ISA T1000 PLUS User Manual page 141

DOC. MIE91093
IEEE - US Inverse
IEEE - US Short Inverse
With IAC and ANSI standards, the different curves correspond
to the following formula.

( t ) s K
Constants of the formula change according to the type of
curve; they are summarised in the following table.
IAC, ANSI
IAC Inverse
IAC Short Time
Inverse
IAC Long Time
Inverse
IAC Very
Inverse
IEC Extremely
Inverse
ANSI
Extremely
Inverse
ANSI - Very
Inverse
ANSI - Normal
Inverse
ANSI
Moderately
Inverse
Rev. 1.34



b

* a


T
I

 


I

R
a
0.2078
0.0428
80
0.09
0.004
- 0.0399
0.0615
0.0274
- 0.1735
29.75 0.9
0.0171 0.0131
d



I
 

 

c


I
R
b c
0.863 0.8
0.0609 0.62
0 2
0.7955 0.1
0.6379 0.62
0.2294 0.5
0.7989 0.34
2.2614 0.3
0.6791 0.8
Page 141 of 145
2
0.02
e

2
 
I
   

c c
 
I
R
d
-0.418 0.1947
-0.001 0.0221
2 2
-1.2855 7.9586
1.7872 0.2461
3.0094 0.7222
-0.284 4.0505
-4.1899 9.1272
-0.08 0.1271




3


 



e