53
NC20 - Manual - 01 - 2015
FUNCTION CHARACTERISTICS
F_27-Char.ai
Inverse time operating characteristic concerning the first threshold (U<) of the undervoltage element - 27
0.9
0.1
1
U
/
U
<inv
0.01
0.01
0.1
1
10
100
1000
10000
t
[s]
0.25
t
U
<inv = 100 s
t
U
<inv = 10 s
t
U
<inv = 0.1 s
t
U
<inv = 1 s
t
=
t
U
<inv
·
[1 - (
U
/
U
<
inv
)]
0.75
Note: match of operating and setting time takes place when U/U<
inv
= 0.25