Basler Electric BE1-50/51B-218 - Manual (Page 13)

Timing Accuracy Example (BE1-50/51B-218)
PU setting: 5 amperes
Current Applied: 6.5 amperes
+ Multiple Tolerance: 6.655 amperes
– Multiple Tolerance: 6.345 amperes
Time Curve: E
Time Dial: 5.0
Minimum time dial
using 6.655 amperes:
46.5470 seconds
Maximum time dial
using 61.3968 amperes:
61.3968 seconds
Curve time using 6.5 amperes: 53.1800 seconds
Curve Characteristics
Nine inverse time functions and one fixed time function can be selected by the front-panel Curve switch.
Characteristic curves for the inverse and definite time functions are defined by the following equation.
Where: T
T
= time to trip in seconds
D = time dial setting
K BD
C M
AD
T
N
T
  
-
M = multiple of pickup setting
A, B, C, N, K = constants for the particular curve
Time characteristic curve constants are listed in Tables 1-2 and 1-3. 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 1-2. Time Characteristic Curve Constants with SW3-3 Open (Off)
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
9252000995 Rev H BE1-50/51B-218/-228 General Information 1-3