Magnetizing Current - Siemens MICROMASTER 440 Operating Instructions Manual

Issue 10/06
3.5.6

Magnetizing current

The value of the magnetizing current r0331/P0320 has a significant influence
on the closed-loop control. This cannot be measured at standstill. This
means that the value is estimated for standard 4-pole 1LA7 SIEMENS
standard using the automatic parameterization P0340=1 (P0320=0; result in
r0331).
If the deviation of the magnetizing current is too high, then the values for the
magnetizing reactance and those of the rotor resistance will not be able to
be accurately determined.
Especially for third-party motors it is important that the magnetizing current
that is determined, is carefully checked and if required, appropriately
corrected.
The procedure to manually determine the magnetizing current and to re-calculate
the equivalent circuit diagram data when the drive is operated with closed-loop
vector control (P1300 = 20/21) is shown in the following.
MICROMASTER 440 Operating Instructions
6SE6400-5AW00-0BP0
3 Functions
95