ABB Relion 620 Series - Page 1127

t s
A
I
I
B k
c
[ ] =
>






−
+














⋅
1
(Equation 195)
t[s] Operate time in seconds
I measured current
I> set Start value
k set Time multiplier
Table 1057: Curve parameters for ANSI and IEC IDMT curves
Curve name A B C
(1) ANSI Extremely In-
verse
28.2 0.1217 2.0
(2) ANSI Very Inverse 19.61 0.491 2.0
(3) ANSI Normal In-
verse
0.0086 0.0185 0.02
(4) ANSI Moderately
Inverse
0.0515 0.1140 0.02
(6) Long Time Ex-
tremely Inverse
64.07 0.250 2.0
(7) Long Time Very In-
verse
28.55 0.712 2.0
(8) Long Time Inverse 0.086 0.185 0.02
(9) IEC Normal In-
verse
0.14 0.0 0.02
(10) IEC Very Inverse 13.5 0.0 1.0
(11) IEC Inverse 0.14 0.0 0.02
(12) IEC Extremely In-
verse
80.0 0.0 2.0
(13) IEC Short Time
Inverse
0.05 0.0 0.04
(14) IEC Long Time In-
verse
120 0.0 1.0
1MRS757644 H General function block features
620 series
Technical Manual
1127