Siemens SINAMICS G120XA, Operating Instructions Manual

Page: 424 / 918

Description: Selects the identification of the stator resistance of induction motors after the Control Unit runs-up (only for vector
control).
The identification is used to measure the actual stator resistance and from the ratio of the result of motor data
identification (p0350) to the matching ambient temperature (p0625) the actual mean temperature of the stator winding
is calculated. The result is used to initialize the thermal motor model.
p0621 = 1:
Identification of the stator resistance only when the drive is switched on for the first time (pulse enable) after booting
the Control Unit.
p0621 = 2:
Identification of the stator resistance every time the drive is switched on (pulse enable).
If a reference value for the stator resistance at an ambient temperature is entered into p0629, then the setting value
for the stator temperature is generated from this value and not from p0350.
When activating the measurement (p0621 = 1, 2), p0629 is determined when first starting the drive. p0629 should be
saved for subsequent use. In order that p0629 matches the ambient temperature (p0625), the function should be
activated with the motor in the cold condition.
Value: 0: No Rs identification
1: Rs identification after switching-on again
2: Rs identification after switching-on each time
Dependency: - perform motor data identification (see p1910) with cold motor.
- enter ambient temperature at time of motor data identification in p0625.
- Reference stator resistance p0629 saved after it has been determined.
See also: p0622, p0629
NOTICE
The calculated stator temperature can only be compared with the measured value of a temperature sensor (KTY/
PT1000) to a certain extent, as the sensor is usually the warmest point of the stator winding, whereas the measured
value of identification reflects the mean value of the stator winding. The accuracy depends very heavily on how
precisely the motor feeder cable resistance is known (see p0352).
The accuracy of the measurement can be improved by entering the feeder cable resistance p0352 and by determining
the reference stator resistance p0629 for the ambient temperature. p0629 is the measured value r0623, which was
determined immediately after the first commissioning with the motor in a cold state. For p0621 = 1, p0629 is also
measured when switching on for the first time and not after the Control Unit has switched on.
Note
The measurement is carried out:
- For induction motors
- When vector control is active (see p1300)
- if a temperature sensor (KTY/PT1000) has not been connected
- When the motor is at a standstill when switched on
When a flying restart is performed on a rotating motor, the temperatures of the thermal motor model are set to a third
of the overtemperatures. This occurs only once, however, when the CU is booted (e.g. after a power failure).
If identification is activated, the magnetizing time is determined via p0622 and not via p0346. Quick magnetizing
(p1401.6) is de-energized internally and alarm A07416 is displayed. The speed is enabled after completion of the
measurement.
p0622[0...n] Motor excitation time for Rs_ident after switching on again / t_excit Rs_id
Access level: 3 Calculated: CALC_MOD_REG Data type: FloatingPoint32
Can be changed: T, U Scaling: - Dynamic index: MDS, p0130
Unit group: - Unit selection: - Function diagram: -
Min:
0.000 [s] Max:
20.000 [s] Factory setting:
0.000 [s]
Description: Sets the excitation time of the motor for the stator resistance identification after switching on again (restart).
Dependency: See also: p0621
Parameters
7.3 Parameters
SINAMICS G120XA converter
422
Operating Instructions, 03/2019, FW V1.0, A5E44751205B AB