Siemens SINAMICS G120XA - Motor Protection by Calculating the Temperature; Thermal Motor Model 2 for Induction Motors

6.7.4 Motor protection by calculating the temperature
Overview
The converter 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 the thermal motor model is used together with a temperature sensor, e.g. a Pt1000, then the
converter corrects the model according to the measured temperature.
Function description
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.
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Figure 6-70 Thermal motor model 2 for induction motors
Parameters
Table 6-67 Thermal motor model 2 for induction motors
Number Name Factory setting
r0034 CO: Thermal motor load - %
r0068[0 … 1] CO: Absolute actual current value - Arms
p0344[M] Motor weight (for thermal motor model) 0 kg
p0604[M] Mot_temp_mod 2/KTY alarm threshold 130 °C
p0605[M] Mot_temp_mod 1/2/sensor threshold and temperature value 145 °C
p0610[M] Motor overtemperature response 12
p0612[M] Mot_temp_mod activation 0000 0010 0000
0010 bin
p0625[M] Motor ambient temperature during commissioning 20 °C
p0627[M] Motor overtemperature, stator winding 80 K
r0632[M] Mot_temp_mod stator winding temperature - °C
p0640[D] Current limit 0 Arms
Further information is provided in the parameter list.
Advanced commissioning
6.7 Drive protection
SINAMICS G120XA converter
Operating Instructions, 03/2019, FW V1.0, A5E44751205B AB 307