Siemens 7SR51 - Logic of the Function; Application and Setting Notes

Logic of the Function
[lo_7SR5_49logicdiagram, 1, en_US]
Figure 5-13
Logic Diagram: 49 Thermal Overload Protection
Application and Setting Notes
The thermal state is calculated using the measured True RMS current.
Operate Time (T):
[fo_7SR5_thermal equation, 1, en_US]
T = Operate time in minutes
τ = Time constant (minutes)
In = Log natural
I = Measured current
I
p
= Pre-load
I
θ
= Overload setting
For the heating curve:
[fo_7SR5_heatingCurve, 1, en_US]
5.10.3
5.10.4
Protection and Automation Functions
5.10 49 Thermal Overload Protection
202 Reyrolle 7SR5, Overcurrent Protection Device, Device Manual
C53000-G7040-C014-1, Edition 11.2019