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NA11 - Manual - 02 - 2009
APPENDIX
Phase overcurrent 50/51 - Moderately inverse time curve (ANSI/IEEE type MI)
F_51-ANSIMI-Char.ai
1.1
2
3
4
5
6
7
8 9 10
20
I
/
I
>inv
0.01
0.1
1
10
100
1000
10000
t
[s]
t
>
inv
=
10 s
t
>
inv
=
60 s
t
>
inv
=
5 s
t
>
inv
=
1 s
t
>
inv
= 0.02 s
t
>
inv
= 0.2 s
t
>
inv
= 0.1 s
t
>
inv
= 0.5 s
t
=
t
>
inv
·
[(
I
/
I
>
inv
)
0.02
-1]
0.01
+ 0.023
Note: match of operating and setting time takes place when I/I>
inv
= 1.664
Summary of Contents for NA11
Page 189: ...189 NA11 Manual 02 2009 APPENDIX...
