6 slip compensation, Slip compensation, Slip compensation ( 271) – Lenze 8400 TopLine User Manual
Page 271: 5motor control (mctrl)
Lenze · 8400 TopLine · Reference manual · DMS 6.0 EN · 06/2014 · TD05/TD14
271
5
Motor control (MCTRL)
5.10
Parameterisable additional functions
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5.10.6
Slip compensation
Under load, the speed of an asynchronous motor decreases. This load-dependent speed drop is
called slip. The slip can partly be compensated for by the setting in
• The setting of
can be done automatically in the course of motor parameter
identification.
Automatic motor data identification
• The setting must be made manually if the motor parameter identification cannot be called up.
How to set the slip compensation manually:
1. Set rated motor current (
) and rated motor frequency (
).
2. Calculate the slip compensation according to motor nameplate data:
3. Transfer the calculated slip constant s to
4. Correct the setting in
while the drive is running until the load-dependent speed
drop does not occur anymore between idling and maximum load of the motor in the
desired speed range.
Tip!
The following guide value applies to a correctly set slip compensation:
• Deviation from the rated motor speed
≤
1% for the speed range of 10 % ... 100 % of the
rated motor speed and loads
≤
rated motor torque.
• Greater deviations are possible in the field weakening range.
• If
is set too high, the drive may get unstable.
• Negative slip (
< 0) with V/f characteristic control results in "smoother" drive
behaviour at heavy load impulses or applications requiring a significant speed drop
under load.
Note!
Slip compensation is only active with the following motor control modes:
•
V/f characteristic control (VFCplus)
•
Sensorless vector control (SLVC)
Parameter
Info
Lenze setting
Value Unit
Slip compensation
2.11 %
s Slip constant (
n
rsyn
Synchronous motor speed [rpm]
n
r
Rated motor speed according to the motor
nameplate [rpm]
f
r
Rated motor frequency according to the
motor nameplate [Hz]
p Number of motor pole pairs (1, 2, 3 ...)
s
n
rsyn
n
r
–
n
rsyn
-----------------------
100%
⋅
=
n
rsyn
f
r
60
⋅
p
---------------
=