Application Guide - NP900 Series
136 (504
)
A996A
Now when trying to load the
cable with the given nominal
current can be seen that the
actual cable current carrying
capacity is much lower than in
presumption conditions. Normal
loading current can now get the
cable too warm and endanger
its withstandability. If in this
case the k
SF
factor would not
been set the thermal image
would show about 68
̊
C
temperature when it in reality
would be 96
̊
C.
Figure 3.2.11-75 Thermal image response with nominal currents and fine tuned k
SF
correction factor.
When the installation conditions
vary from the presumption
conditions like in this example,
the current carrying capacity of
the cable had been reduced so
that 90
̊
C temperature is
achieved already with 550A
current instead of the initial data
given current of 680A.
Figure 3.2.11-76 Thermal response with k
SF
factor correctly set.
Содержание NP900 Series
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Страница 49: ...Application Guide NP900 Series 49 504 A996A Figure 3 2 1 3 25 Definite time operating characteristics...
Страница 50: ...Application Guide NP900 Series 50 504 A996A Figure 3 2 1 3 26 IEC predefined characteristics NI VI LTI and EI...
Страница 52: ...Application Guide NP900 Series 52 504 A996A Figure 3 2 1 3 28 IEEE predefined characteristics EI MI and VI...
Страница 243: ...Application Guide NP900 Series 243 504 A996A Figure 3 3 2 1 122 NPS biased thermal trip curves with kNPS values 7 and 10...
Страница 491: ...Application Guide NP900 Series 491 504 A996A 3 7 5 6 SETTING EXAMPLE...
Страница 504: ...Application Guide NP900 Series 504 504 A996A A996A...