Siemens SIPROTEC 7UT63 series - Page 466

4 Technical Data
466
7UT613/63x Manual
C53000-G1176-C160-2
Frequency Influence referring to k · I
N
Characteristic
Figure 4-18 Trip time characteristic of thermal overload protection
τ Tripping time
τ Thermal time constant
I Load current
I
pre
Previous load current
k Setting factor according to IEC 60255-8
I
Nom
Rated current of protected object
Frequency in range 0.9 ≤ f/f
N
≤
1.1
1% at f
N
= 50 / 60 Hz
3 % at f
N
= 16.7 Hz