Operating Instructions ACTIVE06/07 91
06/07 Operating Instructions ACTIVE 91
9.2.3 Magnetizing Current
The Rated magnetizing current 716 is a measure of the flux in the motor and thus of
the voltage which is present at the machine in no-load condition depending on the
speed. The guided commissioning determines this value at about 30% of the
Rated
current
371. This current can be compared to the field current of an externally ex-
cited direct current machine.
In order to optimize the sensor-less field-oriented control system, the machine has to
be operated without load at a rotational frequency which is below the
Rated frequency
375. The accuracy of the optimization increases with the adjusted
Switching fre-
quency
400 and when the drive is in no-load operation. The flux-forming actual cur-
rent value
Isd 215 to be read out should roughly match the set Rated magnetizing
current
716.
The field-orientated control with speed sensor feedback uses the parameterized
Rated
magnetizing current
716 for the flux in the motor.
The dependence of the magnetizing on the frequency and voltage at the correspond-
ing nominal operating point in question is taken into account by a magnetizing charac-
teristic. The characteristic is calculated via three points, in particular in the field weak-
ening range above the rated frequency. The parameter identification has determined
the magnetizing characteristic of the motor and set the parameters
Magnetizing cur-
rent 50%
713, Magnetizing current 80% 713 and Magnetizing current 110% 713.
Parameter Settings
No. Description Min. Max. Fact. sett.
713 Magnetizing current 50% Flux 1.00% 50.00% 31.00%
714 Magnetizing current 80% Flux 1.00% 80.00% 65.00%
715 Magnetizing current 110% Flux 110.00% 197.00% 145.00%
716 Rated Magnetizing Current 0.01â‹…I
FIN
o â‹… I
FIN
0.3â‹…I
FIN
9.2.4 Rated Slip Correction Factor
The rotor time constant results from the inductivity of the rotor circuit and the rotor
resistance. Due to the temperature-dependence of the rotor resistance and the satu-
ration effects of the iron, the rotor time constant is also dependent on temperature
and current. The load behavior and thus the rated slip depend on the rotor time con-
stant. The guided commissioning determines the machine data during the parameter
identification and sets the parameter
Rated slip correction factor 718 accordingly. For
the fine adjustment or a check of the rotor time constant, proceed as follows: Load
the machine at fifty percent of the
Rated frequency 375. As a result, the voltage must
be approximately fifty percent of the
Rated voltage 370, with a maximum tolerance of
5 %. If this is not the case, the correction factor must be changed accordingly. The
larger the correction factor is set, the stronger the voltage drop when the machine is
loaded. The value calculated by the rotor time constants can be read out via the ac-
tual value
Current rotor time constant 227. The adjustment should be done at a
winding temperature which is also reached during normal operation of the motor.
Parameter Settings
No. Description Min. Max. Fact. sett.
718 Rated Slip Correction Factor 0.01% 300.00% 100.00%
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