Lenze 8200 - Running Optimisation; Slip Compensation

Configuration
8200SHB01997-28
7.5.9 Running optimisation
7.5.9.1 Slip compensation
Code Name
Possible settings
IMPORTANT
Lenze Choice Info
C021
Slip compensation
C
0
2
1
820X 0.0 0.0 {0.1 %} 12.0
821X/822X/
824X
0.0 0.0 {0.1 %} 50.0 * With C014 = -2-,
-3-, controller
dependent
0.0 {0.1 %} 20.0 *With C014 = -4-
Function Under load, the speed of an asynchronous machine is reduced. This load-dependent speed
reduction is called slip. The slip can be partly compensated by setting C021 accordingly. The slip
compensation is effective with all control modes (C014).
- C021 < 0 (with C014 = -2-, -3-)
- “Smoother” drive characteristic, if strong load shock occur or application of several motors.
- In the field frequency range between 5 Hz ... 50 Hz (87 Hz), the deviation of the rated speed is
$ 1 % (guide value). In field-weakening operation, the fault increases.
Adjustment
1.Rough setting of the slip constants (C021)byusing the motor data:
A
d
j
u
s
t
m
e
n
t
s 
n
Nsyn
 n
r
n
Nsyn
ô 100 %
n
Nsyn

f
dr
ô 60
p
s Slip constant (C021)[%]
n
Nsyn
Synchronous motor speed [min
-1
]
n
r
Rated speed to motor nameplate [min
-1
]
f
dr
Rated frequency to motor nameplate [Hz]
p No. of pole pairs (1, 2, 3, ...)
2.Empirical precise setting of the slip compensation:
- Correct C021 until no load-dependent speed drop occurs in the required speed range between
idle running and max. motor load.
3.Example:
- Motor data: 4 kW/ 1435 min
-1
/50Hz
s 
1500 min
 1
 1435 min
 1
1500 min
 1
ô 100 %  4.33 %
n
Nsyn

50 Hz ô 60
2
 1500 min
 1
Preset C021 = 4.33 %
Important If C021 is set too high, overcompensation can occur and lead to an instability of the drive.
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