ABB RER615 - Page 748

t s
A
I
I
B k
c
[ ] =
>






−
+














⋅
1
(Equation 77)
t[s] Operate time in seconds
I measured current
I> set Start value
k set Time multiplier
Table 726: 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 Inverse 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
General function block features 1MRS758755 C
748 REC615 & RER615
Technical Manual