Lenze 8400 StateLine - Manual (Page 215)

Lenze · 8400 StateLine · Reference manual · DMS 12.0 EN · 06/2014 · TD05/TD14
215
5 Motor control (MCTRL)
5.9 Parameterisable additional functions
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
5.9.5 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 C00021 .
• The setting of C00021 can be done automatically in the course of motor parameter
identification.  Automatic motor data identification ( 111)
• 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 ( C00088 ) and rated motor frequency ( C00089 ).
2. Calculate the slip compensation according to motor nameplate data:
3. Transfer the calculated slip constant s to C00021 .
4. Correct the setting in C00021 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
C00021 is set too high, the drive may get unstable.
• Negative slip ( C00021 < 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) ( 126)
• Sensorless vector control (SLVC) ( 161)
Parameter Info Lenze setting
Value Unit
C00021 Slip compensation 2.11 %
s Slip constant ( C00021 ) [%]
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
--------------- =