Motor Protection By Calculating The Temperature - Siemens SINAMICS G120 Operating Instructions Manual

6.26

Motor protection by calculating the temperature

The inverter calculates the motor temperature based on a thermal motor model.
The thermal motor model responds far faster to temperature increases than a temperature
sensor.
If you are using the thermal motor model together with a temperature sensor, e.g. a Pt1000,
then the inverter corrects the model based on the measured temperature.
Thermal motor model 2 for induction motors
The thermal motor model 2 for induction motors is a thermal 3-mass model, consisting of stator
core, stator winding and rotor. Thermal motor model 2 calculates the temperatures - both in
the rotor as well as in the stator winding.
Figure 6-66
Table 6-61
Parameter Description
r0068
p0610
Converter with the CU250S-2 Control Units
Operating Instructions, 04/2018, FW V4.7 SP10, A5E31759476B AG
Thermal motor model 2 for induction motors
Thermal motor model 2 for induction motors
CO: Absolute actual current value
Motor overtemperature response (factory setting: 12)
0: Alarm A07012
The inverter does not reduce the current limit.
1: Alarm A07012 and fault F07011
The inverter reduces the current limit.
2: Alarm A07012 and fault F07011
The inverter does not reduce the current limit.
12: Alarm A07012 and fault F07011
The inverter does not reduce the current limit.
After switching off the supply voltage, the inverter saves the most-recently calculated
difference to the ambient air temperature. After switching the supply voltage on
again, the thermal motor model starts with 90 % of the previously saved difference
temperature.
6.26 Motor protection by calculating the temperature
Advanced commissioning
333