Basler Electric BE1-50/51B-237 - Manual (Page 52)

A-2 BE1-50/51B-237/-238 Characteristic Curves 9252000899 Rev B
Inverse Time Functions
Characteristic curves for the inverse and definite time functions are defined by the following equation:
K BD
C M
AD
T
N T
+ +
−
=
Where: T
T
= time to trip in seconds
D = time dial setting
M = multiple of pickup setting
A, B, C, N, K = constants for the particular curve
Characteristic Curve Groups
Either GE IAC or ABB characteristic curve groups are selected through switch SW3-3. (Refer to Figure 2-
2 for the location of SW3.)
Tables A-1 and A-2 list the time characteristic curve constants used by the relay. 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 PC relay setting applications. Timing
accuracy is ±1 cycle ±2% of time to trip.
Characteristic Curve Constants
Table A-1. Time Characteristic Curve Constants with Switch SW3-3 Open (Off)
Curve
Type Similar To
Figure
Number
Constants
BE A B C N K R
S ABB CO-2 A-2 0.2663 0.03393 1.000 1.2969 0.028 0.500
L ABB CO-5 A-3 5.6143 2.18592 1.000 1.0000 0.028 15.750
D ABB CO-6 A-4 0.4794 0.21359 1.000 1.5625 0.028 0.875
M ABB CO-7 A-5 0.3022 0.12840 1.000 0.5000 0.028 1.750
I ABB CO-8 A-6 8.9341 0.17966 1.000 2.0938 0.028 9.000
V ABB CO-9 A-7 5.4678 0.10814 1.000 2.0469 0.028 5.500
E ABB CO-11 A-8 7.7624 0.02758 1.000 2.0938 0.028 7.750
B BS142-B∗ A-9 1.4636 0.00000 1.000 1.0469 0.028 3.250
C BS142-C∗ A-10 8.2506 0.00000 1.000 2.0469 0.028 8.000
F None† None 0.0000 1.00000 0.000 0.0000 0.000 1.000
∗ Curves B and C are defined in British Standard BS142 and IEC 255-4 (International
Electrotechnical Commission).
† Fixed time from 0.1 to 9.9 seconds.
Table A-2. Time Characteristic Curve Constants with Switch SW3-3 Closed (On)
Curve
Type Similar To
Figure
Number
Constants
BE A B C N K R
S GE IAC 55 A-11 0.0286 0.0208 1.000 0.9844 0.028 0.0940
L GE IAC 66 A-12 2.3955 0.00002 1.000 0.3125 0.028 7.8001
D ABB CO-6 A-4 0.4797 0.21359 1.000 1.5625 0.028 0.8750
M ABB CO-7 A-5 0.3022 0.12840 1.000 0.5000 0.028 1.7500
I GE IAC 51 A-13 0.2747 0.1042 1.000 0.4375 0.028 0.8868
V GE IAC 53 A-14 4.4309 0.0991 1.000 1.9531 0.028 5.8231
E GE IAC 77 A-15 4.9883 0.0129 1.000 2.0469 0.028 4.7742
B BS142-B∗ A-9 1.4636 0.00000 1.000 1.0469 0.028 3.2500
C BS142-C∗ A-10 8.2506 0.00000 1.000 2.0469 0.028 8.0000
F None† None 0.0000 1.00000 0.000 0.0000 0.000 1.0000
∗ Curves B and C are defined in British Standard BS142 and IEC 255-4 (International
Electrotechnical Commission).
† Fixed time from 0.1 to 9.9 seconds.