Operating Instructions ACTIVE 06/0790
90 Operating Instructions ACTIVE 06/07
9.2 Further motor parameters
In particular the field-oriented control requires the determination of further data which
cannot be read off the name plate of the 3-phase machine for the precise calculation
of the machine model. In the course of the guided commissioning, the parameter
identification was carried out to measure the further motor parameters.
9.2.1 Stator Resistance
The resistance of the stator winding was measured during the guided commissioning.
The measured value is stored as a phase value in parameter
Stator resistance 377
and is 3 times smaller than the winding resistance in delta connection.
By default, the equivalent stator resistance of a standard motor is entered to match
the nominal power of the frequency inverter.
Parameter Settings
No. Description Min. Max. Fact. sett.
377 Stator Resistance 0 mΩ 65535 mΩ R
sN
The stator resistance can be optimized while the machine is in no-load operation. At
the steady-state operating point, the torque-forming current
Isq 216 and/or the esti-
mated
Active current 214 should be zero. Due to the temperature-dependent of the
stator resistance, the adjustment should be done at a winding temperature which is
also reached during normal operation.
A correct measurement will optimize the control functions.
9.2.2 Leakage Coefficient
The leakage coefficient of the machine defines the ratio of the leakage inductivity to
the main inductivity. The torque and flux-forming current components are thus cou-
pled via the leakage coefficient. Optimization of the leakage coefficient within the
field-orientated control systems requires acceleration to various operating points of
the drive. Unlike the torque-forming current
Isq 216, the flow-forming current Isd
215 should be largely independent of the load torque. The flow-forming current com-
ponent is inversely proportional to the leakage coefficient. If the leakage coefficient is
increased, the torque-forming current increases and the flux-forming component
drops. The adjustment should result in a relatively constant actual current
Isd 215,
matching the parameter
Rated magnetizing current 716, regardless of the load on the
drive.
The sensorless control system uses the parameter
Leakage coefficient 378 in order to
optimize the synchronization to one drive.
Parameter Settings
No. Description Min. Max. Fact. sett.
378 Leakage Coeff. 1.0 % 20.0 % 7.0 %
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