Question:
Is the motor identification (ID run, this means C0148 = 1) in the 9300EV to be performed with the machine at operating temperature?
Which influence does the motor temperature have on the determined motor resistance values?
Answer:
An ID run with the 'cold' machine detects a lower stator resistor (Rs = C0084) than an ID run with the machine at operating temperature. As the stator resistor's influence is especially important in case of low output frequencies (f < 10 Hz) a too low Rs leads to a reduced breakaway torque. On the other hand too high Rs can lead to instability of the vector control.
Due to the stability criteria we recommend an ID run only with the 'cold' machine.
As a rule, manual adjustment of the stator resistance is not required. In specific cases (especially with a large breakaway torque), by increasing the resistance by approx. 10 – 15 % an increase in the starting torque can be obtained (note: the no-load current consumption of the motor increases at the same time!).
The name plate data are used to calculate the rotor resistance (C0082); therefore the motor temperature has no influence on the Rr.
The detection of the inverter transmission error considers the measured stator resistor Rs. Therefore, the motor temperature has influence on the inverter compensation characteristic (WRK = C1751/x / C1755). Later the motor temperature has no important influence on the drive behaviour.
The temperature rise of the machine during operation without temperature feedback is not taken into account in the motor model by the 9300 vector.
On machines with temperature sensor KTY– provided temperature feedback is activated prior to the motor identification (C0594 = 0 'SD6-Trip') – the resistance values are converted to 20 °C and the temperature rise during operation taken into account in the motor model online.
The motor temperature has no important influence on the inverter error compensation.
