Advanced commissioning
7.16 Motor protection by calculating the temperature
SIMATIC ET 200pro FC-2 converter
180
Operating Instructions, 04/2018, FW V4.7 SP10, A5E34257324B AF
7.16
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 7-38 Thermal motor model 2 for induction motors
Table 7- 32 Thermal motor model 2 for induction motors
Parameter Description
r0068
CO: Absolute actual current value
p0610
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 calcu-
lated difference to the ambient air temperature. After switching the supply voltage
on again, the thermal motor model starts with 90 % of the previously saved differ-
ence temperature.
