Siemens MICROMASTER 420 - Manual (Page 148)

3 Functions Issue 07/04
MICROMASTER 420 Operating Instructions
148 6SE6400-5AA00-0BP0
3.21.1.3 Slip compensation
Parameter range: P1335 – r1337
Warnings -
Faults -
Function chart number:
FP6100
In the V/f characteristic operating mode the motor frequency is always lower than
the drive inverter output frequency by the slip frequency f
s
. If the load (the load is
increased from M
1
to M
2
) is increased with a constant output frequency, then the
slip s when motoring increases and the motor frequency decreases (from f
1
to f
2
).
This behavior, typical for an induction motor, can be compensated using slip
compensation P1335. This therefore eliminates the speed reduction, caused by the
load, by boosting (increasing) the drive inverter output frequency (refer to Fig.
3-62).
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
Fig. 3-62 Slip compensation