9 running optimisation, 1 slip compensation, Running optimisation – Lenze 8200 Frequency inverters User Manual
Page 165: Slip compensation, Configuration
Configuration
8200SHB0199
7-28
7.5.9
Running optimisation
7.5.9.1
Slip compensation
Code
Name
Possible settings
IMPORTANT
Lenze
Choice
Info
C021 Slip compensation
C021
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) by using the motor data:
Adjustment
s
n
Nsyn
Å 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
/ 50 Hz
s
1500 min
Е1
Е1435 min
Å1
1500 min
Е1
ф 100 % 4.33 %
n
Nsyn
50 Hz
ô 60
2
1500 min
Å1
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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