Siemens 7UT51

9
Thermal Overload Protection (49-1, 49-2)
7UT51 v3
110 PRIM-2330C
Figure 9.1
Overload Time Characteristic with a 0% Preload and 90% Preload
t τ ln
I
load
I
max
⁄()
2
0.90()
2
–
I
load
I
max
⁄()
2
1–
-------------------------------------------------------
⎝⎠
⎜⎟
⎛⎞
×=t τ ln
I
load
I
max
⁄()
2
I
load
I
max
⁄()
2
1–
----------------------------------------
⎝⎠
⎜⎟
⎛⎞
×=
I
load
I
max
----------
I
load
I
max
----------
0% Preload 90% Preload