Protecting The Motor By Calculating The Motor Temperature; Overcurrent Protection - Siemens Sinamics G120P Operating Instructions Manual

Functions
7.6 Protection functions
7.6.3

Protecting the motor by calculating the motor temperature

The temperature calculation is only possible in the vector control mode (p1300 = 20) and
functions by calculating a thermal motor model.
Table 7- 23
Parameter
p0621= 1
p0622
p0625
7.6.4

Overcurrent protection

During vector control, the motor current remains within the torque limits set there.
During V/f control, the maximum current controller (I-max controller) protects the motor and
inverter against overload by limiting the output current.
I-max controller operation
If an overload situation occurs, the speed and stator voltage of the motor are reduced until
the current is within the permissible range. If the motor is in regenerative mode, i.e. it is
being driven by the connected machine, the I-max controller increases the speed and stator
voltage of the motor to reduce the current.
Note
The inverter load is only reduced if the motor torque decreases at lower speeds, e.g. for
fans.
In the regenerative mode, the current only decreases if the torque decreases at a higher
speed.
368
Parameters for temperature acquisition without using a temperature sensor
Description
Motor-temperature acquisition after restart
0: No temperature measurement (factory setting)
1: Temperature measurement after the motor is switched on for the first time
2: Temperature measurement each time that the motor is switched on
Magnetization time of the motor for temperature measurement after starting
tomatically as the result of motor data identification)
Ambient motor temperature
Enter the ambient motor temperature in °C at the instant that the motor data is ac-
quired (factory setting: 20° C).
The difference between the motor temperature and motor environment (p0625) must
lie within a tolerance range of approx. ± 5° C.
Inverter cabinet units
Operating Instructions, 12/2014, A5E32923362A
(set au-