Siemens 440 - Manual (Page 162)

Parameter Description Issue 01/06
MICROMASTER 440 Parameter List
162 6SE6400-5BB00-0BP0
3.29.1.1 Slip compensation
P1335[3] Slip compensation Min: 0.0
CStat: CUT Datatype: Float Unit: % Def: 0.0
P-Group: CONTROL Active: Immediately QuickComm.: No Max: 600.0
Dynamically adjusts output frequency of inverter so that motor speed is kept constant independent of motor
load.
In the V/f-control, the motor speed will always be less than the command speed due to the slip speed. For a
given speed command, the speed will drop as load is increased. The speed regulation of drive can be
improved by the technique known as slip compensation.
Increasing the load from M1 to M2 (see diagram) will decrease the motor speed from f1 to f2, due to the
slip. The inverter can compensate for this by increasing the output frequency slightly as the load increases.
The inverter measures the current and increases the output frequency to compensate for the expected slip.
Without slip compensation
M
f
∆ f
f
2
f
1
M
2
M
1
With slip compensation
M
f
∆ f
f
2
f
1
M
2
M
1
f
out M1
f
out M2
Index:
P1335[0] : 1st. Drive data set (DDS)
P1335[1] : 2nd. Drive data set (DDS)
P1335[2] : 3rd. Drive data set (DDS)
Value:
P1335 = 0 % :
Slip compensation disabled.
P1335 = 50 % - 70 % :
Full slip compensation at cold motor (partial load).
P1335 = 100 % :
Full slip compensation at warm motor (full load).
f
f
N
out
6 % 10 %
P1335
100 %
%
f
f
N
set
6 % 10 %
f
f
N
out
Range of slip compensation :
without
slip compensation
with
slip compensation
Notice:
The applied value of the slip compensation (scaled by P1335) is limited by following equation:
Setpoint
channel
100
1335 P
f
Slip_act
f
set
f
Slip_comp_max
P1335
f
act
r0065
r1078 r0063
r0330
100
P1336
f
max Slip_comp_
⋅ =
f
out
r1337
Level
2