Siemens MICROMASTER 440 Operating Instructions Manual page 33

Issue 10/06
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.
START
Quick
commissioning
Motor data
identification
Operation under
no-load conditions
Criterium
fulfilled ?
no yes
P0320 = ...
P0340 = 1
END
MICROMASTER 440
Operating Instructions (Compact)
Quick commissioning routine
Using the quick commissioning routine the frequency inverter is adapted to the
motor and important technology parameters are set.
Motor data identification routine
Using the motor data identification routine motor equivalent circuit diagram
data is determined using a measuring technique.
Determining the magnetizing current
In order to determine the magnetizing current (P0320/r0331), the motor should
be accelerated up to approximately 80% of its rated speed under no-load
operating conditions.
In so doing, the following conditions must be carefully maintained:
− the vector control must be activated, P1300 = 20.21
− no field weakening (r0056.8 = 0)
− flux setpoint, r1598 = 100 %
− no efficiency optimization, P1580 = 0 %
No-load operation means that the motor is operated without a load (i.e.
no coupled driven machine).
Under steady-state conditions, a current r0027 is obtained that approximately
corresponds to the rated magnetizing current r0331. (the current is always
less than the no-load current for a pure V/f control).
Measuring and entering the magnetizing current and therefore the associated
new calculation of the equivalent circuit diagram data of the motor is an
iterative procedure. It must be repeated at least 2-3 times until the following
criteria are fulfilled:
− The more accurate the value of the magnetizing current that was
entered, the better the flux setpoint (r1598=100%) matches the flux
actual value (r0084=96..104%) of the observer model.
− The output Xm adaptation (r1787) of the observer model should be
as low as possible. Good values lie between 1-5%. The less that the
Xh adaptation of the observer must operate, the sensitivity of the motor
parameters after power failures are that much less sensitive.
NOTE
In order to display r0084 at the BOP/AOP, the LEVEL 4 parameters must be
enabled using service parameter P3950=46.
Calculating P0320
Now, the new value can be entered in P0320 from the determined flux-
generating current component r0029 by applying the following equation.
P0320 = r0029 * 100 / P0305
Calculating the motor parameters
The values of the motor equivalent circuit diagram data are calculated from the
entered rating plate data. In addition, the parameters of the controls are pre-set
(subsequently optimized) (P0340 = 3).
6 Commissioning
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