Siemens SINAMICS DCM Operating Instructions Manual page 435

I2t monitoring of the motor: Alarm triggering and fault triggering
The diagrams below show the time after which an alarm or fault is triggered when a new,
constant load is suddenly switched in following an extended period of preloading (> 5×T_th).
T_th = p50114 .. - thermal time constant of motor
Figure 10-46 I2t monitoring of the motor: Alarm triggering
Figure 10-47 I2t monitoring of the motor: Fault triggering
<1> ... Preloading
y ... load current/permissible continuous current (p50100 × p50113)
x ... time/thermal time constant of motor
SINAMICS DCM DC Converter
Operating Instructions, 1.2012, C98130-A7066-A1-05-7619
10.17 Thermal overload protection for the DC motor (I2t monitoring of the motor)
Descriptions of functions
433