Lenze 8200 Frequency inverters - Manual (Page 165)

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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