Thytronic NA30

APPENDIX
174
NA30 - Manual - 04 - 2022
 Phase overcurrent 50/51 - Extremely inverse time curve (ANSI/IEEE type EI)
F_51-ANSIEI-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
= 0.5 s
t>
inv
= 1 s
t>
inv
= 0.2 s
t>
inv
= 0.1 s
t>
inv
= 0.02 s
t =
t>
inv
·
[(I/I>
inv
)
2
-1]
5.64
+ 0.024
Note: match of operating and setting time takes place when I/I>
inv
= 2.789