9252000991 Rev N BE1-50/51B General Information 1-5
Time characteristic curve constants are listed in Tables 1-3 and 1-4. Constants have been selected to
conform to the characteristics of electromechanical relays over a range of pickup multiples from 1.3 to 40.
Values of the constants are provided for use in computer relay setting software. Timing accuracy is ±1
cycle, ±2 percent of time to trip.
Table 1-3. Time Characteristic Curve Constants with SW3-3 Open (Off)
(Series 100 Relays or Series 200 Relays)
Curve Type ∗
Constants
BE1 Similar To
Figure
Number †
A B C N K R
S ABB CO-2 A-1 0.2663 0.03393 1.000 1.2969 0.028 0.500
L ABB CO-5 A-2 5.6143 2.18592 1.000 1.000 0.028 15.750
D ABB CO-6 A-3 0.4797 0.21359 1.000 1.5625 0.028 0.875
M ABB CO-7 A-4 0.3022 0.12840 1.000 0.5000 0.028 1.750
I ABB CO-8 A-5 8.9341 0.17966 1.000 2.0938 0.028 9.000
V ABB CO-9 A-6 5.4678 0.10814 1.000 2.0469 0.028 5.500
E ABB CO-11 A-7 7.7624 0.02758 1.000 2.0938 0.028 7.750
B BS142-B ‡ A-8 1.4638 0.00000 1.000 1.0469 0.028 3.250
C BS142-C ‡ A-9 8.2506 0.00000 1.000 2.0469 0.028 8.000
F None § N/A 0.0000 1.00000 0.000 0.0000 0.000 1.000
Table 1-4. Time Characteristic Curve Constants with SW3-3 Closed (On)
(Series 200 Relays)
Curve Type ∗
Constants
BE1 Similar To
Figure
Number †
A B C N K R
S GE IAC 55 A-10 0.0286 0.0208 1.000 0.9844 0.028 0.0940
L GE IAC 66 A-11 2.3955 0.00002 1.000 0.3125 0.028 7.8001
D ABB CO-6 A-3 0.4797 0.21359 1.000 1.5625 0.028 0.8750
M ABB CO-7 A-4 0.3022 0.12840 1.000 0.5000 0.028 1.7500
I GE IAC 51 A-12 0.2747 0.1042 1.000 0.4375 0.028 0.8868
V GE IAC 53 A-13 4.4309 0.0991 1.000 1.9531 0.028 5.8231
E GE IAC 77 A-14 4.9883 0.0129 1.000 2.0469 0.028 4.7742
B BS142-B ‡ A-8 1.4636 0.00000 1.000 1.0469 0.028 3.2500
C BS142-C ‡ A-9 8.2506 0.00000 1.000 2.0469 0.028 8.0000
F None § N/A 0.0000 1.00000 0.000 0.0000 0.000 1.0000
Notes for Tables 1-2 and 1-3
∗ BE1 Curve Types: S: Short Inverse V: Very Inverse
L: Long Inverse E: Extremely Inverse
D: Definite Time B: BS142 Very Inverse
M: Moderately Inverse C: BS142 Extremely Inverse
I: Inverse F: Fixed Time Delay
† Figure numbers refer to the characteristic curves located in Appendix A, Time Characteristic Curves.
‡ Curves B and C are defined in British Standard BS142 and IEC Standard IEC 255-4.
§ Fixed time delay, adjustable from 0.1 to 9.9 seconds.
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