising inductance must be reduced until the no-
load current and the magnetising current have the
same values.
• Otherwise, the magnetising inductance must be in-
creased.
Tendency of the correction of
PN: Rated motor power
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!
Via the slip compensation (
der high loads can be affected:
• If n
act
> n
slip
, reduce the value in
• If n
act
< n
slip
, increase the value in
Unstable control with higher speeds.
• Check the setting of the magnetising inductance
(
) by comparing the current consumption in no-
load operation with the rated magnetising current
(
)
• Optimise oscillation damping (
"Short circuit" (OC1) error messages at short acceleration
) in proportion to the load (controller cannot
follow the dynamic processes).
Increase acceleration time (
)/deceleration time
(
).
Mechanical resonance at certain speeds.
function block masks out those speed ran-
ges that include resonance.
Speed variations in no-load operation for speeds > 1/3
rated speed.
Minimise speed oscillations with oscillation damping
(
).
Drive runs unstable.
Check set motor data (nameplate data and equivalent
circuit diagram data).
Motor selection/Motor data ( 66)
Setpoint speed and actual speed differ strongly.
0,37
22
90
C0092
-15 %
+15 %
0
P [kW]
N