Siemens SINAMICS PERFECT HARMONY GH180 Function Manual page 110

Advanced Motor Protection and RTD Protection Functions
6.18 Device 51 - Fixed Inverse Time Overcurrent
IAC
inverse curve
TDM=1.0
0
10
1 1.5 2 2.5 3 3.5 4 4.5 5
stator current to pickup current ratio
Figure 6-41 IAC Inverse Pickup Time
Advanced Motor Protection for Variable Speed Operation
108
Manual, AA, A5E46373908A