GE P645

1000.00
100.00
10.00
1.00
0.10
10
100
Operating time (seconds)
Current (multiples of I
S
)
Standard Inverse (SI)
Very Inverse (VI)
Extremely Inverse (EI)
E00600
1
Figure 91: IEC 60255 IDMT curves
2.1.2 EUROPEAN STANDARDS
The IEC 60255 IDMT Operate equation is:
t T
M
L C
op
=
−
+






+
β
α
1
Chapter 9 - Current Protection Functions P64x
196 P64x-TM-EN-1.3