The constant values for the IEEE curves are as follows:
Curve Description
b constant a constant
L constant
IEEE Moderately Inverse Operate 0.0515 0.02 0.114
IEEE Moderately Inverse Reset 4.85 2 0
IEEE Very Inverse Operate 19.61 2 0.491
IEEE Very Inverse Reset 21.6 2 0
IEEE Extremely Inverse Operate 28.2 2 0.1217
IEEE Extremely Inverse Reset 29.1 2 0
CO8 US Inverse Operate 5.95 2 0.18
CO8 US Inverse Reset 5.95 2 0
CO2 US Short Time Inverse Operate 0.16758 0.02 0.11858
CO2 US Short Time Inverse Reset 2.261 2 0
The constant values for the ANSI curves are as follows:
Curve Description
b constant a constant
L constant
ANSI Normally Inverse Operate 8.9341 2.0938 0.17966
ANSI Normally Inverse Reset 9 2 0
ANSI Short Time Inverse Operate 0.03393 1.2969 0.2663
ANSI Short Time Inverse Reset 0.5 2 0
ANSI Long Time Inverse Operate 2.18592 1 5.6143
ANSI Long Time Inverse Reset 15.75 2 0
Note:
* When using UK Long Time Inv
erse, BPN, UK Rectifier, or FR Short Time Inverse for the Operate characteristic, DT is always
used for the Reset characteristic.
P14x Chapter 6 - Current Protection Functions
P14xEd1-TM-EN-1 93